Quiet sound from Hi Fi

[Racefan_uk]

Folks some technical input required!

I've dug an old Technics Hi Fi system out of a cupboard as a friend may want to borrow it this weekend for a party. I've got out the amp, CD player and the graphic equalizer and I've got a signal going through it, but I need to have the volume cranked right up on the amp to hear only a very low volume signal coming out through the speakers.

It sounds like the amp is in 'mute' mode, if you know what I mean, but it's not as I checked that and when I put that on it goes, well, mute and even lower in volume.

Any ideas what it might be? Or would the general opinion be that the amp isn't right anymore?
One other thing, I get the same level of volume if I try headphones directly in to the amp too.

[koenig999]

CD output plugged into phono (record player) input?

Koenig

[Racefan_uk]

No, it's definately into the CD input. I've event tried it on the Aux input and used that from the amp, but I get the same thing. It's weird, it was fine when it was stored away.

I'm getting the sound out of the speakers, but only at very low volume, when the amp is cranked right up to the maximum. Very weird.

[miniman]

Is there a Tape monitor / DAT monitor switch? Try pressing it. My amp has one, and if one presses it with no tape deck connected it cuts the sound off.

[Racefan_uk]

Nope, nothing like that, it has a switch to alternate between A & B speaker settings, but I've got both speakers on the A outputs and the sound is there, just not at the volume I'd like it to be!! lol

[Graham E]

Check the CD doesn't have a mute - some technics ones do.

To test amp, run another signal in, or just ground the inner phono to outer with your finger, should get that lovely "bad earth" noise. If you don't, fiddle with it till it works, or declare it knackered and buy something nice new and shiny with good justification.

[Racefan_uk]

I'm getting a signal out of the CD player, as the equalizer starts bouncing up and down as soon as I hit play.

It's like the amp just isn't trying. My guess is, it's buggered! Damn it.

[Graham E]

try the b outputs, and switch to speakers b?

[OldSkoolRS]

Have you tried the headphone output (if it has one) as this will confirm everything upto the power amp stage (unless the headphone circuit is driven by the power amp via resisitors as some are/were)? Have you another pair of speakers to try incase the damp has got to them and (partly) shorted out the coils? Another possiblity is that there is a strand of speaker wire shorting across the speaker terminals (like driving with your handbrake on ).

There are many possibilities, but some may require opening the amp to check/fix, at least some of the above might get you started.

[bogwoppit]

I would imagine opening an amp might be dangerous, I expect there are some big capacitors in there?

[cjs]

I would start by getting rid of the Graphic EQ, take it out of the circuit. This will eliminate it as a problem.

[gbbird]

Have you checked the speaker wiring? Sounds like you might have the L & R mixed up.

[OldSkoolRS]

bogwoppit said:

I would imagine opening an amp might be dangerous, I expect there are some big capacitors in there?

Yes, I wouldn't recommend it unless qualified, merely suggesting that my intial checks might pin down the fault without having to open it up, but beyond that may require it.

Swaping the left and rights shouldn't reduce volume, only reverse the stereo image.

Agree with the removal of the graphic eq as well.

Edited by OldSkoolRS on Friday 4th September 09:30

[Racefan_uk]

I'd added the GE in after I'd already tried it without and had the same result, so I think I can rule that out as the cause. I gave it up as a bad try last night. However, I'll try the same CD player and speakers with my other amp later and see if that works. If it does, then I'm thinking that the amp itself might not have liked being in the cupboard for the past year or so. Bit of a shame as it's a half decent one too.