Bottlehead Forum

General Category => General Discussion => Topic started by: PerroNegro on March 06, 2012, 04:37:52 AM

Title: Stereomour 45 vs Paramount 45
Post by: PerroNegro on March 06, 2012, 04:37:52 AM

which amp is better suited to run 45 tubes, or what would be the difference in performance/sound?

Title: Re: Stereomour 45 vs Paramount 45
Post by: Doc B. on March 06, 2012, 05:43:17 AM

Stereomour is designed with using 2A3 or 45 tubes in mind. Paramount has been designed for the use of 300B or 2A3 tubes. In other words, you won't have to figure out anything on your own to use a Stereomour with a 45, the parts are included. A 45 in a Paramount would be best done with different iron, adjustment of the voltages and currents, etc. that we have not worked out.

Title: Re: Stereomour 45 vs Paramount 45
Post by: PerroNegro on March 06, 2012, 08:30:02 AM

Thanks Doc,
that certainly helps the decision. What's involved in bypassing the integrated volume/selector functions for just a power amp?
This would be my first full kit. I've built circuit boards, changed parts, and repaired a few components so I'm ok with soldering and reading instructions, also built my own Altec 4722 step up transformer box. I can follow simple schematics.

Title: Re: Stereomour 45 vs Paramount 45
Post by: Doc B. on March 06, 2012, 09:31:40 AM

You simply replace the volume pot with a 100K ohm resistor from the grid of the 12AT7 to ground - ahead of any grid stopper that might be connected to the grid pin. If you remove the volume and selector switch the easiest thing to do is put the 100K right across the input jack from center pin to ground tab. Then run shielded twisted pair from the jack to the grid pin of the 12AT7, with the 220 ohm grid stopper in series right at the tube pin.