Jazz Bass control circuits (passive) - what works for you?

[JapanAxe]

I recently acquired a lovely Jazz (having sworn off them for a good few years) and I find myself facing the same first-world problem that I always have - quick changes to the sound.

 

I know that many people swear by the Volume/Volume/Tone (VVT) setup, and like to juggle the volume controls for subtle changes. Frankly I find these too subtle to be worth bothering with, and I converted my last Jazz to Volume/3-way switch/Tone, a bit like a lot of the passive Yamaha BBs. My current Jazz is a stack-knob with the later variant control circuit (no mixing resistors) and I'm starting to think a little modding might be in order. The everything-on setting alone is worth the price of admission but I have the same issue as with the VVT in that there is only any tonal change over about 1/10 of a turn of either volume knob. It has 250k volume pots but 500k tone pots, so very little happens to the tone until the bottom quarter of the pot rotation. For now I have tacked a couple of 56nF resistors in parallel with the existing 50nF ones, which has improved things from my point of view.

 

I'm currently considering getting a 3-knob control plate and setting it up in one of the following ways:

1. Vol/3-way/Tone
2. Vol/Blend/Tone as per the diagram below - I originally found it on Talkbass but then found that @TRBboy had posted this thread about it last year.

I could easily try both and see which I liked best of course

 

So - what passive blends have members had success (or not) with, and who gave up and either fitted a 3-way switch, or returned the bass to stock?

 

 

 

 

[itu]

Where's you ser/par switch? Push/pull pot? 

[Beedster]

This is my solution, single PUP wired to jack 🙂 

[JapanAxe]

48 minutes ago, itu said:

Where's you ser/par switch? Push/pull pot? 

Just because you could do something doesn’t mean you should!

[Lozz196]

I prefer traditional VVT, that way I can of course get all things Jazz but also get very near Precision if needed by neck full, bridge 20%-ish, tone 80%-ish. 

[PaulThePlug]

2x Vol is a Juggle, Blends often too Subtle or All or Nothing

 

SR500 Passive, Vol and 3 way pup switch - simple

and Hohner B2, Vol and 3 Way Pup switch.

 

I'd give Simple a try.

Edited yesterday at 19:45 by PaulThePlug

[JapanAxe]

17 minutes ago, PaulThePlug said:

2x Vol is a Juggle, Blends often too Subtle or All or Nothing

 

SR500 Passive, Vol and 3 way pup switch - simple

and Hohner B2, Vol and 3 Way Pup switch.

 

I'd give Simple a try.

I’m on board with ‘simple’ but I do like to ride the tone control from song to song.

[HeadlessBassist]

Whichever is the most convenient, I've found that there is a difference in sound between V/V/T and V/Blend/T, so I always leave mine as V/V/T.

 

I really liked the passive tone on the John East J-Tone system, which can be had either way.

 

Never really got on with the concentric Vol/Tone stacks. There's something missing from the sound there and they always sound too bright to me. 

[JapanAxe]

15 minutes ago, HeadlessBassist said:

Whichever is the most convenient, I've found that there is a difference in sound between V/V/T and V/Blend/T, so I always leave mine as V/V/T.

 

I really liked the passive tone on the John East J-Tone system, which can be had either way.

 

Never really got on with the concentric Vol/Tone stacks. There's something missing from the sound there and they always sound too bright to me. 

My stack-knob Jazz is definitely bright compared to my Precisions, but I enjoy the contrast.

[JapanAxe]

I've just finished reading most of the 18-page Talkbass thread, which runs from 2014 to August 2025! I'm going to go for a 100k MN blend pot and cut the traces for full isolation at the extremes, so I've ordered a pack of 5 via eBay. If I don't like it, I've found there's room in the cavity to fit a rotary selector switch.

[Mokl]

12 hours ago, Beedster said:

This is my solution, single PUP wired to jack 🙂 

Too complicated for me

[tauzero]

I've got two basses with V/V/tone bits, one Squier Modified Vintage Modified with an MM bridge pickup which I've modified to V/Blend with an MN500k pot, and an Ibanez SRF705 which hasn't yet been modified but will be, as I really dislike V/V and the fiddliness of adjusting two volume controls to change the overall volume. The piezo volume stays though.

[Stub Mandrel]

Blend means you can't get either of the classic 'hollow' both pups on full sound, or my usual neck full on, bridge ~20% sound.

 

It's interesting, I often gig a p-bass and rarely back it's tone off,  butwhen gigging a Jazz I often tweak the settings.

 

Being able to set both pups full when stuck under an electrically noisy light fitting is gold too. 

[JapanAxe]

1 minute ago, Stub Mandrel said:

Blend means you can't get either of the classic 'hollow' both pups on full sound, or my usual neck full on, bridge ~20% sound.

 

It's interesting, I often gig a p-bass and rarely back it's tone off,  butwhen gigging a Jazz I often tweak the settings.

 

Being able to set both pups full when stuck under an electrically noisy light fitting is gold too. 

With this circuit, centre position on the blend control means both pickups are connected direct to the master volume and tone controls, so that would be equivalent to both volumes maxed in a VVT setup as you say, needed to reject RF interference. Neck full / bridge 20% should also be achievable.

[tauzero]

1 hour ago, Stub Mandrel said:

Blend means you can't get either of the classic 'hollow' both pups on full sound, or my usual neck full on, bridge ~20% sound.

 

MN pots have tapers which go to 100% over 50% of the travel, so both of those are possible.

 

[miles'tone]

VVT with push/pull pot for parallel/series.

[JapanAxe]

1 hour ago, miles'tone said:

VVT with push/pull pot for parallel/series.

I’ve never hankered after the series option, in fact I rarely use it on my Dingwall NG2. I’d be interested to see how the two volume controls interact in series mode.

[miles'tone]

55 minutes ago, JapanAxe said:

I’ve never hankered after the series option, in fact I rarely use it on my Dingwall NG2. I’d be interested to see how the two volume controls interact in series mode.

They don't. The second vol control is out of the circuit in series. 

[Stub Mandrel]

6 hours ago, JapanAxe said:

With this circuit, centre position on the blend control means both pickups are connected direct to the master volume and tone controls, so that would be equivalent to both volumes maxed in a VVT setup as you say, needed to reject RF interference. Neck full / bridge 20% should also be achievable.

 

I had to look up mn pots.

[itu]

https://bourns.com/products/proaudio/products