Waz's MMB-4

[Marcel]

Nice even colour Waz...

[Adam Barnes]

Looks good

[Simon Barden]

No pickguard, just the wood. http://www.buildyourownguitar.com.au...l=1#post146244

[wazkelly]

Thanks Marcel & Adam. Just wet sanded with 1200 half an hour ago getting it ready from some more coats tomorrow night.

[wokkaboy]

nice wiring setup Ralph. Should get plenty of different sounds out of 1 humbucker !
Better check the resistance of the volume pots, are they 250k (for the switch pot) ?

[RalphH]

nice wiring setup Ralph. Should get plenty of different sounds out of 1 humbucker !
Better check the resistance of the volume pots, are they 250k (for the switch pot) ?

As standard, the MMB-4/5 kit has 500K volume pots, however for single coil PUPs, (which essentially this pickup has two of when wired independantly) 250K is common. You could use 500K pots for a slightly brighter sound, but this is a bass and does not have much in the audio spectrum above 7Khz anyway.

[wokkaboy]

ok thanks Ralph, I was getting confused. I put the same preamp in my JBA-4 but think maybe the blend pot was 20k. Makes sense using 250k for the volume.

[wazkelly]

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?

[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]

No, they come wired for parallel operation. That's already a pretty thick sound, wiring them in series might make it a bit too thuddy and bassy. Standard wiring for them just keeps the two coils in parallel, with a volume for each coil, so you can go front or back single coil if you want. The output in parallel mode is quite hot. so series will be even hotter.

Keep that in mind with Ralph's schematic as there is small possibility that the pre-amp might not have sufficient headroom and you get a touch of distortion in the series mode at full volume. Just depends on the preamp design.