Waz's MMB-4

Agree with trying blend pot options first as not much room left in control cavity.

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Here's another wiring option to consider that was employed on the G&L L1000 series basses of the late 1990's. This setup allows two humbucking modes plus a single coil option.

The pickup on the L1000 appears to be wired the same as the GFS, (3 conductor series wired humbucker with centre tap + case braid) so theoretically this should work for you too.

The G&L had a 3 position, 2 pole toggle switch which are quite expensive (and hard to find) so during my experiments I configured a 2 pole, 3 position rotary switch to do the same job. Looks good too.
The rotary switches I've used are only 5 bucks from Jaycar, and the only customising is the reworking of the shaft to accept a fluted knob. And yes- they fit (at least in my case) in the cavity of the MMB bass with a bit of minor sanding.

Attachment 27695

Surely Position 3 will be out of phase with itself, so give a very thin sound that's probably not bothering with? And as the current flows the wrong way round just one of the coils, then it won't be humbucking (I think).

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Originally Posted by WeirdBits

Ok, bear with me. It's a bit difficult to tell from your photos etc., but the original configuration of the Belcat blend/balance pot should have been something like this:
Attachment 27614
The black ground would be connected to either the top left lug or bottom right (with respect the the above orientation), and each of those lugs has a link to the pot case. The red hot from the volume would either be the bottom left lug or top right and have a coated wire linking between those two lugs. Normally, your parallel pickups/coils would then connect to the middle lugs.

However, because your pickup coils are in series rather than parallel we need to connect each coil across the resistance side of each half of the pot, which requires some re-wiring. Essentially, when at the centre detent the signal will then go through each coil in turn rather than through the resistance (mostly) and turning the knob away from the centre will bypass one coil or the other.

First step is to disconnect the pot case link from the lower right lug, otherwise it will short your signal to ground. Next, disconnect the wire link from between the bottom left lug and top right lug.

Then, connect the pickup and volume wires like this:
Attachment 27615
That *should* get you what you want. The sound of the pickup may be slightly different in the centre position compared to what you're currently hearing, due to the change to the way the coils are loaded. And, you'll probably find the balance works a bit more... switchy. That is, you may not hear much change until it's almost fully turned one way or the other and then you'll hear the coil drop out quite quickly. Hopefully ;)

Another option would be to just remove the blend/balance pot entirely and replace it with an On/Off/On mini-switch to select the coils as one/series/other.

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OK, so I have wired it up this way and as predicted not much difference in sounds and if anything just a tad thinner at centre position which should be in series.

Reverted back to original blend pot setup and played around with various combinations and best sound was just hard wired in series with blend pot effectively doing nothing.

Now starting to consider either mini DPDT on-off-on switch or a rotary one as suggested by Ralph however not sure on how to wire up either switch type. Thankfully Jaycar Electronics are less then 1km from where I live and stock both parts but the rotary switch has a long shaft that would need to be cut down. This is the mini DPDT they have and wondering which wires go to which lugs?

Attachment 27799Attachment 27800

Thanks, Waz

This should do it for an On-Off-On, series in the middle position and shorts the respective coils when up and down:
Attachment 27801

Thanks Scott, i will give that a go.
Cheers, Waz

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Quote:

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Originally Posted by WeirdBits

This should do it for an On-Off-On, series in the middle position and shorts the respective coils when up and down:
Attachment 27801

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Hi Waz...this is what I did on my RC-4 build as well. The result was less than impressive from my POV, but it seems to work. I need to make some adjustments, tho (pickup height)...maybe they'll improve the result when I'm done? We'll see...

Thanks mate

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Wired up the DPDT mini switch earlier tonight and that works & sounds best out of all the combinations tried so far.

Thanks guys for all your ideas, guidance & assistance.

Next job is to dig a bit more timber out in the control plate cavity as there is a square plastic terminal block for belcat pre-amp with lots of wires coming and going that is preventing everything fitting in an already cramped space. Don't own a dremel and not keen spending the coin for just this one job. Might have to use a chisel instead unless someone has a bright idea for cutting/recessing at 90 degrees inside a 30mm wide trench which is just on 38mm deep?

For it it sit vertical, thickness is about 6 or 7mm thick whilst horizontally I would need to go about 18 to 20mm deep and drilling in via jack socket hole seems most logical way to go? Will ponder this for a few days before attacking it.

I’m not usually one for product endorsement but I brought a Dremel and it’s my favourite toy at the moment. As an engraving tool it is 100% better than the engraving pen I was previously using.

It's worth getting one with the flexible extension as it makes getting a burr or a sanding drum into a tight corner a lot easier. Also makes engraving-type tasks a lot easier as you can grip the end more like a pen.

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Originally Posted by DarkMark

I’m not usually one for product endorsement but I brought a Dremel and it’s my favourite toy at the moment. As an engraving tool it is 100% better than the engraving pen I was previously using.

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I'd be concerned about the longevity. I had the hobby re-chargeable Dremel that sat in a charging cradle when unused.
Got about 12 months when it carked it.

So I got myself one of these. https://ozito.com.au/products/rotary...0w-42-pce-kit/

3 years (at least) with several guitar projects and it's still going strong.

cheers, Mark.

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Originally Posted by wazkelly

Wired up the DPDT mini switch earlier tonight and that works & sounds best out of all the combinations tried so far.

Thanks guys for all your ideas, guidance & assistance.

Next job is to dig a bit more timber out in the control plate cavity as there is a square plastic terminal block for belcat pre-amp with lots of wires coming and going that is preventing everything fitting in an already cramped space. Don't own a dremel and not keen spending the coin for just this one job. Might have to use a chisel instead unless someone has a bright idea for cutting/recessing at 90 degrees inside a 30mm wide trench which is just on 38mm deep?

For it it sit vertical, thickness is about 6 or 7mm thick whilst horizontally I would need to go about 18 to 20mm deep and drilling in via jack socket hole seems most logical way to go? Will ponder this for a few days before attacking it.

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Waz,

I have a green shed brand dremel style tool....with a flexible extension....and heaps of fittings.

I am at work....residential care in a community home in Bells Reach.

I am supposed to finish sometime Friday.

I will be home over the weekend....either drop in and grind away...it is permanently setup on my desk....or come borrow the machine.

I only use the sanding attachments...no idea what the rest do. 😎

Thanks for the offer Ozzie. Never used one and not really sure what does what either but reckon between us we could figure something out?
I also have work getting in the way of having a life and only day off this week is Sunday. Will send you a SMS Saturday afternoon to see if still ok to catch up on Sunday.

Cheers, Waz

Caught up with Ozzie earlier today and had a good time having a chat, playing guitars, and also got around to digging out some timber in the control cavity of this build to help make the pre-amp and all it's wires fit down low enough for boomerang control plate to sit flush with body....

Thanks for helping me out yet again and loved how your MMB-5 build looks and it is coming along real good.

Cheers, Waz

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Originally Posted by wazkelly

Caught up with Ozzie earlier today and had a good time having a chat, playing guitars, and also got around to digging out some timber in the control cavity of this build to help make the pre-amp and all it's wires fit down low enough for boomerang control plate to sit flush with body....

Thanks for helping me out yet again and loved how your MMB-5 build looks and it is coming along real good.

Cheers, Waz

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You are most welcome. Thanks for bringing the coffee and pies.

I really enjoyed your five string that came along for the ride. Gave me a great insight as to what my mmb-5 will do. Thanks.

Just a query, and maybe weirdy or Simon may correct me...Your nylon bushes are keeping the pots from contacting the metal control cavity cover....and I cannot see a ground link wire running from the back of each pot to the next and then to the ground connector on your socket. Could this cause some of the issues you are having? Consider earthing everything...and it may also give you that noticeable difference between switch positions.

You are always welcome in my workshop. 🎸🎶🎼

G'day Ozzie, everything is earthed to the volume pot.
Stacked blend pot wasn't doing much on coil splits and as you heard with the dpdt mini switch there isn't much happening with one of them either, just more noticeable than using blend that came with the pre amp.

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Originally Posted by ozzbike

Your nylon bushes are keeping the pots from contacting the metal control cavity cover....and I cannot see a ground link wire running from the back of each pot to the next and then to the ground connector on your socket. Could this cause some of the issues you are having?

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In addition to what Waz has said above, the threaded shaft of the pot is in contact with the metal control cover, also via the nut and washer keeping the pot on tight, the pot casings themselves will all be connected together and as it looks that Waz has got at least one ground connection to the back of a pot from the photos, so all should be well. But if you haven't done it yet, then it never does any harm though to double check the ground continuity with a multi-meter, just in case.

Quote:

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Originally Posted by wazkelly

G'day Ozzie, everything is earthed to the volume pot.
Stacked blend pot wasn't doing much on coil splits and as you heard with the dpdt mini switch there isn't much happening with one of them either, just more noticeable than using blend that came with the pre amp.

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All is good. I hope you get the outcome you want.

(Thanks for the wetsanding advice 1200 levelled up nicely. Nice full strength coat over it and those little holes are gorrrnnnn.)

Thanks. 😎

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Originally Posted by ozzbike

All is good. I hope you get the outcome you want.

(Thanks for the wetsanding advice 1200 levelled up nicely. Nice full strength coat over it and those little holes are gorrrnnnn.)

Thanks. 😎

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Good to hear Ozzie.

Do you have any 1500 or 2000 as I have some spare if you need it.

Getting closer to the finish line

Touched up area that was dug out to fit pre amp with some fresh copper tape last night, checked that everything fitted and found it was still a bit cramped. In fact the last pre-amp pot for one of the tone boosts was sitting on top of the jack socket plus wires attached to end of jack socket also looked a bit vulnerable. Ended up removing one nylon washer off all pots to raise their bases by similar thickness and that provided just enough clearance over jack socket which had just been de-soldered and re-soldered with heat shrink added to insulate some bare contacts that may have shorted out if left unattended. At each small change I stopped to check and make sure there was still sound coming out to avoid a lengthy trouble shoot if done all at once and then found no noise....been there and done that too many times before.

It was way past 10 pm when I screwed down the boomerang plate and plugged it in to the Hartke 75w combo and had to keep volume at a sensible level but was quite impressed with the tone of this GFS pickup, and the 3 way mini dpdt switch does actually work and provides a couple of significantly different sounds. all of which are best when left in humbucking series position. When dropping a coil the level also drops a bit and can't wait to play it over the weekend with a bit more volume to see how it really sounds.

Below shots taken early this morning.....still have setting up neck, action, intonation plus another final polish to go.

Attachment 27912Attachment 27913

I’m digging the nice clean natural look. Uncluttered and very nice.

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Originally Posted by WeirdBits

I’m digging the nice clean natural look. Uncluttered and very nice.

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Thanks Scott.

Lots of chrome on the boomerang plate had me wondering whether black knobs might look better but I will stick with this for now and let it grow on me before making that decision.

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Originally Posted by wazkelly

Good to hear Ozzie.

Do you have any 1500 or 2000 as I have some spare if you need it.

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I have both 1500 and 2000...and I have the micro mesh pads from the sandpaper man.

Thanks though.

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Originally Posted by ozzbike

I have both 1500 and 2000...and I have the micro mesh pads from the sandpaper man.

Thanks though.

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All good then. Maybe one more 1200 wet sand after 4 more coats then move up to 1500 should start to bring it home.

Finished, at last.....it only took the best part of 18 months!

This one has been on a slow burner for quite some time and was too busy obsessing with achieving the perfect finish and had to draw the line somewhere or it may still be a work in progress for a lot longer.

Not too many original kit bits ended up being used other than neck & body plus bridge, control plate & screws, neck plate & bolts.

Some of the modifications included:
Rounded over the side profile by hand using 80 & 120 grit sand paper.
MM 5 string headstock shape used without the offset 5th string tuner hole
Allparts 4 in Line Bass Tuner Set
Allparts Tele style Chrome Electrosocket Jack Plate
PBG Bone Nut
GFS MM Pro Plus- Alnico Music Man style pickup
Belcat Pre-Amp
Jaycar mini DPDT on-off-on pickup coil split switch
Straplocks

Also did a short demo video earlier today that requires some editing....hope to post that in the next few days.

Not a kit, but I upgraded a similar bass made by Hamer. Put in a Wilkinson Pickup, which improved the sound greatly.

https://www.aliexpress.com/item/Wilk...27424c4diqinci

About that bridge: there are 3 screws on one end and 2 at the other. I upgraded with a MM style bridge, which has two ferrules where the two screw are, then hex bolts screw into the ferrules. Much more solid sound and feel, and looks better too.

https://www.aliexpress.com/item/Chro...27424c4dC6XNrU

Those links showed some nice upgrade goodies.

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That looks flawless. Great clean looks. Looking forward to the demo.

Thanks Mark. Just need to edit out a few not so good bits.

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Well done Waz, that looks fantastic

Noice one!

Slick and simple. :)

Finally got the demo video uploaded to YT.....

http://youtu.be/fbjI0MssJtc

Pretty cool, sounds great, decent range of tones. I had no idea it was so big, the Steampunker body is so small in comparison.

Yeah, the bottom cutaway has it sitting in an odd position sitting down compared to my J Bass, and as I like to play near the bridge that ends up being further to my right.
Sound picked up a little bit of fret buzz around 1st - 3rd and have done minor tweak to sort that. Most of that was string noise as couldn't hear it when playing through headphones.
Pleasantly surprised with the coil split options, even if output level drops a bit as they are still useable.

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Originally Posted by wazkelly

Finally got the demo video uploaded to YT.....

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G'day Waz.
Sounds good. Makes me now want to re-visit White Wedding.

cheers, Mark

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Originally Posted by king casey

G'day Waz.
Sounds good. Makes me now want to re-visit White Wedding.

cheers, Mark

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Hey little sister what have you done.....