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guitarnerdswe

Member
Joined
Oct 7, 2020
Messages
6
Modding advanced electronics on a 2020 MM Luke

I could write an essay on this project, but I'll try to keep it short.

Outside
I didn't quite dig the hardware colour (the chrome plastic looks cheap IMHO), so I switched the tremolo arm, switch tip, knobs, and tuner buttons as a little nod to the 25th Anniversary Luke. I also tried chrome single coil covers, but it looked weird.



I also put on Wilkinson locking saddles. I switched out the black screws/springs to chrome. Partly for aesthetics, but also because I needed really short height screws due to how I set up the bridge. Also, the supplied intonation screw would mash into the low strings if you tried to intonate them on this particular bridge design, so shorter ones were needed. The black lock screws have a special plating, so they had to stay. Clear plastic tubing went inside the tremolo springs to stop ringing.



Inside
All the electronics are PCB-mounted. Even the tone cap is an SMD component. Which I had to change, since I prefer 0.010 uf over 0.022 uf.

I also had to build my own DPDT+SPST push/push pot to use as a tone pot. Yep, you read that right. It took a lot of work to find all the right parts, and then Frankenstein-ing™ them together through trail and error. One wrong move, and the whole thing is useless, which resulted in a lot of discarded switches and parts.

Basically, drill a hole in the DPDT housing, glue little wings made of metal can lids on a micro switch, then glue that to the DPDT housing.



So why did I build my own switch? Well, the guitar has a pickup level compensation feature, which is used to compensate (boost) the output level of the single coils to match the humbucker. Or in the case of this DIY switch, I use the DPDT to switch the humbucker between series/parallel, and the SPST micro switch activates the pickup comp, so I don't get any volume drop when running the bucker in parallel.



Which leads me onto the next thing: The Luke has non adjustable pickup heights. If one position on the 5-way needs less compensation, they use a board mounted SMD resistor. I wanted more control, so I used trim pots. The white trimpot controls pos 1-3, the blue pos 4. The stock PU comp trimpot on the PCB board controls the humbucker when in parallel, AND both of the other trimpots. That's because they're in series with the main trimpot, but in parallel with each other and the micro switch.



And the heart of it all: The custom made 8 pole stacked M switch from Eyb. This is the only switch that can make all this work, because I need all 8 poles + an extra long lever. Basically, these are the number of poles that are assigned to each task:

2: Pickup selection (hot)
2: Ground (one for load resistor, other for splitting/grounding)
2: Bridge pickup series/parallel & splitting
1: Pickup comp (trim pots, micro switch on tone pot)
1: Selects if the middle pup is grounded normally, or goes to the silent circuit (noise cancelling system).



So what does all this give me that's different than the stock wiring?

Pos 1-3
are basically the same. Standard strat neck, neck & middle, middle. Silent circuit connected, so there's less noise. The only difference is that I have the extra trimpot to fine tune the output level.

Pos 4 is quite different though. Stock, it's middle (+ silent circuit) & humbucker (internal series). Now, the bridge is split to the screw coil, and the middle is grounded normally (no silent circuit). It's done like this to achieve noise cancellation. This position is quite loud, so it needed its very own trimpot to tame it.

Pos 5 is where the push/push "freak of a pot" comes in. If the push/push is down, it's like stock: Full series humbucker. When it's up, the humbucker is wired in parallel, and the pickup compensation is engaged.

Was it worth it? Yes.
Would I have done it if I knew what a massive task it would be? No way. Maybe. Yes.

If anyone wants to know more about any particular part, I'll try to answer to the best of my abilities.
 
Last edited:

tbonesullivan

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Aug 24, 2012
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DANG. I would have taken one look at that PCB and ran away.

Heck I may have to replace the push push pot on mine, and even that is scary.
 

guitarnerdswe

Member
Joined
Oct 7, 2020
Messages
6
Some folk have too much time on their hands!

IMHO, guitars are meant to personalised and customised. We have an expression here in Sweden that goes: -"Shame on the one who gives up" :D

DANG. I would have taken one look at that PCB and ran away.

Heck I may have to replace the push push pot on mine, and even that is scary.

It's actually not all that hard. The volume pot comes with the little flex board attached, so you just have to worry about the tabs attaching it to the solder pads on the board. Soldering off the old one is much harder than soldering on the new one.

If your Luke is from 2012, it has the old electronics layout. Which means, no PCB mounted pots.
 
Last edited:

tbonesullivan

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Aug 24, 2012
Messages
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Location
New Jersey
It's actually not all that hard. The volume pot comes with the little flex board attached, so you just have to worry about the tabs attaching it to the solder pads on the board. Soldering off the old one is much harder than soldering on the new one.

If your Luke is from 2012, it has the old electronics layout. Which means, no PCB mounted pots.
My soldering skills are somewhere between inept and beginner, after trying for years. The electronics in mine have the boost on the tone pot, not the volume. I think. I did look inside and I recall seeing a small PCB attached to the switch part.

I could be wrong though.
 

guitarnerdswe

Member
Joined
Oct 7, 2020
Messages
6
My soldering skills are somewhere between inept and beginner, after trying for years. The electronics in mine have the boost on the tone pot, not the volume. I think. I did look inside and I recall seeing a small PCB attached to the switch part.

I could be wrong though.

Ah, it's that old! Then I know what you mean: The lugs and tabs on the push/push pot go into the circuit board. I would prefer that over the flex board, since they're quite fragile.
 
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