The Amp Garage

Sorry nicosci for the delay with which I reply but I have not followed the discussion until now, I was very curious about Rayan's study and I built the fourth JM :-). There are many studies posted on TAG, many diagrams and in each one there are different components so I used them all comparing them ...

Hi Lovetone,

can you please send photos of your amplifier, possibly in high resolution.

Franco

Thanks Erwin,

I await your communication.

Franco

New run 2023 is in the making: chassis are made and ready for powdercoating and screenprint Hi Erwin, I'd like to build a #94 and I'm looking for a chassis and boards, I could build them starting from a glassnite plate and a Tubetown chassis but.....it's a huge effort :-). Do you still have the cha...

sergio wrote: ↑Thu Jun 29, 2023 1:02 pm At mouser you can found vishay resistor 1ohm 1% 3w

Grazie Sergio, Devo comperare altre cose e aggiungo nell'ordine queste resistenze.

Un abbraccio. Franco

www.reichelt.de is a good source for e.g. resistors. They offer 0,1% tolerances (should be more than enough for this purpose) I generally use 5%/2W Metal Oxide for safety margin. I always measure them before I solder and the tolerances are generally much tighter than 5% their pricing is very reason...

Hi Bepone, Erwin_ve, Martin, Thank you all, everything you wrote is very true. I was caught up in the "mission" of doing the right things as much as possible that I forgot the reality. There's a lot of talk on TAG about how the sound of an amplifier changes if I choose a type and brand of resistor o...

Thanks Martin,

finding 1 Ohm resistors with 1% accuracy is not possible through my regular suppliers in Europe, Tubetown and Tube Amp Doctor.
I found them at Mouser but I have to prepare a larger order.

Franco

Adjust BIAS on Dumble amps hello everyone, what I am making is an observation and my intention: I adjusted the bias of the final tubes in the amplifiers by adjusting the potentiometer placed on the chassis and checking how many volts are present across the 1 Ohm resistor installed between the pin n°...

Hi Rootz and Dorrisant,

you are certainly right not to invade the field of builders who live from their work but at least..... where one can do deeper research on the original #005 Dumble or AN or HPD than has been possible up to now ?
Thanks, a hug.

Franco

Interesting, indeed! Would you mind posting a link to which schematic and layout you used? 8) I used the one from the Dumble files section, look for #102, exactly as it is except for it being 50w, having a power Transformer wound with a extra secondary for the relays, and using a OT with 4-8-16 oh ...

Hi folks, but no one has thought of a simple 1Mega potentiometer as in the Dumble projects? A hug. Franco In higher gain amps you get some of the distortion from the PI itself. If you use the single-gang volume pot prior to the PI you will loose this. A dual pot with sections for each of the PI out...

Hi folks,

but no one has thought of a simple 1Mega potentiometer as in the Dumble projects?

A hug.

Franco

Hi ijedouglas,

really many compliments for your work, each one of us has his own tastes in music so I'm waiting for your demo.
Thank you.

Franco

Hi Stephen1966, I'm following your construction and your experience with the Choke. I need to ask you some questions (which demonstrate how little I know about this fascinating matter :D ) the DMM outputs are in parallel with the OUT outputs, maybe two holes and two bushings on the case can be avoid...