Humbucker - Fishman soundhole wiring combination

musicalstash

Any ideas on the best way to rewire the electrics on a modified
 kawai guitar. 

The guitar has been modded with a 
Fishman soundhole pickup 
Humbucker in the bridge 

With what I think is supposed to a single volume for each. 

Currently each pickup is wired to a pot ( I think) and then wired to a stereo jack socket. 

The pot wired to the neck oivkup doesn't seem to work unless the pot wired to the Fishman pickup is dialed to between 2-9

The Fishman pickup only works if the humbucker pot is full and again only works between dialed between 2-9 before cutting out at full volume.

I have attached a photo of the wiring to the pots.

https://ibb.co/c8V7PnS

https://ibb.co/dM9t1XB

https://ibb.co/XXY8fvc

Any  help would be appreciated. 

ICBM

Can you take a picture showing an overview of the whole thing? It's impossible to work out what's going on from those, though the pot in the middle picture clearly appears to have a huge mess of solder connected to the middle terminal, which could explain some of the problems.

musicalstash

Here you go 

https://ibb.co/Ss2LVZ5

https://ibb.co/MSM2C4M

https://ibb.co/dmmtGKY

https://ibb.co/7Qz7L9K

The pot which has the black and red wires is connected to the Fishman pickup, its middle leg runs to the jack socket, quite messy but doesn't seem to be touching the casing. 
.

ICBM

I can’t make that out at all.

What type of soundhole pickup is it?

Is if possible to get the whole lot out of the guitar so we can see it clearly?

Funkfingers

Assuming that both pickups are passive, magnetic types, the volume pots should be wired like a Fender Jazz Bass. i.e. Signal inputs to central pot terminals, output from outer terminals. 

If one pickup is magnetic and the other requires battery power, there should be buffering when the signals are combined.

The phase relationship between the two pickups could create frequency cancellation issues.

The only truly useful information I gleaned from the photographs is that the pots have been soldered onto so many times that their innards are probably cooked.

ICBM

Funkfingers said:

Assuming that both pickups are passive, magnetic types

If one pickup is magnetic and the other requires battery power, there should be buffering when the signals are combined.

This is why we need to know exactly what type of pickup the Fishman is. If it's an active one, with the red wire being the battery connection which is turned on via the ring terminal of the jack, then mixing it with a passive humbucker will not be successful.

musicalstash

Not too sure if it is an active Fishman pickup (can you tell from the pictures). 

I've taking tried taking it out to look underneath for the model but it's quite fiddly. 

https://ibb.co/c3WfSK5

https://ibb.co/cbzVFG2

Would an active pickup still have an output even when not connected to a battery   

Thanks 

Funkfingers

musicalstash said:

Not too sure if it is an active Fishman pickup (can you tell from the pictures). 

Looks like a Rare Earth model. The protrusion on the underside of the casing is the battery clip. The red wire merely completes the on/off switching from the TRS jack socket.

The critical detail that I cannot recall is the resistance value requirement for the volume pot.

Ideally, the two systems should be either blended via buffered pre-amp electronics (for ease of use) or kept entirely separate (for ease of wiring assembly).

ICBM

Yes, that's the active one - there are two small button batteries in the clip on the bottom. You can't mix that with a passive pickup easily, without buffering the passive one. The output impedance of the Fishman is so low that it will totally obliterate the other pickup when both are at the same volume.

Like Funkfingers I'm also unconvinced that the pots aren't knackered, especially the one with the mess of solder all over it.

If you want to use both pickups in the same guitar you're best to split the outputs either with two output jacks or a stereo jack (which will need to be a more complex type than the TRS one you have, since it still needs to turn on the battery separately from the signal connections), and mix the signal offboard. You can still have volume controls on the guitar - the passive pickup will need a standard 500K pot, the active one probably 25K or 47K - either should work, it's not critical.

Given that you probably want to use separate amps if you have an electric pickup and an acoustic pickup, I would use separate jacks and keep the ground connections separate from each other as well, to avoid a ground loop and hum.

musicalstash

Thanks again. I think the easiest option with my skill set is to remove the Fishman pickup and rewire the humbucker to a standard volume and tone. 

Out of interest if I wanted to use a passive soundhole pickup would still have a similar issue? 

Thanks again 

ICBM

musicalstash said:

Out of interest if I wanted to use a passive soundhole pickup would still have a similar issue?

No, that would work fine - although it's likely to be much lower-output than a standard humbucker.

musicalstash

ICBM said:

musicalstash said:

Out of interest if I wanted to use a passive soundhole pickup would still have a similar issue?

No, that would work fine - although it's likely to be much lower-output than a standard humbucker.

Thanks again.  Just wired it up to the humbucker and added a capacitor for the tone control and all works as it should.