I am selling a PA system - it did work fine - the chap coming to buy it wanted to try it out but got the speaker cables mixed up so ended up cabling the left speaker out directly to the right speaker out - plus cabling one speaker directly to the other. Obviously no sound but when called correctly still no sound.
Would connecting the two ‘outs’’ to each other kill the amp?
Would connecting the two ‘outs’’ to each other kill the amp?
Yes, quite possibly. The reason is because each output is a low impedance point and so trying to feed one output into another is pretty much the same as just shorting the outputs.
You might be lucky and find it is just a speaker fuse that is zapped.
You might be lucky and find it is just a speaker fuse that is zapped.
Well that’s how we found out it wasn’t working but not sure what the damage might be - it is an assumption that the incorrect cabling (i.e. cabling one speaker out to the other out) is the cause but wanted to ask to know for sure - it was working fine a few days go before I advertised it an it hasn’t been bumped or unplugged incorrectly
Possibly. It could be anything from popped fuses to a full scale blow up of the output stages and every possibility in between.
Why not take the top off and have a look but make sure you unplug it first.
Is it blowing mains or supply fuses?
Open chassis and visually check it.
Or amp might already be dead and protection relays may be keeping speakers disconnected.
Al "IF/OR" answers because you didn´t even mention amp brand and model.
Open chassis and visually check it.
Or amp might already be dead and protection relays may be keeping speakers disconnected.
Al "IF/OR" answers because you didn´t even mention amp brand and model.
Sorry, it’s a Peavey Escort 3000, have had the covers off but no idea what I’m looking at - no smell and don’t see anything like a fuse on the speaker outs (but don’t know what a fuse looks like other than a domestic one). My question was really just asking if wiring the outputs together would cause the amp not to work (so I could suggest to the purchaser that he broke it)
Wiring outputs together is often destructive because each channel then sees and works into what is effectively a short circuit rather than a minimum value of load resistance.
Well, maybe.
Those outputs might be wired in parallel any way. Peavey stuff tends to be pretty bombproof, too.
Set it all up as normal and try it.
Chris
Those outputs might be wired in parallel any way. Peavey stuff tends to be pretty bombproof, too.
Set it all up as normal and try it.
Chris
Yes, definitely.
The one who did the misconnecting is responsible.
By the way, quite a clumsy guy.
But, will he recognize his error and pay for it?
Fully agree on old style made in USA Peavey and even on some of its oriental made one, still under Hartley´s guidance.
Today ... whoknows?
And given this particular product, it might even not be a real Peavey product at all, just some third party made PA product, similar to Fender´s Passport (which neither is made by Fender, just distributed by them).
Show a gut picture, we might recognize something, but I suspect Class D amps fed by an SMPS, something which possibly wouldn´t be repaired by Peavey bthemselves,replacing full boards instead.
Is it still within warranty period?
If so, drop it at some Peavey Authorized service shop.
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The outputs are TDA8920 and yes, an SMPS. I can't tell if they designed it in house or not, they have done their own SMPS designs in other models.
Here is the schematic for PA and PS.
Here is the schematic for PA and PS.
That’s very kind of you but unfortunately it doesn’t mean much to me - would you say there are fuses behind the speaker outs (J1 and J2) that might blow in the case of shorting rather than doing more extensive damage?
The only fuse appears to be in the input section of the power supply and is either mounted in an externally accessible fuse holder or an internal fuse holder. It's a 5 x 20mm time delay 4A fuse - either glass or ceramic body.
I think you need to take this to a tech, there are no speaker fuses.
I think you need to take this to a tech, there are no speaker fuses.
Silkstonemike, have you actually tested the equipment since the incident?
If not, give it a go. If I was into gambling, I'd bet it works fine.
Chris
If not, give it a go. If I was into gambling, I'd bet it works fine.
Chris
Hi Chris, yes we tried several times after the ‘incident’ without any joy - switching on and off, trying different speaker cables, trying mic and media, nothing at all. In the end the chap buying the PA admitted it was probably his error that had caused the problem, he paid an agreed amount and he took it away - there’s a Peavey agent in Warrington with good reports so I think he has taken it there for assessment- don’t know if he has tried it in the meantime
Ok, then the Peavey agent will take care of it.
It´s a *complex* amp and PSU well beyond average user repair abilities.
Thanks toEnzo we can see the schematicand yes, there´sonly one fuse, thbe main one.
Just curious: did amp turn on, shine a pilot light, speaker pop, hum, hiss, show any signs of life?
It´s a *complex* amp and PSU well beyond average user repair abilities.
Thanks toEnzo we can see the schematicand yes, there´sonly one fuse, thbe main one.
Just curious: did amp turn on, shine a pilot light, speaker pop, hum, hiss, show any signs of life?
What happened was that the chap coming to buy was so keen to try it out that he was fiddling and unwrapping stuff, got the mic and cable, plugged it in, got the speaker cables and asked if I had power nearby, I plugged the power cable in whilst he plugged in the speakers - neither of us noticed he had cabled speaker to speaker and output to output. Switched on, EQ lights showed that signals were being received both from the mic channel and from the media channel but no sound coming out. Switched off and on again, nothing, then he noticed he’d cabled the speakers incorrectly, so switched off, cabled the speakers properly, switched on, nothing, switched off, tried different cables to the speakers, switched on, nothing, unscrewed the amp section and its cover, couldn’t see anything such as an in-line fuse. Put back together, tried again, nothing