Waz's MMB-4

[RalphH]

Hmmm, food for thought as I have push/pull switches on a couple of other builds too.

I thought these came pre-set as a humbucker already therefore wired in series. The cable reveals 4 wire and bare earth and is identical to HB's that I had in my EX-5 before being replaced with Custom Bensons where push/pulls were used to coil split which essentially created JB single coil sounds. From memory I still kept the pots at 500k and same orange drop capacitor and it has plenty of beefy mid to bottom end sounds in either HB or coil tapped modes.

Curious to try out the blend pot as that will act more like a switch between the front and rear coils and it should also drop them back to single coil mode when biased either side of the mid detent point. If that doesn't work out so good will have another look at your wiring diagram and try and figure out why there are 1k resistors on each vol pot? Treble bleed perhaps?

I think Simon made a comment elsewhere about the lower signal levels experienced with the balance pot configuration when centered. Each pot is only halfway through it's travel when in the middle. The pre-amp should compensate for that to some degree, but my understanding is that the B2T only has less than 3db of flat gain. All the boosting/cutting is at the centre frequencies: Bass:+/-12dB at 85Hz, and Treble:+/-12dB at 7KHz.
Not sure exactly why the 1K resistors are there, may have something to do with the operation when the coils are in series.
Looking forward to trying any and all options; one of the joys of do'in it yourself.

[Simon Barden]

It's a shame the Belcat preamp doesn't have a small adjustable gain boost pot on it. It would make it a lot more versatile and would help you match the output to other basses you might have.

[wazkelly]

Hey Simon, are you referring to genuine MM PUP's or the stock Chinese kit ones? I can only comment on what came with the kit and it is ready set to go as a humbucker, same as what came in the EX-5 which are also the same as in the IB5 & IB6 plus Thunderbird and maybe a couple of others.

You need to run a multi meter across all 4 wires to work out which ones relate to either front (north) coil or rear (south) coil to make any decent sounds.

Here is the link to a post I put up last October on the topic.... http://www.buildyourownguitar.com.au...ead.php?t=6476

Definitely not a pair a coils in parallel as that sound is shite. How do I know? Because I accidently wired them up that way when doing the split coil push pulls on the EX-5 and not a pleasant or useable sound at all. Might be different on the Real deal MMB PUP but on these Chinese suckers, trust me, I know what I am talking about. This unit is just a MMB look alike as far as I can figure out.

Will keep an open mind on the topic in case standard pre-amp wiring sounds dull or crap and maybe then revisit modification ideas.

Cheers, Waz

[Simon Barden]

Hmmm. Not according the PBG wiring diagram. You might have two wires that come connected together like on a series humbucker, but (if you see the wiring diagram), they are supposed to be grounded. Which means they must be wired in series. You simply can't use two volumes on them if they were series wired.

They aren't the same soapbar pickups like with the EX-5 and IB5/6 models, they are very much the thick pole MM type. Soundwise I'm assuming that it will be a similar pickup sound to that on my old OPL MM bass with exactly the same wiring arrangement, which is a big thick punchy sound with both pickup volumes turned up fully.

My suspicion is that being humbucking (the pickup should be with both coils in parallel at the same volume) one pickup is obviously RW/RP with respect to the other and that with your EX-5, the coils were possibly being wired up with one coil reversed, so that you would have got a very thin sound indeed with lots of frequency cancellation. You were aiming for a split coil so weren't purposely choosing the wire connections for a parallel operation (which would probably have sounded fine).

This is where Weirdy would be useful, as he knows all this coil connection stuff well, whereas I have to keep looking it up and working it out. However I've been looking this up and Ralph's wiring diagram is fine for true parallel/humbucker wiring (though the wire colours are the Seymour Duncan ones and IIRC, the kit ones generally use the DiMarzio colours - though I wouldn't bet on it).

[RalphH]

Hmmm. Not according the PBG wiring diagram. You might have two wires that come connected together like on a series humbucker, but (if you see the wiring diagram), they are supposed to be grounded. Which means they must be wired in series. You simply can't use two volumes on them if they were series wired.

They aren't the same soapbar pickups like with the EX-5 and IB5/6 models, they are very much the thick pole MM type. Soundwise I'm assuming that it will be a similar pickup sound to that on my old OPL MM bass with exactly the same wiring arrangement, which is a big thick punchy sound with both pickup volumes turned up fully.

My suspicion is that being humbucking (the pickup should be with both coils in parallel at the same volume) one pickup is obviously RW/RP with respect to the other and that with your EX-5, the coils were possibly being wired up with one coil reversed, so that you would have got a very thin sound indeed with lots of frequency cancellation. You were aiming for a split coil so weren't purposely choosing the wire connections for a parallel operation (which would probably have sounded fine).

This is where Weirdy would be useful, as he knows all this coil connection stuff well, whereas I have to keep looking it up and working it out. However I've been looking this up and Ralph's wiring diagram is fine for true parallel/humbucker wiring (though the wire colours are the Seymour Duncan ones and IIRC, the kit ones generally use the DiMarzio colours - though I wouldn't bet on it).

The attached diagram shows the wiring options for the stock (Chinese) PUP's that come with the MMB's.
Hope this provides more data for everyone.

[WeirdBits]

I think Ralph has it covered.

[wazkelly]

Progress update after about 9 coats of TO wet sanded with 1200 W & D after every 2nd fresh coat. Just started using 50;50 turps/TO mix from around 7th coat and still using a rag trying to build up some thickness before switching to applying finish with W & D paper as that is what helped bring on a glassy surface with the Swampy Tele.


Colour is a bit washed out in these shots as they are first ones taken on my new Samsung A5 and still figuring it out.

[Kick]

You are nailing it again! Great work Waz!

[robin]

Looking good Wazza. I like the idea of an active pre-amp. Should have done that with mine but it didn't even occur to me. By the time I saw your build I had already ordered 2 new pickups.

It might not sound as good as yours, but Meh, its a bass, it just has to be loud. lol.

[ozzbike]

Wow again...Tru Oil is that glassy for you?....looks great mate. I cannot believe that you get this sort of finish with hand rubbed Tru Oil. Great work mate.