Thurston Moore Jazzmaster in for some TLC
I have had my head down working through the guitars that have come through the doors so have somewhat neglected the 'Home of Tone bench' blog of late, but I figured this was a special one so had to share it.
Chris got in touch to inquire about getting this awesome offset looked at as wasn't in the happiest of states. The wiring in particular was problematic, having been replaced prior elsewhere it came back sounding very muddy. After a bit of chat, he opted to send it my way for a closer look and a full setup.
Once with me, I plugged it in and had the very same results Chris had reported. Incredibly muddy and muffled sounding, not good! So off came the strings, pickguard and on with the inspection. There were signs of excessive heat during soldering of the switch lugs as there was a lot of solder splatter as well as some very burnt out fibreboard spacers. So even if that wasn't specifically the cause of the problems, it certainly wasn't healthy there. The volume pot had the correct part/reference number stamped on it, so no initial concerns of the wrong value pot spec being installed causing the darker tone to what's expected, but upon testing found it was reading lower than 200k, instead of the 500k spec this particular model of JM should have. Signs of some heat damage again, so perhaps some contact path damage caused the major reading descrepency here. It's a very simple, toggle/volume/jack config on the Thurston Moore model, so an easy setup really, which is sad to see the issues here but all easily resolved. Chris asked me to replace the full loom, so in went a new Switchcraft 3 way right angle toggle, CTS 450 series SSSP 500k split shaft pot, Pure Tone multi contact jack and Gavitt 22awg cloth covered wire (in green and black for good measure and paint scheme match!).
First up in the new loom and wiring tidy, was to neaten up and organise the pickup and ground wires. I tested the bridge ground wire to ensure there was continuity from the body insert to the wire end, all good there. And popped a meter on the pickups to ensure they're working as they should be also.
I made the new loom on my trusty pickguard template, ready to transfer over to the nice anodised aluminium pickguard(s). On the TMJM model the pickguard is actually split into two, the main part with the switch mounted, and the smaller part with the volume and jack mounted. I often encounter ground continuity issues with anodised finished aluminium pickguards, but noted on this that the factory sand off some of the anodised coating in the areas where the switch, pot and jack mount. I mounted the parts to test their continuity between guard and component and thanks to this prep work, found solid continuity so that I can rely on those instead of needing to add separate wires. But due to the two separate pickguards/control plates, I did of course need to run a ground from the switch to the pot.
Tap tested, I'm good to re-assemble and prepare for the setup.
I inspected the frets which were superb as is, so polished those up. Got the strings on, set neck relief, refined nut sloth depths and worked on the action/radius and intonation. All went nice and smoothly with action set to customers preferences.
Loved working on this rare JM variant, iconic offset model that looks, sounds and plays great. Thank you for sending the work my way, Chris.
If you are looking for Thurston Moore style wiring for your JM, whether it's to convert another model/varient of JM to TM specs, or to restore/repair the wiring on your own TMJM model. Then I offer pre-wired Jazzmaster Thurston Moore harnesses, which can be found on the store HERE
Chris got in touch to inquire about getting this awesome offset looked at as wasn't in the happiest of states. The wiring in particular was problematic, having been replaced prior elsewhere it came back sounding very muddy. After a bit of chat, he opted to send it my way for a closer look and a full setup.
Once with me, I plugged it in and had the very same results Chris had reported. Incredibly muddy and muffled sounding, not good! So off came the strings, pickguard and on with the inspection. There were signs of excessive heat during soldering of the switch lugs as there was a lot of solder splatter as well as some very burnt out fibreboard spacers. So even if that wasn't specifically the cause of the problems, it certainly wasn't healthy there. The volume pot had the correct part/reference number stamped on it, so no initial concerns of the wrong value pot spec being installed causing the darker tone to what's expected, but upon testing found it was reading lower than 200k, instead of the 500k spec this particular model of JM should have. Signs of some heat damage again, so perhaps some contact path damage caused the major reading descrepency here. It's a very simple, toggle/volume/jack config on the Thurston Moore model, so an easy setup really, which is sad to see the issues here but all easily resolved. Chris asked me to replace the full loom, so in went a new Switchcraft 3 way right angle toggle, CTS 450 series SSSP 500k split shaft pot, Pure Tone multi contact jack and Gavitt 22awg cloth covered wire (in green and black for good measure and paint scheme match!).
First up in the new loom and wiring tidy, was to neaten up and organise the pickup and ground wires. I tested the bridge ground wire to ensure there was continuity from the body insert to the wire end, all good there. And popped a meter on the pickups to ensure they're working as they should be also.
I made the new loom on my trusty pickguard template, ready to transfer over to the nice anodised aluminium pickguard(s). On the TMJM model the pickguard is actually split into two, the main part with the switch mounted, and the smaller part with the volume and jack mounted. I often encounter ground continuity issues with anodised finished aluminium pickguards, but noted on this that the factory sand off some of the anodised coating in the areas where the switch, pot and jack mount. I mounted the parts to test their continuity between guard and component and thanks to this prep work, found solid continuity so that I can rely on those instead of needing to add separate wires. But due to the two separate pickguards/control plates, I did of course need to run a ground from the switch to the pot.
Tap tested, I'm good to re-assemble and prepare for the setup.
I inspected the frets which were superb as is, so polished those up. Got the strings on, set neck relief, refined nut sloth depths and worked on the action/radius and intonation. All went nice and smoothly with action set to customers preferences.
Loved working on this rare JM variant, iconic offset model that looks, sounds and plays great. Thank you for sending the work my way, Chris.
If you are looking for Thurston Moore style wiring for your JM, whether it's to convert another model/varient of JM to TM specs, or to restore/repair the wiring on your own TMJM model. Then I offer pre-wired Jazzmaster Thurston Moore harnesses, which can be found on the store HERE
