KT120 replacement options in a Cronus Magnum II

@decooney The CM II or CM III are not low current amps. They come with KT120s but can run KT88s per Rogue.

@tubeguy76 Curious to know what the actual plate voltage is in the new CM III? Is it static, or does PV change when KT88s are installed? (if anyone here knows the design well) and has the real specs. I’ve looked for this before with Rogue, would be interesting to know and share here.

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Note: I’ve seen this complaint before about KT120 or KT150s not sounding as good as KT88s in the Rouge amps starting back with CMII, and with the CMIII too. Always wondered why not.

Sure, there are many amps that can run both with lower plate voltages, yet how the circuit, transformers, design is set up is key in how the larger KT output tubes behave, performs, sounds. The circuit design, voltage, transformers - matters.

i.e. I cannot run KT77/KT88s in my Quicksilver Mono 120s with the larger transformers and higher plate voltage specifically designed to run KT150s. KT120s are okay too. The big monos will burn up KT88s, right on the ragged edge at 600v for most KT88s. It’ll work, but will burn them up prematurely. Having owned amps with EL34/KT88s, KT120s, KT150s, can share KT120s sound glorious in the QS Mono 120s, sound full, powerful, plenty of midrange, can be quite liquid when the big iron gets warmed up and saturated. Similar to VAC, in the right amp design KT120s can sound very nice. Same with Conrad Johnson too with KT120s, nice!

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@mulveling I’m with ya man, only have so many spare quads of KT120s and KT150s lying around. If New Sensor does not figure out how to get them out, its only a matter of time before PSVANE and others start producing clones, Read something recently about Mike at NS/Sovtek reaching out to PSVANE regarding this. Maybe another path of getting production out to clients. Will be tracking this. 

@mulveling I’m with ya man, only have so many spare quads of KT120s and KT150s lying around. If New Sensor does not figure out how to get them out, its only a matter of time before PSVANE and others start producing clones, Read something recently about Mike at NS/Sovtek reaching out to PSVANE regarding this. Maybe another path of getting production out to clients. Will be tracking this.

Unfortunately, I think Psvane DID try to make KT120 several years ago - and it was a complete bust due to failures and general poor reliability. Then their KT120 just quietly disappeared from the market. That doesn’t bode well for them filling in KT120 production.

@mulveling "Unfortunately, I think Psvane DID try to make KT120 several years ago - and it was a complete bust due to failures and general poor reliability."

They did, and yes, several years ago. Same was said about PSVANE 6SN7s, and KT88s too, and fast forward five years, some changes for the better.. New people and equipment acquired since. So far so good on my last pairs of CV181 MKII 6sN7s and helped a few friends re-tube with quads of PSVANE KT88s, no issues past two years.

And now making tubes for some high-end amp manufacturers, easy to spot, see them at my local audio dealer. Several tubes out now since. Quietly working in the background. Counted 75 different versions and levels of tubes in production now this week. They don't seem to be slowing down yet.  

And now making tubes for some high-end amp manufacturers, easy to spot, see them at my local audio dealer. Several tubes out now since. Quietly working in the background. Counted 75 different versions and levels of tubes in production now this week. They don’t seem to be slowing down yet.

@decooney - that’s fair! I might give them a shot if and when their new KT120 hits market. I still kinda want to be a tube snob, but my desire for good sounding tubes (that are actually available) far eclipses that. And I have to admit the VAC-selected Shuguang / China 12AX7’s they use in their gear sound DAMN good - some of the finest!