In Reply to: RE: Initial A/B test between PP and SE 6bq5 amps posted by vinnie2 on June 28, 2017 at 04:17:58:
Vinnie I know you said you did not want to invest in interstage transformers so I would try a direct coupled schematic even if you do not use it in the long run. Get rid of any grid stop resistors again just for the test no ccs no mu followers etc. Find the most basic schematic and no feedback.
You get the point. Also build a bread board adjustable fixed bias at least for the power tubes. Then you can dial in the current by ear.
There is a problem somewhere if you can not hear a difference between those 3 tubes in the set circuit. There is a clog in the drain. I went away from main stream builds years ago but I realize that interstage transformers cost some dough. Come think of it Andy got pretty good results with the cheap Hammond interstage. Might want to search that out.
Well at least you are trying and listening which is more than most anymore. I also just remembered are you still using the high frequency and/or a switcher filament? If yes go ac on the cheap, even if some hum. You can always add back all the great things that are supposed to be great on paper latter.
You got time so have some fun.
Enjoy the ride
Tom
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Follow Ups
- RE: Initial A/B test between PP and SE 6bq5 amps - TomWh 11:28:07 06/28/17 (3)
- RE: Initial A/B test between PP and SE 6bq5 amps - vinnie2 15:34:36 06/28/17 (2)
- RE: Initial A/B test between PP and SE 6bq5 amps - TomWh 20:47:26 06/28/17 (1)
- RE: Initial A/B test between PP and SE 6bq5 amps - vinnie2 15:41:24 06/29/17 (0)