Tube Preamp/Pedal Switch

All frequent questions on switching: true or not true bypass, transistor-based or mechanical.
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mwelch55
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my favorite amplifier: Modded Marshall
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Post by mwelch55 »

I am building a stomp box that can be used as a preamp or as a pedal. This will be based on the preamp of a hot-rodded Marshall.

The output of a 4-stage tube preamp is too hot for the input of am amp, so I wanted to install a switch that will attenuate the output for use as a pedal.
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mwelch55
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Posts: 17
Joined: 21 Jan 2012, 20:45
my favorite amplifier: Modded Marshall
Completed builds: Pedals:
BSIAB2, Tube Screamer Clone, Timmy Clone, Plexi-Drive Clone, Dr Boogie, Rangemaster, GTFO, MicroAmp, Silicon Fuzz Face, Germanium Fuzz Face, Big Muff Pi, Rat

Amps:
Single-Ended Marshall Voiced using 6V6,6L6,EL34,5881,6550, or KT88
Location: Winnsboro, Texas
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Post by mwelch55 »

What is your opinion. Can anyone think of a better way?

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plush
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Post by plush »

mwelch55 wrote:What is your opinion. Can anyone think of a better way?
It should be clicky when switching live.

I'd prefer using fet or ldr for switching.

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mwelch55
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Posts: 17
Joined: 21 Jan 2012, 20:45
my favorite amplifier: Modded Marshall
Completed builds: Pedals:
BSIAB2, Tube Screamer Clone, Timmy Clone, Plexi-Drive Clone, Dr Boogie, Rangemaster, GTFO, MicroAmp, Silicon Fuzz Face, Germanium Fuzz Face, Big Muff Pi, Rat

Amps:
Single-Ended Marshall Voiced using 6V6,6L6,EL34,5881,6550, or KT88
Location: Winnsboro, Texas
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Post by mwelch55 »

Thanks for the reply.

In one position, the output will be the full preamp signal, intended to be sent to a power amp. The other position will be attenuated for use as an effects pedal or amp emulation pedal.
I would need to switch to the appropriate mode BEFORE using it.
If I am going to use it as a pedal to drive the front end of the amp. I won't be switching to preamp mode while using it live. If I feed the full preamp output into the front end of an amp, it would be way too much signal. It may even blow up components in some solid state amps (that happened to me).
If I am going to use it as a preamp, driving the power amp, I won't be switching to pedal output because it would barely drive the power amp.

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