Amp volume dial crackling
Discussion
My Arcam 8r amp has been suffering really badly with crackling when the volume switch was turned, I understand it’s static.
It’s really annoying, but I can get by with it, however just now I switched it on, with no volume set ( as you should) yet the CD sound came through immediately at really high volume. I messed about with the tape and SP2 button to see if I could stop it but it carried on, the the tape did mute it
I then tried the VCR feed, which I use as the input of a Bluetooth adapter and that then seemed OK.
Switched it back to CD and all seems normal again. Unless I touch the volume, then it’s crackling really badly.
What’s going one?
Edit...
It’s just gone wild again, the volume rocketed upwards on CD all by itself.
It’s really annoying, but I can get by with it, however just now I switched it on, with no volume set ( as you should) yet the CD sound came through immediately at really high volume. I messed about with the tape and SP2 button to see if I could stop it but it carried on, the the tape did mute it
I then tried the VCR feed, which I use as the input of a Bluetooth adapter and that then seemed OK.
Switched it back to CD and all seems normal again. Unless I touch the volume, then it’s crackling really badly.
What’s going one?
Edit...
It’s just gone wild again, the volume rocketed upwards on CD all by itself.
Edited by velocemitch on Sunday 6th March 13:47
I don't know the specific amp but if it's the usual mechanical volume control there's a potentiometer behind the knob in which a copper contact runs along a carbon track and the whole thing operates as a variable resistor.
After the knob has been used a lot the carbon track gets dirty and wears out and you get crackling through the speakers and/or big jumps in volume.
If you open the amplifier and spray inside the potentiometer with electrical switch cleaner you may find that improves things.
The proper repair is to fit a new potentiometer.
As a bodge you can sometimes rewire the potentiometer the other way round just by switching a couple of wires over. In other words, you then have a volume control which works anti-clockwise instead of clockwise - the point being that the copper contact will be running on the opposite end of the carbon track.
After the knob has been used a lot the carbon track gets dirty and wears out and you get crackling through the speakers and/or big jumps in volume.
If you open the amplifier and spray inside the potentiometer with electrical switch cleaner you may find that improves things.
The proper repair is to fit a new potentiometer.
As a bodge you can sometimes rewire the potentiometer the other way round just by switching a couple of wires over. In other words, you then have a volume control which works anti-clockwise instead of clockwise - the point being that the copper contact will be running on the opposite end of the carbon track.
Djtemeka said:
It may help if you turn it off then turn the knob fully from low to high to low several times. Failing that, take it in and change the control out.
Mine cost a tenner to fix
Yeah I have tried moving the volume right round quickly, with sound muted, it’s not improved it.Mine cost a tenner to fix
I took to leaving the volume on when I switched it on and off, which may have been counterproductive.
Looks like I’m going to have to find a repairer, or ditch it.
Panamax said:
I don't know the specific amp but if it's the usual mechanical volume control there's a potentiometer behind the knob in which a copper contact runs along a carbon track and the whole thing operates as a variable resistor.
After the knob has been used a lot the carbon track gets dirty and wears out and you get crackling through the speakers and/or big jumps in volume.
If you open the amplifier and spray inside the potentiometer with electrical switch cleaner you may find that improves things.
The proper repair is to fit a new potentiometer.
As a bodge you can sometimes rewire the potentiometer the other way round just by switching a couple of wires over. In other words, you then have a volume control which works anti-clockwise instead of clockwise - the point being that the copper contact will be running on the opposite end of the carbon track.
I don’t have any spray cleaner, but I’ve opened it up for look and it looks like it’s all very well sealed up.After the knob has been used a lot the carbon track gets dirty and wears out and you get crackling through the speakers and/or big jumps in volume.
If you open the amplifier and spray inside the potentiometer with electrical switch cleaner you may find that improves things.
The proper repair is to fit a new potentiometer.
As a bodge you can sometimes rewire the potentiometer the other way round just by switching a couple of wires over. In other words, you then have a volume control which works anti-clockwise instead of clockwise - the point being that the copper contact will be running on the opposite end of the carbon track.
I understand the theory of a potentiometer, but if it’s a normal type one, it must be quite well sealed in?
Photo attached.
ARCAM do repairs (*), but these are old hardware now, and many of the parts, especially custom stuff like the motor driven potentiometer are no longer available. Also, for what the repair would cost I expect you could replace it from eBay.
(* I have an Alpha 9 amp with an intermittent input selector, but replaced it with a '10 from eBay because the switch is unavailable. The front panel on the '10 is faded, but they're unavailable, too. )
(* I have an Alpha 9 amp with an intermittent input selector, but replaced it with a '10 from eBay because the switch is unavailable. The front panel on the '10 is faded, but they're unavailable, too.
)Static seems very unlikely to me.
Dirty pot, possibly.
But the random full volume thing sounds (pun intended) more like a dry solder joint.
Can you get at them for the volume pot?
Happened to my Audiolab 8000A but it is a bit older than 8 years!
Have you reviewed any hifi fora, is it a known issue for this amp?
Dirty pot, possibly.
But the random full volume thing sounds (pun intended) more like a dry solder joint.
Can you get at them for the volume pot?
Happened to my Audiolab 8000A but it is a bit older than 8 years!
Have you reviewed any hifi fora, is it a known issue for this amp?
Theraveda said:
jet_noise said:
Static seems very unlikely to me.
Happened to my Audiolab 8000A but it is a bit older than 8 years!
Are you confusing the model number (Alpha 8r) with the age? The Arcam Alpha 8 is about 30 years old!Happened to my Audiolab 8000A but it is a bit older than 8 years!
It’s done good time I suppose.
velocemitch said:
Indeed... it’s only the second amp I’ve owned, I think I got it in the late eighties!
It’s done good time I suppose.
It's good kit; I have an Alpha 9 amp (with intermittent input switch, now in my study plugged into the PC with some Wharfedale Diamond 7s), Alpha 9 CD player (mains switch occasionally troublesome, but I hardly listen to CDs any more) and an Alpha 10 amp, still going strong.It’s done good time I suppose.
I'd just buy a replacement on eBay, were I you. There's an 8r for £140, IIRC.
Theraveda said:
jet_noise said:
Static seems very unlikely to me.
Happened to my Audiolab 8000A but it is a bit older than 8 years!
Are you confusing the model number (Alpha 8r) with the age? The Arcam Alpha 8 is about 30 years old!Happened to my Audiolab 8000A but it is a bit older than 8 years!
Arse!
But it makes the dry joint possibility more plausible.
velocemitch said:
I don’t have any spray cleaner, but I’ve opened it up for look and it looks like it’s all very well sealed up.
I understand the theory of a potentiometer, but if it’s a normal type one, it must be quite well sealed in?
Photo attached.
WD40 works fine. I understand the theory of a potentiometer, but if it’s a normal type one, it must be quite well sealed in?
Photo attached.
The potentiometer is the black box at the front nearest the front panel...spray around there and some will hopefully make it inside the case...they're sealed quite well though.
The silver bit is the gearbox, and the grey round thing is the motor.
If all else fails, you can buy new ALPS potentiometers complete with gearbox and motor on eBay.
Timothy Bucktu said:
velocemitch said:
I don’t have any spray cleaner, but I’ve opened it up for look and it looks like it’s all very well sealed up.
I understand the theory of a potentiometer, but if it’s a normal type one, it must be quite well sealed in?
Photo attached.
WD40 works fine. I understand the theory of a potentiometer, but if it’s a normal type one, it must be quite well sealed in?
Photo attached.
The potentiometer is the black box at the front nearest the front panel...spray around there and some will hopefully make it inside the case...they're sealed quite well though.
The silver bit is the gearbox, and the grey round thing is the motor.
If all else fails, you can buy new ALPS potentiometers complete with gearbox and motor on eBay.
https://www.ebay.co.uk/itm/121343393095?hash=item1...
How easy would it be to fit?
I can solder ok, but not particularly good with electronics
Looks like a cheaper option than a replacement amp though.
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