Passive-fying a bass

[JeezyMcNuggles]

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):
View attachment 4007564

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?

On a 2 way switch, center is your hot and ground. Both top and bottom are switch positions. So, you wire your leads from the jack to the center, and what you're trying to accomplish with the switch to the tops and/or bottoms.

 

[Mustang Surly]

I keep all my basses' "active" on the pedal board.

"Look, Ma: no batteries!"

 

[RumbleBot]

@Ricky Rioli 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.

I did this type of thing recently with a Tune 6 string. I wanted to be able to run the pickups in series and the stock preamp board didn't allow for that so I put in an Aguilar OBP3 instead so that I could wire pickups and pots any way that I wanted. When doing all of this, I found out that my pickups also exposed both coils separately so I was able to do this wiring by using five push/pull pots:

Bass EQ - pull for neck pickup coils series
Mid EQ - pull for mid 400Hz instead of 800Hz
Treble EQ - pull for bridge pickup coils series
Neck volume - pull for both pickups series with each other
Bridge volume - pull for passive

This gives me all kinds of tonal options including running full passive. Now, soloing the neck pickup with it's coils in series gets me pretty close to a P sound but my go to setting is neck coils in parallel, bridge coils in series, and both pickups in series with each other. It's really a shame that parallel/series switches aren't more standard as stock options as they offer so much more versatility without necessarily even needing an active preamp. Running this bass in passive with all series wiring is hot as hell on it's own!

 

[Tosh]

I simply removed the battery from my Dyna Bass. I might want to put one in again someday....

 

[micguy]

I've converted a few basses to passive. I've always liked the result better then the original active circuit then again, I'm a bit unusual, in that I design audio gear for a living, so I have a bit of an advantage - at least in experience. The most obvious case was a Tobias (Gibson version, not the original) that had a "boom circuit" or some such nonsense to begin with. The low end on it was just fine without that - at least through a decent PA.

 

[Dincrest]

I've had a luthier I know de-active-ate or passive-fy instruments.

I once had a Warwick with active MECs and had those swapped out for Duncans and a V/V/T setup. The tone opened up and improved a hundred fold.

My current bass originally had active EMGs, and I had that luthier swap them out for passive Duncan soapbars and a V/V/T setup, and though it was never my favorite bass, de-active-ating it made it one of my best sounding.

I like the low maintenance simplicity of passive. Sadly, the kinds of basses I prefer to play usually only come active, so I save up to de-active-ate them... usually with Duncans.

 

[Tosh]

....I like the low maintenance simplicity of passive. Sadly, the kinds of basses I prefer to play usually only come active, so I save up to de-active-ate them... usually with Duncans.

thanks - that's good info!

 

[Claymore]

This Ibanez Ergodyne was a 5 knob active bass once upon a time. It is now a 1 knob passive and I regret nothing. I used capacitors and trim pots to dial in my favorite tone for each of the pickups (set it and forget it) and the remaining knob is a blend. I'm not anti-active but the active circuitry for this particular bass did nothing for me so I consider this an improvement. I actually own a TRBX604 and I use active mode the majority of the time on that one.

 

[fermata]

"No more government subsidies for active basses!"

 

[Smooth_bass88]

Cool thread. I'm thinking about converting my Lakland 55-01 over to passive. I just dropped a set of Nordstrand JazzBars (single coil, alnico V, 60s wound) in it and I honestly feel it sounds better passive- I rarely engage the preamp.

 

[rojo412]

Cool thread. I'm thinking about converting my Lakland 55-01 over to passive. I just dropped a set of Nordstrand JazzBars (single coil, alnico V, 60s wound) in it and I honestly feel it sounds better passive- I rarely engage the preamp.

I did a 55-01 with Big Splits and it had a 2B preamp in it with bypass. It sounded UN-FRICKIN'-BELIEVABLE in the passive mode. To say it was a vast improvement is a huge understatement.

What I think some people should definitely realize is, while a bass may have an active preamp installed, that doesn't mean that it's necessarily making the signal better. Personally, on a number of occasions, with a number of preamps, I've replaced them or removed them to find that the signal from the pickups is amazing on its own. Sometimes, I've realized that the preamp did a disservice to those pickups and the lack of it was the best example of "addition by subtraction" that I could ever hope for.

Don't get me wrong, there are plenty of preamps that can make bad pickups sound great and great pickups sound unreal, that is also true. It takes some experimentation, but if you're willing, you can make any number of passive or active components really blow your mind. Don't let a spec sheet taint your ears.

 

[arbiterusa]

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?

All four of my Cort B4FL basses. Ripped the preamps out, rewired to VVT configuration, plugged the extraneous holes and refinished all of them. Three of the finished product here:

The results were spectacular. The cheap Bartolini MK1 pickups have a bad reputation, and I suspect the reason is the crap preamps that they get paired with; they sound real nice by themselves. No replacement preamp, the basses are 100% passive and I’m very happy with the results.

 

[Zoffy]

Yup, took my active Spector Legend 4 Standard and switched to Geezer Butlers. Sounds great, gigs great, and no regrets (also moved the input jack from the bottom to the front 'cause the Geezers only use 3 knobs, not 4).

 

[mexicanyella]

I saw one of these on CL for real cheap, with a dead preamp, and kind of felt sorry for it while being amused at how mëtäl-looking it was.*

I’ve been sitting on it (figuratively speaking) for a year or so but I plan to passive-ify it soon. It’s got a really nice neck profile and is more comfortable to play than it looks like it’d be.

I am trying to decide whether to retain four pots and wire it Les Paul-style, or use three of the holes to wire it Vol-Vol-Tone like a three-knob Jazz Bass, and move the output jack around to the fourth hole instead of coming out the side. I’m leaning toward the V/V/T idea: how bad do I need to have a separate tone for each pickup? Not too bad, is my guess.

I’m also picturing its kray-zee body shape as less scary and more Jetsons, repainted in a lighter 1960s “action color” of some sort...wish it had different position markers! But that’s a topic for another thread.

*The CL seller made it clear that the red-eyed skull control knobs would NOT be sold with the bass. He was hanging on to those.

 

[WillyW]

I think this is just a preamp...

I just remember the single mini toggle up, and the three minis down....

I’m too scared to leave the battery out, but I think it would work without one, and the single mini toggle would then kill everything.... maybe... the middle pot does nothing without the single mini toggle...

I think I just confused myself again...

I do have another one that is truly active pickups, not my favorite...

 

[Ryan in PDX]

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.View attachment 4007717 View attachment 4007718

@JeezyMcNuggles - that stain job looks fantastic!

@Ricky Rioli - You like your bass, so I vote "don't sell it."

I pulled the preamp out of my Marcus Miller Jazz Bass (4 knobs, one switch). It's now wired like a regular passive jazz bass (VVT). The active/passive switch became a series/parallel switch. The fourth knob is now a dummy knob, on a pot that's not connected to anything, much like Leland Sklar's "producer switch."

It's been eight years, and no one has asked me about my electronics yet. I have gotten a lot of mileage out of my series/parallel switch, and the dummy knob has kept sweat, dust, and who knows what else out of the control cavity. I don't miss the preamp at all.

If your pickups have 4-conductor wiring, you could experiment with series/parallel/split switches for each pickup in the holes left by your preamp knobs. If you use the passive tone knob, a switch to select different tone capacitors could be fun. If you solo one pickup pretty often, a solo switch would be great - you seem to be considering something like this already. You could always just leave yourself some dummy/producer knobs, too.

 

[JeezyMcNuggles]

@JeezyMcNuggles - that stain job looks fantastic!

@Ricky Rioli - You like your bass, so I vote "don't sell it."

I pulled the preamp out of my Marcus Miller Jazz Bass (4 knobs, one switch). It's now wired like a regular passive jazz bass (VVT). The active/passive switch became a series/parallel switch. The fourth knob is now a dummy knob, on a pot that's not connected to anything, much like Leland Sklar's "producer switch."

It's been eight years, and no one has asked me about my electronics yet. I have gotten a lot of mileage out of my series/parallel switch, and the dummy knob has kept sweat, dust, and who knows what else out of the control cavity. I don't miss the preamp at all.

If your pickups have 4-conductor wiring, you could experiment with series/parallel/split switches for each pickup in the holes left by your preamp knobs. If you use the passive tone knob, a switch to select different tone capacitors could be fun. If you solo one pickup pretty often, a solo switch would be great - you seem to be considering something like this already. You could always just leave yourself some dummy/producer knobs, too.

Thanks man

 

[bassbrad]

I have two basses that I modified from active electronics to passive and could not be happier. One bass is simple and has perfect tones while the other is more complex and offers a lot of options.

The first is a Peavey Verdine White Signature or a rebranded Rudy Sarzo that had the Peavey DynaBass circuit that was quite crusty and noisy after several attempts to clean and repair i decided to go with all new pots and keep it simple with a Volume - Volume - Tone and replace the output jack. The hunbucking pickups have a stout output that has a lot of grunt, punch and a really nice slap tone. I used some cheap pots to fill the holes.

The second bass is a Peavey DynaBass Unity LTD that had the stock pickups replaced with Seymour Duncan Hot Vintage Precision and a Jazz Stack V. The previous owner had tried to use the DynaBass circuit and it was not usable but I planned to go passive anyway. I decided to get a bit fancy with a 3 way switch then a Volume and Tone for each pickup and a ground bus for added quiet in the studio since the bass is primarily for the studio.

 

[Matty Koff]

Every bass I've owned has stayed in the condition I bought it in, minus dings here and there, with the exception of a MIM Jazz I scored for $250 that had some shoddy wiring and crackling pots. I simply replaced the pots.. put some aluminum knobs on the thing. Eventually sold it but other than that.. if I'm unhappy with a bass I'd rather just sell it and put the money towards something else.

I currently own 4 bass guitars, and one of them is passive. Recently brought it home from my drummer's house, an American Special P-bass.. and it's a freaking great sounding bass lol. I've been running it direct into my audio interface without tweaking the EQ in the slightest, with some old/dead rotosound flats.. and it just sounds freaking good. That being said.. two of my basses have passive pickups with an active pre-amp + EQ bypass switch.. and while they sound pretty good with flat EQ as well, I love being able to adjust their tone on the fly. They both sound good with the EQ bypassed but I tend to keep them switched to active and adjust EQ @ the bass for more beef or more growl/treble as I see fit.

Then there's the SRH505F I have listed for sale atm locally, which I think the only reason the piezo is active is because it's in the bridge, so it's not adjustable, so to balance out the volume of the strings you use the gain staging knobs on the back.

Anyway before I type an entire book.. if you love the way the bass looks and feels and how it sounds with the EQ bypassed and know you want to keep it.. do whatever you want to it. . But if you have any doubts she's a keeper it might be worth keeping in mind that to some of us a modded bass is less appealing than its stock configuration.

 

[Bodeeni]

I rewired both my Jazz Deluxes passive and put the jack back in the back hole. Now they plug in bottom or top. For some of the actives with a lot of knobs I would leave the pre and add a passive option with a battery kill switch. I did that to a MTD and a Bongo, both with excellent results.