How to identify whether pots & electronics are 'imperial' or 'metric' on 2 Japanese guitars?

willo

So in the New Year I will be upgrading the electronics of two Japanese guitars. One is a 2014 Tokai Les Paul Special, the other is a 1980 Navigator SA120 (ES335 style - so no backplate to take off and look through).

I would ideally like to buy pre-wired looms from somewhere like Axes R Us. This means though that I need to get the spec right - and the Imperial or Metric specification is something I don't know how to answer, although I have heard people say that Japanese guitars are often metric.

How do I find out whether the electronics on these two guitars are metric or imperial?

And is there any need to make a distinction between metric & imperial for pickup replacements?

Thanks in advance

Funkfingers

I would expect the threaded portions of the stock MIJ pots, jack socket and selector switch to be Metric.

Metric replacement components will fit Metric drilled holes neatly. They would also fit Imperial holes albeit somewhat loosely.

Imperial replacement components might fit sloppily-drilled Metric holes. Be prepared to enlarge holes using a reamer:

Neilybob

When I chatted with Monty regarding this at a guitar show he said best to take the guitar to him or send him photographs with a measuring tape over the pots. 

Interesting to see what pickups you put in Navi SA as I'm on the fence about whether I like hot (currently) or not so hot pickups in my Navi SA. 

Dave_Mc

If you take the knobs off you should be able to measure the shaft diameter- that should tell you whether the pots are metric or imperial. (Actually you'd only need to remove one if you're willing to take the risk that they're all the same- extremely likely, especially if you bought it new and it's never been messed with.)

You might be able to measure the shaft diameter of the pickup selector without removing anything.

ICBM

It’s almost certain they’re metric. However, they are also likely to be pretty decent quality, most likely full-size Alphas, and not needing to be changed at all.

If you want to change the pickups and you can bring yourself to do the 335 the ‘cheat’ way by cutting the pickup cables in the cavities, that will save a vast amount of work.

Dave_Mc

ICBM said:

It’s almost certain they’re metric. However, they are also likely to be pretty decent quality, most likely full-size Alphas, and not needing to be changed at all.

If you want to change the pickups and you can bring yourself to do the 335 the ‘cheat’ way by cutting the pickup cables in the cavities, that will save a vast amount of work.

I'm not sure about the Les Paul Special model, but IIRC my Tokai Tele had MIJ pots (I think they were probably full-size too, but I'm not 100% sure as it was a while ago; I also think they were metric). They were absolutely fine from what I remember, I just changed mine because I needed push-pushes for the tapped pickups and to switch a treble bleed in and out.

Just out of interest, is the "cheat" way just cutting the cables fairly close to the pickups, so you can get at them through the pickup cavities, and then connecting the new pickups' hot and ground wires to the hot and grounds of the old pickups' cables?

ICBM

Dave_Mc said:

Just out of interest, is the "cheat" way just cutting the cables fairly close to the pickups, so you can get at them through the pickup cavities, and then connecting the new pickups' hot and ground wires to the hot and grounds of the old pickups' cables?

Yes. Cut the old pickup cables in the cavities - I would do it about 1" from the pickups, not right against them, to allow enough length to re-connect them if you want to put them back - and solder the new pickups to them, with some tape or heatshrink to insulate the hot connection. It looks like a bit of a bodge, but there's no difference electrically or sound-wise. I also prefer to coil up the new pickup cables under the pickup rather than cut them short, so you can re-use *them* in a different guitar later if you want to as well.

If you want to make it less of a bodge - and if there's room in the cavities - you could add some proper terminal strip screwed to the cavity floor to make the connections - but it really makes no practical difference, unless you're going to be changing the pickups a lot.

BillDL

willo said:

I would ideally like to buy pre-wired looms from somewhere like Axes R Us. This means though that I need to get the spec right - and the Imperial or Metric specification is something I don't know how to answer, although I have heard people say that Japanese guitars are often metric.

If you buy a pre-wired loom that has "imperial" potentiometers, buy replacement knobs to match the pots while you are at it.  Metric or "Import" pots have 18 splines on the 6mm diameter split shafts, so your existing knobs would fit them. Imperial pots like the "USA" spec CTS pots have 24 splines on the 6mm diameter split shaft, so you need knobs with 24 internal "teeth" to match.  It IS possible to push either type of knob onto either type of shaft, but you would either have to use excessive force or conversely you might end up with knobs that are too loose a fit.

A tip about pushing the knobs onto pot shafts.  I recently managed to push the backing "can" / casing of a CTS branded pot off the back of the pot, ruining it.  The casing is soft metal and is only held to the remainder of the mechanism by thin tags that are bent over.  Either ICBM or Funkfingers mentioned that some CTS pots no longer have the little retaining ring that prevents the shaft from being pushed all the way through.  You need to apply pressure to the back of the pots while pushing on knobs.  That's easy enough on a guitar with a rear control cavity, but less easy to reach through an F-Hole with a finger to push up on a pot mounted in a semi-acoustic.  The correct fit of knob to pot (18 or 24 spline) means you shouldn't have to apply too much pressure.  Try the knobs on and off the shafts of the pots before mounting them inside the guitar.

guyinlyon

willo said:

I would ideally like to buy pre-wired looms from somewhere like Axes R Us. This means though that I need to get the spec right - and the Imperial or Metric specification is something I don't know how to answer, although I have heard people say that Japanese guitars are often metric.

I didn't know that anyone in the Japanese Empire built electric guitars...

ICBM

guyinlyon said:

I didn't know that anyone in the Japanese Empire built electric guitars...

Guyatone did, in the 1930s - the first electric guitars made in Japan, although they were Rickenbacker-style lap steels.

https://uniqueguitar.blogspot.com/2018/08/guyatone-guitars.html

Sorry, historical thread hijack .

willo

Thanks guys, as always.

Had a look inside my Tokai LPS and that's using Alpha pots on the volume (value unclear), and 500K 'GF' pots on the tone (think these are Goldo brand, from having a read around). In any case, I'm happy enough with them, they can stay in place and I will just need to replace the (broken switch).

On the Navigator 335, I'm less clear, obviously because its not easy for me to open up. I might have a play around. But I'm a little sceptical of the whole electronics purely because, over time, I've become less happy with the pickups. They are quite hot and, much like @Neilybob , I'm thinking to swap them for something lower output, more chimey and classic.

BillDL

Not many people have an endoscope type of camera to look inside a hollow or semi-hollowbody guitar, nor a tiny mirror like a dental one.  Probably the easiest way to get an idea of what the pots are in a 335 style guitar without removing all the wiring is to undo the nut on one closest to the F-Hole, allow the pot to drop into the guitar, and flip it over with your finger through the F-Hole to look at the markings on the case or the brown bakelite type lip onto which the solder lugs are mounted (using a small torch if needed).  Before dropping the pot through the hole you can tie some strong thick thread to the top of the shaft to pull it back up through the hole, or even line it up on its back under the hole and push a flat blade screwdriver through the hole to gently wedge it in the split in the shaft, but being one that's very close to the F-Hole you can often just use your finger to steer it back up through the hole again.

Dave_Mc

ICBM said:

Dave_Mc said:

Just out of interest, is the "cheat" way just cutting the cables fairly close to the pickups, so you can get at them through the pickup cavities, and then connecting the new pickups' hot and ground wires to the hot and grounds of the old pickups' cables?

Yes. Cut the old pickup cables in the cavities - I would do it about 1" from the pickups, not right against them, to allow enough length to re-connect them if you want to put them back - and solder the new pickups to them, with some tape or heatshrink to insulate the hot connection. It looks like a bit of a bodge, but there's no difference electrically or sound-wise. I also prefer to coil up the new pickup cables under the pickup rather than cut them short, so you can re-use *them* in a different guitar later if you want to as well.

If you want to make it less of a bodge - and if there's room in the cavities - you could add some proper terminal strip screwed to the cavity floor to make the connections - but it really makes no practical difference, unless you're going to be changing the pickups a lot.

Brilliant, thanks John! 

Dave_Mc

BillDL said:

Not many people have an endoscope type of camera to look inside a hollow or semi-hollowbody guitar, nor a tiny mirror like a dental one.  Probably the easiest way to get an idea of what the pots are in a 335 style guitar without removing all the wiring is to undo the nut on one closest to the F-Hole, allow the pot to drop into the guitar, and flip it over with your finger through the F-Hole to look at the markings on the case or the brown bakelite type lip onto which the solder lugs are mounted (using a small torch if needed).  Before dropping the pot through the hole you can tie some strong thick thread to the top of the shaft to pull it back up through the hole, or even line it up on its back under the hole and push a flat blade screwdriver through the hole to gently wedge it in the split in the shaft, but being one that's very close to the F-Hole you can often just use your finger to steer it back up through the hole again.

I just bought a cheapish wee foldy mirror on Amazon for use with acoustics- it had a light in it, too (although for very occasional use the battery is usually dead the next time you need to use it!). However, it might be a bit big for semi-hollows...

Rolson 60515 Two LED Telescopic Inspection Mirror,42 x 65mm : Amazon.co.uk: Automotive

BillDL

Hey @Dave_Mc I don't pay money for anything if I can make it myself because I've spent my life skint and making improvised tools.  The inspection mirror I've used since around 1990 is the aerial from a portable radio with a small rectangular plastic backed vanity mirror (formerly my ex's) fixed to the short section with the hinge.  The handle is a mini maglite torch with the bulb holder removed and with thin extension wires passing from the torch through the hollow aerial to the bulb holder epoxied to the mirror.  I saved the entire £9.99 on that Rolson one on Amazon 

Dave_Mc

BillDL said:

Hey @Dave_Mc I don't pay money for anything if I can make it myself because I've spent my life skint and making improvised tools.  The inspection mirror I've used since around 1990 is the aerial from a portable radio with a small rectangular plastic backed vanity mirror (formerly my ex's) fixed to the short section with the hinge.  The handle is a mini maglite torch with the bulb holder removed and with thin extension wires passing from the torch through the hollow aerial to the bulb holder epoxied to the mirror.  I saved the entire £9.99 on that Rolson one on Amazon 

LOL I'm so bad at DIY trying to make stuff would probably actually cost me money! Plus I'd have to start buying tools to make the stuff, which would cost more unless I were doing it a lot...