Can anyone help me -
I have a arcam alpha 2 amp from new for 23 years.
The unit powers up fine and the green light works. All input channels seem to work. All the fuses are intact and there is no sign of burn or damage to the circuit board . All components look OK.
The problem is that the some of the sound spectrum has been knocked out and the loudness is reduced when the balance is neutral. Turning the balance all the way does not knock out one of the stereo channels as it should.
Instead when I turn the balance all the way, either L or R - the amplification/bass increases and both speakers give out the same volume.
Any ideas - Arcam want £160 just to look at it.
I have a arcam alpha 2 amp from new for 23 years.
The unit powers up fine and the green light works. All input channels seem to work. All the fuses are intact and there is no sign of burn or damage to the circuit board . All components look OK.
The problem is that the some of the sound spectrum has been knocked out and the loudness is reduced when the balance is neutral. Turning the balance all the way does not knock out one of the stereo channels as it should.
Instead when I turn the balance all the way, either L or R - the amplification/bass increases and both speakers give out the same volume.
Any ideas - Arcam want £160 just to look at it.
It could be physical damage from the sound of it. Check all the pots etc for being soldered OK and check the PCB for damage (hairline cracks) around all the pots/switches.
Beyond that and a scope is the definitive approach to seeing where its going amiss.
Beyond that and a scope is the definitive approach to seeing where its going amiss.
it sounds like something is shorting the two channels together, so you get mono - on a lot of stereo recordings this can subtract a lot.
Can you check what's coming out of the TAPE OUT sockets? That'd help rule out the input selector switch and tape monitor switch being damaged.
Can you check what's coming out of the TAPE OUT sockets? That'd help rule out the input selector switch and tape monitor switch being damaged.
I think the problem is probably related to the pots - I have exercised the pots, lubed them, used alcohol and also tried basting them with air - All makes no difference - Sadly I think this lady has had her day..... :-(
If it is just the pots they should be fairly replaceable. 20K is a bit of an odd value but 22K should work just as well.
edit: Just looked at an "inside" picture of one of these amps, they are just standard 16mm pots by the looks of it. My concern would be if the selector switch was broken. Even the tape monitor switch would be replaceable.
edit: Just looked at an "inside" picture of one of these amps, they are just standard 16mm pots by the looks of it. My concern would be if the selector switch was broken. Even the tape monitor switch would be replaceable.
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I have just discovered something else - When only either L or R is plugged in from source, the volume control normalizes, with good increasing volume in the one working speaker. When one channel is plugged in the balance control seems normal at neutral. It works fine like this when either channel alone is plugged in. The problem starts with all of the inputs, where both L and R are plugged in together. The volume response becomes sluggish and there is a 'tinny' quality to the sound. Also with both channel plugged in the balance at neutral knocks out the voices but leaves the background music.
Try this - set the tape monitor switch to on, connect a source to the Tape In jack... does the same thing happen?
Same issue with tape-in from source - actually even with only one channel plugged sound through both speakers??
This is starting to feel like a bereavement after all these years...we've laughed and cried together..
This is starting to feel like a bereavement after all these years...we've laughed and cried together..
Just a though...Since it is a 23 years old amp...can it be some old electrolytic caps that are dry-out in the circuit?
Getting one channel through both speakers points to something causing a short between L and R channels as I suspected.
It is not beyond repair, but what is your skill level?
It is not beyond repair, but what is your skill level?
The worst part is its not even completely dead - wounded more like it - I should really send her off for recycling or landfill maybe :-(
Actually I might bury her at the bottom of the garden.......
Actually I might bury her at the bottom of the garden.......
If you feel a repair is beyond you, sell it on ebay, making a clear note of the fault. Someone sufficiently skilled will buy it and repair it.
If you were near Norwich, I would offer to look at it for you.
If you were near Norwich, I would offer to look at it for you.
Jaycee - Are you linked with Arcam?
I bought her out of the box in Norwich in June 1990 for £200.......
I'm based in Berkshire but will be at Latitude Festival next week. If anyone you know is going I can bring it along and meet. Seems such a same to put her down without trying something.
I bought her out of the box in Norwich in June 1990 for £200.......
I'm based in Berkshire but will be at Latitude Festival next week. If anyone you know is going I can bring it along and meet. Seems such a same to put her down without trying something.
Nope not linked with Arcam, just a diy hobbyist 🙂 I have serviced a few Arcam amps before though. The Alpha series were very nice amps for the money. Most of my comments so far have been based on looking at the service manual.
Unfortunately I'm not trendy enough to know anyone whose going to Latitude!
I am fairly sure this is quite a simple fault circuit wise, so it'd be an absolute shame to bin it. Offhand I can't think of any more tests you might be able to do that'd narrow it down.
Unfortunately I'm not trendy enough to know anyone whose going to Latitude!
I am fairly sure this is quite a simple fault circuit wise, so it'd be an absolute shame to bin it. Offhand I can't think of any more tests you might be able to do that'd narrow it down.
I could always post it to you on an unconditional basis - you could have a look see and we could take it from there.
Yes we will be trundling along at the festival probably in a drunken stupor with my mothers shopping wheelie thingy in tow...Trendy ? not so sure ....undignified more likely
Yes we will be trundling along at the festival probably in a drunken stupor with my mothers shopping wheelie thingy in tow...Trendy ? not so sure ....undignified more likely
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