Hi all, I've now built the above amp, the TA3020-based "digital" amp (I know it's not actually digital) and now two Amp Camp 1.6 power amps to be bridged and controlled by an Objective 02 headphone amp in pre-amp mode.
All's good, but recently I got out the chip amp and dusted it down as I've been listening to the others in the meantime and I think I might have a dry joint somewhere-please advise.
Last night I hooked up the chip amp and all sounded good, but this morning one channel is substantially muted.
This happened a few months back without solution to the problem, but last night I gave the Alps pot and the selector switch a blast with some Servisol 10 and it seemed to be ok, however, this morning it was like I hadn't done anything to help it and one channel really down.
Just turned it on again and now it appears to be ok, arghhh.
I keep changing inputs (I have two, one for a tuner and one for CD), speaker outlets, left right swaps, etc and it appears that when it isn't working properly the same output channel is muted, but now annoyingly it seems OK.
So: is there a way of testing the speaker outputs or indeed the inputs to see where the fault is coming from?
I should say that an electrics colleague who I no longer have contact with advised me to put some Ansar Super sound caps in line with the output to the amp boards by way of speaker circuit protection, of sorts, I'll see if I can post pics of all of the above.
I must admit that the intermittent nature of the fault leads me towards a dry joint conclusion.
Apart from this fault, the sound has been excellent.
All's good, but recently I got out the chip amp and dusted it down as I've been listening to the others in the meantime and I think I might have a dry joint somewhere-please advise.
Last night I hooked up the chip amp and all sounded good, but this morning one channel is substantially muted.
This happened a few months back without solution to the problem, but last night I gave the Alps pot and the selector switch a blast with some Servisol 10 and it seemed to be ok, however, this morning it was like I hadn't done anything to help it and one channel really down.
Just turned it on again and now it appears to be ok, arghhh.
I keep changing inputs (I have two, one for a tuner and one for CD), speaker outlets, left right swaps, etc and it appears that when it isn't working properly the same output channel is muted, but now annoyingly it seems OK.
So: is there a way of testing the speaker outputs or indeed the inputs to see where the fault is coming from?
I should say that an electrics colleague who I no longer have contact with advised me to put some Ansar Super sound caps in line with the output to the amp boards by way of speaker circuit protection, of sorts, I'll see if I can post pics of all of the above.
I must admit that the intermittent nature of the fault leads me towards a dry joint conclusion.
Apart from this fault, the sound has been excellent.
It seems like when one channel goes down, it doesn't go completely, it just becomes dull.
If it went off completely, I could track the problem, it's just lacking in definition as If someone had turned a balance knob away from that channel
If it went off completely, I could track the problem, it's just lacking in definition as If someone had turned a balance knob away from that channel
It could be the selector switch. I woould try turning it L & R multiple times for a minute or two to see if this does the trick. I have also found that if you put up and down or L & R pressure on the seletor shaft when it is on the correct input this can sometimes cause the signal to drop out suggesting a problem. Have you reflowed all the volume and selector board solder joints?
Thanks, I did try swopping the input over to the other RCA pair and no difference, but will do as you say and swivel around for a minute or so and see if it helps.
What I was hoping for was a technical way of testing ie. with a multimeter.
I'm fairly convinced that this problem is not linked to the PSU, but I'm not an electronics expert by a long shot-more of an enthusiastic soldering chap.
What I was hoping for was a technical way of testing ie. with a multimeter.
I'm fairly convinced that this problem is not linked to the PSU, but I'm not an electronics expert by a long shot-more of an enthusiastic soldering chap.
Ok tried that, and as suspected no joy.
I've moved speaker terminals and the diminished sound moved with it.
I moved RCA inputs and no change indicating that it's somewhere on the output stage.
Can ayone help? I'm guessing it couldn't be the LM3886TF chips?
One thing that I thought it might be is the PSU's perhaps there's a subdued power output from one leading to dimished output, but where to test?
It's driving me nuts, any help would be gratefully appreciated.
Thanks.
I've moved speaker terminals and the diminished sound moved with it.
I moved RCA inputs and no change indicating that it's somewhere on the output stage.
Can ayone help? I'm guessing it couldn't be the LM3886TF chips?
One thing that I thought it might be is the PSU's perhaps there's a subdued power output from one leading to dimished output, but where to test?
It's driving me nuts, any help would be gratefully appreciated.
Thanks.
I am sure there should be details of voltages at various points on the boards for trouble shooting purposes. I will see what I can find. I once had some of the BrianGT boards but sold the amp years ago😕
I have done a lot of searching but can't find a schematic with any voltage readings at certain points, say resistor junctions etc. The only LM3886 amp I now have is a completely different design to the BrianGT so any readings are likely to be meaningless. It could be worth going over all the solder joints to see if that has any effect as it won't hurt.
Thanks anyway, I'm going to start a new thread as my title didn't really say that I had a problem with it.