Metropoulos Forum

When the tone knob on my 5e3 clone is set at anything greater than 7 I can hear a "white noise"/shhhhh sound as soon as the volume knob for the bright channel is turned past 2. The hiss gets louder as I turn the volume knob. No matter whether a guitar is plugged in or not. Here's a short video to demonstrate the hissing : https://www.youtube.com/watch?v=BYI_41DYOh0" onclick="window.open(this.href);return false;

What I've already tried:

Removing V1 (12ay7) (v2 still plugged) -> hiss is still there but slightly lower.
Removing V2 (12ax7) (v1 still plugged) -> hiss completely goes away.
Exchanging V2 with another tube -> almost no difference.

All resistors carbon composition. Any ideas ? Cheers.

Dear Belf. Did you find a solution? I have the same issue..

Regards,
Gabriel

Try lifting one leg of the bright cap that is soldered to the bright volume pot. Just unsolder one leg of the cap and then listed to the amp. Many times I have found that the bright cap will add considerable hiss to the circuit. Is yours ceramic or silver mica?

danman wrote:Try lifting one leg of the bright cap that is soldered to the bright volume pot. Just unsolder one leg of the cap and then listed to the amp. Many times I have found that the bright cap will add considerable hiss to the circuit. Is yours ceramic or silver mica?

I don't have the amp right now (I am on the job), but is a Ceriatone 5E3, I think it is exactly the same than this: http://www.ceriatone.com/images/complet ... bo/b3B.jpg One is 500pF, the other one 0.0047uF. What you are saying has complete sense. Also, the bright channel has random noises, proportional to the volume increase, like small discharges. It sounds dirty, but is not loud enough, I can play anyway on this channel.

The bright cap allows higher frequencies to bypass the volume pot. Occasionally this will create some extra noise. I have found from experience that some caps can be a little noisier than others in this position.

Make sure the heater wires are correct. So make sure the same wire that goes to pin 2 goes to the next pin 2 and so forth pin 7 to pin 7, pin 45 and 5 to pin 4 and 5, pin 9 to pin 9 etc.

The amp was sounding well, this issue is quite new, but it is not loud enough. Thank you for the help