I have a cd jukebox and the amp has developed a distortion in both channels. It's more apparent in the base speakers and seems to go away as I increase the volume. Would this be a problem in the power supply?
Got a scope? Maybe the push or pull transistors are shorted? Easy to see on a scope.
The power supply would normally be a good guess, since it affects both channels. However, the typical problem of too low a positive or negative (or both) supply would normally be expected to cause clipping on outputs that tried to exceed that level. So it would sound worse at high levels, not better. The problem you describe sounds more like a description of crossover distortion, which is a fixed amplitude step as the wave passes through zero, so it's a smaller percentage of large signals.
I ownder if you actually have 2 separate bass channels. Is it possible that the jukebox is using a subwoofer approach, with a single bass channel for low frequencies? (They might feed it to 2 separate speakers.) If that is the case, then the distortion is in a single amp and there are many possible causes. One typical casue of crossover distortion is inadequate bias on the output stages, but you have to be careful since too much will quickly cause thermal runaway in many circuits, which will definitely let the smoke out!
Best regards,
Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis
It may be this distortion is there at all volume levels it's just not detectable to my 55 year old factory abused hearing. I don't think this juke is using a subwoofer as the speaker inputs got to discrete connections on the output stage of the amp and the amp has a 5-6 transistors on each channel mounted to a large fan cooled heat sink.
Observation of the output signal on any old scope will instantly reveal symmetry on the output or not.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.