I've been on a bit of a voyage of discovery lately and I thought that what I had learnt might interest others. Bear with me, it's a bit of a story, and at the same time, this might be old hat for some of you out there, in which case I apologise for wasting your time.
I'm about to start building a Trainwreck Express clone amp. One of the characteristics of this amp is its ability to go from Clean to Mean, at a twist of the guitar's volume knob, while at the same time, not significantly increasing the output volume. As a result, the guitar volume knob effectively functions as a gain control. Unfortunately, not all guitar pots are created equal, and in order for this to work effectively, one requires a nice slow taper pot.
I've been in contact with a guy in the US who owns a number of original Trainwrecks, and has demoed them extensively on Youtube, and one of the things he told me was that the old Centralab pots used in the 50's and 60's Gibsons were ideal, in that they came on really slowly. He had also taken resistance measurements of the Centralab pots in his '59 Les Paul at each of the knob markers, and kindly shared this information with me, and so began a quest to try to find a new pot that had a similar taper to the Centralab pots as used in Vintage Gibsons. This gent indicated that in his experience, one ideally wanted a pot that produced only 10-20% of its available volume, at 60% of the pot's rotation.
I managed to convince a number of online retailers who make wiring harnesses to take resistance measurements of their pots and send them to me. I then plotted all these measurements onto a graph so I could compare tapers. I also conducted the same measurements on some pots I had available to me, and plotted those too. The results are rather interesting.
For a start, some of the really popular pots used by the likes of RS Guitarworks in the form of their "Superpots" and others who use the WD Music spec 550K CTS pots have a far faster taper than the Centralabs. As a result, they're a bit like an On/Off switch low down on the taper.
I managed to establish that Gibson launched a new pot in 2009 for their Historic Customshop guitars, the Historic pot, made by CTS, which my 2010 R9 came fitted with. Interestingly the taper of this pot is almost identical to the old vintage Centralabs in the late 50's Les Pauls. Unfortunately my LP Studio uses long shaft pots and so the Historic pots wouldn't have fitted. My plan was to take a set of Historic pots, remove the wafer and transplant it into a long shaft pot so I could have some pots with the same taper in this guitar too.
I made some enquiries around getting a set of Gibson 500K long shaft audio taper pots, also made by CTS, that were going to have the wafers from some Historic pots transplanted into them, but before doing so, in the name of science, we decided to plot the taper of the standard pots on the same graph. The results were surprising, but in retrospect, not so surprising. The tapers of the 500K Gibson long shaft audio taper pots are exactly the same as the Historic pots. Clearly Gibson, although charging double for the Historic pots, due to their "Vintage Correct Taper", simply decided to use the same tapers in their standard 500K audio tapers pots too, and simply not tell anyone.
As a result of the above, I have just finished upgrading my LP Studio with a complete new wiring harness, including 500K Gibson audio taper pots, Luxe Bumblebee caps, and a switchcraft switch and jack. Having just tested it, I am very pleased with the results. The old electronics, which were still stock, including the 300k linear pots, used in all USA Gibsons are literally going in the bin. The difference between the new and old electronics is like night and day.
Moral of the rather long story: If you have a USA Gibson, or any humbucker guitar that uses long shaft pots, you can perform a rather significant upgrade in tone, as well as get much more range out of your volume control by switching to the 500k Gibson long shaft Audio Taper pots.
If you have a Historic Gibson made before 2009, or another guitar that uses short shaft pots, you can get get a much slower taper pot, that will enable you to clean up better by fitting one of the currently available Gibson Historic short shaft pots.
Here's the graph with the different pots tapers plotted on it for you to see:
Link to Full Size graph:
http://img.photobucket.com/albums/v206/cliosport/PotTaperComparisons.jpg
Here's my newly completed harness in my LP Studio:
