The Amp Garage

Hi Ben, I am using a 12AT7. I get some 80V on the 12AT7 cathodes. I would love to see the MOSFET version. How do you like the sound? Do you hear a difference between MOSFET and tubes? I might use a 12AU7 for kicks some time. Maybe a 12AY7 (need to find one though..). I have the CF cap coupled, since...

Hi guys, I finished it today (had half a day off): Preamp: Plain Vanilla values 220k,3k3,150k,2k2 0.1 and 0.05uF Tonestack 0.047uF Cl2 Overdrive: 220k,3k3,150k,2k2, 220k into trimmer (100k) -> 68k, 0.01uF and 0.005uF decoupling in OD, 100k pots Footswitchable (still have some pops though): pre OD Ma...

Hi Gary,

thanks for the help! Now I see it!

I will go this route and report back!

Thanks again,

Electron

As far as the PS is concerned, you can use two flat pack 120V - 9V X-formers, one feeding the other 120V - 9V -> 9V -230V. Thus you will get 230 - 230V on the secondaries. You guys from the US need to get a 230V - 9V X-former. I tried this on a homebrew Dumbleator and it works like a charm. You will...

Hi Bob,

could you please elaborate a bit more on the circuit you used?

I tried to find the mods by Gary to no avail.

I have one 12AT7 as a driver tube and one half 12AX7a.

Thanks in advance,

Electron

Given that the copper traces or on the upper side, tweaking is no problem even with PCBs. The end points of the traces should be rather large in diameter, to make tweaking easier. I found it MUCH more easy to tweak my Power Supply PCB than the eyeletboard. One could design the PCB in such a way, tha...

I would like to take it a bit further.... Look at what is happening at the SLO-clone forum. There seems to be a new design evolving from all the cloning, taking the strenghts and loved sound from the SLO but making it even better (hopefully a nice FX-Loop soon). For example the Double-EQ SLO. I thin...

Hi there,

I only know of 12BH7 being used as the post PI CF driving the grids of the output tubes. I doubt that Dumble uses 12BZ7

Electron

That is the amp. Silver alligator. The PI tube is a 12Ax7a. PI values are as in an ODS, Prescence knob is 5k though, prescence cap is 3.3uF. Iron: MM Power transformer (MusicMan). The CF after the PI needs a large negative voltage (bias) around -150V. Look at TUT for details on this circuit. Look at...

Indeed, the schemo I posted has the second EF86 wired as a triode. Only later on did I find out, that the second EF86 is wired as a pentode. The screen has a 0.1uF cap going to ground and a 680k resistor tapping of the B+ for the screen. Think standard Pentode stage. You have to omit the stage befor...

Up for Funkalicousgroove

@Funkalicousgroove, I am working on a schemo of it. Will post that. @Gary: now I see... Thanks for the fast reply. I plan on doing the following: 1 hole AT7 driving standard Fender Reverb tranny. 1/2 of 12AX7 being a CF driving FX loop. 1/2 of the same 12AX7 being the Recovery amp for the Reverb AND...

Hi Gary, I have a question concerning your Reverb mix schematic. Do you ground the 22nF PI input cap of your modified PI? If I understand it correctly, you take the signal from the Relais or Master Volume, then part of the signal is send to the Reverb input cap (550pF), the Dry is routed via the 100...

Hi there, so here is a bit of what a have. Please be reminded, that I can only share what I personally have found out. Some other stuff remains secret due to request. The SSS I had a chance to look at used EF86 tubes. The preamp used the same Tone stack values as most Dumbles (0.1uF, 0.047 Tone caps...