| ampage Tube Amps / Music Electronics |
For current discussions, please visit Music Electronics Forum. |
ampage archive
Vintage threads from the first ten years
Hum at volume 7, decreases at 10
:
 10/25/2005 7:49 AM |
|
| Stone | Hum at volume 7, decreases at 10 Hello I have a strange problem to one of my guitars (but to the others, too, but they are all wired similar). When I turn down volume, especially to 7, I got hum, very loud, also when using humbuckers. While increasing volume up to 10, the hum decreases and gets more silent. I have grounded the backside of the pots, wired all pickup ground connections to the pots backside. The trems ground connection is connected directly to the output jack. I am using strat style guitars, with 5way switch, but no tone controls at all. Any ideas? I think I miss something ... Regards, Stone |
|---|---|
| 10/26/2005 1:06 AM |
|
Steve A. |
Stone: What value pots are you using? This might not be applicable but one problem with using higher value volume pots is that you sometimes get hum when you turn them down to 7. The reason is that the higher value of the pot "floats" the pickup farther from ground... Another possibility is that you are creating ground loops, which will act like a radio antenna.  The classic example is a Les Paul, with ground wires looping from pot to pot in a complete circle. Bad wiring! It is better to break the loop so that there are only 3 wires going between the 4 pots.
So what do you do with the pot holes that would normally have tone controls? If you are going to omit a tone control I would at least add a resistor and cap to ground to load down the pickup a little bit. Maybe 270k -470k for the resistor and something like 0.022uF for the cap. To the guitar and amp it would look like a tone control set to 10 (which is the normal way of things...  )
Steve Ahola P.S. You might want to look at the guitarnuts site for ideas on how to modernize the grounding scheme for a strat. |
|---|---|
| 10/26/2005 1:58 AM |
|
| Stone | Hi Steve Thanks for your advice. I think I have to check and rewire the ground connections. Currently the ground "between" pots and trem is shaped like an "Y" looking from the output jack. I am using 250k and 500k pots. Depends on what the manufacturer recommends. Regards, Stone |
|---|---|
| 10/26/2005 9:30 AM |
|
| Steve A. |
Stone: Hmmm... or should I say "hum"? What is most perplexing is that you said all of your guitars exhibit this behavior (and with humbuckers)... have you tried different amps? Steve Ahola |
|---|---|
| 10/27/2005 10:25 PM |
|
| Stone | Hi Steve Hm ... how could I explain it? I am using Strat-style guitars, built by myself. So every guitar has the same wiring (nearly, with respect to the pickups), which may cause to fail every guitar when there is an error within the wiring. I have used different amps, cables, and so on. Nothing helps, except using a wireless system, so I believe I have a ground loop or something like that, but I cannot detect it - I think I have to strip down one of the guitars and check it over and over again. The guitarnuts site helps a lot and gives some good advice how to shield. Yesterday I found out, that one of my small power supplies (which supplies the Midi Footer) causes a lot of hum. Now I only have got a little "bee swarm" in it. It is not so noisy at all and I think comes from a ground loop or somethin like that. Yes, we have neon light within the practice room, but it does not matter if I switch it off or not. Sorry, should have added this information first ... Regards, Stone |
|---|---|
| Page 1 of 1 |