Oh, and one more thing I forgot to mention.

I am thinking of adding these to the mix for that extra special touch.








I believe I have found a great combination  which is still budget friendly.

Thanks for the post Dom,

Yes, I agree with what you say here. No way would I immediately jump to conclusions and spend hundreds of dollars for the "final" voiced caps until I had a solidified sense of certainty that I was making that absolute best choice based upon my testing.


I will buy at the price point of the lower values for esoteric capacitors. They are what makes the most for fine tuning anyway, so very much the most critical. I am limited by my audio budget as to what I can spend on these capacitors. This is why things have to be done over time as we can afford to buy the more expensive items.

Yes, I agree that using the best premium parts available is always going to make the most difference in quality. But there can always be a compromise where a more affordable choice can be made without sacrificing the majority of that gain. If I am satisfied with what I hear overall in the music (mostly classic rock and Classical genre), then I have attained my goal. I can always do final tweaking with costlier caps in the future. I just can't do it all at once. (wish I could)

Another reason I am doing these upgrades is out of shear curiosity. I want to gain that experience and really know by personal listening evaluation exactly what these changes do for music overall. I see this as a scientific project for which I am going to gain knowledge from. Even though we may take a different approach  than another who has success in their endeavors, doesn't mean that we are limited  for alternative measures to in effect, gain the same degree of gain. I know the type of sound I am looking to achieve. The only way to find that is through experimentation. The bad thing about this concerns the time involved between the upgrades, and the fact that so many hours are required for each upgrade to season properly before the real end result can be determined.

Is there a DIY circuit that can be made cheaply to "burn-in" capacitors at a rapid rate? If there is, I want to build it and put it to use. This would speed up the process.

I am going to take what I learn from modifying this DAC, and apply it to the ToriiMK3 amplifier at a later date. I will need to examine the layout of that amp to see what I will need for cap values. I am also considering high grade silver/copper hook-up wire (larger gauge) to use in this amp as well. I am also considering  premium quality step attenuation to replace the stock volume control. I am sure that some premium Miflex bypass caps wouldn't hurt either. Knowing how huge the capacitor bank is inside, I know the cost is going to be high. Still much cheaper than buying a new amp which still does not have these high end capacitors. I love this amp, but I know it can be better, but at a huge cost factor. In the end, it is worth it.


Today, I received the new 6dj8 tubes to replace the cheap Chinese 6n11 versions. The seller tested them and made sure that my set was balanced.  These are old stock which are dated for 1980.  They look great, but have expected surface corrosion on the pins which most old tubes have from age.  Not bad, but enough to distort the signal. I do this with all of my tubes when needed as general maintenance.

I cleaned all of the pins with fine Emory paper until shiny. Then I cleaned the pins with DEOXIT cleaner, then treated with DEOXIT gold lubricant.

I just installed the new tubes into the DAC and turned it on to warm up. They have been in use now for about an hour. They will take at least 20 to 30 hours before they start to relax and perform more as they should.

What I noticed immediately with these new tubes versus the 6n11's was as follows. Right out of the box, fresh install, zero time on tubes, and with the audio system stone cold, my initial impression surprised me much more than I expected from this tube swap.  The sound of this DAC using the Chinese tubes was way too bright and in my face (shouting perhaps?). The volume loudness was way too strong as if the gain was too high. I could barely turn up the volume control on the amp without it being too loud. I suspected that the 6n11 tubes were the cause of this. That is why I wanted to immediately change them for something better.

As soon as I turned on the DAC and listened briefly with a cold system, it already became apparent, actually instantly, that my assumption was correct about the characteristics between these tube designs. The difference was not subtle, it was actually quite large. I noticed immediately that the balance of the music was smoother and far more laid back. (using a Telarc audiophile CD of Mozart)

I have to increase the volume control on the amp to a much higher level now to get the listening level I prefer. This was the reason why I chose a 6dj8 tube to use for now. So far, the indication is a vast improvement which I believe seems to be the right choice. This alone has made a dramatic change in the sound of this new DAC.

I have about 50 hours of break-in time now on the new DAC. The way it sounded before I made the tube swap was already far better than the first night I tried to listen to this fresh DAC. That was a horrible experience the first few nights I tried to listen to this. Now with the better tubes, and some time on it, I think it is getting close to sounding fairly decent. Of course the new tubes have set me back a bit with burn in optimization, but the upgrade is still better than the sound with the 6n11 tubes.

Hey Will, it seems that I did alright buying this set of tubes. Too early to tell, but out of the gate, they make a positive difference.  After a few days go by, I will be better prepared to make that analysis for a fair rating. I do however, feel that I got my money's worth at this time.  We shall see. I am going to try and listen to this system tonight after a few hours of warm up and stabilization.


I also received my set of Sprauge Vitamin Q paper in oil caps rated at 0.10uf. These are pretty large for the rated capacitance.

Going through my capacitor collection, I found a set of ERSE MPX (pulse) series caps in the 3uf range These are much greater quality than the Dayton caps, so I will be using these for initial testing as my base caps. The physical size of these caps are actually 50 percent smaller than the Solen caps that came in the DAC. The Vitamin Q caps are just about the same size as the 3uf caps from ERSE.

My plan is to listen with just the new tubes tonight to get a preliminary idea of the sound before I do the first cap change. The total capacitance will be reduced to 3.1uf after the upgrade.  So I think tomorrow, I may perform this upgrade with this group for use until I can get the V-cap ODAM's next month. By that time, this DAC will have a good amount of playing time on it. This will provide a better base to start from when I get ready for the next cap trial.

I am expecting an improvement with the ERSE/Vitamin Q upgrade by a large degree. I just hope that I am correct in my assumption. The testing begins here. It is going to be a long journey, but one that I will enjoy.

The other bypass caps that I ordered won't be here until next week. Not a rush on those.

So I shall get back with you on my listening impressions concerning the tube change in a day or so. This is somewhat insignificant at this stage of the game considering that the tubes have no time on them other than a few hours.. I will provide the initial details anyway, and go from there as time passes. But as I said, I already noticed a huge change in the music.

I shall get back to this later. It is time to go listen for awhile.

RPS. For cap burnin I mentioned the Frybaby 2 or 3 earlier. They are not dirt cheap, but pretty good value, especially used, and if you go back and read what I said there, you will get my impressions. I don't know if the dude sells plans or not... but for me, these have been a necessity.

That is interesting the big difference with the tubes. I recall the 6N11s I have being big and bright, not that much different going to a real ECC88 or a 6N23P. Makes me wonder more which Russian type it is.



I suspect that with the, to me, nicely balanced and high quality Odams as a base cap, you can hardly go wrong. And that refining it with a Miflex Copper Oil would likely be a really nice combination, adding complexity with the KPCU version of revealing harmonic complexity and warmth. My guess anyway. A few things came to mind with this most recent direction though.


The first, starting with a lesser, but decent, relatively open and fast base cap, and adding to that more refined caps like KPCU, the bypasses will definitely tune the base cap with the special qualities of the "bypasses," if a synergistic blend for the qualities you need, potentially making the decent base cap a quite good cap.

What I am hearing now with a inexpensive 1.5 Mundorf Aluminum Oil EVO, 2- Miflex KPCUs - 0.1 and 0.022, and those followed by two Mallory 150s, a 0.001 and a 0.0022 (5 caps), is pretty amazing to me... and both sets, if bought now, would be less cost than the just 1.5 Odams at the reduced price from buying a pair. I did bypass the power supply some, by sound also, which makes these output caps that much better. But still, this cap set, with the tubes I am using, and in my setting, is feeling beautiful in this DAC. Not that it would necessarily suit your specific needs, but interesting to me.

I may be able to pull one of the small Mallorys, but it is captivating now, and I am content waiting for it all to settle, the DAC, and other component tuning I have done since getting the DAC, still settling in. With the right gain tuning, everything seems pretty complete in beautiful balances. But there is still some work to do.

When the gain stage balancing is a little off toward full/warm, a slight veil shows up over all balances, mostly revealed as veiled speed and subtle loss of edges. If there, it can have a slightly synthetic feeling "warm" quality. I just noticed it this morning, getting close to having no issues, those that remain showing more I guess. I think more DAC power supply bypassing might solve it... but perhaps replacing a Wima or two also, as this "offness," when it shows, reminds me of why I had to move on from Wimas back in the day. Still, it is intersting and encouraging that if the gain stages are nicely tuned, the veil disappears into a great musical adventure...



Anyway, all things considered, I don't have reservations about your Odam base choice. But just wanted to point to the complexity of all this, and my, once again, noticing that the more refined a system/room gets, the narrower the parameters are toward enhancing what we have, potentially making really good stuff not quite right in a given setting without some effort. This, in my setting, where I am always hovering in a zone that is beautiful to me, but can lean overly warm and euphonic for my tastes when off, points to the potential benefits from the sort of cap setup I am using. The base cap, somewhat lacking in tonal characters, is not awesome on its own, but sets up a pretty clean canvas to expand on. And with the right bypassing, it can end up better than a well loved and expensive base cap, especially if the tonier cap is not quite right for the component and system combination.

Further, in this setting, this DAC reveals all it does pretty powerfully, and being biased toward a revealing, but also a slightly slow, dense and warm signal (a little euphonic)... I have been needing to tone down signal density some to solve leanings toward a little overly strong bass on some recordings, associated thickness into the mids, and over consolidation of fine detail and speed information. But also, oddly, over-differentiation of textural information showed up with more powerful tubes, especially in early burnin... a new for me example of strong signal density potentially consolidating fine musical information, but in this case, leaving the bones of textures revealed.



Under these conditions, with this DAC and setting, especially since I have found that 2.2uF pushes density a bit far for me, showing as off first with bass thickening... my guess is that a Miflex KPCU 2.2 (the recommended cap size when upgrading this DAC), even well bypassed, might not the ideal for me. Likely beautiful, and rich, but for my needs, guessing it could be a little overly warm and slow, especially with darker recordings. Alternately, some of the folks out there talking about this DAC love Jupiter Coppers and Miflex KPCUs...

I gave up on Jupiter Coppers a long time ago, able to get them to sound great, just not able get past hearing their particular signature, part of which for me, a tendency toward what I hear as an imbalance between clean highs and softish/slowish bass.

I could likely make Miflex Copper Oils work, though I might not be able to finally close the lid on the DAC. But being into pretty notable speed and complexity, they might just be a little warm/slow down lower especially as a base cap here... My balances so defined and narrow, especially with the challenges of long bass waves, I need the bass fast and textured, and just can't have the low end feel slower or thicker than natural bass sound in a good room, or slow compared to the mids and highs... a certain edge I try to avoid going over even if pretty mild and only on dark recordings.

Also, I really like a subtly euphonic sound, but when bass fullness/slowness leaks into the mids a little too much, with my love of speed and complexity, euphonic beauty to some, can be darkish masks for me past a delicate edge... off-balancing speed some, reducing leading edges, space, inner detail, harmonic complexity. So having worked a long time to get and hold just-so sweet warmth, with bass depth and complexity, everything being musically smooth/warm, but with really good speeds and textures bottom to top, I likely would not risk the high cost and size using KPCUs as a base cap with this warm leaning DAC and my current room sound. Whereas, as tuning caps/bypasses, or for coupling caps, or mixed with a little cleaner caps as PS bypasses, I love KPCUs ....

EDIT: But in yours... if the DAC stays a little bright after burnin and playing with tubes, they might be really right! And don't get me wrong, part of what I love about these caps is that they are open and harmonically rich, warmish and a little smooth/oily, but not overly so in most cases. I am just a hair splitter on shaping sound, so imaging here.

That said, I will probably buy some 1.5 Odams to see what I can pull from them as base caps.



So adapting to our own sound is for sure real. But since there are always favorite rooms at shows, and super popular gear that many fall for, etc, I get that we have different tastes and conditioning, but these common loves indicate we also have common human tendencies that are more universal. My guess is that lots of us may be heading roughly for similar natural sound qualities, roughly...  but since we get there in wildly variable ways due to system and room complexities, and always starting wherever we are, it is finally hard to gauge what is best for each system/room.

And this points to another consideration. Compensation. Especially once our systems get more refined, seems issues that come up may not just be the sound of what is new and being worked on. For me, those things that challenge me, but remain compelling as something that will bring up the whole, are pointers to adjust them, but also to reevaluate and refine other system tuning..... Tricky though, as even if we have been super careful not to get off the many balances in our journey, we can grow used to being off as "normal," tricking ourselves. So though difficult, I have come to appreciate compelling challenges in integrating really good new things.


I could go on about this, but I have already taken up too much of your thread... just saying that especially in refined systems that show most everything, a potentially great component could sound off, especially before burnin and refinements of feet, cables, tubes... in part from revealing base system issues we did not notice. In my case, this DAC is leaning warm/euphonic, and in yours, your DAC so far leaning bright and coolish. I suspect these are both true. But how they are causing our systems to change could perhaps be amplified by previously unnoticed issues from sound developments that were inadvertent compensations from integrating past changes and gear. I know for me, this DAC as I have been tuning it, has caused me to improve other components. And as my system/room gets better, this has become somewhat common for me.



The second thing I thought of when you said you would get Odam base caps, was that this is a really good cap, likely creating the need for at least the larger toning bypasses to be really good in order to improve the Odams. So I think you are on a good track looking at Miflex KPCUs to bring up your value, likely making the V-Caps pleasantly more complex. But not knowing how the Sprague Q sound as small bypasses... they may be great, or they may bring the whole down. Still, pretty cheap, so not a big deal... and like you say, experiments will tell the tale. It does always shock me when I give it attention, that for very small bypasses, low cost Mallory 150s have so far consistantly been my favorite in electronics, regardless of cost, my go to caps no matter what is under them. But based on your interest, I did do some low key sound research and ordered a few spragues to check out, always on the lookout!



Final thought for me, the Odam being a really good cap, and if you find yourself liking a value near 2.7, this quality base cap might allow you to go directly to classic bypassing for speed and finer detail with a .022 Miflex KPCU, and perhaps a .0022 Sprague on that for a first try.

Or if you end up preferring being in the 3.3 range, choose a 2.7 Odam base, and go with the Chinese made 0.47 CU oil....especially if both are really good caps, I am thinking it probably won't matter that your basis is not fully 3.3, and again, you could likely go directly to a 0.022 KPCU without a 0.1, and then a very low value sprague.

BTW, Hificollective is currently out of 0.1 KPCU like you have marked on the Ali-Express page, but they are a lot cheaper at Hificollective, and the 0.1 is the only one they are out of. There is shipping, why I tend to sort of stock up there when I do shop, but check out the prices.

Also, dealing directly with Chris @ VHAudio is good I think, supporting his work... and the shopping cart creating better prices as you go from one cap to more. Also he has been around a long time and done a lot of experimenting, so a good resource.

Onward. Have fun tonight and tomorrow with your DAC experiments and listening!

I was unsure if this was the best location for another post on the Carver C-9, but it seems like a good spot since I read about it here a few months ago. I recently bought one online that had been rebuilt by 4krow not too long ago. I was surprised that his first post introducing the C-9 on this forum dates back to 2010. Here is what the C-9 does:

"Carver C-9 Sonic Hologram Generator:

1. This device enhances the stereo image, creating a broader, three-dimensional soundstage.

2. It works by manipulating the phase and timing of audio signals to cancel out crosstalk between the left and right speakers.

3. It's about creating a sense of "imaging" and "soundstage."

As soon as I played it, I liked what I heard. There was no loss of SQ (my initial concern before hearing one) and a much broader and more three-dimensional soundstage. At the end of an enjoyable first evening, I thought the next day I would probably switch back to my familiar audio sound by simply pressing a button on the C-9 that eliminates its effect. The next day, however, I kept it in the chain for the rest of the weekend.

I like this unit and kudos to those who mentioned it earlier. I did not know its contribution would be so enjoyable and significant. Should I find it only a passing fancy, I can quickly return to the original sound with just a push of a button next week, or next month, or…

RPS,

I certainly plan on sharing my experience with the C-9 now that I have the C-9 back from 4krow after modifications. I've been letting it settle in for a while and I should be able to shed some light on my findings shortly. My main source (streamer/DAC) was out of commission for a little bit, but I have that back in the mix as well. I'm finally able to do some real focused listening. Between the large number of CD's you sent me, and streaming, I'm able to get a pretty good handle on how things sound with and without the C-9 in the mix.

Tony,
I'm hoping to start a thread on my experience with the C-9 and I invite you to chime in if you can with your experience at some point. It would be great to compare notes with all users of the C-9 and get feedback on likes and possible dislikes. Anyone who wants to share information on the topic will be more than welcome.

So I am thinking that, especially if you continue to love this tube, narrowing down what it actually was before being labelled Amperex, could be good for future reference, and who knows you may love different makes and vintages of the same type in your DAC.


Will, I could not be more pleased with another tube. This tube is so incredibly involving with the ability to draw you into the music with absolute finesse and artistic appeal. The sound quality of this tube reminds me of the more laid back presentation which a 6dj8 would provide, yet holding a great reserve in dynamics like a 6922 tube would provide, when demanded from power hungry transient responses.

I compare this firm degree of control to that of a well designed Class A amplifier with an abundance of power on tap, just quietly sitting at the ready for that huge power demand to show what it is capable of, while idling by on the relaxed side of things during the rest of the musical passage.

When this tube delivers, it does so with authority, yet with subtle caress as it portrays the musical passage. What is so revealing is the inner fine detail, those intricate complexities which seem to float openly within compiled layers of texture within the harmonic overtones. It is difficult with lesser grade systems to hear such pure effortless depth and transparency within musical overtones, as clearly and pronounced as what I am hearing now with these tubes. And this was only by changing the tubes. (although this is not as evident as what's to come) It gets much better.

I will have to reflect back upon the quality of my acoustical environment, and state that this really sets the platform for which this degree of musical quality can easily be revealed. I doubt that the results would be the same in a normal untreated room. My listening space is fully equipped with professional grade components, extremely effective in their design and purpose. The music confirms this to a very high degree of acceptance.

Finally, I have a listening space that doesn't get into the way of the music! Making changes to the sound signature are revealed in stark naked reality, noticeable at any rate of influence.

The stock sub-standard Solen caps are still in place during this time.  To think that I am hearing this level of  detail with less than stellar capacitors in place, and with very limited break-in time, I can only imagine what is to be revealed with high quality capacitors balanced correctly, leading this DAC into major high end territory.

I consider this tube design to be one of the best kept secrets in audio. It truly is a gem of extreme value. I don't recall ever being taken back to this degree of surprise from a simple tube change before. The only other tubes that made this much of a difference to me was that of the re-tooled Mullard EL34 power tubes made in Russia by New Sensor, as the owner of the British Mullard tube rights.

I never heard the original British Mullard designs, but I will tell you this, as magical and smooth as these are, I find it hard to imagine something better. I have used Svetlana, Electro-Harmonix, and other well respected Russian tubes, but they did not compare with these in my system on the same level.  But we all know how these things can surprise us. I absolutely love the sound of the re-tooled Russian versions of the Mullard EL34. I find no reason to look elsewhere. The same goes for the signature I get with the Electro-Harmonix 5U4GBEH rectifiers. You know when something sounds "just right" with every type of musical genre, then you are satisfied.

This combination I find the most musically convincing of any other combination I have tried in the past with the Torii designs. Again, I find this sound so near perfect that I simply don't need to look elsewhere. This is like having a beautiful young wife with a PHD in physics, and wondering what another similar woman might be like having a PHD in chemistry. I guess it depends upon personal taste and desire. That seems to always be the factor in audio.

At any rate, the current combination of tube synergy within my system, provides the perfect balance that I desire.

This new DAC tube stage completely sets the bar for something that will blow the lid off anything I had in the past, at least from a digital perspective. This set of "unknown" mystery tubes are the core "reactor" as the driving force.

I will get into the sound of these tubes more when I begin evaluating this DAC with high quality music formats.
(I already have, just not ready to disclose the results at this time due to expanded trials of capacitors) I think you get the drift as to where the focus of this sound quality is going. Now with proper tubes in place, I can accurately find the right balance within my capacitor testing. It is pointless otherwise.

I thought my ZERO DAC sounded pretty good. It does for using a dual OPA627 opamp stage, but this is no comparison for what I am hearing now. These two DACS are like two different worlds. I am comparing apples to oranges here, but you see my point. I am not going to return to the solid state output stage after hearing the magic which this tube stage provides.  So much closer to the audio truth. Analog reference being that truth.


I will be going over my latest changes and results shortly in a upcoming post. I am rapidly making strong advances with my current configuration. During the initial burn in process, this new DAC architecture is reacting like an out of control roller coaster ride. But things are much better now. Little "Goddess-Zilla" has been an unruly little B***h!  I will break her under my control. I am hearing stability now.


This is the frustration I imagine as one tries to break a new wild mustang in the corral while trying to avoid getting trampled to death in the process.




I am feeling very confident going forward with what I have now, plus the proposed future addition of the Vcap ODAM in conjunction with the copper foil in oil cap design. The addition of the Miflex bypass will come later, but soon. I am looking at this combo with logical perspective which provides flexibility along with overall satisfaction to meeting my "sonic" goal. Of course, there will be fine tuning required, but within this mix to a minor degree. As the saying goes, everything is subject to change.

After considerable thought, I am thinking that I should go with a 2.2uf V-cap, combined with the well reviewed Chinese copper foil/oil caps filling out the range @ 1uf. This being a factor of 3.2uf as a base, I have plenty of room for flexibility using various "tone" caps to get the balance just the way I want it. I have heard the Russian PIO caps and I am really impressed by what these have done to the overall sound so far. This way, I can take the base cap down to the 2.2uf rating and expand from there.

I had an overly bright and sharp high frequency response after I replaced the Solen caps with the ERSE pulse caps in conjunction with the Sprague 0.10uf Vitamin Q paper in oil tone cap. It was like blowing the roof off and exposing the sky above. Just too bright and way too sharp. The detailed presence of the upper registers became much more revealing, leaving nothing unexposed. This became a tell all for recordings which were recorded too hot in the high range.  

As a result, this DAC sound signature became very subjective as to music genre limitations. No longer was this sound "universal" for all music genres. Anything like an electric guitar playing high notes as in high energy rock was not tolerable. It was not distorted or unresolved, the high pitch was simply too hard on my hearing. I have better hearing potential than I thought. This new DAC has exposed my actual auditory perception. I have lost nothing in pitch changes. The only thing I lost was what failed to be revealed in the recording. That is a thing of the past.

For an example, the second Boston album was based upon high energy guitar sound along with real cathedral type organ pipes. That sound energy is intense, an intensity which can get out of control with the wrong system. With a system and acoustical space such as what I am working with can be very brutal when something is amiss. Everything gets revealed, good or bad. This reminded me of the sonic torture I endured working around the shrill F-15 engine intakes back in the 1980's during launch and recovery. Very loud and taxing on the ears to say the least.

But, on the flip side, here is the positive side of this new sonic signature. What I have now is the ultimate platform for Classical music. Especially the realistic sound of a grand piano playing solo. What is exposed within the overtones of each key is mind boggling to say the least. The exposure to this depth of detail and intricacy which is quite noticeable within the key elements of the piano are something to be admired with complete awe if you are unaware of it. I have extreme upper extension now. Great for piano (absolutely stunning!), but bad for most other music.

Okay, so I have adjustments to make. I need to bring this high level energy into balance. This going into the next stage of upgrade mods.

*On a side note: the funny thing is this before I made the first cap change, with the Solen caps still in place using the new tubes, the sound had a nice even balance along the frequency range (although it was not as revealing of transparency as what should be heard). A full powerful low energy presence, a full and smooth mid-range, and a decent high frequency limit that did not get out of control.

What was missing however, was the intricate detail from the higher registers as well as a loss in high frequency openness. I would say that throughout the entire range, there was a good deal of masking and coloration going on. The sound was good, but not great. I was surprised by the sonic strength that I heard. It did well in that regard.

Overall, the sound was acceptable for the most part, but obviously masking much of what should be heard with inner detail. I noticed some questionable results coming from the bass strings, as the bass notes were a bit smeared and out of focus. The mid-range was acceptable, and overall, the music was pleasing, regardless of what I listened to. That was about to incur a drastic change.


Obviously, those substandard caps have to go. They were getting the soundscape dirty.

So, the trial and error begins. Let's throw our hat into the ring and see where this goes. The first test performed with the ERSE main caps, bypassed with the Vitamin Q 0.10 tone caps. The four 0.22uf WIMA caps are still untouched at this point.

So I told you what the result of that change was. There is still much work to do, but we have major change in
play. Extreme detail and presence is heard throughout the entire range, but the music is on steroids and it needs to be tamed down in the upper regions. It is as if someone turned the treble control to maximum and cranked the amp to ten on the dial.  If all I ever listened to was piano, acoustic guitar, and wind instruments, then I would love the way it is now. But I can't be that restricted in my music selections.

The next phase which will attempt to correct for this issue of unbalanced, over emphasized treble comes into play.

I only had the new Russian K40Y-9 0.033uf paper in oil bypass caps handy at this time. I still have not received the smaller values as of yet. So, I thought, why not. I went ahead and soldered these in place along all six capacitor locations as bypass caps.

So now, I have the ERSE pulse cap as the base, with the same Sprague Vitamin Q 0.10uf PIO bypass cap. But now, I added a Russian K40Y-9 0.033uf paper in oil bypass cap along that combination. I didn't stop there.

I decided to solder one of these Russian bypass caps along each of the four 0.22uf WIMA caps on the bottom of the board. The WIMA's are still in place. Now I have 0.25uf along each of these WIMA capacitors with a slight increase in value.

Not sure if this was going to be that noticeable, but it was the only option I had available. I had a feeling that the stock WIMA caps might be a part of the high treble I was getting. The only way to find out is to see if this mod makes any audible change, hopefully for the better.


Now I do want to make clear that by this time, I have about fourty+ hours of playing time on the new DAC configuration (minus the additional Russian bypass caps). This could have very well been enough burn in time to stabilize the other caps and tubes to something more subdued. Perhaps, but I doubt enough to make things really better this soon. I would say that it did help some.

Images of these mods will be posted shortly.

So off I go to the audio room to evaluate this DAC again. I am thinking, this sucks, most likely won't be much better. Now I have to wait until I get better caps to enjoy music again. It is always good not to expect too much from such a small change. When something good happens, the result seems far more significant.

With that in mind, I let the system play for a couple of hours and came back to listen. I can't tolerate any more of that high frequency torture.


So I want to take it easy and play something mild. I know that if this doesn't secure my acceptance, then going on will be most likely pointless until better caps can be used.

I played the ultra high end audiophile LPCD 45II M2 Master recording of Moussorgsky: Pictures at an Exhibition, which includes the Ravel version as well. This came from the Mercury Living Presence label which was recorded back in 1959 (Russia) through 1961(USA). There are many variations of this theme on the disc. The main edition is that of Byron Janis playing solo piano of this title. Just piano, nothing else. This is a direct from master tape 1:1 transfer void of any external contamination, noise shaping, filtering, compression, or limiting by any degree. Straight and raw recording without manipulation, just as perfect as possible next to the master tape. What you hear is stunning by way of realistic sound quality. These are very special recordings to say the least.

It depends upon the quality of your audio system as to how much of this is really perceived. I love it when guys with mediocre systems, and no acoustical treatment try something out like this, then pass it off as a joke because they could not tell the difference.  Seems pretty typical in the world of audio. I have read posts where guys state that these are no better than any other recording. The only problem is that they have a bad system which can't express it within the music. And if it did, the bad room acoustics put the final nail in the coffin. It just isn't going to happen.


continued next post....

Hey Tony, thank you very much for posting this info concerning the C9 here.



I think that Chipster has some upcoming information relating to this unit with actual music reviews in the near future. When he does, be sure to participate on his ongoing thread. I as well as others will most likely post info about this unit there as well.

So welcome to our little elite C9 holography club. We are growing. With your continued support as well as what 4Krow and Chipster are doing about promoting it's value, I can see even more hard core audiophiles taking a chance on this unit due to curiosity. Just ask JB about his experience. There is a pattern here.

The more people who get on board with complete satisfaction, the more that will follow. If I had any influence upon your decision, then that makes me very pleased to know that I exposed you to something great that perhaps you may never have tried.

It sounds like you have agreed with the general consensus here concerning the necessity of the C9, and why it makes your music sound so special.

All I can say is this to anyone reading this and has even a hint of curiosity concerning what holography will do to transform your listening experience, just look at the record here.

Now 4Krow has been promoting this unit for many years. Other than him, I set out to convince as many people as I could to at least try this technology out and see for themselves. So far, there are at least four or five of us not including 4krow that are recent undertakers of this technology. I had this circuit in my Carver equipment way back in 1986. It is not new to me. I have just been absent from it's use for many years. I am so glad to have it back.

If you may, it would be nice to know about your audio system and your acoustic architecture. Perhaps you could discuss that a bit on Chipster's new thread. It would be nice to hear your impressions of the C9 with various music.



Hey Chipster, looking forward to your new thread!


This should be interesting.

Tony et all.

Welcome to the Carver C-9 gang. I do agree with your experience of the unit in the Decware chain. Good recordings sound 3D played with or without the C-9. The C-9 adds depth on those not recorded as well and definitely will make the speakers look as an accent piece of furniture-the boundless sound becomes the focal point.

Interesting talk on capacitors.

I have been busy with an unexpected event when a deer did not look both ways before crossing the interstate the other night. Trashed my new car. Now trying to replace it. Doing 65mph the impact was not really felt. Did not even have time to apply brakes! Hit the deer dead center. Subrau got their act together when it comes to protecting occupants!

JB, sorry to hear of your accident, and glad Subaru did well by you. I Don't have a C-9, but I have not been able to hear sound as coming from my speakers for a really long time. This room is not perfect, but with progressive efforts over years, it is incredibly good in resolution, speed and complexity balances over the range, and soundstage.


RPS. exciting... you are finding bypassing! Your DAC being on an apparently good platform to hear it, and first in the chain, a great place to start, hearing it all from the DAC. I guess it is all relative and there are no real absolutes in how we get the deeper experiences of sonic and musical balances, but as the subtle stuff emerges, like you are hearing even in this green stage, I can't do without it. I always hear even the smallest bypasses clearly, always doing good things if the right cap and value for optimizing balances. Then with time it smooths and refines with enhanced complexity. Then, all settled in the gear and in my perception, I might hear something a little off, and perhaps try a different bypass here or there, knowing now at least close to what I can expect from different caps, values, and blends, taking the whole deeper. Each refinement for me, so far ends up showing more, which then allows me to learn more about what I have and how it might be improved. Same with tubes, cables and all else.

The way you describe those "Amperex" tubes, makes me think of 6N23Ps. And I suspect part of the power of their effect for you is like in my DAC.... the tubes revealing their inherent characters in unusually big ways. Having tuned everything here previously, with great connectors, really good wires, resistors, caps, bypasses...I really don't have many weak links anymore... all my components and cables tuned for optimal transparency, resolution and speed, and the parts choices making all that more revealing, but also more musical.. to me musical being more like musicians in a great room, very real and lucid but without hardness that has often been traditionally associated with clarity. So far, adding another pre stage that has compelling traits, and is highly optimized in the same vein as the rest, compliments and brings up the whole with complexity and adjustability, finally offering more benefits than impediments. I think the output stage of my DAC, and it sounds like yours too, could be in a sense considered like a pre-stage with one setting once tuned, tubes and cap choices resulting in gain-like adjustment qualities.

But where I was going... with my amps and pre-stages, these highly revealing and fast components all show the tubes used in really big ways. But my DAC, guessing a lot due to its simple output stage, shows tube changes notably more intensely... "intensely" indicating its sort of "hybrid horse" like character in showing all the inherent tube sound qualities, for better or worse, more intensely. In my case, doing loads of experiments with different tube types, and tubes within each type, and playing with lots of output caps and combinations from the start, it has been a bit of a wild ride.

Interestingly, it also showed what was to me lacking in the base design for the complexity and speed I need in sort of big ways. I have been gradually "finding" that, also with power and clarity, the process more particular and less flexible ultimately due to this power of expression. So the caps and tubes are amped up in revelation comparatively to previous gear, as is all that they "say" or don't "say," with so many choices, making finding ultimate balances a little tricky, but also rewarding once I settled into the tubes I liked best and refining the rest for that range.

From your descriptions, it appears that your DAC design is similar in the powerful revelation of parts adjustments.


Tubes and caps are so interesting, when we find ones "right" for improving the component, better than past ones, another level of more compelling revelation and musicality is revealed. And as you have found, just the effects from good bypassing with decent caps is amazing in and of itself. Then we find more...like your nice idea to try bypassing the 0.22 Wimas with the PIO 0.033s you had on hand and see what it does. In my experience, it is possible that you made the Wima as good or better with the bypasses, than having replaced with Wima with a pretty high quality cap. The warming vibe of the PIOs, and probably the small value increase, I suspect contributed to more body and smooth warmth... a new basis for refinement of speed, and resolution of fine detail in space also from the bypasses... the combination showing some ways of exploring the potential of bypassing.

But then, what would it is sound like replacing the Wimas with a really nice, well balanced and fast cap, and bypassing it with a cap that compliments and improves the better cap.....and then, and then, and then.


I bet you find similar with all your explorations, but I am always surprised how much better things can still get after the last moves settled in and felt like they made things "about as good as it gets."

As a point of reference, my Torii IV I started bypassing and exploring parts and wire modifications I think the last of 2016. The most recent modifications were maybe a year and a half ago when I got caught up by my 845 amp. The Torii and CSP3 together were long and deep progressive learning grounds for modifications. With a fairly strict criteria that each modification needed to settle, and then proved as an improvement before moving on to the next, and not a compensation that could throw things off, it went on for years.

I was as diligent as I could be in holding relative balances, using the same tube sets over the period, keeping the same basic spectral balances, etc... so that I could read the changes as clearly and consistently as possible. Mostly one-by-one part position experiments with pre-burned in parts, it was fun and informative, learning a lot about the sounds of different parts and wire, and exploring various ways and levels of bypassing.

An example, finding the resistor I liked most on the cathodes of the input tubes, at first I might have tried 3 or 4 or 5 nice resistors before "finding" the one that made the most notable refinement to most aspects of the whole sonic experience.... Or progressively making bypasses where the bypass caps complimented each other, and the whole system/room, based on how they improved each pair of the power supply caps. Each pair associated with different power paths, I found I liked them best bypassed with different overall values and cap combinations. And finally the electrolytic caps in the MKIV replaced with film, that changed the bypass needs.

Anyway, the only parts that stayed were ones that improved all the many balances of the basics associated with speed and resolution brought out with musicality and minimal coloration.

For me, as it turned out, all these qualities fit together... needing the correct spectral balances to avoid veils and slowness, or tending lean or sharp... and refining speeds, fine detail and space with good sounding parts and wires resolving hardness into musical complexity that is more textural and harmonically complex everywhere, top to bottom, including decays that are balanced evenly across the spectrum... also improved speed complexity resulting in better leading edges and a complex range of dynamics across the spectrum.

Still, after finding these things again and again, as the system reveals more, I hear and learn more, revealing more areas for refinements. In the case of the Torii IV, amazingly, most parts and wires ended up being replaced, sometimes several times over the years, and each change had to be a real improvement to the whole. This to me was a really interesting and compelling exploration into sonic refinement, and that starting with an already really nice pre-25th mod design!


EDIT: I guess you may be moving to the output's power supply cap bypassing now??? With good bypassing there, it will most likely enhance all you did so far on the output board! Not sure what you have to work with, or what the Wimas were doing...were they acting as bypasses or not???.... but if the electrolytic caps are not bypassed, might want to start with 0.1s them... On my Torii's 47uF, and later 40 radials, a 0.1 on each cap as a base bypass or a little bigger woke things up. And on my DAC, the same on a smaller sized 6.8 uF film cap was a decent base bypass start. Actual size of the PS caps seems to matter and presumably output needs. In some of my pre stage boxes, the electrolytic caps are small and higher uF, and overall 0.1 is for me, usually enough, or too much of a bypass base cap on a pair of physically small, but higher uF caps. But this is me and with a lot of refinement work for fast and easy flow having been done everywhere, so worth some experiments.

I find on the power supply that after a certain value point, density and punch get over-done, sounding overstated... then if more overdone, density starts to dynamically consolidate what is there, making it a little artificial sounding and potentially too hard... and beyond that, the density can show as overweighting bass in the balances with hyped mids and highs that can be too dense and hard. Something like that... So if your sound seems about right, and you just want to bring up speed, dynamics, fine information and lucidity without changing the spectral balance much, a first try with 0.1 base bypass, with a very low value bypass on it will at least will tell you a lot, perhaps "right" or pointing to going higher or lower. My take anyway, espeically not knowing what you have to work with!

Believe it or not, I am actually going to make this post short!






JB, sorry to hear about your accident. I think about this risk every time I drive, especially at night. The evidence is all over the country highways and main interstates.

That was a nice Subaru. The best part of it saved your life.  When you get your new Subaru, do like the fighter pilots did in WWII. Every time they had a kill, they would place an enemy marker on the side of the aircraft as a tally of victories for that aircraft.  I can just see that deer head symbol on your fender now.

Anyway, stay safe and I hope all is well after that accident.



CAJames, glad to know that you are reading and enjoying my little experiment.  We are in full agreement concerning that piano performance. It would be nice if you could compare the LPCD audiophile version against the standard redbook version. I wonder what your perception would be of the two different formats. I never heard the standard CD, but it sounds like it was already a great recording. That is most likely why it was chosen to make this audiophile master recording. I have yet to hear anything top this!

Stay tuned, there will be much more to follow.


Will, I have much to respond from what you are saying here. I just don't have time right now as the day is getting away from me.

I am preparing for bypass surgery on my DAC this afternoon.  I have to place the young DAC in intensive care tonight and see if she pulls through.

I shall give the details of the results tomorrow perhaps.  Monday and Tuesday have more parts expected to arrive. The adventure never ends. I shall keep you updated with each change.

Chipster, the "truth" analogy holds great merit!






Be back soon. I have work to do.

Sounds like a big learning exploration is on!

At this point it sounds to me like you are hearing the effects of too much, or a little off-balanced bypassing. But also it is good to know that, depending on the caps used, what is not too intense in bypassing with one cap, can sound too intense (or not) depending on the characters of the caps used.

Where we start is clearly bigtime, whatever tendencies the DAC has designed into it in the power supply and all else, and that being amplified by the power of the output being so revealing. Wasn’t your DAC on the ‘hottish” side in your setting before modifications, improving notably with the Russian tube. A good pointer to how much the DAC shows changes…but also, it may be that the DAC is tuned from the maker to be a little hot, and perhaps needs subtler tubes and/or bypassing to get the sound you need??? Regardless, I suspect that with more tube experiments you would find most all would notably change the sound of your DAC for better or worse, indicating how much the tube foundation effects the whole.

Caps in my experience are the same, especially with these highly revealing outputs. But across the board, some might help a certain piece of gear and others might hurt it, just like the 6N11 were not to your taste and system/room, and the Russian tubes very much to your taste there. Also your cap choices are so far pretty limited, as are the values, and the cap sonic characters affecting the qualities of the different bypass value sound, it is hard to know without more comparison if the caps are optimal helpers for your DAC signature. But I suspect the bigger imbalances are based on the values and/or numbers of bypasses being too much or not necessarily right for all the places you have them... tipping up “breathing,” pressuring the top too much on harder notes especially, and causing some sibilance. Or perhaps your small bypasses are too strong in self-sound for what is ideal, why I like Mallorys over Duelunds in many cases (and most others I have tried), because, here anyway, the Mallorys do nice things to bring out the very high and fast stuff subtly and musically, not in your face. I will be better able to guess on these things sometime soon, having some Spragues coming, but some thoughts.

Also, as you are finding, tubes, caps, and bypasses all strongly affect each other… and without burnin and settling, it is hard to know the full effect of one change, and how the next affects it. Related, with your tubes, your output caps sets, your wima bypasses, your power bypasses, and all the bypasses of bypasses… to me that is a lot of stuff fast! I always start bypassing based on the particular component balances. And having played with this a fair bit over time, I have found basic things that help me get balanced sound, like roughly adhering to the 1/10 guidance in bypassing, as well as having learned the sound of many caps, and narrowing down to the ones I find help me get my sound easiest. But as much or more, I never bypass by rote, always by sound, be it the cap choice, or the value, needing to be relatively clear what I am working with in order to make better choices for the next experiment.

Even now, after years of steady play with this, I try to wait for one move that appears on first impressions to be heading in the right direction to settle in before moving on. Especially with new stuff, this also helps me learn the subtleties of the component and give it more time for burnin before doing too much. Otherwise I don't know if it was the right choice, or what I am building on... things I need to make the next choice with more confidence that what I hear is the change and not the previous move still settling as well. And finally, as I have mentioned, if each choice helps the whole in most all ways, while better assuring that each part is in balance with the whole and improving it holistically, this reduces the need and desire for compensation that might help now, but show up later as problematic. The upshot though, is that I can't know how to improve the sound with different sounding parts if I don't know what the sound is.

Leading to burnin effects, and in the case of these DACs, negative burnin issues being amplified by expressive output stages. In mine, the intensity of changes of tubes and caps is still there after burnin, but they show notably smoother, more complex, and with more musical tolerance after more complete burnin. From how I hear it here, I attribute this to smoothing with more complexity resolving strongly stated rigid per-burnin sound. My DAC designer suggested it would get pretty steady after 100 hours, which may have been sort of true with ups and downs. But I am guessing more like 300-350 was when part of my earlier tuning troubles were revealed as notable contributions from pre-burnin rigidity. Now, still revealing more and more complexity, it is notably easier to make changes, and it is sounding really close to the big beauty.

Though not a total solution before the DAC is burned in, this is why I use a Frybaby and then let the parts settle in with music before doing the next modification. In my experience every cap matters to the whole, and not having used most of those caps you are so far trying, I can't say if I would use them or not….or if I did generally like them, whether I would like them in your particular DAC, especially on masse.

But I can say I tried lots of popular caps before arriving at the ones I use in modifications, also finding I prefer the sound when caps support complexity, whether a base cap or bypass. For me, ending up with caps that balance some musical warmth in a relatively neutral way, and with really good complexity, has been tricky… And to compliment caps with slight warmth, I often use caps with less warmth for pulling speeds and space with fine information. I always find that by using different but complimentary caps, both together, and spread around, the added complexity can help pull the natural beauty, without hardness or other anomalies based on the cap sound, or value choices and combinations being too much or too little. And if an addition doesn’t give me musical complexity without sacrifices elsewhere, I explore until I have choices that do.


It is cool that you are learning and having fun with bypassing, making a lot of changes in multiple areas, and quickly, good learning. But with the currently limited cap selection of types and values, and from looking at the pictures, it does not surprise me that some issues are showing up. Within the cap sound you have, I am guessing a good part of the issues are that some of the bypass cap sets and conglomerate values might be close to, or good for your balances, and others not...

I can’t read most of the values in the pics. But even if the Spragues and KY40s offer really good sound for your bypass needs, from your sound impressions, the DAC seems likely to be over-bypassed in general. If you have put a 0.082, and a 0.033, on the 0.22 Wimas… that is a lot conceptually for basic bypassing. But in the context of whatever the Wimas are already doing, these bypasses could be way too much. Not being able to read the traces, from their location, if not bypasses of sorts, I am guessing they may be refining the power to the tubes in similar ways as bypasses can, and being small, and right at the tubes, they are not power supply caps in the ways the electorlytics are. Also being film, and already more fast and revealing than electrolytic caps, by having added about 1/2 again to the value with bypasses, that is heavy bypassing in my experience. Don't know, but guess this could contribute to an issue with subtle “pumping” that goes too hot for some notes and recordings. My inclination as a first learning experiment toward finding the beauty, would be to use only the 0.033 or a smaller value bypass on the Wimas and see what it does.

Also, regardless of the power of self sound from different caps, very small values pull more from the top… my preference for these is almost always for milder caps with greater complexity, as opposed to strong sounding ones with more concentration of complexity. Depending on the cap used, the same values can vary widely within these parameters. This in mind, the next thing I might try, is to take off one of the three Erse bypasses. If after toning down the Wimas it sounds pretty right overall, but still a little intense up in the very top, maybe try pulling the smallest bypass first and listen. Or if it is still has a little too much surge and over-expressive feel, especially on strong notes, I would probably try keeping the smallest bypass and removing the middle value one…

Some thoughts anyway that I hope might help as you dig into the complexity and benefits of bypassing.

Sometimes, the shotgun approach can hit the intended target and get you where you want to go. This drastic measure actually worked in my favor.


In my last upgrade modification trying to pinpoint where my high frequency problem was coming from, I had targeted the right area, I just didn't go far enough to remove the actual problem of which I had suspected was the core problem all along. This problem just worsened as I upgraded the path down line from this point.  As I increased the definition of the tube output, I was also increasing the high pitched glare that was amplified throughout the signal path.

This was like high frequency distortion, a overpowering synthetic presence which completely destroyed the music in the upper range. This was notably masking the details within the music which actually sounded stressed during various passages.

I suspected that since there were four WIMA caps along the critical input stage where the signals were fed from the DAC, these had to be the culprit causing the sound degradation. When I soldered the bypass caps on the bottom of the board for each WIMA cap, the sound quality itself improved, but the high frequency distortion became worse, as if being amplified.

I had already planned to remove and replace these with high quality oil based capacitors of the same value, then adding a 0.10uf bypass cap to each new 0.22uf cap to start with and see where it goes. I knew it had to make an improvement. Not sure if it would completely solve the problem and put the music back into proper perspective, but it would certainly be the proper path to getting there.



I ordered some Cornell Dubilier 0.22uf@200VDC  Milspec designation: P009A1KC224K-CD Vitamin Q type capacitors to replace the WIMA caps with. This should completely turn things around.


I received these caps on Monday and performed major surgery to the board that afternoon. The WIMA caps are gone now, with the new Vitamin Q Paper In Oil caps in their place. I have high hopes for positive change once this mod is completed.


These are the crappy WIMA caps that were at the core of the high frequency problem. These do not belong in a high-end DAC.






Here is the upgraded view after my tube stage came out of surgery and rolled into intensive care for some audio recovery.





This modification was a royal PITA which took a significant amount of time to complete, but it was worth it. Just had to clean up all of the Flux residue and check the circuit path for possible shorts, and proper integrity before powering it up.

Then it's off to the audio room to see how this modification sounds.




















Starting to look like a deformed science project gone wrong, but it sure makes up for it with absolutely devine musical quality. This tube stage is rapidly approaching high end territory with a refined sound signature which is almost at it's optimal goal. Once the main caps are replaced with the combination V-cap ODAM's and the copper foil in oil types, this DAC will be ready to play in the major leagues as a very strong competitor.

It already sounds as good or better than any DAC that I have heard before this, and it is not done yet. Little "Goddess-Zilla" is coming into her place of being. She awakened after her recent surgery with a new perspective  to be better than ever, developing her wings like Icarus, ready to fly high, soaring into audio perfection. Except that I will guide her away from the sun. I don't want her wings to melt getting too close to the heat source.

This current configuration is very close to the ideal mark. This is far from what I heard in stock form before any mods were done. This is not even the same tube stage, not even close.


So immediately after I fired the DAC up after the WIMA cap change, I could already notice the difference. With a cold system and green parts inside the DAC, it was obvious that the work has paid off. Knowing that things are going to sound much better once the system warms up and some time goes by, I am just satisfied that it does sound so much better than before.

So that solved the high frequency situation. I listened for about two hours last night. It did sound even more refined once the operating temperature settled in to normal range. The music I played sounded so much better. I am thinking that now I have a platform to work with. This is going to improve even more as time goes on.

I let the system play all day while I was doing other things. After dinner, I went up this evening to evaluate the current state that it is in after running all day and having some time to settle in.

I played the two discs that I played before as a reference. First, the familiar Tull symphony live recording, followed by the live Natalie Merchant recording in the HDCD format.

The Tull recording was even better now than past listening sessions, even with my other DAC. The sound quality is almost perfect in current form. I can only imagine what is possible with superior main capacitors in place such as the V-cap ODAMS. There is no doubt in my mind that it is going to be great to say the least. I am satisfied with the sound signature now, but I know it gets even better with the right upgrade.

I stated that previously, the Natalie Merchant recording had a couple of issues that "peaked" with some noted sibilance during high notes with her voice.  Glad to report that not only has that problem been resolved, but now, these same passages are well controlled and sound absolutely fantastic. This recording is not only back to being very pleasant in form, but actually, the overall sound quality is even better than anytime that I ever listened to it.

I no longer have that irritating glare anymore. I am very pleased at this point where I am currently at. So I know that I am set going in the right direction. I may subtract a couple of the bypass caps later, but  I might wait awhile and leave things as they are to let it break-in and get some adjustment time first. It is at the point now where I feel good about it and like the way it sounds. So this provides a good starting point for future upgrades.

So it is confirmed. Changing the WIMA caps for the PIO caps made all the difference and solved the problem.

I could go on about how rich and dynamic, yet controlled and balanced the sound quality is now from what I have heard so far, but I will save that for later.


Things are heading in the right direction.

It is time to listen again and check out some other soundtracks.

I shall return later after some time with the new DAC.

This is the latest modification configuration which I finished last night. I spent a couple hours listening to the results.

From what I heard as a result of this latest refinement, those extra bypass capacitors were simply unnecessary in the circuit. (I am not surprised by that, but had to confirm it.)

The high frequencies were previously enhanced way too much. That bright top end is under far better control now.

The top end has leveled out proportionally with the mid-range, and bottom end of the frequency response. Seems like an ideal balance across the entire frequency spectrum now. I still have much more evaluation time before I can confirm this completely. So far, I really am pleased with the current performance.





















The list of upgrade modifications which are in place currently are as follows. So far, this arrangement is the most favored by my listening evaluations. I still have to upgrade the main caps with 2.2uf V-caps+ 1.0uf copper/oil types for the next improvement coming soon in the near future.



*HEAVY DUTY TOROIDAL TRANSFORMER

*UPGRADE TO HIGH QUALITY 6DJ8 VACUUM TUBES

*UPGRADE MAIN CAPS (2.2uf/3.3uf), *ERSE 3.0uf "PULSE" COUPLED WITH 0.10uf PIO BYPASS CAPACITORS

* THE FOUR 0.22uf WIMA CAPS REPLACED WITH VITAMIN Q PIO TYPES, ALONG WITH 0.0022uf PIO CAPACITORS

*REMOVAL & REPLACEMENT OF TOSLINK 10uf CAPACITOR UPGRADED TO 2200uf CAPACITOR

*ADDITION OF 0.10uf PIO BYPASS CAPACITORS ALONG POWER SUPPLY CAPS FOR TUBE STAGE



At this current level, the sound quality has improved tremendously to say the least. There is still advancement to be made from it with additional upgrades, mainly with the V-cap mod. This DAC/Musical Fidelity X-10D tube stage combination easily sits at the top with high end DAC's costing thousands of dollars retail.

This design is incredibly responsive to small mods, making it very easy to dial in the sound signature exactly the way you want it. Just takes time to master that goal. The influence of tube swapping, and capacitor types really have a direct impact upon it's overall sound. Definitely go with PIO caps as a minimum. I strongly recommend the old stock Sprauge Vitamin Q caps, and the old stock Cornell Dubilier PIO caps. They are very powerful tools for shaping the sound signature.

The PIO caps made a huge difference in this tube stage. I doubt that a better upgrade is possible for such a low investment, not even close in my opinion. I have to question the "real" difference between these, and super expensive esoteric caps, as to how much "better" these costly versions really may be? I will find out soon enough, but for now, I am extremely pleased with my current results.

Just letting it burn in for ten hours each day, every day, so that the burn-in gets accelerated. It will continue to improve in minute subtle ways as the circuit gets settled in, and seasoned.

Very impressive to say the least!