The Amp Garage

Thanks for the advices! The amp cover made it better in a great way with less hum and sensitivity. Changing tubes around I came to non microphonics combination. I also untied star ground and connected last three electrolytes to ground bus. Less noise, too. Still, there is "shrillness" and amp is too...

Shilded cable is grounded on volume pot,only one side.Oscillation is still there,doesnt matter if i press grid wire down against chassis.

Thanks to ya all! I've found oscillation in second triode of V1. I put ceramic cap 47 pF between grid and anode and I eliminated oscillation so far. But it showed bad for the tone itself. It is not organic. Do you have more suggestion? I would like to take cause of this away more than consequence. I...

Added 1n cap in parallel to 100k resistor in NFB and now harsh treble is gone.No oscillation, but for my taste is lifeless

Less oscillations,sound is too bright.Its sensitive when tach guitar strings-,less hum, like ground issue?

For now

I know,but det walue doesnt work

Hi again!
It's coming to sense, slowly but for sure.
How up shold I go with the resistors?
Now I have 220k at the input and 100k at volume pot

Little better

Thank you all.When i add grid stopper on first stage oscillacion become less.Stil persists on one side output stage,with or without plaget cable.Circuit material is textolit-izotex.

Thanks so far! I put all new tubes and they are not/should not be the reason for the hum and oscillations. I cleaned up the paint off the chassis where I attached the ground. I eliminated bright switch to lower possibility of oscillations since I am aware of its sensitivity. Pots are being isolated ...

Hi, this is my first Trainwreck build. Already built few Fenders and Marshalls and repair many. Tube only. I used Ceriatone layout just as a path to get to some point where I could continue on my own or with the help of the net. Metal chassis. Tubes' voltages are OK. The trouble is in oscillations a...