Series/Parallel + Blower Bypass mod diagram help for Jazz bass

[taBass]

I recently came across a cool mod that combines a series/parallel switch with a blower bypass switch on a Jazz Bass. The mod also makes the bass stereo-compatible, where the pickups can output to separate channels.

Here’s the gear I’ll be using:

• 2x Bourns push/pull 250k pots
• CTS 250k pot
• Switchcraft stereo jack
• Orange Drop 0.047µF cap

I’ve got the standard Jazz bass wiring down, and I could also handle the series/parallel mod thanks to the many diagrams available online.

However, I haven’t been able to find a wiring diagram for adding the blower bypass mod on top of the series/parallel switch, let alone one that combines all these mods in a single setup.

Would anyone here be willing to help out with a diagram or point me in the right direction? Any advice would be hugely appreciated!

Thank You!

 

[BassDaddySky]

I would imagine you would lose stereo in series. And possibly in bypass mode too.
How about posting the diagram(s) you do have. Maybe someone will be able to help you combine them

 

[Jon Cowens]

Perhaps you could explain your goals. What functions do you want?
What is it you want to bypass? the master tone? I don't know what a "blower bypass switch" is.
This is an interesting idea.

I agree with BassDaddySky that series and each pickup output to separate channels is incompatible.
You could get both pickups to both channels in series mode. Is that what you want?

But if you just want stereo, we can pan the signals.
a really simple way to achieve stereo is by connecting what were the ground lugs of both volume pots to the ring of the stereo jack. The volume pots act as pan pots with a stereo cable plugged in sending the respective pickup left or right, depending on which you choose.
however, you need a master stereo volume pot to control volume.

Please tell us more of your objectives.

 

[taBass]

Thanks for the responses!

Some answers:

• Yes, as I understand the stereo mode negates the mods — it would just pass an "unmodded" signal from the pickups.
• "Blower bypass" (or "blower/bypass") in this instance refers to bypassing everything so the pickup signal goes directly to the output. I would think some other forums will explain it better than I can.

But I actually found a full diagram for the mod! While searching for answers, I watched the video again to which the original idea source linked to: YouTube. The description included a link to purchase the diagram for $5. It’s just a sketch, but it contains the info I need.

That said, I could use some help understanding some of it!

Don't want to copy the whole diagram here, but I think it would be okay to include a small section:

However, most other diagrams I’ve seen, like Invalid Link Removed, show the DPDT switch oriented the other way up.

Should I trust the orientation in the diagram I bought, or flip the switch pin layouts?

 

[Jon Cowens]

I apologize if this explanation is juvenile. I don't know your skill.

Measure the continuity of the Bourne push/pull switch to see where the circuit path is directed.
Using your diagram shown: the middle row connectors of the DPDT switch are common.

When the switch is up. The middle connect to the top and the pickups are in series.
The negative of neck pickup connects to the positive of the bridge pickup

When the switch is down. The middle connect to the bottom and the pickups are in parallel.
The negative of the neck pickup connects to ground and the positive of the bridge pickup is passed through.

I say up/down generically as I don't know the Bourns push/pull pot configuration.
The Seymour Duncan circuit has pull/up as series and push/down as parallel.

Thanks for the explanation of the blower bypass. We would wire a Gibson EB0 this way - straight to the jack was the phrase we used.

Are you connecting the output each pickup to a different amp?
A Ric-O-Sound variation.

 

[Matt Liebenau]

To reinforce what Jon said, on most push pull pots the middle set of contacts connect to the bottom terminals when the knob is pulled up. If you want knob up to be series connect the short jumper across the 2 bottom terminals. The connections on the switch can be verified pretty quickly with a multimeter. Even the ones Harbor Freight occasionally give away with a purchase will work fine for most instrument stuff.

 

[Crater]

The "blower switch" can't be implemented as you're wanting to do without a 3-pole switch; you need two poles to route the pickups' signals around their individual volume controls and a third pole to lift the ground of the volume and tone controls so they don't affect your signal in "blower mode." Three pole toggle switches are available but not in a push pull pot as far as I know.

 

[Jon Cowens]

Would the Fender S1 switch/pot work? Doesn't it provide 4PDT?
I know its durability has been questioned.

I see if we don't lift the ground we would be routing a common ground to the separate amps (signal paths)

 

[Crater]

Would the Fender S1 switch/pot work? Doesn't it provide 4PDT?

Yes it would. I hear it's hard to get the proper knob for the S1 switch/pot though.