The Amp Garage

So the goal is to match impedances and not to add flavour of the MOSFET? That means that you’d also have to match output voltage levels. A tube will put out much more voltage than the power amp would require. That would at least something i’d Investigate too. Secondly i’d Place the mosfet after the ...

The reworked half dumbleator and cathode follower would look like the top schematic in the next picture.

I think I could get away with a 100k bass pot on the HRM board at this point. Should give me a much more usable range, because currently it sits at 1 or 2 on a scale of 10, so 25k to 50k. The Opal is a mix between different Dumble topologies. Two Rock can claim they came up with their own designs ba...

Thanks ChopSauce, Edwin and Marcus. I always try to work neat Chopsauce, it prevents me from making mistakes and makes modding a lot easier. Also, working with pcb's makes it actually easier to work neat. Will post some more about the power amp at a later moment. It's currently not without its flaws...

Thanks Marcus! You should have seen my first failed attempts. After a couple of PCB's I got a feeling for etching, drilling, silk screening. When I get past the prototype stage I frequently order factory made PCB's. Made my whole pedalboard that way from a Deep blue delay clone to a Landgraff OD and...

I've been a long time visitor of the amp garage and based on the great information found here, I build a 2xEL84 Rocket reverb some years ago. That little amp is now my main gigging amp for small clubs and is great on its own when (turned up to push the output section) and as a pedal platform. Howeve...

I tackled a few problems: The input is quiet now. No more strange sounds when I plug in a guitar. The grid of the first tube is getting its ground reference and measured 1M from grid to ground which is good. The screens stopped glowing after replacing the 100r resistors for 470r's. The difference in...

hans-jörg wrote:Hello,
I would remove these small blue coupling caps. They give you a very hissy sound. Jm2c.

Hans-Jörg

Those are 500 pF ceramics. Albeit they give very little hiss, I might swap them. What would you suggest in these spots? Silver mica?

Given the noise when a guitar is plugged into the input and the high current draw on V1, I suspect that the grid of the input stage does not have a good ground reference; i.e. the 1M grid leak resistor does not have a good ground, or the input jack is not wired correctly. The reverb hum is somethin...

The last ones.

Almost there

More pics.

Hi, I'm Bas (pronounced as Buzz in English). Not a newbie on amp building, but no expert on Trainwreck amps too. I recently finished a 2xel84 rocket reverb based on the layout of Normster and have got a couple of issues with it: 1) The reverb hums a lot when turning up the reverb return pot (the one...