Wiring diagram for ACTIVE pickups

[TheGreek]

I ordered some ACTIVE pickups for my Kawai - the original pickups had 9 (yes 9) wires going to various parts of the existing original preamp. I don't understand the wiring diagram at all. Local luthier found it confusing. Does this look right?

 

 

The new pickups only have two wires. I can post other photos (pickups themselves) to make more sense if required.

Edited November 1, 2022 by TheGreek

[Doctor J]

Black is Pickup earth

 

DPDT are serial/parallel switches
 

Brown is north coil start

White is north coil finish

Green is South coil start

Yellow is south coil finish

 

If you've only got two wires on the new pickup then the two lugs on the right side of the DPDT switches as the pic is orientated, your signal and your earth heading to the volume controls, are relevant. The DPDT switches are no longer in the circuit as the new pickups don't facilitate coil tapping.

 

Edit -> Actives usually have at least three wires. Signal, earth, and one which gets connected to the battery to power the active part.

Edited November 1, 2022 by Doctor J

[BigRedX]

That diagram looks very straight-forward except for the active part - what does it do? AFAICS it's just a buffer and doesn't add any active tone shaping (frequency boost) to the instrument.

 

The rest of the wiring is standard 2-pickup with a three way pickup selector and series/parallel switches for each pickup. Apart form the active section, it's the sort of circuit that would be more common in guitar than a bass, but nothing really out of the ordinary.

 

If your new pickups are only 2-wire, you won't be able to use the series/parallel switches, as there is no access to the individual coils with only two wires.

 

What exactly are you hoping to achieve with your new pickups? Last time I tried swapping the the supplied pickups in a bass with EMG actives it made absolutely zero difference to the sound, and with this new system you will actually be losing some tone shaping characteristics, unless the new tone controls allow cut and boost.

 

Edit: Follow-up question is there actually any difference in tone between the active and passive outputs with the bass wired with the existing circuit as shown?

Edited November 1, 2022 by BigRedX

[TheGreek]

I was forced down the route of replacing the pickups as the output on the bridge unit was significantly lower than the neck. 

 

My local tech is unavailable due to a cancer diagnosis,  local luthier in recovery so doesn't want to take on anything that isn't straightforward. 

 

TBH I feel like I've paid a premium for less tonal range. 

[BigRedX]

If this was my bass and the problem was simply that the two pickups were unbalanced, I'd be asking for recommendations for someone to rewind the bridge pickup to the same spec as that of the neck. However before that I'd want to go through a complete diagnostic of all the components in the circuit to ensure the problem doesn't lie elsewhere with something like a dry joint or a failing pot. Out of interest do you get the same fault using both of the outputs?

 

TBH apart form the active section which appears to be totally self-contained and therefore can be temporarily ignored, this looks like a very standard late 70s guitar type circuit so anyone who is having difficulty understanding it probably shouldn't be making alterations to the electronics and wiring.

 

Are you able to return the "replacement" pickups?

[Doctor J]

With the bass plugged into an amp, tap the pickups lightly across the top with a metal screwdriver to identify the architecture and make sure both coils are working in both pickups. You should hear a hearty thump where the magnets are located and the coil is live. 
 

Are the bottom of the pickups open or sealed with epoxy. The Aria pickups from this era are well known for coils dying but they're epoxy sealed and un repairable. It's worth having a look and seeing if the problem can be fixed. The original pickups look like they're passive, there is no direct connection to the battery.

[BigRedX]

Just had another look at the diagram in the OP and the description says there are 9 wires going to the pre-amp section but I can only see 5 drawn. Is the diagram correct?

 

And @TheGreek is this the bass that Andy JR rescued? If so could you provide a link to the thread where hopefully there will some decent photos of the pickups and wiring.

Edited November 2, 2022 by BigRedX

[TheGreek]

Replacement pickups for my Kawai. 

 

More photos to follow. 

[TheGreek]

So the preamp (?) for the pickups arrived today. I'm still not any wiser but may have found someone locally who can install the new tech.

 

First image is the original pickups which are sealed.  A Dremel was required to remove the sealed part.

 

Second image is the new preamp I believe. 

 

Final Image is the back of the new bridge pickup. 

 

[TheGreek]

Any idea what a fair price would be for the installation?

[TheGreek]

Need to bump for ease of access. 

[Grangur]

Mick and I met the other day after Mick dragged me out of bass-fixing retirement for this interesting beast. 
Here's a link to a similar bass for those who would like to see what we're talking about:
https://reverb.com/item/27705275-1980s-japan-made-kawai-fiib-f2b-alembic-copy-bass-guitar

 

Mick doesn't have the drop-tuner, but the bass has the potential to look very similar, if given some love and attention. That said, every "scar" is a sign of experience, so not everyone would want it looking so perfect, maybe.

 

There's come interesting info on the bass on the Kawai page:

https://kawaius.com/technical-support-division/faq/kawai-bass-guitars/

 

What I'm writing here is, largely, thinking aloud about the possible routes forward we could take on this.

 

From the info on the Kawai page we can see the original active pups had a number of pre-progammed "tone characters".
So from this we learn that the switches connected to each pup are not for series/parallel switching as I first thought. This also explains why the circuit in the bass also has no tone capacitors on the tone pups.

 

Considering we don't have these original active pickups and we now have 2 passive pickups, it's fair to say the 3 multi-position pickup selector switches installed on the front are redundant.

 

Moving forward, we need, therefore, to think of tha bass as wiring from scratch. So we have a few options to consider:

 

Passive 1

For simplicity the bass could be fitted with thenew 2-wire pups as a passive circuit and connect it in a VVT configuration. I know, it sounds great to think we could wire it with a volume and tone on each pup, but I've never had a lot of success in wiring this way. Although we might think of each volume and tone as a separate circuit, then feeding to the next and on to the jack, strangely electronic circuits don't think this way. What actually happens is both tones affect all the tone.

 

The negative side to this is we have 7 holes on the front of the body, ignoring the jack socket. VVT would only use 3 of these.  I know Leland Sklar likes his DFA switch, we could install one of these, but having 4 could be a bit OTT.

 

Passive 2

To the above VVT circuit we could add a series/parallel switch to each of the pickps. This would use 2 more of the 4 redundant holes.

This could be good, i guess, if this is your thing?
What it would call for is for me to attack the wiring provied with each pickup and add a second cable for delivering the connection to the centre connection to the 2 coils, back to the selector switch.

 

Active 1

Among the goodies Mick supplied to me I have the G201 "preamp". Yes it has a battery clip, but there is no adustment. So no need for the holes in the body.

Being a cynical person I'm also wondering what tonal quality the small circuit in the package will bring. What will it do, other than make the signal bigger?

 

Do we need it "bigger" or will the 2, 2-coil humbucker pickups give all the "big" we need?
What's the advantage of this over simply using the bass amp with the comprehensive controls on the front of that? Maybe use a Pre-amp pedal if that's your thing?

 

Active 2

Get another pre-amp. Maybe an East U-Retro pre. This would use up a good number of the holes. We would still have 2 holes left, I believe. I guess, in addition to the East amp you could have 2 pickup selector switches.
https://www.bassdirect.co.uk/bass_guitar_specialists/East_Preamps_U_Retro.html

 

Real life use

What Mick also needs to also consider is his own needs/desires. This is a nice bass with some history, but it's not ever going to be "as original". So, Mick, think about what you're going to play. Yes, some folk could be turned on by a massive scope of sounds, but this all costs. If the reality is that your needs will be met with 2 great pups and a VVT, then lets go for it.

 

Yes, you can have a DFA switch, but we do have another option. Since leaving the world of messing basses I've gone into wood-turning with a lathe. What I could do is turn dark wooden plugs that could be small and knocked into the redundant holes. These could also be tapped back out again if the holes were wanted back in use again.

 

If it were mine, I'd keep it simple.

Edited November 18, 2022 by Grangur

[Woodinblack]

1 minute ago, Grangur said:

Among the goodies Mick supplied to me I have the G201 "preamp". Yes it has a battery clip, but there is no adustment. So no need for the holes in the body.

Being a cynical person I'm also wondering what tonal quality the small circuit in the package will bring. What will it do, other than make the signal bigger?

 

How big a circuit do you need, and what tonal quality do you want. That would be using a preamp as a buffer, which means you get the sound of your pickups without loading by everything else.

You don't get the signal 'bigger', you get the signal low impedance so you don't get noise or the effects of loading.

[Grangur]

3 minutes ago, Woodinblack said:

 

How big a circuit do you need, and what tonal quality do you want. That would be using a preamp as a buffer, which means you get the sound of your pickups without loading by everything else.

You don't get the signal 'bigger', you get the signal low impedance so you don't get noise or the effects of loading.

Thank you. I'm a simple guy. I've never got into effects, pedals and stuff. Happy to be educated.  I can wire this stuff, to some level. I'd also be delighted to pass this project to anyone else who's better equipped to do it.

[Woodinblack]

Just answering the question - obviously what you want is up to you, I generally would go for not drilling more holes if you can!

[TheGreek]

I've made it clear that I don't have a clue what the electronics actually do so don't understand the limitations of the parts.

 

One of the reasons I bought this is that Kawai have a well deserved excellent reputation for tonal range.  I'd prefer not to lose this if possible. 

I would also prefer to have an active bass.

The correspondence I've had from the pickups builder suggest that the installation of the replacement pickups would be straight forward,  some of the contributions here supported this.

I know this might be a bit greedy but I want the best bass I can get with the parts available. 

[Grangur]

On 18/11/2022 at 18:18, TheGreek said:

I've made it clear that I don't have a clue what the electronics actually do so don't understand the limitations of the parts.

 

One of the reasons I bought this is that Kawai have a well deserved excellent reputation for tonal range.  I'd prefer not to lose this if possible. 

I would also prefer to have an active bass.

The correspondence I've had from the pickups builder suggest that the installation of the replacement pickups would be straight forward,  some of the contributions here supported this.

I know this might be a bit greedy but I want the best bass I can get with the parts available. 

 

The tonal range that this bass has a reputation for, and you're wanting to re-build, will have been be created by the original pickups with their integral pre-amps and the specialisd control switching circuit in the bass.

 

Regrettably, one of the original pickups has been, in the most part destroyed. This has destroyed the option of having the orginal tone of the bass where the bridge pickup is concerned.

I have no doubt the new pickups are straight-forward and easy to install into a conventional circuit, found in most bass guitars.

 

The circuit in the bass is NOT a conventional circuit.

 

What I also know is the new pickups don't have integral pre-amps found in the old Kawai pups. Whatever pre-amp you choose to have installed won't be identical to the pre-amp that's in the orignal pups, so the sound won't be the same as original.

 

Your circuit wiring diagram shows the wires to the pups as being  green, yellow, white, brown and earth.

What the pickups actually have are brown, white and earth.

So the wiring to the switches as shown in the diagram isn't possible without changing the cables and connections to the pickups.

 

Mick, your bass is of excellent construction. Its a solid through-neck beauty and I'm sure it will be a nice bass. It's possible the bass could be wired to be "as original" in respect of the neck pickup; if that one pup, and the related circuit works.

 

What it will never be is the same as it originally was in respect to the bridge pup.

 

Sorry, Mick, but I'll be returning the bass to you as it is and wish you all the very best with it.  As discussed, I'll be happy for you to come and collect the bass, or I can ship it at your cost.

Edited November 19, 2022 by Grangur

[TheGreek]

Thanks Richard. 

 

I'll get in contact to arrange collection. 

[TimR]

I'd put active pickups in it and 3 tone plus a volume control.

 

3 blanking plugs.