5E3 volume noise

[silverjet]

Hey

I have build a 5e3 clone kit, but when I use the vol on my guitar it is very noisy. I have tried with many guitars and it is all the same. I sounds like a bad pot or a pot that havent been used for a long time, it scrats.

Hope to be heard and helped

Thanks

[Chuck H]

It sounds like there is DC on the amps input. Try a different tube in the first preamp socket.

Chuck

[silverjet]

Hey

I tried few other preamptubes now, still same noisy volume scrat on the guitars. I´ve measured if the couplings caps is leakin, but no, that aint the problem.
On the input jack i measured 0,45mvdc that is normal, right?

Any suggestions

[Chuck H]

Can you post viltage readings for V1?

This seems really unusual. I can't even reason out what would cause a scratchy guitar pot other than DC at the input jack. Are you measuring for DC with a cable plugged in from tip to ring on the cable? With no cable plugged in you have a dead short.

It's possible that if V1's operating parameters are cattywhompus that the guitar volume setting is effecting that tubes bias causing DC artifacts to appear only during adjustment. But thats a guess.

Have you checked for DC riding on the chassis?

Chuck

[silverjet]

A bit strange, yes with this volume noise, I´ll measure the V1 tomorrow and post them here, maybe I will solve the problem, then I will for sure post the answer

What about the volume control on a 5e3, is there anything to do, to have a more linear sweep from 1 to 10, I think that all the range is from 1 to 3-4
2 is pretty loud. I uses a 500kA pot for volume.

I´m pretty sure that theres allready many 5e3 builders that has asked this question, so maybe a link would be fine

Wrock

[Enzo]

If ther is no DC blocking input cap, grid leak can cause a buildup of charge on the grid and reach the guitar. Even a half a volt can make the pots scratch.

[silverjet]

Hey Guys

I have solved the problem, I don´t understand why, by I desoldered the two 68k resistors that goes to the input, and solder them directly on the input jacks. Now no noise at all, really strange, maybe the resistor, when soldered to the board can pick up som static, that place some DC on the input, I don´t know.
It didn´t make any sence at all

Thanks you for posting replyes, I´m new here, but I can allready see that this is a good forum filled with good DIY´er

Silverjet

[Enzo]

Or the resistors were noisy and the heat of the solder work cooked some of the crap out of them.