LP Supreme Tone Cap Upgrades

Dry Joints
I noticed an intermittent problem with my bridge pup cutting out – it let me down at a recent jam session so I had to take the plunge and sort it out. The guitar differs from a standard Les Paul in that it has an arched back (as well as the front) with no access panel on the rear for either the pots or selector switch. The only access is through the enlarged jack socket plate.

I bought the guitar ‘used’ in May 2013 and quickly noticed that the output wire to the jack was twisted around the jack socket lug and not soldered! Well, as I feared, after dismantling yesterday I discovered that both pups were connected in a similar manner. Also the ground wires from the pups were soldered very badly – classic low wattage soldering iron with not enough heat – leading to several dry joints.

Russian PIO Capacitors
From my point of view the only option was to dismantle the electrics and start again from scratch. I took the opportunity to swap out the two standard ceramic capacitors and replace with some NOS Russian paper in oil ones that I’d ordered from eBay for another project.

Ibanez Bridge Pickup
I configured the loom in a way that would allow me to easily swap pickups in the future, so for now I left out the standard Gibson 498T bridge pup out and replaced it with a mid 1980’s Ibanez Super 70 with cream open coils.

Wrap Over Tailpiece
I also decided to try out wrapping the strings over the tail piece.
To my surprise this has made an incredible difference! I’ve had a nagging buzz on the top E string which despite trying dozens of fixes, I’ve never been able to resolve – well, its gone. Also, the 10 guage Ernie Ball strings now feel more like 9’s. As the angle made by the strings leaving the tailpiece to the bridge has now changed, it’s allowed me to tightened the posts for the tailpiece hard up against the body which seems to have induced more sustain too. These differences are all based on playing the guitar unplugged – I cant wait to play her through my rig tomorrow!

Parts List:

  • Russian PIO Paper-in-Oil Tone Capacitor K40P, 0.022uF (like K40Y-9) MATCHED PAIR
  • Mid 80’s Ibanez Super 70 pickup

Why The Poor Wiring?
After cutting the loom out, I discovered 2 professionally soldered connections which were non-standard. I suspect that a previous owner has had the standard pups swapped out professionally, and then bodged back in the originals before selling it on.

Update Oct 2014

Although very impressed with the tone from the neck pup with the Russian NOS cap, I wasn’t that happy with the bridge pup tone, so I swapped it out for a Jensen style one.


Description: K40Y9 are one of the best sounding Russian capacitors. True PIO, sturdy construction, never leaking, never aging. You are likely to enjoy Jensens quality at a fraction of a cost. The offered capacitors are NOS

Russian PIO Paper-in-Oil Tone Capacitor K40P, 0.022uF (like K40Y-9) MATCHED PAIR

Description: If you are reading this you probably already know all about the added warmth and vibrancy you can get from upgrading your guitar’s standard tone capacitors to vintage spec paper-in-oil caps.  These capacitors, used for decades in Soviet military applications, are becoming the stuff of legend – they give you all that tone without having to pay through the nose for modern USA reproduction versions.  They are however becoming harder to find all the time, so they are not as cheap as they once were, but not yet that much more than a high-end modern poly-film capacitor.

Sadly 0.022uF K40Y-9 capacitors are becoming very hard to find, so they cost more than other values.  However I have sourced these very similar capacitors which are much more affordable.  The K40P-2 uses the same paper-in-oil technology, wrapped with the same aluminium foil, in the same kind of glass sealed case.  Best of all, they sound very much like the more famous (and expensive!) K40Y-9.







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