The Amp Garage

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...

martin manning wrote: ↑Wed Mar 13, 2024 11:42 am
What have you got planned there? What FET, Vdd, and bias?

I have a 12V tap left on the transformer, so I'm not bound the FET or the LND boost.

martin manning wrote: ↑Wed Mar 13, 2024 2:34 pm Can you get 2N4416A? Mouser carries that one, should be fine for traditional D FET boost.

Yes but 20 bucks for the delivery. No way...

What have you got planned there? What FET, Vdd, and bias? I'm not sure yet. The suggested transistors for the original FET are hard to get and expensive. There is a project in a German DIY tube amp forum called LND Boost, which is very promising. https://www.tube-town.net/ttstore/en/lnd150-boost-fo...

Roe wrote: ↑Wed Mar 13, 2024 7:09 am we need a new clip!

Just very quick, this time with humbuckers
https://photos.app.goo.gl/ZnWGDBBf58YuEi4y9

Fantastic! I think we've all been there before... ;^) Hey Martin, after some further testing, I really dig the step filter with your configuration. I mean, I have no comparison to the original one, but this is excellent for shaping the tone to different cabs/guitars etc. The amp works really great ...