Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Big_Mike on July 10, 2022, 12:52:58 pm

Title: Dual 50 Amp
Post by: Big_Mike on July 10, 2022, 12:52:58 pm: Finally getting back into building amps, and am thinking of building Sluckey's Dual 50. Anyone built one? It would be really neat to have a Marshall 1987 and 2204 in one package. Anyone compare the Dual 50 with an actual 1987 and 2204?
Title: Re: Dual 50 Amp
Post by: Bieworm on July 10, 2022, 03:15:17 pm: Quote from: Big_Mike on July 10, 2022, 12:52:58 pm
Finally getting back into building amps, and am thinking of building Sluckey's Dual 50. Anyone built one? It would be really neat to have a Marshall 1987 and 2204 in one package. Anyone compare the Dual 50 with an actual 1987 and 2204?

Built one last year. Great amp! Be aware both amps share the same tone stack, so forget about making it switchable.. both require different settings
Title: Re: Dual 50 Amp
Post by: Big_Mike on July 10, 2022, 04:02:35 pm: Quote from: Bieworm on July 10, 2022, 03:15:17 pm
Quote from: Big_Mike on July 10, 2022, 12:52:58 pm
Finally getting back into building amps, and am thinking of building Sluckey's Dual 50. Anyone built one? It would be really neat to have a Marshall 1987 and 2204 in one package. Anyone compare the Dual 50 with an actual 1987 and 2204?

Built one last year. Great amp! Be aware both amps share the same tone stack, so forget about making it switchable.. both require different settings

Thanks for the info! I don't intend to make it switchable, so the shared tone stack is not really an issue. Would it be possible to have two separate tone stack controls for each amp? It would make for more knobs on the front, but might make switching back and forth easier.
Title: Re: Dual 50 Amp
Post by: sluckey on July 10, 2022, 07:36:43 pm: Quote from: Big_Mike on July 10, 2022, 04:02:35 pm
Would it be possible to have two separate tone stack controls for each amp?
Sure.
Title: Re: Dual 50 Amp
Post by: Big_Mike on July 12, 2022, 11:37:53 am: Cool to know, would you just make the switch between the 1987 and 2204 sides after the tone stack? Just curious how you would do two separate tone stacks.
Title: Re: Dual 50 Amp
Post by: sluckey on July 12, 2022, 11:45:29 am: Build two complete preamps. Then connect a 220K resistor to the wiper of each treble pot. Tie the other ends of the resistors together and connect to the MV hot lug. Connect the wiper of the MV to the PI input cap.

The two 220Ks make a passive mixer and the MV works for both channels. If you rather have a switch just replace the two 220Ks with a SPDT switch.
Title: Re: Dual 50 Amp
Post by: Apexelectric on July 16, 2022, 05:16:11 pm: Converted an old Traynor YVM-1 into a Dual 50 and did make it foot switchable for the channel, bright and jumpered options.