Modding elelctronics on OLP MM3 Project Bass

[Vefa Erdem]

Hello everyone. This is my first post on the forum, and will be a long one, sorry for that in advance.

I have an OLP MM3 5 string bass with a single humbucker, of which the sustain and low B sound I am happy with. Since this is an affordable bass, I wanted to do some experiments on it. I have modded it so that the signal from pickups goes directly to the output jack, by-passing the stock vol and tone pots, which really extends the dynamic range and eliminate the noise of my bass. Yet it still sounds dull, more likely a PJ configuration, rather than a MM-style bass (I am not expecting an original MusicMan sound anyway, just aiming for a versatile and definitive sound, for example good voicing slap tones and funky low ends).

I have recently Invalid Link Removed for an incredibly cheap price from China, with 3 band EQ, a volume and a blend pot on it. This makes 5 pots and it is too much for a stingray type OLP cavity (I dont want to route extra cavity in my bass, it has got a nasty one already for a 9V battery, which is "carved" before I've purchased ). For this reason, I am trying to find a stacked potentiometer in order to combine volume and blend in a single pickguard hole, but i am not able to find one with a blend pot. Do you have any idea on where can I find one? In case I couldn't find a solution for this, another alternative is using a concentric stacked pot in order to use for a volume control per coil, this would eliminate the need for both blend and vol pots. Did you have experienced any drawback on this idea (such as noise, control difficulties, etc.)?

Apart from that, I don't have any experience with a bass which have a series / parallel switch on it. So I also want to try and see how it influences the tone. I've seen some videos (like this) with satisfactory results. And finally, another switch which turns off all the active EQ system and sends the neutral pickup sounds (passive) directly to the output, linked through only vol/vol stacked or blend pot.

So, to sum up all these, here are the options

a. 3 band EQ + vol/blend stacked pot + series/parallel switch + bypass switch (I guess it is possible to combine this last two with a on-on-on switch, right?)
b. 3 band EQ + vol/vol stacked pot + series/parallel switch + bypass switch
c. 3 band EQ + vol pot + coil selector switch + series/parallel switch + bypass switch
​

This list would go on forever and more I think of it, it more confuses me (a push-pull for bypass? DUH! )

I don't know which is more nonsense, but these are the ideas I want to experiment on. In terms of practicablity, feasibility and reasonableness, do you have any suggestion on these ideas, what to do or definitely NOT to do, or combine (and not to combine) an idea with any other?

Thanks in advance everyone!

 

[Vefa Erdem]

Anyway, I have finished it without any coil selector. And this is how it looks now.




I have soldered 4 capacitors to the MID push pull pot; a 27nf to input lugs and a 5,6nf to output of push state for 800hz, and 120nf and 33nf to the pull state for 400hz. My selection of these two MID frequencies were random, just to see how it respond. Freq. selection made a difference, but not a huge impact (difference between the 400-800hz), probably because of the lack of quality of OLP's stock pickups, or maybe because I am using Ampeg SVX amp sim. software and a reference headphones, or just the quality of the those no name capacitors. I'll try it in a studio environment soon. And probably I will replace the push-pull mid freq. selection with a concentric (twin, stacked, whatever it is) one to make the bottom pot to sweep the mid freq. that will be bosted. However, the effect of the series/parallel switch is just amazing. I think every manufacturer should add this option somehow.

My passive signal goes through the S/P switch, then the volume pot, and directly to the output jack. Not a fan of a TONE pot. I am satisfied with both passive and active sound, however, the gain difference between them is HUGE, which makes me crazy. I will add a trim pot to my preamp as soon as I figure out how it works. Yeah, maybe it is over-modded (mid selection may be excluded, but the S/P switch will definitely stay here), but I'm trying to find out how guitar electronic works, and what are the possibilities. I'm a bit geeky at this point.

By the way, if anyone planning to buy pots from China, don't do that.
Well, for now that's it folks.

 

[xOriginalNinjax]

Instead of doing a coil selector and a series/parallel switch, I would advise looking into a 4-way switch. I considered it on my J/MM Aria bass, but went with series/parallel/single (I think it's rear coil) on-on-on switch instead because of the size of the pre-routed hole I was using. The 4-way would rotate and give you series, parallel, single front, single rear (not necessarily in that order) and only take up one spot in your cavity.

As for mid-select, I'm a fan of a push/pull or on-on switch option, though I've read of people doing a stacked blend setup, so you have a center frequency (say 800hz) and can go down from there or up, as well as boost or cut. Some people might find this useful, but I've found that boost/cut is more usable than frequency change. I've also found that most of my passive basses record better than my active basses, but again, ymmv.