Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on June 15, 2022, 08:56:24 am
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I have built the preamp (including the effects loop recovery stage) up to the master volume pot just before the phase inverter. I have run this tap into my combo amp and the level is too high. What do i need to add to this? I have marked with a red X where i have an output jack wired. Should i run a 100k resistor from the center lug of the MV pot to ground (voltage divider)? Does a cap in series come into play?
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That mv pot should control the level you are sending to another amp. That level of signal is meant to be sent to a power amp input. It is way too hot to send to an instrument level input.
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That actually might be okay. i intend to feed it into a fractal unit. I have to figure a way to tame the level. This tone is all there but the level is too high i think
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Connect a 100K between the MV pot wiper and the output jack. Then put a 10K between the output jack and ground. This will give you a 10:1 voltage divider. If still too hot, reduce the value of the 10K.
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that worked great. I settled on 82k/3.3k. Can you tell me what the cap in this diagram does?
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It passes AC and blocks dc.
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as a protection from shock? does it affect the sound in any way?
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It'll keep out any possible DC coming from whatever you plug the preamp into, and in the possible event of your preamp emitting a DC, it'll keep that out of whatever it's plugged in to.
A 0.047uF shouldn't affect the tone, but if you're concerned, a 0.1uF definitely won't have an effect either.