Jazz Bass blasphemy: VVT --> VBT

[dje31]

I know traditionally, Jazz Bass controls are VVT, but I've always preferred a blend / balance control instead of individual volume on 2 pickup basses.

Would I be accused of blasphemy or heresy for such a modification? Anyone else done this? Any reason not to do this?

[Mushroo]

I doubt very many people in the audience will notice. The difference in tone will be slight, and probably not make a big difference in the context of a full-band mix. So I say, go for it!

[dje31]

I wasn't so much concerned with folks noticing it. Besides, we're bass players! Who the hell notices us? (Besides other bass players, of course...)

What would account for tonal differences? Just curious.

[Mushroo]

If you don't think anyone will notice, and you're not planning to make an announcement, then why worry about being "accused of blashpemy or heresy"?

In regards to your second question: Why do you think changing your wiring scheme wouldn't change the tone of your bass? It seems logical to me that different electronics = different sound, no?

[jay loren]

It's so much easier to just turn down one volume knob if needed.
I learnt to appreciate the VBT setting from playing my Jazz Deluxe bass extensively and converted my RW Jazz as well. There are companies that sell pre-installed control plates which makes the conversion process a breeze.
Go for it!

[Raymeous]

Just do the mod.

If you prefer Volume, Blend, Tone; then get it set up that way. You're the one playing YOUR bass. If there is a tonal difference, which I doubt, it would be so slight that in the context of a live gig, nobody would notice. If the "purists" have a problem with it, they can take a long walk on a short pier as the saying goes. It's YOUR bass, make it work for you.

My most modded instrument at this point is my first electric guitar (got it at 13 and now 40) which used to be a Fender Strat. The only original parts these days are the body, the middle pickup and cover, and the lower half of the tuning keys (I'm not kidding just the lower portion), the rest of it is all modded.

I say go for it and make it YOURS

[Basshappi]

It's your bass, set it up the way that you prefer.

[dje31]

The whole blasphemy / heresy thing was more in jest than anything, a poke at the purists.

I'm typically a "buy-and-hold" type, instead of a "flipper" when it comes to gear. That being said, when I do mods, I usually keep the original stuff around regardless, should I want to restore it to OEM spec.

As for tonal differences, I guess I hadn't taken into consideration that it would have any appreciable effect, but technical / EE types / dabblers are no doubt more tuned into that than me. I figured volume is volume, but I suppose V=IR plays into it, rheostats, potentiometers, etc.

[RedMoses]

I have that on all my Fender style Basses...

[Mushroo]

Ah, I didn't get the joke, sorry.

My understanding from reading dozens of Talkbass threads on this topic is that, on a passive bass, Vol/Vol has a *slightly* more agressive or "hot" quality, compared with Master Vol/Blend, which might be described as more "polite." The reason being that a blend control is actually two volume pots wired in reverse to the same shaft, therefore Vol/Blend/Tone is actually Master Vol/Vol 1/Vol 2/Tone (4 pots in the chain instead of 3 pots). Certainly Vol/Vol is one component (a minor component, perhaps) of the "classic Jazz bass sound."

As I mentioned originally, the slight difference in tone may be insignificant (or perhaps even imperceptible) in a full band context.

[dje31]

Cool, Mushroo! Thanks for the clarification. I figured there had to be a good reason for why it wasn't more commonplace, and since my three current basses are all active (one with a passive bypass), they all have a blend knob.

Looking real hard at a Squier VM Jazz 77, but may re-think the rewiring, now that I know the reasoning behind it.

[Mushroo]

For the record, I have passive VVT and VBT basses, and they both sound great. But the differences between the instruments are so great (the VBT is not Fender-style) that it's impossible for me to say what % of the difference in sound is due to the electronics.

Also I encourage you to check out some of those historical discussion threads I mentioned, as I remember some *very* knowledgeable people sharing their opinions.

[awilkie84]

I'm not a fan of VVT controls. I've rewired all but 1 of my basses to VBT. The last one will be VBT, soon. I just need one of the EMG balance pots, so I don't have to splice my pickups.

[dtripoli]

Yes, you blasphemes heathen, it is heresy.
That is also the name of our band, so consider this a cease and desist order.

..on a friendly note, as my daddy used to always tell us, "It's your toys, do what you want with them even it it means breaking them, you have my blessing"

[Stealth]

Originally Posted by Mushroo

My understanding from reading dozens of Talkbass threads on this topic is that, on a passive bass, Vol/Vol has a *slightly* more agressive or "hot" quality, compared with Master Vol/Blend, which might be described as more "polite." The reason being that a blend control is actually two volume pots wired in reverse to the same shaft, therefore Vol/Blend/Tone is actually Master Vol/Vol 1/Vol 2/Tone (4 pots in the chain instead of 3 pots). Certainly Vol/Vol is one component (a minor component, perhaps) of the "classic Jazz bass sound."

And you're exactly right with the description.

If anyone's up for some technical explanation, here goes. We'll assume identical pots (say, 500 kΩ for more modern basses).

With a V/V/T combination with everything on full, you have three of those pots' resistances (V₁, V₂, T₁) in parallel with the pickups for a total of 166 kΩ* loading down the pickups.
With a V/B/T combination with everything on full, you have four pots' resistances in parallel (V₁, B₁, B₂, T₁) for a total of 125 kΩ* loading down the pickups.
With a V/B/T with ungrounded blend pot's contacts (those contacts remain floating - unconnected at all) you have only two pots' resistances in parallel (V₁, T₁) for a total of 250 kΩ* in parallel.

The effect on the sound is as follows: the smaller the loading resistance, the darker the tone - so in our above example the VB_uT would be the brightest, followed by the VVT and the VBT, using all with identical pots. The VB_uT has a small change in that neither pickup will ever be completely muted, but quite a few TBers have tried it and loved it regardless. Sadly, I haven't yet.

* Note: Resistances are summed inversely, that is, the total resistance R_T of resistances R₁, R₂ and R₃, is calculated as follows:
1/R_T = 1/R₁ + 1/R₂ + 1/R₃

[awilkie84]

Originally Posted by Stealth

And you're exactly right with the description.

If anyone's up for some technical explanation, here goes. We'll assume identical pots (say, 500 kΩ for more modern basses).

With a V/V/T combination with everything on full, you have three of those pots' resistances (V₁, V₂, T₁) in parallel with the pickups for a total of 166 kΩ* loading down the pickups.
With a V/B/T combination with everything on full, you have four pots' resistances in parallel (V₁, B₁, B₂, T₁) for a total of 125 kΩ* loading down the pickups.
With a V/B/T with ungrounded blend pot's contacts (those contacts remain floating - unconnected at all) you have only two pots' resistances in parallel (V₁, T₁) for a total of 250 kΩ* in parallel.

The effect on the sound is as follows: the smaller the loading resistance, the darker the tone - so in our above example the VB_uT would be the brightest, followed by the VVT and the VBT, using all with identical pots. The VB_uT has a small change in that neither pickup will ever be completely muted, but quite a few TBers have tried it and loved it regardless. Sadly, I haven't yet.

* Note: Resistances are summed inversely, that is, the total resistance R_T of resistances R₁, R₂ and R₃, is calculated as follows:
1/R_T = 1/R₁ + 1/R₂ + 1/R₃

Any wiring diagrams around for the ungrounded balance route?

[dje31]

Beauty! The engineer / nerd in me appreciates the insight...and I write that in all honesty and no snarkiness.

[Stealth]

Originally Posted by awilkie84

Any wiring diagrams around for the ungrounded balance route?

Take any schematic with a blend pot and when it comes to wiring that pot, "forget" to connect the grounds.

[thisSNsucks]

I dig the VBT setup when there are is an active EQ in the mix but I have to say as far as passive goes, VVT is where it's at. Reason being, lowering the volume on both pickups just a hair on a jazz causes some weird loading things to go on and it gives a real cool darker tone that's different than just rolling off the tone knob. That's how I like to run my jazz these days.

However I wouldn't have anyone burned at the stake for converting their jazz to VBT lol

[dje31]

Okay, I've stewed about this for a bit now, and come to terms on separate volume controls for a passive J. So, taking that one step further, why not also have two tone controls, one for each pickup?