Tube Amp Archive

Thanks !!

It was the selmer schematic which was not a good choice. I just adapted the tone and volume schematic of the Fender 5F2 and now everything works perfectly.

Thank you very much, and maybe see you for a next amp project !

Hi everybody !

I finished my custom amp, and it sounds great! Volume, tone and negatif feedback knobs all work perfectly.

I would like to thanks you for the thread and for your responses.

Here few pictures of the amp with my home made guitars.

Enjoy !

Yes it is working fine do I did not measure all the voltages. Really nice sound ! I just have a main problem with the tone pot. I did like on the selmer schematic but it does not do anything when I use the tone pot. Just at the end, it decreases the general volume. It is really strange. I tried to a...

Hey I did few measurements of voltages : EL84 : Pin 3 : 8,3 V Pin 7 : 255 V EZ 80 Pin 1 : 228 V Pin 3 : 270 V Pin 4, 5 : 6,4 V Pin 7 : 230 V What do you think about these ? I also measured the voltage across all my caps, and all of them display something between 70 and 250 V excepted my 100 uF cap o...

I did not found any wiring error..=( Yes it was almost impossible to solder on screws !! The tin did not stick to it ! Yes, I really thing, once all my improvments done, to do again the wiring with new wires and with a nice layout. I would like to add a Negative feedback loop like "Uncle doug" did i...

Great ! I'll do that !

I will post my different voltages later !

Do you have an idea for my tone pot problem ?

It works !!!!!!! No 50Hz Hum, but few little sound cracths while attacking a bit more on strings. Idea ? Actually the big problem was on my output tranformer !! I shorted it while I plugged the central pin of the primary on the ground ! It is not supposed to be connected. I thought that it was a kin...

Ok for the common lead, I'll do it. I checked again my wiring, it fits to the schematic. You did not tell me what you think about the 47 V DC across the pin 3 and the ground of the rectifier. Is it enough to load the caps ? What I really can not understand is why these caps are not loaded as I have ...

Yes I read 133 ohm across pin 3 and ground of the rectifier socket while the rectifier is out. So wiring error ? I do not know if it is related to my problem : -About the output transformer, I see on the selmer schematic that the secondary wiring has no wire connected to ground, but when you have a ...

Okay, I read 238 V AC across pin 1 and pin 7 I read 47 V DC across pin 3 and ground. My center tap is grounded yes ! I have to precise a little something :oops: When I say that the radio worked, it was not exactly as easy. Actually, the radio lighted on, but I did not received any broadcast, there w...

I just tried to power on without the 12ax7 and without the EL 84, and I had exaclty the same results.

Hum and stop !!

Yes I used the selmer little giant mk3 shematic of the beginning of the topic. The tubes come from an old radio and the radio worked before unmounting it. So I deduced that the tubes was OK...maybe it is a first mistake. The output transformer is the one bought on ampmaker, therefore the only techni...

Hi everyone !! javascript:emoticon(':D') Let's first introduce quickly myself ! I am a 24 years old french musician located in Toulouse, who built 3 electric guitars and I am now going a step forward. Indeed, I am building my own Selmer Little Giant mk3 using parts from an old tube radio (Radialva s...