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McIntosh 1900 Volume Control / On-Off Switch Replacement

bwv1

bwv1

Active Member
Past posts have suggested that the new, replacement volume control / on-off switch for the McIntosh 1900 available from McIntosh as well as other sources is not an exact replacement for the original one in several important respects, making me shy away from using any of those.

There is a replacement pot available at the auction site that is billed as an "exact replacement", offered by someone who must know a lot about vintage replacement pots as he seems to offer a lot of them for various applications. He tells me it is "exact". An experienced tech who I trust warned me that it may not be "exact", either electrically or physically, based on a prior purchase from this seller for a different, exact replacement pot that required substantial modification to work properly.

So, has anyone tried to use this "exact" replacement pot for a 1900 from the auction site that sells lots of pots and was it even close to original electrically & physically?
 
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The one I have seen huckstered on EBay was the same control, Made in Canada, that Mac parts supplies as a generic replacement for the 5 control part numbers they offered back in the 70s.

To really expect a drop in replacement for a almost 50 year old design is a little much.

Hire your local tech and have him customize it for your unit.
 
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c_dk said:
The one I have seen huckstered on EBay was the same control, Made in Canada, that Mac parts supplies as a generic replacement for the 5 control part numbers they offered back in the 70s.

To really expect a drop in replacement for a almost 50 year old design is a little much.

Hire your local tech and have him customize it for your unit.
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There is a seller who is offering a variety of replacement controls that are not PEC on eBay.

I've ordered, measured, & tested a few of these controls.

Every one I've ordered mistracked at the low end of the volume. I'm guessing that they come in at 10% tolerance.

One arrived with the shell pushed in so that the wiper of one section would hit the shell at that spot....

The last one I ordered crackled like a dirty pot. I contacted the seller to ask if he'd seen this in other units only to be told it was my problem / installation / unit. It was the pot.

It's too bad really. I support the idea of making drop in replacements, but at $90.00 a pop I expect better quality, or at least a bit of quality control. It wouldn't take much to set up a rig to check the tracking before shipping them. Let the manufacturer deal with the rejects...or order a tighter tolerance part.

I will say that the taper is more in line with the original controls, as is the position (resistance) of the loudness tap.
 
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Audio Classics says they can rebuild your pot to work like new, I haven't tried it yet however........
 
Hi, everyone,
I have been posting in a different thread about this very issue. I bought the $120 replacement pot from Mac - poor tracking. They sent me another - poor tracking. These are Canadian made. Then I bought the $90 one from the guy on ebay - poor tracking!!! On the low volume side, one side measures 50 ohms, the other 500 ohms!! Ridiculous! Hardly 10%...hardly 20%....Very frustrating. OK, I will now check with audio classics.....I am VERY skeptical at this point, and wonder if this issue can be resolved????
I'll let you all know how it goes with audio classics.
 
bwv1 said:
Al- Yes, that is what I decided to do. I will report back here when it is completed.
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Any news yet? I am curious about this approach - may send in my 1900 for this while the option is available - although my 1900's control is not too bad and is usable.
 
The one I used, purchased on ebay, was an exact drop in replacement, and tracks near perfect. I don't know if it is the same guy. I talk about it in the other pot replacement thread. I kept the old one...if AC does a great job, I will send it in. I've been using the 1900 nearly daily since then, though I am about to pull it out again to finish the restoration work, as all I did was a total recap and the pot/switch replacement. I just have to recap my other C33 first.
 
Well, the AC rebuilt pot has significant tracking issues I am sad to say. Not sure what I am going to do next, but I will post any progress.
 
bwv1 said:
Well, the AC rebuilt pot has significant tracking issues I am sad to say. Not sure what I am going to do next, but I will post any progress.
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One would think this should have been tested by AC before being sent out?
 
Send it back and have them fix it, one would think they would of tested it before sending it back to you.......my 2 cents.
 
Original product literature claimed volume controls were "precision tracked" (with actual quotation marks used) in a number of pre-C32 models but none of them really were across the entire range in practice. However they did tend to "tighten up" around the 11:00 - 1:00 range +/-.
 
Back in the day, the MPI4 gave a nice graphical display of the tracking. You would get your system all balanced and then as soon as you changed the volume setting, the balance changed as well. It was just something we lived with.
Larry
 
Well mine (original) works pretty well but not perfectly, so I guess that's as good as it gonna be. I will continue to use a power strip to switch the 1900 on and off to avoid rotating the volume control every time I switch on and off and so delay wear.
 
Hello, everyone,
I am finally ready to report my status on this volume pot issue. The guy on ebay that sells the $90 pot accepted my return of the poorly tracking pot, and sent me another. Finally, checking with my ohm meter, it tracks fine. So, I was relieved to finally resolve this, and return the mac 1900 to the customer. I went ahead and installed the pot, only to find out it was dirty!! Crackling sounds when adjusted, but, it did track fine. So, I squirted in some deoxit faderlube, which as you all know, is specifically designed to work with the carbon traces in all pots. This did not resolve the problem. So, again, I am at a loss what to do. The guy on ebay, his name is "hifiaudio" is refusing to deal with me any further claiming I have damaged the pot by using faderlube. This is, of course, is utter nonsense! He simply wants to steal my $90...yes, $90 for a stinking pot!! I am in the process of resolving this problem through Ebay, but I fear they will not play ball with me. They seem to have come to the decision that I should not receive a refund....WITHOUT even consulting with me!! I had no idea Ebay was like this. I sent them a message explaining the situation, but I am not very hopeful. Anyway, you all, PLEASE do not do business with "hifiaudio" through ebay. The guy will send you a faulty pot, and will not deal with you in resolving this!! He is a CROOK!!!!
 
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So, I am again at a loss as to how to fix this volume pot issue! One thing I know for sure...I will NEVER AGAIN do any work on a MAc 1900!!! I am open to any advice from you all!
 
johnhoef said:
Hello, everyone,
I am finally ready to report my status on this volume pot issue. The guy on ebay that sells the $90 pot accepted my return of the poorly tracking pot, and sent me another. Finally, checking with my ohm meter, it tracks fine. So, I was relieved to finally resolve this, and return the mac 1900 to the customer. I went ahead and installed the pot, only to find out it was dirty!! Crackling sounds when adjusted, but, it did track fine. So, I squirted in some deoxit faderlube, which as you all know, is specifically designed to work with the carbon traces in all pots. This did not resolve the problem. So, again, I am at a loss what to do. The guy on ebay, his name is "hifiaudio" is refusing to deal with me any further claiming I have damaged the pot by using faderlube. This is, of course, utter nonsense! He simply wants to steal my $90...yes, $90 for a stinking pot!! I am in the process of resolving this problem through Ebay, but I fear they will not play ball with me. They seem to have come to the decision that I should not receive a refund....WITHOUT even consulting with me!! I had no idea Ebay was like this. I sent them a message explaining the situation, but I am not very hopeful. Anyway, you all, PLEASE do not do business with "hifiaudio" through ebay. The guy will send you a faulty pot, and will not deal with you in resolving this!!
Click to expand...
PM me your info...I have a 1900 parts unit I can send you the Volume Pot...I thought I had 2 but only found 1...Hopefully this with track better.

1900Vol.png
 
I have been following your odyssey for a while now and wish I could help. Hopefully Joe's volume pot will do what you need.

I have a C28, which I believe is also a victim of the typical poor-tracking volume pot, and I have been told that this is something that plagued them from factory/new, at the very bottom of the volume scale it could have poor tracking between channels. For me this is not a problem, not just because it is a display unit, but also because I seldom touch volume pots other than to tweak them (power on/off through a "smart outlet" strip) and I don't use headphones, so usually above 9:00. I have never noticed poor tracking on the C28, but don't want to buy a replacement part that is not acceptable (obsessive people buy parts like this because they're available, not because we need them). Depending on the users' needs for loudness compensation the amplifier can be set a little lower to allow the preamp to be within the best range. Unfortunately the receivers don't have this option.

McIntosh does offer a new C28 pot, which I've been considering for a spare, in case mine ever starts to fail. This is what keeps me interested in your thread, noting that the new pot will likely not track well at low gain, and that the eBay seller's pot won't either (and I'd much prefer to give the money to McIntosh if they are equal parts). Seems like they're both coming from the same supplier but I have more confidence in the return policy of McIntosh than this seller (you aren't the first to report problems with the eBay seller, the pot quality, and his resistance to refunding for bad parts).

I wish you well, and it might just be a matter of an understanding between you and the owner on the low-volume tracking inaccuracy being acceptable. I will continue to follow and hope for a happy ending to this thread.
 
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