Car Audio Amp missing 2 pots

[Cobalt60]

Hello. I have a car audio amp that I feel is worth repairing. It is an M-Audio M600XE 700W amp. There are 2 potentiometers that have been broken off, and I would like to know what to replace them with. One is for "gain", the other is for "bass boost".

Thanks

-Chris

 

[Cobalt60]

Anybody? Im assuming all standard pots start at 0ohm, then work their way up to whatever theyre rated for. Im also guessing an audio amp would use an audio taper pot, but I also assume thats not incredibly important just to get the amp functional.

So what I really need to know is, what will the max ohm rating be of the pots? Doesnt have to be exactly what came in it stock, just something that will get it to work reasonably similarly to stock and also not blow up.

-Chris

 

[Torben]

You're probably right about the audio taper thing but the only way to give you an answer as to the values would be to guess wildly. I mean, there's a chance that someone on the board happens to repair those and has a service manual but it might take a while before they happen upon this post. Patience.

When you say the pots are broken off, do you mean just the shafts are missing or have the entire things been ripped off the unit? If the pot bodies are left, what are the markings (if any) on them? Many pots just state what they are right on the body.

There also might be revealing markings on the PCB where the pots mount or where the connecting wires from the pots connect to the board if the pots are not mounted right on the board.


Anyway, good luck!

Torben

 

[Cobalt60]

OK thanks very much. I got the amp with the pots already gone, only the pins from them are left. However, I think you are correct in that all of the information I need is printed on the amps PCB. Underneath where the "gain" pot would be is printed "B50KX2", and underneath the "bass boost" pot is printed "C2K5X2".

I cant figure out what the first letter means, but I think I know what the rest means. So I believe the first pot would be a 50k ohm pot, and the second would be a 2500 ohm pot. I believe X2 means that it is a 6 pin pot as opposed to a 3 pin.

Thanks!

 

[Torben]

OK thanks very much. I got the amp with the pots already gone, only the pins from them are left. However, I think you are correct in that all of the information I need is printed on the amps PCB. Underneath where the "gain" pot would be is printed "B50KX2", and underneath the "bass boost" pot is printed "C2K5X2".

I cant figure out what the first letter means, but I think I know what the rest means. So I believe the first pot would be a 50k ohm pot, and the second would be a 2500 ohm pot. I believe X2 means that it is a 6 pin pot as opposed to a 3 pin.

Thanks!

Awesome! I think you are reading the Ohms right. I think the X2 does refer to a 6-pin pot, and if the amp is stereo, then I suspect the pots are dual-ganged--the kind that contains two pots which turn together with the shaft, not the kind with two shafts like this one: 25K and 50K ohm Dual Ganged Potentiometer CTS 1377852: In Stock Buy Now | West Florida Components .

I would guess that the B in B50KX2 indicates a linear pot and that the C in C2K5X2 means an antilog (or reverse taper) pot. That might be hard to get your hands on.

Standard disclaimer: I'm not a pro repair guy by any stretch of the imagination--just a hobbyist. Hopefully if I'm totally off base I'll be corrected. That's what I'd try first though.


Cheers,

Torben

 

[Cobalt60]

Thanks again. Its surprisingly hard to find info on pot taper codes, but I did find a link that confirms your theory:

General Guitar Gadgets - What does Pot Taper mean? Audio? Log? Linear?

 

[Cobalt60]

OK well now maybe you can help me choose the pots? Id like to get these from Radio Shack, but they dont have any 6 pin pots. Could I use a 3 pin pot or might this result in some sort of loss of sound quality? Also, if I did use a 3 pin pot, would I get the same ohm rating?

Thanks again

 

[Nigel Goodwin]

Unfortunately these types of pots are usually custom made for that application, to get the exact ones you would probably need to aquire them as a spare part from the amplifier manufacturer (which is probably difficult).

 

[Torben]

OK well now maybe you can help me choose the pots? Id like to get these from Radio Shack, but they dont have any 6 pin pots. Could I use a 3 pin pot or might this result in some sort of loss of sound quality? Also, if I did use a 3 pin pot, would I get the same ohm rating?

Thanks again

You're not likely to find much useful at Radio Shack, and what you do buy will be hideously overpriced.

You haven't filled in the location information in your profile so I don't know where you are--therefore I don't know what sources to guide you to. In Vancouver, I'd direct you to the block at 28th and Main, since there are a couple of good component shops there. Elsewhere I'd try to give you a link to a mail order site, or others on the board from the area might have better ideas.

From the Radio Shack reference, though, I'm guessing Canada or the US. In that case, check out DigiKey Corp. | Electronic Components Distributor | Canada Home Page or DigiKey Corp. | Electronic Components Distributor | United States Home Page as appropriate and search for the pots. You might have to hit eBay or a small local TV/stereo repair shop for the antilog pot though--they're not seen much any more.


Regards,

Torben