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Hoffman Amps Forum image Author Topic: Tube Preamp pedal based on Orange Amp  (Read 1915 times)

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Offline holthausen

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Tube Preamp pedal based on Orange Amp
« on: November 14, 2019, 11:35:38 am »
Hi guys,

Im thinking on build a preamp pedal based on an Orange amplifier (Dark terror, Rockerverb, Jim root n4), basically I'm thinking to cut the circuit on effects loop to use it with an IR (Impulse response) like Mooer Radar, for live solutions or use on return on amps.

I wanted to know if someone could give me some light on this project.

Im using the Multisim simulator to test some modifications on the circuit (dont know if this software is good to describe the real comportment of tubes). Using a 1k5 cathode resistor on V3A,  the output signal melts all the resistors in path, is this ok (1kV+ signal)? Thats why on the schematics attached i raised the value to 10k.

I was planning to use 4 stages (2 x 12ax7) without the cathode follower, but something was telling me to put it as the original schematics with one more tube. So... I got an extra half tube, that i set as parallel triodes on 1st stage.

I added a 3pdt switch to add a second channel with just 2 stages (1st tube with parallel triodes and V2A). Also added a DPDT switch to give and extra boost, adding a 20u capacitor as cathode resistor bypass on V1.

I was planning to use Bass midlle and treble tone stack, but i ended changing it to 1 shape control (Middle cut).

Another question: Worth bring the cathode follower before the tone stack?

Anyone that could give me some advice with this project i would aprecciate.

Cheers,

PS1: I'll mount the same power supply as the schematic attached.
PS2: The preamp is always ON, switching between clean/crunch to drive,

 


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