croft pre problem

[wee tee cee]

My son runs a croft pre/power set up.

the pre has a single motorised volume pot.

it is only putting out treble in the left channel with no bass and is crackling and popping

he has tried changing the valve but it made no difference

we will try different interconnects tonight just in case

any ideas folks?

[Firebottle]

Could be a failing coupling cap from the description.

A quick check of circuit voltages would point in the right direction.

[wee tee cee]

Thanks Alan,
Would that be expensive to put right?

[Firebottle]

No if that's all it was.

[mikeyb]

Thanks Alan,
Would that be expensive to put right?

Spoken like a true Scot

I can see the beads of sweat from here

[wee tee cee]

tried to sort things out last night....we were both a tad pished.

might have killed the power amp as well.

much wailing and knashing of teeth.

[Primalsea]

Oh no! Hopefully not the case.

Could also possibly be a bad solder joint in the preamp on the left channel. Normal procedure is to measure voltages and components, comparing the good right channel to the left. Also prodding the circuit with a wooden or plastic dowel. If it is a bad joint a prod in the right place will recreated the pops and cracks you mention.

Generally it’s better not to work on HV valve circuits while under the influence

[wee tee cee]

Got the power amp working again had blown 2 out of three of the fuses.

My son will e mail Glen Croft to see what he can do.