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Re: what did u do with X100B Re: why poeple alway talking about dynaco ST-70 ?

William,

I didn't change the PSU caps; the caps I changed were coupling caps and the decoupling caps. In the PSU, I did add a choke. The choke was after the doubler caps, and mine is 10H.

After triode strapping the outputs I decided to get rid of the NFB. That increases the gain and reduces the BW, but I judged the OPTs were large enough to respond low enough considering I had only 6-8W. It turns out that the OPTs were good for it, but the hum increased to an unacceptable level.

So, I installed the choke; mounted it where the bias pot is, and turned the bias pot sideways so it could be accessed from under the chassis. Of course, the choke lowered the B+, so the entire string of resistors in the filter had to be trimmed, but that isn't much of a job.

In the phono section, I changed tubes to 6072s, got rid of the EQ switching, and installed a passive EQ network calculated for these tubes. The phono stage was very much better.

Cheers/Fader
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