Quote:


Rectifiers are funny like that. Pre-STR the two best sounding rectifiers out of well over a dozen options in my (non-Decware) preamp were a high dollar GEC U52 and a JAN RCA 5Z3 of unknown provenance that I got used for 10 bucks. If anything the RCA had the edge. Rectifiers are like a box of chocolates...

Hey Mike,

There are two things I know for sure: Zenith did not make its own tubes, and RCA made more tubes than anyone else, and by a good margin. So odds are the Zenith is a rebranded RCA, but tube taxonomy isn't really my thing so I can't give you a good answer. The important thing is you are liking what you're hearing, and your tubes and UFO should make beautiful music together for years to come.

I have been reorganizing the house so did not look at all my rectifiers, but I found a bunch of RCA 5U4G-STs and some cool straight bottles with the same internals (no bottom mica and really nice tubes)... I think all are late 50s, and they all have top micas like the one you pictured Mike. But these also all have top/side rectangular getters, and I can't tell from your pic for sure, but not seeing a flash on top, guessing your "Zenith" has a bottom getter(s).

I could not find my newer (I think 60s) RCAs, but did find some Raytheons with this top mica shape also, and they have bottom rectangular getters... thinking these may have been made in the mid to late 60's, but a long time ago, so not sure I can trust my memory.

I have not used 5U4G-STs in a really long time, but as I recall, the sound changed pretty noticeably with seemingly minor structure changes, some with thicker plates and some lighter, the thicker ones darker and fuller, in my case, less to my liking. Also, the straight bottle ones with the same internals as far as I can tell, also from the late 50s, were my favs in many tubes sets during my 5U4G days. As I recall, a little more open, fast and dynamic.

Yes,  Could be Raytheon.  They made many very nice tubes. Raytheon made tube for other manufactures and they have same rectangular top mica.  Compare yours to these.  Both are Raytheon one is branded Admiral in yellow lettering as well.

https://www.ebay.com/itm/285990101619?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&s...

Looks good! Can’t wait for the Elrog - 575 shoot out.

Anyone interested in this set of 845s that just got posted for sale?

https://www.facebook.com/share/p/tL5zjuJYZRncpo1Q/?mibextid=oFDknk

Knock yourselves out

Well... Now we're cooking with gas!

Oh... It gets worse!



Have a great trip!

All of my components are outfitted with Graphene Sluggos now. If I blow one of those, I might have to seriously rethink my system power requirements...

They are good, but I like the mercs more. Granted, my Elrogs are brand new. Between the dual STRs and the Graphene Sluggos all baking in right now, that's a lot of change all at once. And the Mainstream. Woof. Probably too much. Once I feel like the Graphenes are settled in I'll cook the Elrogs for a while and make a decision. The journey is the destination, yada yada...

I have some mid-size Xenon glass I'd be happy to let you try out if you are interested.

FWIW, I would not have the merc around if I had kids. No no no no no. It's not an acceptable risk.

EDIT: I just checked out 1616s. Those seem pretty cool. I'm curious, as always.

Have you considered the venerable 596?

I've had good luck with Valvo branded stuff. Nice.

Definitely message me if you want to do some tube trading!

🤪👍👍A lot of variables to manage.  I prefer 1 mercury 866A in my STR 104 balanced with a 3B22 or 2 866A’s with one 300b.  What brand 866A’ are you running? I have RCA’s that seem very good.
I also like using the 5v type 83’s mercury tube with similar mix.

Slight update:

Philco globe 866 paired with Cetron 822B sounding best in the 104 right now, with dual ER845s in the 1004.

I really want to prefer the 575As in the 1004, and it is close, but the ER845s just have a cleaner presentation overall. Definitely not sterile, though. These are good tubes.

I a/b'd the Philco globe 866 with the RCA 866A once I got everything else settled. As I remembered, they sound very similar. Philco globe has more definition in the mid-bass (electric bass guitar sounds more like a stringed instrument than just a general low-end force), so I'm sticking with that for now. That might change once the Graphene Sluggos open up a little more.

I did add the Snubway and Mainstream back in and they remain positive additions. Adding that Cetron onto the 104 cleaned the upper mids and highs up enough that it's much easier to hear what each separate component adds to the overall effect now.

Tonight I am doing myself the favor of not listening to the same three songs over and over for a while...  ;D

Adamaley- I can only speak to the 3B28.  I purchased a NOS pair of RCA that tested very strong and I have to say they are nothing special.  The 3B22 that came with my STR sound better. The bottle shape looks cool and they cost nothing so all is not bad.  If I was to do it again I would skip these tubes with all the other choices.

What's next?

I ordered an LSA Lightspeed Attenuator on eBay and it arrived this morning. It's a passive preamp. Right now I have it between the CSP3 and the ZMA, with the CSP3 volume pot wide open. It's sounding really good -- cleaner and clearer than the CSP3 at the same volume on its own.

https://lightspeedattenuator.com/

I got the idea from the crazy-long ZMA upgrades thread on this forum. I'm going to bypass the volume pot in the ZMA next. I never use it anymore, and it's an easily reversible mod.

Nice! I haven't tried any of those tubes. I will be interested to hear what you think!

I got the following correction from Al:

Oh, sorry, I misread your model fo tubes as 575A instead of 572B, actually you can use 572B in your STR with a 845 >> 300B converter and set to 5V settings and top cap cable, but you should not use with the 845 >> 866A converter since the current of this tube is too high and might kill the power supply in a long run.
Best regards
AL

This confirms that we can try the 572B tube in the STR-1002 and 1004. I can't speak for the 104.

Your setup is looking fantastic. Since I'm going non-mercury, I won't get to try some of these certified sonic and visual beauties you are enjoying.

Yes. A little one incoming precludes me from the mercury goodness. Hence the reason I'm digging for all the non-mercury possibilities.

Al just gave his blessing for the 8020W half wave rectifier tube using the 845 --> 300b adapter. Same adapter works for the 572B. I didn't other the 300b adapter with my STR, so it'll be a while before I can try them

CAJames --

I don't know that I've "moved on" from the Elrogs fully - they are clearly excellent tubes - but for the moment I'm very much enjoying the mercury 872A plus non-mercury USAF-596 combo. I tried something similar with 866s in the 104 and Elrogs in the 1004, but the current combo won the shootout, even if maybe only by a couple of hairs.

As for the 8008: I'm getting a little more comfortable with the idea of making my own STR accessories. I just need a little more inspiration and free time...

Al told me to limit 575s to 5-6 hours. When I told him I often keep my system on most of the day, he said that should be fine if I took the bottom panel off and elevated the unit about two inches. Apparently, heat is the main issue, so providing additional ventilation is the remedy.

Still loving my STR with the Elrog 845s, but I haven't spent enough money on tubes lately so I bought a couple of NOS 211s. They should be here for the weekend, will be an interesting comparison I think.

3 hours in and the GE 211s sound great. Huge, dynamic sound with great bass extension. Not the liquidity or "refinement" of the Elrogs, but close and it has only been 3 hours. I think these are going to be great sounding tubes, and at $275 per they are an excellent value.

This thread has been pretty quiet, presumably because everyone has been too busy listening to post.

For me, I've been ridiculously happy listening to the GE 211s for the last month or so, but this morning I decided I needed a reality check so I put the Elrog 845s back in. I've still got the same tubes in my Woo Audio preamp, to which the STR is connected and only changed the input tubes on my UFO25s since I had the Elrogs in before. After listening for a couple of hours this morning my conclusion is the Elrogs win over the GEs. The Elrogs make the sound a little bigger, a little more liquid (but not warm) and with a little better low end. The GEs are very much in the race though, probably the biggest (relative) weakness is the mid- to low-bass but they add some high end sparkle that is very nice on e.g. female vocals.

I haven't heard any of the high end Chinese power triodes, but the GE 211s beat the bargain tubes I have by a lot (although I guess for completeness I ought to listen to them again as well), and don't cost much more. Certainly way less than new Elrogs. I'm still not tempted by mercury rectifiers, with the Elrongs and GEs I just don't feel any need to mix mercury tubes with the cats.

In other news I've recently made friends with the choke. I guess I shouldn't be surprised that like everything else it needs to burn in before it sounds its good. I had only listened to it for a couple minutes, hated it, and decided I would never use it but a few weeks ago I decided to run it overnight, and the next day it sounded way better. Much more subtle and not at all unpleasant, esp. with old not-so-good recordings.