Adcom pre-amp pot?

rj45 · 23rd May 2006, 06:44 PM

Hi all,

I'm the proud owner of an Adcom GTP-400 preamp-tuner with
a funky volume control pot. I've removed it, but hours of paging through Mouser, Jameco, etc web sites has proven frustrating.

I'd like to get a "drop in" replacement. I know ALPS is much better,
but I don't want to deal with making it fit.

The Adcom part is labeled:
V50KBX2 4TR-2586

Does anyone know where I can find a replacement?

Thanks,
RJ

Nisbeth · 23rd May 2006, 06:58 PM

Got any pictures of the original pot?

/U.

Nelson Pass · 23rd May 2006, 07:35 PM

I thought it was an Alps. If you can't easily get one, try
a 24 position selector switch (make before break) wired with
resistors - they're a pain to make, but very worthwhile for
performance and longevity. I like the Elma and Grayhill switches
the best.

anatech · 24th May 2006, 03:04 PM

Hi RJ,
Is the control noisy, or does it cut out?

If it's noisy, check for DC voltage across it. If you need a new one, contact Adcom, or a warranty center near you.

-Chris

rj45 · 24th May 2006, 04:50 PM

Good questions!

no pic (yet)

dual-gang.
4 solder pins on the bottom.
panel mount, long (1.25") shaft.

Pot cuts out left channel at < 50% volume,
some scratchiness above that level, occassionally
distortion.

Tried massive amounts of TFE on the control.
Helped a little, but not nearly enough.

AFAICT, it's a cheap carbon comp wipe, maybe
plastic, don't know.

-RJ

anatech · 24th May 2006, 05:00 PM

You can install a better control (switched resistor or conductive plastic), or you can get another original type.

If you get the original, it fits the board and the knob will fit too!

-Chris

Nisbeth · 24th May 2006, 05:52 PM

How big is it? The black Noble has 4 pins on it?

/U.

rj45 · 25th May 2006, 02:01 PM

Here's a pic of the pot

anatech · 25th May 2006, 02:04 PM

Have you called Adcom?

rj45 · 2nd June 2006, 02:22 PM

Well, I broke down and called Adcom - I was not happy about the $25 minimum order (for a $3 pot), but figured that I had already exceeded that $$ just in my time searching catalogs and web pages.

No Joy. Adcom cheerfully told the part was not available. Wah!
They DID email a copy of the service manual, but the quality of the scan was so bad, I'll need to trace the circuit just to find out what this puppy is doing with it's 4 connections per channel.

I got a good deal on the preamp - $40 - but it may be wasted $$ if I can't replace the pot successfully.

Thanks for the help!

-RJ

23rd May 2006, 06:44 PM	#1
rj45 diyAudio Member Join Date: May 2006 Location: Atlanta, GA	adcom preamp pot? Hi all, I'm the proud owner of an Adcom GTP-400 preamp-tuner with a funky volume control pot. I've removed it, but hours of paging through Mouser, Jameco, etc web sites has proven frustrating. I'd like to get a "drop in" replacement. I know ALPS is much better, but I don't want to deal with making it fit. The Adcom part is labeled: V50KBX2 4TR-2586 Does anyone know where I can find a replacement? Thanks, RJ

24th May 2006, 04:50 PM	#5
rj45 diyAudio Member Join Date: May 2006 Location: Atlanta, GA	adcom preamp pot specifics Good questions! no pic (yet) dual-gang. 4 solder pins on the bottom. panel mount, long (1.25") shaft. Pot cuts out left channel at < 50% volume, some scratchiness above that level, occassionally distortion. Tried massive amounts of TFE on the control. Helped a little, but not nearly enough. AFAICT, it's a cheap carbon comp wipe, maybe plastic, don't know. -RJ

2nd June 2006, 02:22 PM	#10
rj45 diyAudio Member Join Date: May 2006 Location: Atlanta, GA	adcom part not available Well, I broke down and called Adcom - I was not happy about the $25 minimum order (for a $3 pot), but figured that I had already exceeded that $$ just in my time searching catalogs and web pages. No Joy. Adcom cheerfully told the part was not available. Wah! They DID email a copy of the service manual, but the quality of the scan was so bad, I'll need to trace the circuit just to find out what this puppy is doing with it's 4 connections per channel. I got a good deal on the preamp - $40 - but it may be wasted $$ if I can't replace the pot successfully. Thanks for the help! -RJ

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23rd May 2006, 06:58 PM	#2
Nisbeth diyAudio Member Join Date: Jan 2001 Location: Denmark	Got any pictures of the original pot? /U.

23rd May 2006, 07:35 PM	#3
Nelson Pass The one and only Join Date: Mar 2001	I thought it was an Alps. If you can't easily get one, try a 24 position selector switch (make before break) wired with resistors - they're a pain to make, but very worthwhile for performance and longevity. I like the Elma and Grayhill switches the best.

24th May 2006, 03:04 PM	#4
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi RJ, Is the control noisy, or does it cut out? If it's noisy, check for DC voltage across it. If you need a new one, contact Adcom, or a warranty center near you. -Chris

24th May 2006, 05:00 PM	#6
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	You can install a better control (switched resistor or conductive plastic), or you can get another original type. If you get the original, it fits the board and the knob will fit too! -Chris

24th May 2006, 05:52 PM	#7
Nisbeth diyAudio Member Join Date: Jan 2001 Location: Denmark	How big is it? The black Noble has 4 pins on it? /U.

25th May 2006, 02:04 PM	#9
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Have you called Adcom?

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