high volume hum!!!!

[Gasgreg]

I built a Weber kit amp based on a Fender Deluxe Reverb. This amp has great sound, but has a hum that increases with the volume. If I touch the mounting straps or screws, the hum reduces about 80%. Any suggestions? It seems a little worse now than when I finished it a year ago.

[Chuck H]

If you have changes to single coil pickups, that would explain the change from then to now. The fact that when touch chassis grounded parts the hum reduces is reason to think there may be a grounding issue with your guitar or amp. If your guitar and amp are grounded properly you should get the same hum reduction when touching the strings on your guitar. Which is (hopefully) what is happening when you play your guitar!?! So, if not, I'm thinking there may be a ground fault somewhere.

[Enzo]

Does it do this with nothing plugged into the input?

Have you plugged the amp in somewhere else? Your house wiring could have a missing or mis-wired ground.

[Gasgreg]

high volume hum!!!!

If you have changes to single coil pickups, that would explain the change from then to now. The fact that when touch chassis grounded parts the hum reduces is reason to think there may be a grounding issue with your guitar or amp. If your guitar and amp are grounded properly you should get the same hum reduction when touching the strings on your guitar. Which is (hopefully) what is happening when you play your guitar!?! So, if not, I'm thinking there may be a ground fault somewhere.

I just tried 2 guitars that I built,and an Epiphone Sheraton II. One with Bill Lawrence single coils, and the other with Seymour Duncan Humbuckers, and the hum reduces significantly with the guitars plugged in, and laying my hand across the strings. When unplugged, the hum increased, but when touching the chassis mounting straps, it reduced quite a bit. The Tele with Lawrence single coils is completely shielded, and the difference in hum between guitars is almost nil. With only a cord plugged in, it increased, and there was a considerable difference between a couple of fabric covered Fender cords, and a coiled cord I had laying around... I think I may have to pull the chassis, and double-check all of my grounds. I appreciate the input...............Thanks..

[Gasgreg]

Does it do this with nothing plugged into the input?

Have you plugged the amp in somewhere else? Your house wiring could have a missing or mis-wired ground.

I haven't tried plugging it in elsewhere.... This may be my next thing after checking my ground circuit onthe chassis. Thanks for the input....

[loudthud]

There have been reports of problems with the input jacks that Weber supplies. Most of the time the contacts on the switching part of the jack are not making good contact. Another possible problem is the jacks not making good contact with the chassis. Clean the contacts with a spray cleaner like Deoxit and make sure the jack nuts are tight and there is no corrosion between the jack and chassis.

[Gasgreg]

There have been reports of problems with the input jacks that Weber supplies. Most of the time the contacts on the switching part of the jack are not making good contact. Another possible problem is the jacks not making good contact with the chassis. Clean the contacts with a spray cleaner like Deoxit and make sure the jack nuts are tight and there is no corrosion between the jack and chassis.

I'll check this when I pull the chassis.... I know that there are many parts supplied with Weber kit that are not of the highest quality, but as a starting point, no other kit is even close price-wise... My project was way out of my league to begin with (it was one of the most complex kits), but taught me a lot. I'm not sure that i could have bought a better sounding amp than this for twice the money....

[loudthud]

No question Weber kits are a good value. I'm assuming you used their layout : https://taweber.powweb.com/store/6a20_layout.jpg

How did you make the grounds to the eyelet board that are shown between the board and the pots? Did you use a brass plate between the pots and the chassis?

[Gasgreg]

Yes... The kit came with the brass plate. I was going to solder a wire from the pots to the plate, but was afraid of forming a ground loop, but it seems that I've done just that somewhere in the circuits. I liked working with Weber's layout, although a little instruction manual with a few do's and dont's would have been handy. I'm sure their kits are designed for the more seasoned veteran, but at the same time, the vet would use several much better components. It's wierd that they use extremely good resisters, yet such poor quality tubes, pots,and jacks.

[olddawg]

Yes... The kit came with the brass plate. I was going to solder a wire from the pots to the plate, but was afraid of forming a ground loop, but it seems that I've done just that somewhere in the circuits. I liked working with Weber's layout, although a little instruction manual with a few do's and dont's would have been handy. I'm sure their kits are designed for the more seasoned veteran, but at the same time, the vet would use several much better components. It's wierd that they use extremely good resisters, yet such poor quality tubes, pots,and jacks.

Resistors are inexpensive compared to pots and jacks. There isn't a huge difference in price between cheap and quality resistors. But they can really increase their profit margin by skimping on pots and jacks. Btw, if you use a shorted plug on the input do you still have hum?