Question: 2 valves in a DR-103

[lffish133]

If I were to run a DR-103 with two of the power valves pulled and half the output impedance, wouldn't this pretty much sound (volume wise), and preform exactly like a DR-504 ? After looking at the schematics on MHuss's site, it looks to me like they would be approximately the same. Thanks for the input.

[OldSchoolDave]

...exactly like a DR-504 ?

Pretty close. Never tried the two side-by-side, though.

Keep in mind that the output transformers are different between a DR103 and the DR504. So, you'd have an "oversized" transformer working at half capacity instead of a "perfectly sized" transformer working at 100%.

Dave

[Dr.HI-TONE]

It should sound close. I haven't A/B'd them before either, but maybe we can at the convention for scientific research purposes?

-Clayton

[lffish133]

Yeah I was thinking about the output transformer thing too, I'm sure they wouldn't be exact, but I'll bet they would be dang close, that would be interesting to A/B them side by side and listen for the differences.

[mhuss]

I've put 4xEL34, 2xEL34, 4x6V6 and 2x6V6 in my '103 clone, and it always sounds good! The 4x6CA7 option is the one that puts hair on your toenails, however!

--mark

[ozzyatfrbrich]

I guess this is directed at Mark or anyone who has used 2x6CA7, 4x6V6 or 2x6V6 in a 103. Were there mods required other than bias? Any harm running 4x6V6 for months / years?

Sorry if I am asking dumb questions but I haven't gotten a handle on output tubes and OTs.

Thanks,

Kenny

[mhuss]

Only use the JJ 6V6s, as normal ones can't handle the high voltages.

Otherwise, yeah, just a bias tweak and you're good to go.

--mark