The Amp Garage

Definitely a flavour. One I don’t like, but it is easy to try it out for yourself. Hang the 22meg resistor from mid pot to bus bar and it is easily replaced by a pot or smaller resistor. Dumble tweaked, revised, refurbished. We should do to. There’s a lot to be learned from these little experiments.

I installed a 1meg pot to do the partial lift and was surprised it had very little useable range. Meaning: I kept it in the first 25% of its rotation, mostly around 100k. Anything above it did not give much of an extra boost, but more compression and saturation. I ended up installing a 100k pot inst...

I can't deny the principle of supply and demand and the effect on prices that comes with it. But really, how much does this limit players buying Dumbles? There are roughly 293 ODS's not in JB's collection. Of those probably many are in other collections never to be shown or heard by the rest of the ...

I do not have any problem with his purchases and him showing it to the world. Even the 'why not?' is okay to me. Tone deaf would be giving a large party funded with public money in times where everybody needs to pay more taxes and cut expenses to make ends meet. We had that happen in our municipalit...

Thanks for explaining again. I went over the grounding sections of Morgan Jones' and Merlin's book. I also took a much closer look at the grounding schemes of the Peavey Classic 20 and 30 (as wel as some other models), the Blues junior and Vox AC15c1. They all do grounding different, but have some o...

That looks like a nice score! Are those transformers anywhere comparable to something you'd find in a JCM800 2204 of the same age?

Yeah, very different amps. He used the JM sig extensively a decade ago I think. I'm not a connoisseur when it comes down to JM gear, but remember seeing pics of the JM sig and Dumble SSS #002 together on stage. I suppose he was fully relying on pedals for driven tones when using those two amps toget...

Do you also have much more gain than expected? Maybe the 510p treble cap is shorted somehow? Or indeed no ground connection on the tone stack. Some pictures might help.

I don't understand what you mean, maybe because we're both not native English speakers. Do you mean the cathode resistor and bypass cap should go to the g2 filter cap? Or do you mean they should go to B+ (output anodes) filter cap? That is what the new PCB does. That is what Fender did back in '57 a...

I'm going to take a bit of a risk with this design. I'm not yet incorporating all feedback you gave me. If that is wise? Time will tell. I partly stick to the grounding scheme Fender used in their Tremolux. I've had great luck with ground planes in pedals and my hifi amps. Quiet, stable designs. Som...

Good catch! Main objective was to lower the gain a bit. Why? The power amp has much more gain than the LTP+CF combination. The windows started to rattle with the master on 1. The amp did lose its wilder side though. Local feedback made it even cleaner, which was not what I was looking for. It did br...

And the schematic minus all relais. I think this amp would benefit from a deep switch instead of a mid boost, though that is subjective.

No full layout. It's 90% SSS005 though.

Sure Roe! It's quite easy to try this one out. Different bias arrangement, like in an ODS and an adjusted dropping string. Really not much more to it. Fun amp for sure, sounds like a monster when overdriven and loud. Although I think it needs to be super loud to get the full potential.

Here's the bastard son of the 005 and Odyssey power amp.

No, that's a 9k1 tail resistor. But 10k would also work well. The PI bias resistor is 510 Ohm, but 470 Ohm also works. The amp is low on gnfb. I think that is a big part of the sound of 005: big, loose and spongy bass. I made an 005 with an Odyssey Deluxe power amp and it is a totally different amp....