Hartke HA3500

[Carlosraj]

Hi


I have another issue with this amp. The amp is functioning alright, it is only when I turn on the "EQ". This is constant crackling and popping noise. I have replaced all the electrolytic and non electrolytic caps and the ICs as well in the EQ circuit, but the noise is still there. Can it be due to the EQ faders or can dry joint cause this problem. Please assist.


Thanks

 

[Carlosraj]

Attached schematic. Please note that the attached schematic is slightly different from the actual amp. This amp uses TL074s for the EQ circuit.


Thanks

 

[JMFahey]

Can it be due to the EQ faders or can dry joint cause this problem.

yes, or switch itself, or connectors, or crcked joints or ... or ... or ...

The Scope is your friend.

We can only guess.

 

[Carlosraj]

The problem was due to DC leakage. The voltage for the EQ fader LEDs was entering the signal path thru the faders.



Thanks