Tube Amp Archive

The ground. Thanks!

Got it straightened out

pdf64 wrote: ↑Sun Jul 14, 2024 8:25 pm Upload photos and videos to free sites (eg imgbb YouTube) and provide a link.
My guess is oscillation.

https://youtube.com/shorts/HWwBZlTn7fE? ... Unpfgyj8gx

1) Did this amp ever produce full volume, or were you just to the point of getting ready to start it up when you arced? If the amp has never demonstrated the ability to reach full volume, I’d look at touching up solder joints and andding a little flux along the signal path to V1, and repeat down the...

I tackled this build and have been trying to bring the background noise down. V4 & V5 have a persistent 60 hz signal that drops off when capacitance of the grid wire increases. If I touch the coupling cap from the PI to power tubes, the hum drops to an expected level. If another probe touches the gr...

Thanks for the quick responses! This forum rocks!

Has anyone done the 100 watt build with any of the suggestions, and care to elaborate on how you feel about the route you went?

I’m getting the last of my parts assembled to begin a 100 watt build based on 124. Could anyone guide me to a good source for the 300uF 350V electrolytic capacitors, as well as the 2kL pot for the presence control?

Thanks for the kind welcome. Today, I played with NFB resistor value, and increased the first grid stopper to 68k, after noticing that I couldn’t induce oscillation if I removed V1. I also noticed that when a guitar is plugged in, it’s becomes much less inclined to oscillate. IMG_8373.jpeg IMG_8372....

I’m a new lurker here, looking to learn as much as possible. I’ve built a few amps so far this year, and honestly never cared about the nuances of amps until I decided to expand my hobby / possible next career into amp building and design. I’m retired from the military (lost a leg in the process), a...