Amplifier issue

[donparsons]

I finally got around to setting up a pair of the sound advance outdoor speakers aimed out at the pool (just in time for "winter")

I have the output from my sonos zone player going in to a Soundcraftsman A2801. In June I used the same amp to run a pair of speakers in the same spot and everything worked fine.

Today I get very low level treble and no bass out of one channel and the other channel is fine. I swapped speakers sides and I get the same result so it is definitely the amp.

Any ideas? TIA

[curt_c]

Re: Amplifier issue

Sounds like a coupling cap has gone bad....

C

[donparsons]

Re: Amplifier issue

Sounds like a coupling cap has gone bad....

C

If I open the case am I likely to see evidence?

[AJ]

Re: Amplifier issue

Possibly, if it's an electrolytic cap. It might be bulged and/or leaking.

[curt_c]

Re: Amplifier issue

If I open the case am I likely to see evidence?

Only if you are looking for clues at the scene of the crime...:D

Electrolytics tend to dry out, and as they dry out they can lose capacitance. As we know from crossover HP filters, a small value cap will not pass bass frequencies. Hence my suspicion that a cap is the perpetrator of this crime.

The Unsub may not have left any physical evidence behind, but if my suspicions are correct, you can bring the perp to justice by simply replacing the electrolytic caps in the amplifier signal path.
–Replacing all of them, including the power supply caps isn’t a bad idea either. Most of the caps will cost pennies each to replace and a couple of hours with a soldering iron. This is a common practice with those of us who own ‘legacy’ equipment and refer to it as recapping.

Other suspects might be the speaker relay contacts (assuming it has them) and any switches or pots in the signal path. -If it moves, shoot it! (with some Deoxit.)

Otherwise, this may be a task best left to the BAU, -or at least a qualified service tech.

C