Thoughts on Audio Research D70

I wouldn't put 8 kt120s into it. Consider how much more current the filaments will draw. 8 kt88s in tetrode mode should be able to power the hungriest of hogs. The apparent lack of power is from the stock caps. If you are not comfortable with DIY or non factory mods, ask Calvin at audio research if they offer recapping service for the coupling caps like they did i(infinicap and dynamicap) in the 90s. The relcap plus wonder cap combo is not conducive to good sound at all.

Sbrown, Thanks for sharing that info on the KT120's. I was wondering about this and was going to call Arc about it. You just saved me the call, LOL.
Too bad, as the KT120 is a very good tube. With decent 6550's getting a little hard to find, I'm glad I just re-tubed with SED's.

Sbrown, I just replaced the 6550 in the power supply of my CD-8. ARC sold me a 6550 WE. No idea what it is, but if ARC sells it, I'm not worried.

@sbrown if you are just after the sound of the kt120 and not the marginal increase in power you can use just 4 tubes in your 115. That's how I sometimes run my old vt130 anyway. Make sure you are using one tube per phase per channel. Filament supply is parallel so you will never be stressing the unit with half the power tubes.

I was asking about the kt120 more from a increased tube life perspective as I knew that I wouldn't get a power increase without mod's to the amp. I don't have any issues with power with 115 - it seems to be able to drive about anything I hook up to it. ARC did recomend the Sovtek 6550WE's which seem fairly easy to find.

I have no issues with a non factory mod. I am considering recapping it but haven't made up my mind on which cap(s) to go with. Any suggetsions??