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Bill's Shop: Projects, Mods & Repairs / 90's Gibson Thunderbird Bass Pot Values / awful sound when Tone knob is on
« on: February 11, 2022, 10:09:29 AM »
Hoping someone can point me in the right direction on this one, I've got a 90's (from what I can tell) Thunderbird Bass and it's been always been a bit off, in terms of tone/sound.
Apologies for the super long first post, but might help with the diagnostics:
I discovered the 3 point bridge was bent and broken when I took it off, the bolts had been the only thing holding it on. It crumbled into 3 pieces.
I upgraded it to a hipshot bridge and the sustain on it is amazing now, it was almost non existing before.
Next I took a look at the internals, I can't seem to find the correct values of the pots online, but what I had was:
Neck Pickup Pot - reading 241K Linear taper , must of been 250K
Bridge Pickup Pot - reading 236K Linear taper , must of been 250K
Tone Pot - reading 367K Linear taper, not sure what it would of been 500k?
The cap on the tone pot read 0.019uf and was replaced with a Mallory .047 Capacitor @ 630 volt
I took these measurements with just the pots - nothing else connected.
It looks like the previous owner might have put these pots in and I was just wondering if anyone could confirm the proper values. I can find wiring diagrams and it is hooked up properly, but nothing solid for pots values.
I had some spare CTS good quality pots kicking around and played around a bit, I found that that the pickups seem sound better with Linear and the tone with an Audio taper. (just my opinion wasn't that bad with all audio taper either)
After all that I still find with the tone knob enabled (anything past 0-2 really) the bass sounds good but is picking up a "twang" sort of sound into the amp like too much treble or something, this is just mainly on the A string, if you play it open it sounds awful. The string height is easy to adjust and I've raised it and still get that noise.
If you turn the tone completely off, all that noise is gone, but the bass doesn't sound as good. Any help/advice would be greatly appreciated, this is the only Thunderbird I have access to and can't compare it to anything similar.
Apologies for the super long first post, but might help with the diagnostics:
I discovered the 3 point bridge was bent and broken when I took it off, the bolts had been the only thing holding it on. It crumbled into 3 pieces.
I upgraded it to a hipshot bridge and the sustain on it is amazing now, it was almost non existing before.
Next I took a look at the internals, I can't seem to find the correct values of the pots online, but what I had was:
Neck Pickup Pot - reading 241K Linear taper , must of been 250K
Bridge Pickup Pot - reading 236K Linear taper , must of been 250K
Tone Pot - reading 367K Linear taper, not sure what it would of been 500k?
The cap on the tone pot read 0.019uf and was replaced with a Mallory .047 Capacitor @ 630 volt
I took these measurements with just the pots - nothing else connected.
It looks like the previous owner might have put these pots in and I was just wondering if anyone could confirm the proper values. I can find wiring diagrams and it is hooked up properly, but nothing solid for pots values.
I had some spare CTS good quality pots kicking around and played around a bit, I found that that the pickups seem sound better with Linear and the tone with an Audio taper. (just my opinion wasn't that bad with all audio taper either)
After all that I still find with the tone knob enabled (anything past 0-2 really) the bass sounds good but is picking up a "twang" sort of sound into the amp like too much treble or something, this is just mainly on the A string, if you play it open it sounds awful. The string height is easy to adjust and I've raised it and still get that noise.
If you turn the tone completely off, all that noise is gone, but the bass doesn't sound as good. Any help/advice would be greatly appreciated, this is the only Thunderbird I have access to and can't compare it to anything similar.