Preamp wiring question.

[NancyJohnson]

I'm looking to swap out the pre-amp on one of my Lull basses (currently there's a John East unit in there); it's got two Lull 60s-style Thunderbird humbuckers.  I have three pot-holes and a small micro switch hole.  I'm reluctant to drill additional holes.

 

Ideally (as I've had reasonably good results from these), first choices are a Darkglass Tonecap or a Spector Tonepump, but these both seem to require 4+ pots.

 

Question is (and whether anyone has done this), is whether it's possible to wire the pickups to a stacked-knob pot, then take this feed into a couple of additional stacked pots (for whatever the preamp does bass/treble/mids/whatever) and use the micro switch to just turn the bass off or just leave it installed doing nothing.

 

Help!

 

 

[PaulThePlug]

You tried Passive?..

[NancyJohnson]

1 hour ago, PaulThePlug said:

You tried Passive?..

Yup.  I kind of like the added oomph from a preamp.  Wasn't always the case, mind.

[Hellzero]

I did this to my Acacia Custom 4 and some other basses @NancyJohnson: a stacked knob with two volumes (originally I intended to use a stacked volume and blend, but the cavity is not deep enough and can't be deepened anymore), a stacked knob for bass and treble, plus a Delano stereo pot for the mids and passive tone (so a single knob).

 

As it had two switches, one is active/passive and the other is the mid frequency selection.

 

The preamp is an Aguilar OBP-3.

[Hellzero]

I just checked the pot values of your two favourite preamps.

 

The Darkglass has 50 kOkms EQ pots, so a stacked pot is easy to source and a stacked volume 500 kOhms is easy to source too, so 3 pots with the stacked volumes, stacked mids and separate bass or whatever ever configuration you want.

 

For the Spector Tonepump, a stacked volume 500 kOhms is again easy to source, but a stacked 100 kOhms/10 kOhms is quite hard to find, so again 3 pots with the stacked volumes, the separate bass and the separate treble.

 

A killswitch is very easy to implement.

 

If you can use a soldering iron, it's a very easy job.

[Hellzero]

Here's a link to the stacked linear 50 kOkms with center detent: https://www.amazon.co.uk/Alnicov-Guitar-Stacked-Concentric-Potentiometer/dp/B08MPK9Q4J/

 

And the stacked logarithmic 500 kOhms: https://www.allparts.uk.com/collections/potentiometers/products/stacked-concentric-pots-500k-500k-metric

 

They both come from the same manufacturer. 😉

[NancyJohnson]

I've popped Dark glass and email; I just want to confirm there's nothing sinister in the supplied pots and that it's ok to not use them (their loom is solderless connections).

[PaulThePlug]

^ Good Darts!

[NancyJohnson]

The John East unit is out and I'm just waiting for the Darkglass Tone Capsule is incoming.  Going to test both 9v and 18v before deciding which to sick with.

 

I did get a reply from Chris Kollias at Darkglass along with schematics, pots, Dupont connection details etc.  I've not really found anything online that helps with wiring this unit into concentric pots, so if nothing it might be of some help to future installations elsewhere.

 

Thanks to @Hellzero and @KiOgon (who has offered remote assistance).