bypass amp speaker relay - OK?

kappclark

I have tried cleaning the speaker relay on my aging (20 years + ) Parasound amp, and it works for a bit, then the right channel gets weak,... so I removed the relay and did a bypass..

What an improvement in channel balance and stereo image..can't believe what I have been missing !

...I can't see how this would damage the amp - it sounds great now..

Did I do wrong ??

CoolJazz

The relay isn't there so much for the amp as for the speaker.

Muting the output, by the relay opening, is used to avoid the transients on power up and down and to allow the circuit to stabilize before connecting to the drivers. Those snaps, crackles and pops have a fair amount of DC in them which speakers don't do to well with.

Different types of rellays have different ratings for different circuit conditions. If the contact point builds up and gets less conductive, that's whrre the trouble starts. Some styles of contacts you can clean with special small abrasive strips...kind of like a file, but with those muting ones I'd have looked into some kind of contact enhancer. After that comes replacement...which would be wise to pursue in your situation I think.

Good luck!

CJ

kappclark

Thx CoolJazz...

The unit was serviced about 5 years ago, and he put 1 amp speaker fuses in...would these protect against the DC surge/pops etc if they were very strong ?

disneyjoe7

CoolJazz, has a point, and feel its best to put back the relay. So the question is how did you try to clean it in the first place?

kappclark

THX for reply

I removed the relay, used a matchbook cover to slowly clean the contacts..I may have used a bit of de-oxit. The right channel seemed to come back, and wouldn't suddenly drop out at low volumes..I did this cleaning once before..

Since I removed the $10 relay, there are no drop outs or signs of weakness, collapsing soundstage etc...I listen to mostly classical at low volumes, and never 'abuse' the equipment.

although the Parasound comes on now instantly, there is a turn-on delay in the preamp, so no sound for 5 secs..not sure if this helps.. also, the speakers outputs are fused inside the amp..

I know I might be rolling the dice here, as I am compromising part odf the design,....just not sure the risk is all that great..could I actually blow up my Monitor 60's listening to chamber music ?

CoolJazz

Sounds like you used a nice cleaning technique. Sometimes contacts can be helped and sometimes not much or for long. They can be frustrating when as you say, it gets iffy and you have annoying problems!

Sound delay through isn't so much the issue either. The design has the muting relays there for a reason. Without it you can pass ugly's at start up and power down, plus you may lack a failure shutdown if something in the amp goes really wrong!

As far as risk...I wouldn't feel to worried about using it bypassed while a relay was found and installed. You're already past the point of the first power up burst not frying a tweeter. But it simply isn't a good idea in the long run. Parasound is around and it should be possible to run down a replacement. Or look for the relay brand or form factor through a parts supplier like Digi-Key, Mouser or Allied Electric.

Good luck with it!

CJ