Tube DIY Asylum

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RE: I don't think so.

Posted by Ralph on February 1, 2017 at 10:12:41:
Using single stage of 12BH7 or 6SN7 does not give you the output impedance low enough to drive the power amp
This statement is outright just plain false. These tubes have been used as driver tubes in amplifiers for decades, and would work easily at the output of a preamp- and would be rather gutsy in that regard.
Also, but how would CJ , ARC also make use of 6h30 for thier high wnd preamp model if the HF osc is that bad?
That's a loaded question, but the short answer is apparently (IMO) 'not that well' (again, just my opinion; I don't think its all that hard to find better sounding preamps). One would hope that their gear lacks any HF oscillation tendencies! My impression personally is that microphonics (not oscillation) is really the big issue. I've seen some of these tubes that were so bad that you could yell at them and hear yourself in the loudspeaker. Its really hard to build an audio circuit that sounds right when the tube won't behave.