Mini Pot Comparisons...

This is sort of a continuation of a couple of earlier threads.

I have not used mini-pots much in the past. The one time I did was because I could not get dpdt switches on any other sort of pot. I didn't have a lot of options at the time (or so I thought) so I just threw in some Alphas.

I am now facing an ES4-B build, and can only get the minis through the F-hole. I have been hearing lots of discussion about various mfgs of pots here, so I thought I'd order a few and see how they looked and how they spec'd.

I have ordered a couple of CTS, a couple of Bourns and a couple of Alphas. All minis. Nothing fancy. I did not order any boutique or mil-spec pots. Partly because I'm a cheapskate, partly because the open frame pots are easier to tweak, and partly because my examination could end up ruining the pot....

The first of the pot I ordered came from ebay today, a CTS 250K Audio pot.

Attachment 8795

Attachment 8796

It checked out as an audio (log) taper, and spec'd at 237K which is within 5% of 250K. I tested it with an audio source and could not hear any scratchiness. I know people have reported scratchiness with CTS pots here, this one seemed fine. I put the meter on the pot and tested for scratchiness after I put it back together. Did not seem the worse for wear. Not too scientific a test, but what the heck.

The coolest thing about this pot is that when you take it apart, it's very much like the regular sized (24mm) CTS pots. That means the resistor wafer is not attached to the shaft, so the wafers are swap-able. With the regular sized pots I have used this feature on a number of occasions, particularly where I wanted a switching or stacked pot, but could not find one with the value(s) I wanted. I just purchased the one I could find, and swapped out it's wafer with one from another pot with the desired value. It also allows you to swap the wafer if it ever gets scratchy. I even once used a wafer from a non-CTS pot to put a truly weird value (1 meg reverse audio) in a CTS switching housing. it has been working fine now for about 7 years...but I digress.

The other bit of good (or bad) news depending on taste, is that because of the way it's built, it's a bit stiff to turn just like the big ones.

So, bottom line, unless you're going for a boutique pot, this looks like a pretty viable option to me.

Will report on other pots as they come in...

I like stripping CTS pots and make them into loads, i prefer my home made CTS no loads to the Bourns no load.

I choose my pots what my intentions are for the guitar to be doing, each have a different task.

I got a Bourns 500K Audio mini pot today. I had an Alpha mini (100K linear) in my pot bag. (That sounds druggy, should I have said potentiometer bag?). When I found it I also found a no-name mini that I pulled out of my Frankenjazz to put in push-pull pots. It turned out to be 500K Audio.

Attachment 8833

Bourns went first. It spec'd at 478K, well within 10%. It had an audio taper just like it was supposed to. No scratchiness when hooked up to an audio source.

Attachment 8834

When I pulled it apart, it was constructed with the wiper wheel permanently attached to the shaft. No swapping wafers with these guys!

Attachment 8835

The Alpha spec'd closest to it's rating of any pot I tested (100K, linear).

Attachment 8836

It looked very similar to the Bourns in both construction and quality of manufacture. Like all the pots I looked at except the CTS the wiper is permanently attached to the shaft in such a way that the wafer can't be removed without destroying the pot. Passed the audio test with no scratchiness.

Attachment 8837

There are some subtle differences in the construction as compared to the Bourns but they seem very minor. The case is slightly different as is the wiper mount, but the wiper look to be pretty much the same.

There are a few differences in the cap. It's stamped metal with a brass fitting on the Bourns (like the CTS). It's cast metal on the Alpha (and on the no-name). That seems to be related to the hole they are designed to fit through. Bigger on the CTS and Bourns. Smaller on the Alpha and no-name. I can't see any way it makes sonic difference.

OK, so much for the name brands. Will continue in the next post with the no names...

Continued from the last post...

In a way, the biggest surprise was the no-name pot. It spec'd fine, and had the same basic construction as the Alpha and the Bourns

Attachment 8838

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When I pulled the no-name out of the Chinese bass that became the starting point for my Frankenjazz, I though it looked a lot like an Alpha, and assumed it was a knock off, or maybe a “generic” made by Alpha for the cheapskate market.

What surprised me is that the case, wiper, plastic wiper wheel and the wafer had no discernible differences at all from the Bourns. The solder lugs were a bit different, and the cap was slightly different, but all the working parts looked the same.
From any angle where you cant see the cap or the stamp on the bottom, I don't think you'd be able to tell the difference. Here's a shot from the bottom.

Attachment 8840

As you can see, the Alphas have a dimple on the left side of the housing, Bourns and no-name on the right. (Ugly glop of solder was already on the no name when I pulled it out of the my cheap Chinese bass ;-) In fact, the pots are so similar that I could put the Bourns guts and top in the no-name housing and visa-versa. They fit like a glove. I had two more of the no names and tested all three for scatchiness. One may have had a little scratchiness. The other two seemed fine. If I were to use the no-names, I'd hit them with lubricated contact cleaner and listen to them again. Since I don't have an immediate use for them, I didn't try that, but it's worked for me in the past to clean up scratchiness as long as the actual wafer is undamaged.

It seems that the no-names are either a virtually identical clone of the Bourns, or perhaps Bourns makes a generic for the cheapskate market. That does not mean that the quality control is as good with the no-names as with the Bourns. Part of what you pay for may be to have someone check the pot to see if it's any good when it arrives from the Chinese factory. On the other hand, the Bourns was similar enough to have interchangeable parts with the no-name, and that was a surprise to me!

Good chance that the Chinese have reverse engineered the Bourns, they are probably cloning them as well and putting them on the market as the real thing.

It's all just speculation, but I suspect they come out of the same factory. They are visually identical except for the "B" stamped on the bottom of one of them. They are the same right down to the shape and color of the molded parts.

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So stuff keeps trickling in...and in the meantime I have been mapping out the switching and tone circuit I'd like to put in. I like having a master volume, and have never seen a reason for more than one tone knob. Unfortunately the pickups that I ordered have about the same about put...which means they may not be totally balanced. So...I am looking at my Frankenjazz, that has Volume-Blend-tone knobs. Never been completely happy with it, in part because their is a slight drop in volume at the center detent in the blend pot. The reason is most likely that the Alpha blend pot I put in it is really a "pan" pot rather than a true "blend" pot. Turns out that true blend pots have been tough to get... (Here's a discussion of the issue)

http://guitarnuts2.proboards.com/thr...blend-pan-pots

Deep down in that article, someone mentions that there are Bourns true blend pots available... So I ordered a couple. One for the ES4-B and one for the Frankenjazz. Hopeful, that's me.

Meanwhile I got a Bournes push pull and compared it to the alpha. I have not pulled it a part. I don't expect that the differences in the wiper/wafer will be much. On the other hand the build quality difference in the switch part is obvious without opening up the case. The Bounrs is much better.

You guys may convert me yet ;-)

Really great info and write up fender, thanks

Well that pretty well confirms what I had suspected with the Bourns pots...
I wish I still had a few of the ones I got some ten years back so I could compare them with the new ones.
From memory, the older ones had a very clean and "sharp" edge to the logo stamp where as the newer ones are softer edged.
Much like many things you buy now, I suspect they are made by a third or fourth party manufacturer....
I guess that unless you get the military spec ones, you will be getting these third party made ones.
Is this a bad thing?
Probably not, just so long as they fall within the ten % range..

Thanks fender this has been an interesting post

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