freestompboxes.org

I hang on the schematic.

Probably my fault, but...I didn't know this brand, is it famous and appreciated in Germany?
Have you tried this tube booster? Can you describe it a little, please?
Thanks!

Yes, I tried.
It works fine to boost a tube amplifier but not in conjunction with a solidstate amplifier.
I am was not happy with the sound when the booster is overdriven itself.
The normal mode is an all frequency range boost, the roll off frequency is about 32 Hz.
The mid mode emphasizing the mid as expected from the naming of the mod, the roll off frequency is about 470 Hz.
The glas mode is designed to bright up the humbucker pickup tone, hence the pedal name, the roll off frequency is about 680 Hz.
The mute switch is a momentary switch, the muting will remain on as long as the button is held.

Intripped wrote:Probably my fault, but...I didn't know this brand, is it famous and appreciated in Germany?

Yes,

but wait, I could show an early work from from him,
just now on my bench,
The worst hack-butchered amp I have ever seen.
Implanting 4 EL34 into an late 60s Vox AC30 TopBoost.
Chassis cut everywhere to fit all those 'improvements'.
No additional venting/ventilation.
Got it with 32Ohm speaker impedance so those tube are looking into 12k.
While measuring power tranny big blobs of solder getting loose.
Worst case scenario.
Vox-o-Grande called by Thomas Reußenzehn, haha.
Deliberate destruction of british cultural heritage called by me.

electrip

The worst hack-butchered amp I have ever seen.
Implanting 4 EL34 into an late 60s Vox AC30 TopBoost.
Chassis cut everywhere to fit all those 'improvements'.
No additional venting/ventilation.

I agree, in my opinion, poor workmanship of the stombox too.

Is the schematic of that amp available?

I don't know why, but I have the feeling that I am missing a (680 ohm ?) resistor at the cathode of the first stage....

BTW, I didn't know, that this guy is still alive & active.

tube-exorcist wrote:I don't know why, but I have the feeling that I am missing a (680 ohm ?) resistor at the cathode of the first stage....

BTW, I didn't know, that this guy is still alive & active.

There is indeed no cathode resistor applied,
the circuit is very similar this one:
The bias voltage is produced by the very small residual grid current through the grid resistor.