Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Throstur on August 18, 2010, 05:00:42 pm
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Few years back I put a gain stage and a master volume into 50W plexi and also a bassman. Worked out fine.
I am now building a bassman and there is an extra hole where the ground switch is supposed to be. I thougt it would be nice to keep both normal and bright channel and put a master volume in there. Anything against this? Does anyone have a schematic or layout that shows how this could be done?
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Put a 500k or 1M audio taper after the tone stack before the phase inverter.
Sunn Model T (http://www.schematicheaven.com/newamps/sunn_model_t.pdf) has one.
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The ground switch location is usually very near some high AC voltage. That's a noisy location for low guitar signal.
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What if he uses shielded cable?
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A lot of old cheap amps actually put the AC ON/OFF switch right on the volume control, so you can do it. Using shielded cable will definitely be a good idea. I'd still rather have the MV mounted somewhere away from noisy stuff though. Maybe remove one input jack? Drill a hole at a less noisy location? etc? Lots of options on a new build that would be better than the ground switch location. It will work there though.
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A lot of old cheap amps actually put the AC ON/OFF switch right on the volume control, so you can do it. Using shielded cable will definitely be a good idea. I'd still rather have the MV mounted somewhere away from noisy stuff though. Maybe remove one input jack? Drill a hole at a less noisy location? etc? Lots of options on a new build that would be better than the ground switch location. It will work there though.
IŽll in this case throw it in the ground jack hole and wire it with shielded cable just Žto see if it works. If it makes noice IŽll just throw it out again. The reason is that I have a chassis from Mojo that is already drilled, chromed and marked. IŽll get back with results.
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