Quicksilver V4 tubes

Yea,  it’s been a while since I had the KT88’s’s in my amps  I had thought about doing this a while back and initially Mike said to me that because the newer V 4’s before they stopped manufacturing them had updated transformers to accommodate the bigger KT 120 and KT 150 tubes! so naturally, I was a bit surprised to see that he had said to someone else that you can use the other tubes and older V 4’s as well as his message back to me, which I have included here!

The older V4s can use the KT150s however I feel the Chinese KT88s sound better than the Russian ones. 

Mike

Tung-Sol is the only manufacturer that makes the KT-150 and the KT-120. It will not be easy getting these or any other Russian made tubes. I have used the JJ KT88 tubes with my QS amps. Take a look and you will see that the Russian tubes are not available!

https://www.tubedepot.com/t/tubes/power-tubes/6550-kt88-kt90

Chaps, you can't willy-nilly swap tubes of the same pinout: Filament currents vary from 1.4A for the KT77 to 1.7A+ for the KT150.

Power is calculated from B+ and the current available. Changing from KT77 to KT88 will not provide more power. It will sound different due to the transfer function of the drive vs the tube power curve non-linearity. Along with the mismatch inherent in ALL tubes of the same type.

IGNORE ALL recommendations for a specific tube from Joe AudioPhool unless he has the same equipment in the same room! AND listens to the same program.

Myself and another really like the JJ KT88 in our M-125 monoblocks. He has Klipsch and I have custom ET LFT8b. I've never heard his system and he's not heard mine.

Apex Matching is really good.

See ieLogical Rolling for more on matching and aging.

To @vlad427 , I have those same (the largest) transformers in my QS Mono 120 amps, and mine were made to specifically run KT150s or K120s. Designed with higher plate voltage to run these tubes only. Unlike you, I cannot run KT88s in mine Not for long, it will burn them up according to Mike. If he told you to run KT88s, there is a reason for it, and likely the KT88s will/can run "in their window" of optimum operation, bias, plate dissipation on the mark with your specific version of the V4s. While his answers are short, no less meaningful. The advice is solid, sometimes he does not share all the reasoning or details behind it.

If you’ve been running EL34s in the V4s for a while, its possible you might have gotten use to how they sound, maybe a bit lighter weight with slightly less drive and less impact than KT88s - with your particular speakers. I track them and just re-checked, still seeing no great hope for quads of KT120s or KT150s from sovtek Russia. The war. I keep quad spares of 120s, 150s,, and a backup SS amp to run to rest my larger KT tube amps, if it helps to know. It’s not worth it right now. If I could run KT88s in my amps right now, I would. They can sound really nice, decent kick. Notably less cost.

Do you stil have your former KT88 tubes, or have you checked out other new sets of KT88s lately?

KT 77 Gold lions sound best kind of a mix between a kt88 and el34  and I would look into buying nos smaller input tubes , when was the last time they were replaced ?  Old tubes can still work but loose lots of detail over time 

Brent Jesse recordings , or vintage tube services.