Question for hifi guys, left channel going quiet.

jonnyburgo

Tried two turntable through my charity shop Sherwood amp, after a while the left channel starts going quiet and thin sounding, the same through both A and B speaker channels. If I switch the amp off and on again all is good for another 20 mins or so then it happens again. Any ideas?

Snap

I think it might be the cartridge connection on your turntable. I had this on mine, fannied around with the connectors and it sorted out. Did some reading and the consensus was that this is a known thing. 

Jalapeno

jonnyburgo said:

Tried two turntable through my charity shop Sherwood amp,

Or this might be why it was in a charity shop

- thought the H&S mafia had done for s/h electrical goods ....

viz

Snap said:

I think it might be the cartridge connection on your turntable. I had this on mine, fannied around with the connectors and it sorted out. Did some reading and the consensus was that this is a known thing. 

Same - I tried everything including swapping my ears, in the end swapped the cart out and it’s fine. 

crunchman

Do you have a CD player or tuner?  If you do, does it do the same thing on those?

jonnyburgo

Snap said:

I think it might be the cartridge connection on your turntable. I had this on mine, fannied around with the connectors and it sorted out. Did some reading and the consensus was that this is a known thing. 

Ive tried it with two different turntables, same results, I dont have a cd or tuner to check with

jonnyburgo

Jalapeno said:

jonnyburgo said:

Tried two turntable through my charity shop Sherwood amp,

Or this might be why it was in a charity shop

- thought the H&S mafia had done for s/h electrical goods ....

yeah possibly, Ive had a good couple of years out of it for £10 though!

randella

crunchman said:

Do you have a CD player or tuner?  If you do, does it do the same thing on those?

This was going to be my next question.  Even a lead that converted a headphone jack to 2x phono would do, then you could try it with your phone.

I had an old Denon amp which did exactly as you describe, but I never got to the bottom of it - sorry.  I just put it down to a failed power transistor on one channel, and very luckily inherited a rather nice Technics amp at the same time.

I'm not going to page the resident amp guru as I don't want to mither, but I wonder if he does chance in here, he might have an angle?

exocet

When the left channel disappears - have you tried flicking any input source selection switches (where you select Tape / Aux / Phono) etc. My old Cyrus amp had dirty switch contacts that caused a channel to disappear in this instance switch cleaner sorted it.

ICBM

If it's consistently after 20 minutes and turning it off resets it immediately, it sounds like a faulty component causing a DC voltage to slowly build up until a gain stage becomes biased to cutoff - probably caused by a failing electrolytic cap.

If that sounds like a pain in the backside to troubleshoot, it probably is - the easiest way is to change every electrolytic cap in the thing, but there are often rather a lot in hi-fi amps... and even then it might be something else.

robgilmo

Had this problem with my old Pioneer amp, turned out there was a faulty speaker terminal, but if yours happens on both A and B it might not be that. First thing I would do is take a look at all the connections , in and out , make sure they are clean, when its working , give them a wiggle. It does sound like an internal fault though.

jonnyburgo

Cheers guys now I don't want to tempt fate but o. The front is a "direct" button that bypasses the controls and gives a signal that can be controlled with the volume, I switched that on and then off a few times and it's been good for the last 30 mins or so. Hmm, we'll see

robgilmo

That direct button bypasses the tone and balance controls, could be a dirty pot , switch, or something in the tone controls circuits, could be a dirty balance pot.

fretmeister

Is one of your ears full of wax? 

Kittyfrisk

Hi @jonnyburgo ;
Hope you get things sorted.
In case you don't & are looking for an affordable solution, I have a working (when retired) Sherwood Newcastle R-125 that you can have for free. The only issue is that the P&P might be more than it's worth 
Comment away 

jonnyburgo

Kittyfrisk said:

Hi @jonnyburgo ;
Hope you get things sorted.
In case you don't & are looking for an affordable solution, I have a working (when retired) Sherwood Newcastle R-125 that you can have for free. The only issue is that the P&P might be more than it's worth 
Comment away 

Thanks mate that's a very kind offer, it's working fine now but if that changes Imay be in touch!

randella

All's well that ends well, then.  I was miffed when that Denon of mine packed up as it was a great-sounding amp, but the Technics that replaced it is better.

Now on to the next conundrum - I bought a CD the other day before realising I no longer have a CD deck.

Can you cure stupidity by replacing old electrolytic caps?