Tube Amp Archive

I used a coping saw for my first build. It took some time, some blades and it's not very accurate. But it did the job. Cheers
Gerhard

Garveyte01 wrote: ↑Sat Mar 01, 2025 3:35 am So I reworked my bias pot connection and I have about-35 dc volts on my control grid, but I’m still getting severe tremolo (fast oscillation) and from what I can read on my current limiter it is drawing 30 volts to ground

You might have to swap the OT primary connections.

Hello, I stumbled over a recent show from Carlos Santana on Youtube. No Boogie at front, but an ODR. Looks like #60 CarlosSantanaDumble.png ODR 0060 and ODS 0204.jpg Video: https://youtu.be/3Q1s4ahmxY0?si=XNpRvyuF0juxIARg Didn't know he owned that one. I know, he is using Dumble amps for a long time...

I've built a #124. Works great with both. Lots of clean headroom, even with high output humbuckers. Great thick overdrive, without getting muddy. And very versatile, too. It can make a Tele sing.

martin manning wrote: ↑Tue Sep 17, 2024 5:44 pm Why? As the filter circuit is understood here, the inductor has no audible effect.

I can approve, you filter design works perfect (after I cleaned up my mess). No need to add an expensive snake oil device

Which VOX? I think you are looking at the AC15/30 design. But then there are different iterations of these amps too, which are quit different. Most Dumble amps are based on Fender circuits, and there is nothing I know about, that has a EL84/6BQ5 cathod biased poweramp section, nor an EF86 preamp sta...

martin manning wrote: ↑Thu Mar 21, 2024 5:37 pm Very nice! Adding the FET boost was worth the trip, eh?

It's a nice feature, and prevents me from leaving an unused jack in the amp.

G.

Here is the final result: IMG_20240321_114524.jpg IMG_20240321_114550.jpg IMG_20240321_114600.jpg I finished the FET boost with relay switching: IMG_20240321_114600.jpg There was a diffrence between Martins drawings and what I have done with Erwins relay board, NO2 and COM2 needed to be switched aro...

I just finished my #002. I must say, if you leave the reverb out, you miss a big highlight of this amp. The reverb is one of the best I've ever heard in an amp.
But I'm a reverb hound and if you're not, leave it out.

Cheers
Gerhard

I buttoned it up for the first time.
Cheers
Gerhard

If you need schematics, layouts etc. for an SLO have a look here:
https://drive.google.com/drive/folders/ ... sp=sharing

Feel free to contact me, if you have further questions.
Cheers
Gerhard

https://www.reichelt.nl/nl/nl/jfet-s-c8417.html?r=1 Very suitable as audio input amp. Low noise, low bias, high transconductance In my own amp i used this one: https://www.reichelt.nl/nl/nl/transistor-2sk-30-2sk-30-p2181.html?r=1 yet I found some 2N4416A in my stash. I don't know the source, from w...

martin manning wrote: ↑Wed Mar 13, 2024 4:47 pm I guess what you were saying is that you have 12VAC available for a relay power supply.

Yes. But there is nothing that holds me back to put an additional regulator and electrolytic to step down from 12 to 9V for a booster. Or is there something I've missed?

Raja_Kentut wrote: ↑Wed Mar 13, 2024 4:03 pm look at reichelt.de… they offer some in TO-92 package, real cheap enough to try some of them if they suit your taste…
Search for „jfet“ on their site, than narrow down to „N“ type

No 2N4416A there...I can order some other types, stick them in and look what happens...

I have a 12V tap left on the transformer, so I'm not bound the FET or the LND boost. Not quite sure what you mean there, but if you have a 12VAC source then you will need a rectifier and filtering to make that usable for a transistor boost. The Dumble JFET or the LND boost could be powered from B+5...