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Modifying a 381?

Posted: Mon Nov 01, 2004 2:04 pm
by squid
Alright, I've committed myself to making some modifications to my 381. Ideally, I would like to add electronics that bring it in line with the 381JK, although I suspect that will be extremely difficult. (I've already sent a copy of the Ric JK schematic to Tonewerks and was told that it was pretty much useless without more detailed info. I wouldn't expect Ric to divulge those kinds of secrets publicly, but I was hoping that someone might be able to figure it out in rough terms. Tonewerks did refer me to someone else and I'll be following up with them later this week.)

I'm willing to do this in stages. I figure that switching the pick-ups out would be a good start, and to that end, I've ordered Ric HB's from Mike Parks. The next step would be introducing a coil tap. I'm hopeless with electronics. I'm willing to have a crack at it -- with input from the forum, of course -- but I'd rather give the instructions to someone who knows what they're doing.

I did a search of the archives, and saw that Kenny Howes was making similar inquiries in and around 2001 but abandoned the project. I also found this:

http://personal.nbnet.nb.ca/mccorp/thacker39112.html

Does anyone know who did these mods and if they're still in business? What I'm looking to do is pretty simple by comparison.

Thanks all.

Posted: Mon Nov 01, 2004 5:10 pm
by kennyhowes
Could be very tricky...all we did was drop a reject JK circuit into my guitar, and there ain't no more of them...

I would think it would be possible to do, especially having the schematic available, but the original one is all on a circuit board. I would think that hard-wiring it up would be a spagetti-like mess of wires...

Now, a simplified version could involve the basics: a phase switch, a coil-tap, and some kind of active preamp.

I'm sure that there's folks here who have done some custom trick-wiring to their Rics who can suggest some stuff...

Posted: Thu Nov 04, 2004 4:02 am
by squid
Minor question here: can anyone tell me how the humbuckers are mounted on the 381JK? More specifically, are they mounted on grommets or foam rings? I'm not going for authenticity here. I just figure there's probably a reason for going one way or the other, and I'd rather go with Ric's accepted wisdom. Thanks.

Posted: Thu Nov 04, 2004 5:59 am
by brian
Foam rings. I'll try to take some pictures and post for you a little later.

Posted: Thu Nov 04, 2004 6:07 am
by kennyhowes
Foam rings it is. Either would work, it's a personal preference, but get the grommets from us if you choose to do that; those from the hardware store could eat your finish. I'm sure there are other topics on this board discussing that...

Posted: Thu Nov 04, 2004 7:19 am
by adam_swapp
John,

I can't help you with the JK circuit (doesn't that have active electronics?), but I have installed a coil tap on a RIC HB. Look here then click on "Electronics" on the left menu. You could also wire up the phase shifter rather easily.

Let me know if you need any more info.

Posted: Thu Nov 04, 2004 8:38 am
by squid
That's extremely helpful, Adam. Thanks. How would you have set up the push-push pot (or pots) if you had opted for humbuckers in both neck and bridge positions with a coil tap for each pick-up?

Posted: Thu Nov 04, 2004 1:59 pm
by adam_swapp
John,

That depends. You'll notice that I have wired the circuit to put a 500K resistor in parallel with the 500K volume pot when the coil tap is engaged. This will, in effect, create a 250K volume pot for a single coil pickup. I don't know if that was necessary, but I thought it might be cool, and I had spare lugs on the switch to connect it.

If you want to do it simply, you can use a single switch to engage the coil tap for both pickups at the same time. If you want independent control of each pickup, you'll need a second switch. I substituted a 250K pot/push-push for the 5th knob. If you're going for independent control, you might swap out the volume knobs instead. Remember, though, the shafts on the push-push switches are smaller than the 3/8" shafts on the normal pots. You'll need a sleeve of some sort to keep it firmly in the pickguard hole. I used a bit of duct tape. Image You can also buy sleeves for this purpose from Allparts.

Posted: Sat Nov 06, 2004 6:10 am
by brian
There is an article in the archives (Rickenbacker guitars 2000-2001)on this guitar. I can't get the link to it to work. So if you search for model 391/12 and "and" the keywords you should find it. It is 3 pages long so use the next button. It describes what the controls do.

Posted: Sat Nov 06, 2004 6:15 am
by brian
Did anyone here ever get a copy of the schematic mentioned in the article ?