Mod circuits from Daveplaysbass
Posted: Wed Dec 27, 2017 4:31 pm
This is the place to look for circuits from Daveplaysbass, the gentleman who originally created all the single coil (non-K model) mods.
Ken...
Ken...
A Technical Forum
For G&L Basses
https://www.bassesbyleo.com/forum/
jamjax wrote:Questions:
- The subject Tribute's pickup cavities were described as being shielded. How did they do it at the factory? (Anybody got pics?) I can have a go with some shielding paint or copper tape (both of which I have), but I wouldn't mind emulating the stock approach.
- Curious: How am I supposed to interpret the numbers on the switch's diagram in the doc? (There are 1s, 2s, and 3s, and sometimes comma-separated combinations.) I stared at it for a minute and didn't understand those labels.
jamjax wrote:Push/Pull Pot: Dave's docs go into detail on the specifics of the 4PDT switch but the push/pull potentiometer's specs are omitted. I took a gamble on shaft length, etc., and settled on this one: Bourns PDB183-GTR02-254A2 from Mouser for $5. It would be helpful to have specs (and part number options) in the docs, since others might know less than I do (and it still took me some time to track this one down). I haven't installed it, so I'm not sure I've got the right one yet.
jamjax wrote:4PDT Switch: It can be hard to find one of these which one can buy individually. I also was incredulous at the price and spent an uneconomical amount of time trying to hunt down a bargain (which I never found). Unless someone else finds a great bargain for you (the next tinkerer reading my post), just stop searching and pay the $25 plus shipping for one of these things. (You may find a better price until you realize you have to buy a minimum of 1000). I got this one: C&K 7411SYZQE from Mouser.[/list]
Shipping from Mouser was 7 or $8 to VA, USA.
jamjax wrote:The subject Tribute's pickup cavities were described as being shielded. How did they do it at the factory? (Anybody got pics?) I can have a go with some shielding paint or copper tape (both of which I have), but I wouldn't mind emulating the stock approach.
jamjax wrote:Curious: How am I supposed to interpret the numbers on the switch's diagram in the doc? (There are 1s, 2s, and 3s, and sometimes comma-separated combinations.) I stared at it for a minute and didn't understand those labels. UPDATE: I understand now: The numbers are each shown between two contacts. If a given number exists between contacts, those contacts are bridged when the switch is in that position number.
daveplaysbass wrote:I believe the Tribute pickups have a 5th wire coming off it that is green that ties directly to painted cavity with a metal terminal and screw. That green wire is a direct short or connection to the green wire that goes from the pup cavity to the control cavity. That is why after I got into my first Korean Tribute long ago, I changed all the wiring diagrams to always have the green wire at "signal ground". The older US G&Ls do not have any of this.
Ken Baker wrote:Might that extra green wire be the equivalent of the blue lead in the US -K models?
The non-K L series pickup has four leads; green & yellow and black & white. The green lead starts off at the coil and is a very short length to connect to one corner of the pickup's base plate. From the other corner of the base plate a long green lead extends into the cavity and is connected to ground. The other three leads run from the coils to the cavity.
The -K pickup has the same color leads as the non-K plus a blue lead. The green & yellow and black & white leads all run from the coils to the cavity. The blue lead runs from the base plate to the cavity and needs to be grounded.
In theory, the non-K pickup is ever so slightly unbalanced because of the base plate being in-circuit with one coil and not the other. The -K pickup is balanced because the base plate is not in circuit. The difference in impedance is so slight that it can't really be heard, but instrumentation can see it.