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

[JapanAxe]

2 hours ago, jd56hawk said:

VVT with a turbo switch.

 

What does the Turbo switch do? I’m kind of afraid to ask…

[neepheid]

Which Jazz circuit works best for me?  Probably the one with no output jack...

 

Merry Christmas!

[HeadlessBassist]

1 hour ago, JapanAxe said:

What does the Turbo switch do? I’m kind of afraid to ask…

 

It forces a rush of compressed air into the tone wood molecules and makes them vibrate more quickly. As a result the bass resonates faster, making the sound sweeter, generates a more purposeful tone, and thusly the player becomes faster, with improved technique and accuracy, and becomes more God-like.  🤣

 

You did ask. 

 

Happy Christmas one and all!

Edited yesterday at 13:20 by HeadlessBassist

[Geek99]

2 hours ago, HeadlessBassist said:

 

It forces a rush of compressed air into the tone wood molecules and makes them vibrate more quickly. As a result the bass resonates faster, making the sound sweeter, generates a more purposeful tone, and thusly the player becomes faster, with improved technique and accuracy, and becomes more God-like.  🤣

 

You did ask. 

 

Happy Christmas one and all!

What if it’s vintage tonewood? 🍿
I’m also assuming that a longer g string screw on the bridge saddle makes it sound different also 

Edited 22 hours ago by Geek99

[HeadlessBassist]

38 minutes ago, Geek99 said:

What if it’s vintage tonewood? 🍿
I’m also assuming that a longer g string screw on the bridge saddle makes it sound different also 

For best results, dredge your vintage tonewood from the bottom of a lake, same as they do for those highly expensive drum kits.

 

As for that screw in the G string saddle, I’m selling them for £40,000 each. Right, who wants some Magic Beans then..?

[JapanAxe]

41 minutes ago, Geek99 said:

What if it’s vintage tonewood? 🍿
I’m also assuming that a longer g string screw on the bridge saddle makes it sound different also 

Well spotted! The bass came without the correct 6-32 intonation screw (actually a bolt). The original would be  1 7/16in (39mm) long. I sourced some 2in bolts and cut one a bit longer, as I suspected the original had been lost because it didn’t adequately engage with the bridge saddle.

 

This topic is crying out for a PhD thesis!

[ezbass]

My J type has Delano pickups, which are actually split coils in a single coil casing. These are wired to a VBT config. I can achieve 5 tonal settings from this, not including the tone control (.100uf) roll off: if 6 o’clock is typical 50:50 blend, 5 and 7 o’clock give either a more neck or bridge flavour of the mid position, whereas anything beyond those points is either all neck or bridge.

[JapanAxe]

2 hours ago, ezbass said:

My J type has Delano pickups, which are actually split coils in a single coil casing. These are wired to a VBT config. I can achieve 5 tonal settings from this, not including the tone control (.100uf) roll off: if 6 o’clock is typical 50:50 blend, 5 and 7 o’clock give either a more neck or bridge flavour of the mid position, whereas anything beyond those points is either all neck or bridge.

That’s the thing, once you back off a stacked volume control or a VVT volume more than one notch out of 10, I don’t hear any further change. 
 

EDIT: Hoping for more variation on a blend…

Edited 18 hours ago by JapanAxe

[JapanAxe]

I mentioned earlier today I had 'another idea' - I've implemented it, and it works!

 

When thinking about what didn't work for me about the stacked-knob setup, the main issue was the tone pot taper, where there was little effect until the bottom quarter turn of the pot. I removed the extra 56nF caps and added a 510k resistor between the wiper and the 'hot' lug of each tone pot, thereby converting the existing 500k tone pots to 250k with a somewhat different taper. The tone pots behave much better!

 

Curent plan is to to stick with this, but also acquire a 3-control plate and build it as Vol/Switch/Tone or Vol/Blend/Tone.

 

Watch this space...

 

[jd56hawk]

8 hours ago, JapanAxe said:

What does the Turbo switch do? I’m kind of afraid to ask…

The tone switch is Series/Parallel switch. 

[itu]

Yoy could even add another J pickup to the bridge position. Talk about supercharge. 

[Sté]

VVT. And those stock from my Sire U5 are really efficient. 

[tauzero]

As regards V/B/T, I thought I should post a version of the wiring diagram that I worked from:

 

 

This may be clearer:

 

 

In this, the opposite ends of both tracks are cross-connected, rather than leaving one end floating as in the diagram in the OP.

[JapanAxe]

12 hours ago, tauzero said:

As regards V/B/T, I thought I should post a version of the wiring diagram that I worked from:

 

 

This may be clearer:

 

 

In this, the opposite ends of both tracks are cross-connected, rather than leaving one end floating as in the diagram in the OP.

 

Thanks, I came across these when I was looking into options.

 

I drew out the circuit in the OP and added in the second cross-connection as per the lower diagram, then compared the two. The OP circuit simply puts a resistance (let's call it R) in the path of one of the pickups at a time, to attenuate its signal. The effect of adding the cross-connection is to add a second resistive path in parallel:

1. At zero attenuation there is no difference.
2. At maximum attenuation the resistance in series with the pickup is now ½R instead of R.
3. At the halfway point, it becomes ⅜R instead of ½R, so the taper of the blend has changed.
4. Also with this circuit you wouldn't get the effect of completely disconnecting a pickup if you cut the resistive tracks near the end.

It would be a quick and easy thing to try though.

 

In the upper diagram, the second cross-connection is tied to ground, which is a different approach altogether and has the effect of loading the pickups, which the OP circuit doesn't.