tech question re: amp

[Wayner]

Hey guys,

I recently picked up a used Hartke 3500 head to run through my 4x10 cabinet.

I'm not a technical geek, but sometimes the amp runs just fine, and then at other times, I turn it on, and get a loud hissing noise. You can hear a little bit of the bass, but it gets drowned out by the hissing.

I'm thinking there might be a loose connection somewhere inside the amp. Again, I'm not sure, so that's why I'm asking. Anyone have any idea what might be wrong here?

Thanks in advance!

 

[Munjibunga]

You might try replacing the preamp tube.

 

[basstrader]

+1 Munji

Try using the preamp out and power amp in jacks to see if it's in the preamp or power amp. Of course you will need another head. Also try the effect loop return, it's in adifferent place in the signal chain than the power amp input.