MTX 4002

[S Merlington]

If i turn the gain or crossover pots up this amp makes the speaker flutter like crazy..

Any ideas? Maybe bad pots?

 

[Perry Babin]

Possibly but that generally causes more of a crackle than than a flutter (assuming that the amp isn't set to low-pass).

Do you have excessive DC on the output pins of any of the op-amps?

 

[S Merlington]

On Pins 1 and 7 of the TL074C I get -0.16 volts So no real DC on the output pins ..

Pins 8 and 14 rest at 0.00 volts

If i turn the Pots down the DC on pins 1 and 7 drops to 0.00 volts

Also when i turn either the gain or crossover pot up with a speaker connected the amp will start drawing excessive current

 

[Perry Babin]

0.16v is enough to cause the amp to push the amp nearly to clipping.

What happens if you connect the shield ground to the amp ground?

 

[S Merlington]

No change when i connect the rca shield ground to the amps ground

 

[Perry Babin]

Do any of the op-amps have more than about 0.005v difference between the two input pins for each section? Place the probes directly on the two input pins for each section.

 

[S Merlington]

No All remain at 0.00 volts

 

[Perry Babin]

Post a photo of the inside of the amp.