Strange problem with stereo receiver.

[yepimonfire]

First off, this thing is old as dirt, so IDK if it's worth trying to fix it or just get a new cheapo, but this issue posted in the video does it when either turning the volume down or adjusting the balance, only happens to the left channel, the sound coming out of it is fuzzy, and some internal protection circuit flips when you hear the pop. All analog volume and balance controls. Dirty POTS or something else?

 

[markw]

Offhand, I'd say it looks like DC making it's way to the speaker. That's an amp problem.

 

[Seth=L]

Agreed, don't keep doing that. You run the chance of burning up the voice coils in the speakers.

Probably not worth repairing.

 

[TLS Guy]

Agreed, don't keep doing that. You run the chance of burning up the voice coils in the speakers.

Probably not worth repairing.

The only thing that will do that is DC offset. However since it happens when you use the volume or balance, then there must be something in the volume control circuit that is creating DC. Most direct coupled output stages will amplify DC. The protection should not only shut the amp down but disconnect or short the speakers. It looks as if in that old receiver it just shuts the receiver down eventually, but does not instantly protect the speakers.

This sort of thing is very damaging to speakers. I would think more likely than not you already have some shorted rings on the speaker voice coil.

Before you buy and new receiver, (and don't buy a cheap one, they are junk) check the DC resistance of the drivers in the left and right speakers. If the left DC resistance of the left bass driver is lower than the right, then the speaker needs reconing before you connect a new receiver, or you will blow it.

You will need to remove the drivers to make these measurements.

It is vital you do this before connecting a new receiver to that speaker.

 

[Seth=L]

Before you buy and new receiver, (and don't buy a cheap one, they are junk) check the DC resistance of the drivers in the left and right speakers. If the left DC resistance of the left bass driver is lower than the right, then the speaker needs reconing before you connect a new receiver, or you will blow it.

You will need to remove the drivers to make these measurements.

It is vital you do this before connecting a new receiver to that speaker.

At this point the OP may as well replace the speakers as well, regardless.

 

[Jay aLBERS]

Cool ! I've never seen a speaker that could do 1htz.

 

[highfigh]

Cool ! I've never seen a speaker that could do 1htz.

They'll all do 1Hz. Won't like it, but.....

Someone came into the stereo store where I worked and asked "Will these speakers handle 200 Watts?". The other sales guy answered, "200 Watts? Sure! They'll handle 200 Watts. Once.".

 

[markw]

Cool ! I've never seen a speaker that could do 1htz.

Actually, it's closer to zero hz.

 

[Seth=L]

Cool ! I've never seen a speaker that could do 1htz.

I used to have a tone generator that did 1 Hz. All it did was make the woofer move really slow. No sound was obviously produced.

Someone came into the stereo store where I worked and asked "Will these speakers handle 200 Watts?". The other sales guy answered, "200 Watts? Sure! They'll handle 200 Watts. Once."

I've told people stuff like that before.

 

[yepimonfire]

The only thing that will do that is DC offset. However since it happens when you use the volume or balance, then there must be something in the volume control circuit that is creating DC. Most direct coupled output stages will amplify DC. The protection should not only shut the amp down but disconnect or short the speakers. It looks as if in that old receiver it just shuts the receiver down eventually, but does not instantly protect the speakers.

This sort of thing is very damaging to speakers. I would think more likely than not you already have some shorted rings on the speaker voice coil.

Before you buy and new receiver, (and don't buy a cheap one, they are junk) check the DC resistance of the drivers in the left and right speakers. If the left DC resistance of the left bass driver is lower than the right, then the speaker needs reconing before you connect a new receiver, or you will blow it.

You will need to remove the drivers to make these measurements.

It is vital you do this before connecting a new receiver to that speaker.

The speakers also get the cheap and old as dirt label. They still sound and function normally, and aren't worth my time to recone if they are broken.

 

[Seth=L]

The speakers also get the cheap and old as dirt label. They still sound and function normally, and aren't worth my time to recone if they are broken.

Chances are the speakers are still fine, and if you're serious about continuing using them I would take TLS's advice and put a meter on them to be sure. I'm not sure how easily those optimus/realistic/radioshack speakers are to take apart though. I know you've had them for a VERY long time. You've certainly gotten your use out of them.