Sovtek MIG50: 511V plate voltage. Which "dark" 6L6 tube?

[Harold]

I recently bought a 90's Sovtek MIG50 with the original tubes in it. After replacing the poweramp wiring (was a real mess!) and all pots, I added pre PI master volume and fitted the preamp with JJ's.

The amp is still very bright and lacking (sub)lows. I guess that this might be due to the 20+ year old Sovtek 5881's (6P3S-e with the "coin" base). I even clipped the bright caps, but that didn't fix the brightness.

Schematic: http://www.el34world.com/charts/Schemat ... G50-60.pdf" onclick="window.open(this.href);return false;
(My MIG has 100nF PI coupling caps and a few minor other differences from this schematic)


I was recommended the JJ 6l6GC, but the datasheet tells me that the tube might not be happy running on the MIG's 511VDC plate voltage.


Any other recommendations for a fat, "dark" 6l6 that can handle a lot of voltage?

[Tremblayamps]

I threw KT-88's in a marshall 2204 and it gave it fat low end. You can try both 6550 and KT-88's. You will have to mod the Bias section most likely to handle the 88's. It would be r27 on the schematic (10k). After the I the put the 88's in I would never go back to 34's in that amp.

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[Harold]

Well, I've gone a slightly other path with my Sovtek Mig50

• Put in a IGOT-JMP50 output transformer
• Switchable V2a cathode bypass: none, 680nF and 220uF
• Switchable fixed resonance: 2n2
• Changed the 47nF in the tonestack to 22nF
• NFR to 100k (instead of 39k)
• Internal jumpering of both channels
• And ... JJ 6l6GC's

Of this list, the output transformer made the biggest difference! With the fixed resonance engaged, I have to roll down the bass to at least 2-3, so that's a nice "bedroom level mod".

[Tremblayamps]

What are your thought on the ig transformers. I'm in the midst of a soldano project and im trying to find the best transformers and the ig transformers came up but i haven't reviewed them to much yet

[Harold]

What are your thought on the ig transformers. I'm in the midst of a soldano project and im trying to find the best transformers and the ig transformers came up but i haven't reviewed them to much yet

Well, Ingo has had some difficulties manufaturing them due to personal reasons but he is up to speed now and building a nice stock. His new webstore also doen't allow items to be sold which aren't in stock.

I bought two "Marshall" 50W OT's and one 100W. I've only used one 50W to replace the stock OT in my Sovtek MIG50 and it's a helluva difference! Loads of clear lows and way less "barking" aka annoying high/mids.

I have a couple of original 2203 and 2204's which I'm thinking about upgrading with IG transformers since they're kinda cheap ...

There might also be another MIG50 on it's way