Have Rotel RB-1080 stereo power amplifier. Problem: no sound from left-hand speaker. All connections are OK. Get sound from left-hand speaker when I connect it to the right-hand speaker connections of amplifier, thus problem is NOT with the speaker nor with the pre-amplifier. Any suggestions would be appreciated, Rob Arnold

Try to plug a set of headphones into your amp.

If only one is working this means that either you're not getting both signals into the unit (check the signal input connectors, resolder any bad contacts), the signal doesn't get to the preamp or from the preamp into the power amp or the signal does not come from the power amp (check solder connections on preamp and power amp components, also check internal connectors - unplug, clean, reconnect).

If both headphones work well instead, then you're getting both signals into the unit and the preamplifier and the final amplifier are OK, since many amps derive headphone signal from the power amplifier via some power resistors - check for any power resistors around the headphone plug or in the section that has wires going to the headphones plug to see if this is the case - if it is, this means that the signal does get amplified, but it is not getting from the power amp to the speaker - in this case, check the following:

--- speaker connector solder contacts on the circuit board could have some damage - resolder if necessary


--- A / B speakers selector switch (if there is one, it could be a physical switch or a soft touch button driven relay so check for both) - there might be a bad solder contact on the switch pins or the switch / relay contacts may be dirty - resolder and/or clean the contacts (if they can be easily accessed).


--- final amplifier section: bad solder contacts on any power transistors, voltage regulators, power resistors, diodes, coils or other components, including internal connectors (anyway, if both headphones work well, these are all unlikely because the power amp is sending both signals out OK, however, you may want to give it a check, just in case...)


--- delayed speaker turn on relay or other relays - check for dirty relay contacts, clean with some fine sandpaper (you need to remove the relay cover which can be a bit tricky / difficult to access, mostly it's a snap-on cover, could also be resin filled and therefore impossible to open).


It could as well be a bad power amp (do the headphones test), the above suggestions are just a quick look at some common audio amp problems and possible solutions.

Also, if your unit has got many hours of use, it would be fair to check the input signal connectors - the solder contacts do get damaged when you plug / unplug the RCAs many times.

Hope all of this is not getting too lenghty and confusing... just post me some feedback if you have questions.

regards

3rq8 (Triarcuate)