If this is PcX,Tube New Tung-Sol KT120 (Super 6550/KT88) (partsconnexion.com) they sold out already. I got 2 off ebay and they work great. I have a spare now for the inevitable.
KT120 replacement options in a Cronus Magnum II
I have a "new to me" Cronus Magnum II" that came with a shot KT120. Thankfully the am still plays with half the power on the one channel. I'm having no luck finding this tube. Being made in Russia and in high demand I expect the situation to stay lean for some time. Rouge reported that the KT88’s, KT90’s, and KT77's are all compatible. I'm new to the tube amp space and I was hoping to read for a few months before going tube shopping, but I have a situation.
Has anyone "downgraded" the Magnum II to one of these other tubes? I'm guessing I should buy a pair so both channels have the same output. Is that right?
What are your thoughts for the best way forward? I spent most of my budget so a pair of KT150's is really not an option.
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Tried to make the switch from 120’s to 88’s in my Atlas Magnum III to save some money, but it was so much better with the 120’s in my system that I just had to spend whatever it cost. Fortunately, I found a matched quad of Tung Sols for $400 and was given a single replacement to try to get the most out of the 3 I was left with. The world needs more KT120 tubes. They’re musical and authoritative; truly fantastic and hopefully a future-proof, new classic. Good luck with your hunt. |
Probably so. I’ve seen this comment when amps are not truly optimized to run KT120s or KT150 tubes properly within their optimum operating window. Just because the tube fits in the socket, does not always mean it’s going to sound its best in any amp. Worth researching more. Is the amp truly designed to run KT120/KT150s well? Ask the designer for the plate voltage, rec bias - check values of the tube spec vs. the amp capability. Compare. Running a KT120 or KT150 tube "cool" in an amp with lower plate voltage and low bias current, well under its optimum operating window, will have more of a sterile un-engaging sound. Drop in a smaller KT77/KT88 in the same amp, running it hotter inside its desired operating range - now sounds nice. How is that, hmmm. Now, move that same set of KT120s or KT150s to an amp with bigger transformers, i.e. running 600v at the plate, biased at 60-70ma, moving up to 70-80% plate dissipation, now the same tubes running inside their optimum operating window, no longer being run "cold" or "cool", now sounds like a nice sounding tube amp again. The BlueGlow Electronics guy has a nice YouTube video about this, running tubes "in their window". No need to run big tubes in smaller low current amps not designed to run them properly - just a waste of money, fwiw.
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