Passive-fying a bass

[Ricky Rioli]

My TRBX has an active/passive switch. I never use the active, and so I've got at least a couple of knobs doing nothing that could be put to better use.

Have you ever removed the active circuitry from a bass? Did you replace it with anything else? Did it make you any happier, or did you wish you hadn't bothered?

 

[jj.833]

I had this:

Originally it even had a piezo bridge. I was never really too happy with it, so in the end I converted it to this:

The pot is volume, the switch is useless. I was surprised how much more useful the bass is now. I think it's mainly because there's nothing to tweak, so all the sounds I need to hear must be done by fingers. I didn't know how much can be done by fingers, until I forced myself to try. I'm not much of a precision guy and I don't play flats, but this works perfectly for most of my music.

I also have a jazz bass, which I turned exactly opposite way, from passive to active, and I don't use passive mode ever. I guess it's a good think to try a change whenever you feel like it. The passive/active modification can be done without irreversible changes, so you can gain, but cannot lose.

 

[TheLowDown33]

I've done this a few times. I usually get creative with series/parallel switching, kill switches, cap selection for tone controls, etc. Then I don't use half of it lol. It's somewhat tough to gauge how useful the mods will be unless you've had experience with them before, but like the poster above said, what you're inquiring about it completely reversible so if you don't like the results all you're out is a couple bucks and a few hours worth of work.

 

[Ricky Rioli]

I'm feeling encouraged already

The plan suggested to me is to have the switch going between two totally separate passive circuits: one standard, with volume, blend, and tone knobs; the other only for the neck pickup, with just volume and tone. Then, for example, I could go from neck solo with 100% tone, to bridge (or neck+bridge) with 0% tone, at the flick of the switch.

This was suggested to me because neck solo is where I like to be most the time, and when I want to use the bridge pickup, it's always with the tone near 0%. And because I've got 5 knobs and a switch to use. Not sure what I'd use the battery compartment for, though.

 

[two fingers]

@rojo412 talk to this guy.

(Adam created a crazy passive masterpiece for me.)

This was originally a LeCompte STSS. The neck was twisted. Adam built a new neck, and installed all of the electronics. The knobs are volume neck, volume bridge, and tone (with a pull pot for .1 and .47 caps). The switches are series/single/parallel for the bridge and series parallel for the pickups combined.

It's a passive monster. The original active electronics were a bit "polite". I can cover a lot of sonic ground with it now.

So, yes, I had active electronics ripped out and replaced with passive electronics and I'm thrilled.

By the way @Ricky Rioli Welcome to TalkBass!!!!

 

[rojo412]

@two fingers definitely benefited from the passive conversion. What used to be in there was way less than what it became.

@Ricky Rioli Having that many pot holes is definitely something that could give you options. What you're describing almost sounds like a modified version of something like a Les Paul wiring scheme. From what I do know of various dual-tone wiring descriptions is, having different tone knobs may still only result in one tone knob in 2 different places. But I'm not well versed in that personally, so someone with more experience in that field may have to chime in on it.

But with similar functionality, you could wire up all kinds of different switching options at the tip of your fingers and achieve the same kind of results.
- You could have it so there is a switch to go from blending the pickup signals to just the neck. That would basically be just diverting signal from that pickup to either the volume or the pan and switching the pan signal to either the volume or the ground.
- You could do a tone on-off switch or push/pull if you want the tone taken out of the signal chain.

If I was working with 6 holes and doing a passive setup only, depending on pickup specs, personally I'd do something like:
- Volume
- Pan
- Tone
- Series/Parallel switch for the pickups
- Tone bypass
- Tone cap select

If you have the TRBX 500 or 600 series, with the dual coil pickups, I'd see if you can also wire the pickups themselves in different ways. That would open up series, parallel, or single coil modes for the pickups each, which definitely adds functionality (and complication) to the mix. You could replace various switches with push/pull pots and still have all of the different functions, but add in switching for the pickups to do their thing too.

This is also dependent on how much you want to complicate the setup. From what you were describing, it sounds like a simple setup for function is what you're after. Adding all of this would make it do anything you wanted, but certainly require more switches to be flipped in the process. So that is basically up to you.

 

[Ricky Rioli]

Having that many pot holes is definitely something that could give you options. What you're describing almost sounds like a modified version of something like a Les Paul wiring scheme. From what I do know of various dual-tone wiring descriptions is, having different tone knobs may still only result in one tone knob in 2 different places.

That was my initial question: if you had a tone knob for each of the two pickups, one on 100%, the other on 0%, and you're using a pan knob, would you actually have much control? So the plan suggested to me only ever has one tone knob involved. The easiest way to picture the plan is that the bass would contain the wiring of a P bass and also, but completely separately, the wiring of a J bass.

If I was working with 6 holes and doing a passive setup only, depending on pickup specs, personally I'd do something like: Volume, Pan, Tone, Series/Parallel switch for the pickups, Tone bypass, Tone cap select

I admire people who can have so much versatility and use it efficiently and effectively. I would simply find it very distracting

This is also dependent on how much you want to complicate the setup. From what you were describing, it sounds like a simple setup for function is what you're after. Adding all of this would make it do anything you wanted, but certainly require more switches to be flipped in the process. So that is basically up to you.

All I want to do is play the bass as if it were a p-bass, occasionally accessing one single j-bass preset sound. If, instead of (1) turning the pan half/all the way (2) turning the tone down most/all the way (3) turning the volume up a bit, I could just flick a switch....it's a seductive thought!

 

[rojo412]

The easiest way I could think of in a mod would be having a switch that bypasses the blend and sends the neck pickup signal only. You'd still have to dial the tone as needed, but you'd basically be able to do that with a DPDT switch and it could be push pull or toggle.

I think this would be the way to do that (correct me if I'm wrong):

If you wanted to have this switch also control a pre-set tone level, I think a 3PDT switch would be in order. When the neck pickup is soloed, are you looking to have it with muffled tone or with wide open tone?

 

[bolophonic]

I had an active bass a long time ago. I put Fender Original ‘62 pickups in it and sold the entire EMG pickup and harness on eBay for more money than I expected. Huge upgrade. I don’t fiddle with knobs very much.

 

[ruju]

I would just leave the electronics as they are and get a trbx174 to play passive. They are cheap enough new. Play,look and sound great.
Then keep or sell the active bass. That's just my opinion though.

 

[Ricky Rioli]

I would just leave the electronics as they are and get a trbx174 to play passive. They are cheap enough new. Play,look and sound great.
Then keep or sell the active bass. That's just my opinion though.

The 174 has a deeper neck and a wider nut than the 604, so it wouldn't be a like for like replacement. One thing that sold me on the 604 over a similar Ibanez SR was the ability to turn the active off and have a passive tone knob. I agree that it would be more sensible to move the 604 on and get a passive bass and mod that instead, but then my 604 looks like this....not sure I want to say goodbye to that

 

[Seashore]

I've been happier with passive VV wiring in my Ibanez basses than I ever was with the sounds I could get out of their preamps. In fact I may have been happiest with the SR1006 before I moved the pickup positions around, I had the current "neck" pickup in the bridge position wired straight to the jack for about a year. No doubt the simplicity is part of the appeal. I may try a higher end preamp at some point but I'm not in a rush.

 

[Ggaa]

I took a noisy 2 band MEC preamp out of a Warwick LX5, changed out the pups too for a pair of Bart jazz pups. Passive all the way, sounds great. Works well with my pedals, octaver included.
Nothing against active, had an Ibanez 5 with Barts and a 3 band eq. Also sounded great.

 

[fermata]

I 'pacified' a Ray4 a few years ago and was pleased with the result.

With five knobs and a switch you have a lot of potential options! I think the trick is to keep things on the simple side and only controls that you'll actually find musically useful.

Another interesting passive control to consider is a Wilde Q-filter, like on a Gibson Ripper.

 

[ruju]

The 174 has a deeper neck and a wider nut than the 604, so it wouldn't be a like for like replacement. One thing that sold me on the 604 over a similar Ibanez SR was the ability to turn the active off and have a passive tone knob. I agree that it would be more sensible to move the 604 on and get a passive bass and mod that instead, but then my 604 looks like this....not sure I want to say goodbye to thatView attachment 4007591

No!...lol. definately don't sell that 604..I played one a few months ago, thought about buying it and it was sold the next day.
I hear what you are saying. I have a Jackson Spectra bass with active/passive, and coil tap. I never touch the 3 band EQ unless it's to turn all the treble off.
The active and passive mode are very similar. I get more of a volume/ tone difference going from humbuckers to single coil.

 

[JRA]

Have you ever removed the active circuitry from a bass? Did you replace it with anything else? Did it make you any happier, or did you wish you hadn't bothered?

i have:
- removed active circuitry from some/most of my instruments.
- i replaced the active stuff with passive stuff.
- it made me "happier" (but TBH = i want to keep at least one active ax...just in case ).
- i'm glad i've made the changes to passive when/where did!

most of my axes have two-pickups. i've become accustomed to (and prefer) VBTT. mine are PJs, but i'd use that configuration as my starting point with any ax, active or passive. good luck with your conversion!

 

[ZedLepp]

So I passive-fied my TMB100. I just removed the active circuit and wired the pickups the concentric pots.
Now when I turn up the volume on both pickups it's like they start to cancel each other out.

 

[rojo412]

So I passive-fied my TMB100. I just removed the active circuit and wired the pickups the concentric pots.
Now when I turn up the volume on both pickups it's like they start to cancel each other out.

Try reversing the hot and ground on one of the pickups and see if that fixes it.

 

[JeezyMcNuggles]

My TRBX has an active/passive switch. I never use the active, and so I've got at least a couple of knobs doing nothing that could be put to better use.

Have you ever removed the active circuitry from a bass? Did you replace it with anything else? Did it make you any happier, or did you wish you hadn't bothered?

Yup. I dont use actives. So I ripped out the pre and stacked pots out of my talman, and wired up 500k pots instead. I still have the switch. I wired it to my bridge. But, you could just wire the hot to it first, then to your first pot, and use it as a kill switch. As far as the extra knobs on yours go, mine only had two stacked pots to begin with, so I actually added a knob. I wasn't left with extras. So, I don't have any pointers on that one. But, go for it.

 

[JeezyMcNuggles]

So I passive-fied my TMB100. I just removed the active circuit and wired the pickups the concentric pots.
Now when I turn up the volume on both pickups it's like they start to cancel each other out.

Whats your pots look like? Take a picture of your innards.