Samsung L4A amplifier one channel louder

[DJduck]

I have a Samsung L4A that was made sometime in the 80s or 90s. I have had it for about 3 years and it sounds brilliant. Lately it has developed an issue. Well actually it has always been like that but lately it has begun to annoy me. Judging by the VU meter, the right channel is outputting more than the left channel. I know that it's not a computer related problem, since I have it hooked up as mono (both channels are connected to left, using it to power a dual voice coil subwoofer). I have replaced some of the caps and cleaned the pots so far, but it has only improved sound quality. Is it failing output caps or transistors or what? It uses two transistors in each channel and one 42v 6800uF Pannasonic cap per channel, no op-amps. Before I start replacing shit, I thought I might ask others what they think. It's rated for 80 watts a channel. Got no dummy load or oscilloscope to test what power they actually have, but since it's a vintage, beefy amp, I think it can do what it is rated for

[DJduck]

Re: Samsung L4A amplifier one channel louder

Anyone?? Also, if someone has any info on how many ohms per channel can this thing handle, then please, do let me know. I have been powering a dual voice coil Pioneer sub with it, each coil 2 ohms, and I don't think that it is a good idea Probably need to buy a car audio amplifier for it

[rhomanski]

Re: Samsung L4A amplifier one channel louder

You will need test equipment to see what the output from both channels really is. Without it you are only guessing. Some amps have an adjustment just for meter deflection. If that is off the meters will be different.

[DJduck]

Re: Samsung L4A amplifier one channel louder

Ok. I do not have an oscilloscope, but I can hook up a powerful speaker and my multimeter, and play a 1000hz tone. I will turn it up till it starts to clip and see what the voltage is. Then divide it by ohms and see the result. Would that work?

[tom66]

Re: Samsung L4A amplifier one channel louder

No, the output is AC. Your multimeter will read DC volts, and the average DC level of a pure AC waveform is 0V.
You might be able to get away with a high output AC sinewave at 50Hz, but your meter should be true RMS type. Most cheap meters are not true RMS capable.