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https://www.decware.com/cgi-bin/yabb22/YaBB.pl AUDIO FORUMS >> General Discussion and Support >> Question about Rachael https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1717416829 Message started by Alan Arkin on 06/03/24 at 13:13:49 |
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Title: Question about Rachael Post by Alan Arkin on 06/03/24 at 13:13:49 Hi there... I recently purchased a used Rachael for my system, which replaced a 300b integrated amp (10 watts per channel). I jumped at the chance to buy the Rachael because I have long wanted a Decware amp. I have it hooked up to my Rega Planar 6 with Ania cartridge, a Darlington Labs MP-7 and SU-7 phono preamp and step up transformer, and use Zu DW6 speakers. I have a relatively small listening space that is about 12X12, though part of a larger room. I have been very impressed with the level of detail from the Rachael compared to my prior amp. The only issue -- to the extent it is one -- is the difference in power. I pretty much have to max the volume out (from 3 o'clock to max) on the dial to get it to the volume I like to listen at. I still need to sit with it some more but I was wondering what people would recommend in terms of being able to boost out a little bit more power -- I imagine a preamp like the CSP3 would solve that "issue." Can anyone recommend another preamp for this setup? Thanks! |
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Title: Re: Question about Rachael Post by Tony on 06/03/24 at 14:30:40 Hi Alan, Congratulations on picking up a Rachael. From my experience with the Decware preamps, that should give you the extra power. Two other alternatives come to mind: ZRock and Zbit. ZRock 3 is a new model of this product and give you that boost, but a second hand ZRock 2 would also do the trick. If you are a bit bass-shy like me, then the Zbit would be my choice. As I understand it, once ordered, the waiting line for either of these is different (shorter) than the line for amps. |
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Title: Re: Question about Rachael Post by will on 06/03/24 at 15:05:43 Alan, In my experience unless your phono pre is putting out less than the Rachel's optimal input voltage, you will not get more "power" from a preamp. I don't know your phono pre setup, and maybe you are not getting enough voltage to the Rachel, being able to turn the Rachel up to full power, guessing without distortion at all up on the volume pot??? The current version of the Rachel is listed as reaching full output power with a 1.2 volt input. "Circuit type Single ended Class A Triode Power output 5.8 watts RMS into 8 ohms Input voltage 1.2 volts for full output" So, if your setup provides that voltage or more, adding a CSP3 will give your its sonic flavor, and with gain tuning between the Rachel and CSP3 you can tune the tonal balance, density, weight, dynamics, lucidity, etc... This can give the impression of the little more power, but I am thinking the Rachel's output power will not increase if you are already feeding it 1.2 volts or more...that is unless this spec has changed since your Rachel model??? |
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Title: Re: Question about Rachael Post by CAJames on 06/03/24 at 15:14:47 Quote:
I agree with with Will. First, let me say there is a difference between "power" and "gain." Gain is how fast the output voltage (aka volume) increases as you turn up the volume knob. Power is how much current the amp can source into your speakers at a given output voltage. So just because you need to max out the volume doesn't necessarily mean you are lacking power, just the new amp is lower gain. That said, I find a tube preamp adds just a little secret sauce to the sound makes your system sound better/more powerful even it isn't producing any more watts. |
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Title: Re: Question about Rachael Post by Rhtubes on 06/03/24 at 15:36:46 Hi Alan. The previous generation of Rachael or the SE34I.5 requires 2.5V for maximum output. |
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Title: Re: Question about Rachael Post by Alan Arkin on 06/03/24 at 16:12:32 Thanks for the insights. There is no distortion when the dual volume knobs are maxed out. I have a Darlington Labs MP-7 phono preamp and the SU-7 step up transformer. I know the MP-7 and SU-7 have a series of DIP headers inside them. I don't really have a handle on them but I know the SU-7 has headers to change the gain and loading. They were set before I got them. I wonder if changing them would have any effect. |
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Title: Re: Question about Rachael Post by HockessinKid on 06/03/24 at 16:18:59 Your phone pre and step up dip switches should be adjusted depending on the output of your MC cartridge. I'd check the manufacturer website for instructions on how to best set the gain for your specific cartridge output. For example, if the switches are set for a moving magnet cartridge your volume will be very limited. HK |
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Title: Re: Question about Rachael Post by will on 06/03/24 at 16:21:17 I agree... a good idea to check with the phono pre maker for details and adjustments. More voltage output from a pre stage tends to increase lucidity and weight also, though it can come with more noise as well depending on all else. If you can increase the voltage into the Rachel to a point where you get some distortion near the top volume pot settings, you will know you have reached the max power of the Rachel. |
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Title: Re: Question about Rachael Post by CAJames on 06/03/24 at 16:22:00 Quote:
Yes. I did some quick googling and it looks like both the MP-7 and SU-7 have adjustable gain. I would do some research on the dip switches and how to increase the gain. |
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Title: Re: Question about Rachael Post by Tone-Deaf on 06/03/24 at 17:22:39 Hello, Alan, and congratulations on your new amp! By the way, I have an SE34I.5, and like you am very happy with the detailed sound of the amp. I just wanted to add that my understanding of the input voltage needed bring the SE34I.5 to full power was 2.5 volts, as Rhtubes noted. Will is correct that the product page on the web indicates that the SE34I.6 reaches full power with 1.2 volt input. But based on a quick look I did not find a confirmation of that number anywhere else (I looked at the manual, and did a few quick searches using of the search function for this forum). Just wanted to suggest that you might want to confirm that 1.2 input voltage (instead of the 2.5 input voltage for full power on the prior model) - perhaps by a quick call or email to Steve. I think it is easy for a typo to creep into a website, and I think the answer to that question may be important to decide what your options may be to get more volume. |
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Title: Re: Question about Rachael Post by will on 06/03/24 at 18:04:13 Good points TD. Alternately, if you find out about adjusting the dip switches anyway, and at the same time find out what voltage the phono pre setup is putting out stock, this could help answer it. If it is say, 2 volts, and you can open your Rachel volume to full without any subtle distortions on hot transients, guessing your Rachel is likely optimal at the 2.5 input voltage. In which case, you may be close to full volume now and not know it. As CAJames suggested, full volume on the pots is not necessarily an issue, but in this case it does not tell the whole story necessarily either. So in one sense... if you can get to listening levels that are high enough volume as-is, without distortions, then you are probably fine as-is. But if you want to find out for sure what is the max volume available in your setup, this is why I suggested that if you can increase voltage from the phono-pre setup without issues to a point where you can hear subtle distortions at higher Rachel volume pot levels, you will know the amp is putting out all it can. Though specs can definitely be useful, I always find that finally experiments make it real and teach me more. |
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Title: Re: Question about Rachael Post by Sean on 06/03/24 at 18:56:41 You’ve got a pretty low output on the cart at .35. I suspect the dip switches need changed. I listen almost exclusively to vinyl. There are so many variables in the vinyl chain. I’ve found occasionally using a digital source helps to see if the vinyl side is setup correctly. Sort of a sanity check. Have you tried a digital source to see if the Rachael can get the volume level you think you should get? Just a thought. |
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Title: Re: Question about Rachael Post by CAJames on 06/03/24 at 21:12:45 Quote:
This is point I missed. A 72 dB phono stage (which is typically the max) would give you an output of about 1.4V, which would max out the 1.5V Racheal but leave you wanting more if you had the 2.5V version. I don't know for sure how much gain you can squeeze out of your SUT and phono pre, but if you have the 2.5V Racheal you may need an actual preamp. |
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Title: Re: Question about Rachael Post by Yakatak on 06/03/24 at 21:27:24 The first reply to the OP's question, by Tony, has a slight error. The ZBit is an balanced to unbalanced convertor. I'm sure Tony meant ZStage, which is a gain preamp, and will boost your signal. |
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Title: Re: Question about Rachael Post by armstdav on 06/03/24 at 22:20:11 Alan, I owned an SE34i.2+, which was a forerunner of the Rachael, and ran it into ZU Druids, which are very similar to your DW6s. Even with a preamp, I found the 6W/channel wasn't really enough to get those 10" FRDs moving. I got a Torii MK IV (25W/ch) which was a much better match and drove them well, still with a preamp. All the above posters are correct about making sure you're feeding the Rachael enough voltage, but I guess my advice would be to borrow a preamp if you can and see whether the Rachael will drive the DW6s to your satisfaction under any circumstances. You may be more satisfied finding an amp with more power. |
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Title: Re: Question about Rachael Post by Dominick on 06/04/24 at 14:03:46 Edited: In terms of a preamp you have the Decware ZTPRE and CSP3. If you are looking to just add a bit of gain to your setup, a utilizing a ZSTAGE would help. I loved my ZSTAGE as a gain stage and ran it for like 10 years before I upgraded to the CSP2+ preamp. The CSP3 will give you great flexibility with the ability to roll a variety of tubes that also doubles as a headphone amp. Hope this helps, Dom |
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Title: Re: Question about Rachael Post by Alan Arkin on 06/04/24 at 14:04:20 Thanks for all the insights. In emailing with the owner of Darlington Labs, he believes that the Rachael has a very low input sensitivity at 2.5 v and that a line preamp (of +12 db) is needed. Alternatively, he said that I might be able to turn the gain up on the step up transformer beyond what is needed for the cartridge and make up the gain that way. A few questions, as this is somewhat new territory for me: 1. Is a line preamp the same as a regular preamp? The ones I have seen seem more limited -- i.e. like the ZSTAGE. If I need to add one to my system, I'd like it to be as transparent as possible. 2. Other than the ZSTAGE, can anyone recommend another one? I've seen some recommendations for the Mapletree Line 2CRM. 3. Would switching my phono stage to something like the ZP3 zen triode phono stage provide the right amount of power for the Rachael? In the end, I may just keep it as is but I want to understand my options. Thanks! |
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Title: Re: Question about Rachael Post by Lon on 06/04/24 at 14:06:30 1. A line preamp these days denotes a preamp that is without a phono preamp stage. So you would run your phono preamp output into the line stage preamp and then from there into the Rachel. |
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Title: Re: Question about Rachael Post by HockessinKid on 06/04/24 at 14:17:40 Alan, A line preamp simply does not have a built in phono preamp. So you need a separate phone preamp, which you have. The ZStage is not a preamp. I suggest if you consider a new or used preamp, check out the Decware CSP3. It's a great match for Rachael and provides a lot of flexibility and plenty of adjustable gain. Switching your phono preamp is not the best solution in your case, given the Rachael output voltage. At best you'll marginally get modest gain and likely will introduce some noise/distortion by boosting the the MC gain too much. The Decware ZP3 is designed for high output moving magnet (MM) cartridges so swapping this for your current phone preamp will not solve your volume issue. Best course IMHO add a good tube line preamp like the CSP3. There are a lot of upgrade options available as well. The 25th Anniversary modifications are highly recommended. HK |
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Title: Re: Question about Rachael Post by Dominick on 06/04/24 at 14:40:26 Roger…..thanks for catching my mistake. Yes the ZSTAGE is merely a gain stage. I’ll make that correction in my previous post. Dom |
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Title: Re: Question about Rachael Post by Sean on 06/04/24 at 15:46:41 Alan, did you look into the dip switches on the SU-7? Before adding any other components, I would play with the settings first. From the Darlington FAQ https://www.darlingtonlabs.com/support: Currently we ship units set to 220 ohms and 23dB gain (for the SU-7). Onto the Aria page: https://www.rega.co.uk/products/ania LOAD SETTINGS FOR ADJUSTABLE MC STAGES Impedance 100 Ω Capacitance 1000 pF Gain Setting High (‘On’ position for Rega phono stages) I would open the SU-7 up and switch from 220 to 100 for loading. Set the gain to 23db. Take a test drive and see if you hear an improvement. You can play with the loading/gain to find a sweet spot. |
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Title: Re: Question about Rachael Post by CAJames on 06/04/24 at 15:47:58 Quote:
In theory you may be able to increase the gain on your SUT, but that has other consequences. As you increase the gain you also increase the (effective) output impedance of the cartridge, and that can affect the frequency balance of your playback. It doesn't cost anything to try, and it may very well be a good solution for you, but if you get more volume but "funny" sound that likely the reason. |
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