Schematic review: mid-80s Kramer Focus 3000 - multiple mods

[fido5150]

Howdy everyone.

I’m in the process of restoring an early-to-mid-80s Kramer Focus 3000 (actual date unknown), and although I want the exterior to look stock, I want to hot rod the internals. Well, I at least want to include some stuff that Kramer didn’t think of back in the early 80s, and make this guitar better than the higher-end Pacer Deluxe this guitar was emulating.

In stock configuration this guitar is HSS with dual linked tone controls (I think bass/treble), master volume, and a DPDT switch that splits the bridge humbucker.

What I want to do instead is this:


Overall I think this is a fairly uncomplicated schematic compared to some I’ve seen here, lol. The stock DPDT switch has been repurposed to switch the Gilmour neck pickup mod on or off, and if it’s switched on then it sends the signal to the phase inverter DPDT switch on the neck pickup tone pot (pull to invert). The coil splitter for the bridge pickup will instead be routed to the DPDT switch on the bridge pickup tone pot (pull to split), and converted to a PRS-style partial cut, with a 10K 10-turn trimpot to set the level of the partially split coil by sound.

This also has independent tone controls for the neck and bridge pickups, with matching pots and greasebucket circuits. Stock had 250K pots all around. Volume is a linear 500K pot and the single coils have 470K matching resistors.

Also a standard Duncan treble bleed.

I think that’s about it. I’m a newbie at wiring guitars, but have grasped it just enough to be dangerous, so if somebody more experienced than me could look it over and make sure I haven’t made some boneheaded mistakes that would be awesome.

I’ve spent the past few days cobbling this together after scouring the forum here, watching YouTube videos, and searching Google, so the odds of this being correct aren’t very high, lol.

A couple other things, the humbucker is a Duncan Pearly Gates wired in standard coil split arrangement. The green/teal paths are the green wire and the braid. Red/white goes to the splitter. I also may have gotten the push/pull switches on the tone pots set up backward from normal convention, so I marked up/down next to the switches so that it’s more obvious what my intent is.

Thanks!

[MattB]

Hi, fido5150.

It looks to me like everything will work. I like the idea of putting the phase switch after the neck-on. Seems like that should make the switching more flexible.

For the push/pulls, the lugs closest to the pot are connected in the up position. It looks like you have them drawn the other way round.

I wasn't familiar with the YM-50 switch so I googled it.

I'm assuming this picture I found is correct:

[newey]

fido5150-

Hello and Welcome to G-Nutz2!

MattB has answered your questions, and he has indeed found the correct pinout for the YM-50 (It's the garden variety import Strat switch.) You do have to be careful that the 2 common lugs are not jumpered together at the factory with that style of switch (just in general, not specifically the YM-50s), I've seen some where that was the case, there was a solder "bridge" behind the common terminals.

I like the idea of putting the phase switch after the neck-on. Seems like that should make the switching more flexible.

I'm not seeing this part at all. As I look at it, if I'm on the 5-way switch with N + M, and I want to put the neck out-of-phase with the other pickup, I could just manipulate one switch to do so if the phase switch were just wired as normal, directly after the neck pickup and before the other switching. The way this is wired, I'd need to manipulate two switches to get the out-of-phase N + M, unless I was already in the "neck on" position on that switch. ( N + B OOP would only be available with the neck on anyway.)

Also, it's a great diagram, but I had difficulty seeing all the connections given all the caps overlying them. Some more spacing so the caps could be drawn further away from the pots would help legibility. But I'm just being picky, a good first effort here for sure.

[fido5150]

Thank you for the replies! It’s very much appreciated.

Yep. That definitely looks like the YM-50 switch. This Kramer was made by ESP in Japan in the early 80s, and since it’s a thinner body guitar they had to use the shorter switch due to depth constraints.

And also thanks for the tips on wiring those pot switches. I probably drew the connections upside down, but I indicated on the diagram what my intent is. I’ll make sure and check everything with a multimeter before I wire them up. I’ve been there, and wired switches backward before, lol.

I agree the reverse-phase neck arrangement does get a bit convoluted in the N and N+M positions, I like your suggestion of reversing the phase before the switch newey, so I’ll look into that. I definitely want everything to be laid out logically.

Sorry about crowding things too in that diagram. I cobbled it together from diagrams I found, and I tried to use little dots at the end of each wire connection, but they kinda got lost with the transparency.

I definitely appreciate the feedback, and the welcome. Thanks!

I should get the remaining parts to restore this guitar within the next couple of weeks, and then the fun begins.

[fido5150]

Thanks for the tip newey, that actually simplified the wiring a bit.

In my prior diagram I also had to switch the ground or I ran the risk of lifting the ground if I pulled the pot while in the neck position and the other switch wasn't on. This way it's no longer a problem. I did a quick rework of that circuit in Photoshop, and for the sake of simplicity I removed everything else but that circuit.





I traced it out mentally, and it seems to work. Both sides of the pickup appear to be connected in all positions, and lifting the pot should switch the phase without having to enable the switch first.

The funny part is no matter how many times I went over this diagram in my head, it never occurred to me to invert the phase before the on/off switch instead of after. I had severe tunnel vision, lol.

Thanks again.

[newey]

Aug 17, 2022 20:29:28 GMT -5 fido5150 said:

it never occurred to me to invert the phase before the on/off switch instead of after.

That's the way it's typically done, the phase comes "first in line".

The revised "stripped down" diagram looks fine, as far as it goes. The rest of it from the first diagram drops right in.

The fact that you didn't think of it is the reason for this forum. We've all done our share of face-palms here, usually resulting from that same old tunnel vision.