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Active to passive mod: update


saxofunk

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There may be another change on the horizon for my Tobias Toby Deluxe. The tone isn't quite what I want, and I have fallen in love with the independent volume controls on my G&L - the Toby has master volume and a pickup blender.

 

The electronics are on a board, so any change means total replacement. The current set up is the stock active circuit with Volume, Pan, Bass and Treble. If I go passive there are four holes to fill; my thought is to go V/V/T/T, V/V/T/dummy, or V/V/T on a custom pickguard.

 

Questions:

1a) Can I use the stock pickups since they were "designed" for use with an active preamp?

1b) Should I?

1c) Should I try but be prepared to change if they suck?

1d) Can I run the pickups straight to the output jack to see what they sound like a la carte?

 

2) Based on two volumes: What passive electronics options are there for a pair of J-style single coil p'ups?

- Matt W.
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1a) if they are passive pickups, yes

1b) why not. :) Low $ output for such an adventure, and easily cured if botched.

1c) I would do 1d) first

1d) Yes

 

2) You could do V/V/T/T which should be easy to do and useful enough, or you could do V/V/T + something interesting (like a Vari-tone type switch).

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Getz - Thank you. I certainly will try 1d first, that makes sense. I'll try it one at a time and together.

 

RABid - I'm familiar with basses that have active/passive options. I gave half a thought to puting a bypass switch inside the control cavity for the experiment - one side switching through the preamp and the other side running the pickups direct to the ouput. But that still doesn't give me twin volume control. With the current circuit board, there's no room to add a switch to the front of the bass without some radical woodwork.

- Matt W.
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I agree with Getz on part 1, especially about delaying a PUP change. They might be great with the new wiring. If not, you wanted the separate volumes anyway, so no harm done.

 

As to part 2, I have found very little value in varitone arrangments. I have found very little value in many of the options that basses have (coil tap, etc.). I tend to vary tone a bit, vary pickups (in your case, volumes for each PUP), and want everything else up full. But that's me.

 

Best of luck!

 

Tom

www.stoneflyrocks.com

Acoustic Color

 

Be practical as well as generous in your ideals. Keep your eyes on the stars and keep your feet on the ground. - Theodore Roosevelt

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I'll have to try a bass with that. I have something like that on one of my basses, but I think there are issues with the way it's implemented.

 

I'll try to get to a store in the next week or so and see....

 

Tom

www.stoneflyrocks.com

Acoustic Color

 

Be practical as well as generous in your ideals. Keep your eyes on the stars and keep your feet on the ground. - Theodore Roosevelt

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Matt:

 

With a few small alligator clips, some wire and some solder, you should be able to jumper the current pickups to the output jack...take the battery out and you've got a passive full-on bass. At least you could see how it sounds without cutting any wires. This is assuming the pickups are passive, of course, which they likely are. Look in the control cavity...if there are 2 wires coming from each pickup, they are passive...if there are 3 wires from each pickup, they are active (one's the power supply).

 

So the onboard preamp is one board with all the pots mounted to it? Hmmm...any markings on it? You said the preamp has volume, blend, bass, and treble. I'm sure there are probably others, BUT the only onboard pre that comes to mind with this configuration that has all the pots physically mounted to the board is the one made by MightyMite. (This is assuming I read your comments above correctly.) Take a look at this link and see if this looks like the preamp in your Toby...these seem to be get OEM'd frequently.

 

http://www.mightymite.com/pickups/bass/basspreamp/index.html

 

This is the same preamp my prior Conklin GT-5 had in it stock...it wasn't bad, but it did leave lots to be desired IMHO. Do the pickups have any name stamped on them also? You often see the MightyMite pickups and preamp paired up, so if the preamp is MightyMite I'd almost bet the pickups are too. I found that electronics combination to be quite warm and thumpy, but really lacking any midrange bite (of course, that was on the GT-5, which had some unusual woods).

 

If this is what you got, you *might* get quite a bit of mileage by replacing the preamp and pickups. But, still do one piece at a time if possible...that way you can see the improvement for each independent change.

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Originally posted by Dave Sisk:

Matt:

 

With a few small alligator clips, some wire and some solder, you should be able to jumper the current pickups to the output jack...take the battery out and you've got a passive full-on bass. At least you could see how it sounds without cutting any wires.

You have no idea how grateful I am that you suggested this. A thousand thank yous!

 

This is assuming the pickups are passive, of course, which they likely are. Look in the control cavity...if there are 2 wires coming from each pickup, they are passive...if there are 3 wires from each pickup, they are active (one's the power supply).
There are two. I suspected they are passive pickups. That's confirmation.

 

... I'm sure there are probably others, BUT the only onboard pre that comes to mind with this configuration that has all the pots physically mounted to the board is the one made by MightyMite... Take a look at this link and see if this looks like the preamp in your Toby...
That looks like it. The markings are on the side that can't be seen when installed. Wouldn't you know it, I wrote that down last week and misplaced the paper.

 

This is the same preamp my prior Conklin GT-5 had in it stock...it wasn't bad, but it did leave lots to be desired IMHO... I found that electronics combination to be quite warm and thumpy, but really lacking any midrange bite (of course, that was on the GT-5, which had some unusual woods).

 

My sentiments exactly. I didn't realize what I was missing until I heard another fretless bass live. Mine lacks midrange color. FWIW, the body is maple, so it never lacked top end unless I strayed into half flat strings.

 

Do the pickups have any name stamped on them also?

 

Only the Tobias name. I had them out a couple years ago; there are no markings on the back that I recall, just lots of epoxy.

 

If this is what you got, you *might* get quite a bit of mileage by replacing the preamp and pickups. But, still do one piece at a time if possible...that way you can see the improvement for each independent change.

 

Dave

I'm hoping to keep the stock pickups and replace the preamp with decent pots. If the pickups alone don't do it, then it will be a while before I spend the bucks to replace them. At this point I am very hesitant to consider another onboard preamp until I can experience a few first hand. I need to pick up a pack of gator clips, and I'll do that tomorrow. ;)

 

Thank you Dave!

- Matt W.
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If the pups on your bass are passive pups with active electronics, you're good to go.

 

Firstly, I would desolder the pups from the existing electronics, and remove the electronics as a whole rather than desoldering anything else on the circuit. That way you can always go back easiliy - no harm done.

 

After that, I would either go for vol/vol/tone/tone or vol/vol/passive-serial switch/tone.

 

I have two passive basses with four holes.

 

Firstly, they were both configured vol/blend/tone/tone.

 

I didn't like the blend setup, so wired them as vol/vol/tone/tone.

 

It was great.

 

Then I read about series/parallel switches, and gave that a go.

 

It worked fine, but I rarely switched it over to series, so went back to vol/vol/tone/tone.

 

vol/vol/tone/tone is my preferred configuration.

 

YMMV

 

:thu:

 

Go for it!

 

:D

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Hey Matt...no prob, glad to have helped a bass-brother! I don't know for sure, but I'd suspect the lack of bite comes from the pickups as well as the preamp, but you should definitely try it and see. The Mighty-Mite stuff is decent, it's just not fantastic. If the pickups have Tobias stamped on them then I'll bet they are indeed Mighty-Mite pickups...the GT-5 had Conklin stamped on the pups. Check the install guide on Mighty-Mites site and see if the dimensions of the pups match what they have listed. I'd think that (especially with a fretless...you've defretted this guy, right?) that lack of bite is even more detrimental. I've heard Bill Dicken's play the Bartolini-equipped Conklin GT-7 on a DVD, and it didn't seem to lack any bite. However, as I understand it, that bass has both Bart pups and preamp. So, I guess what I'm saying is I don't know how the Mighty-Mite pups will sound, but try it and see.

 

I kind of have the same gripe about my Dean fretless these days. It's passive with EMG-HZ's, and it's warm and thumpy, has some good whine in the mid-range, but still doesn't have a real good bite to it. I'm thinking of installing the EMG-BQS preamp that I have lying around...bought it for another bass project that I abandoned, so I don't have a use for it right now. It has a mid control that is sweepable over a very wide range, and I'm thinking that might be really useful, particularly on a fretless. But, I do keep looking for another 5-string fretless at a good price that I could "exchange" it for too. So, whichever I get around to first will be the solution I guess!

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Well, the only mark on the preamp that looks like a model number says E2-0038, all other marks are just the tags for component locations. The pickups don't match what is currently on MightyMite's site, but the old advert claims they are custom designed - so they may be another MightyMite product in disguise.

 

They are 94mm and 91 mm long and 17mm wide. Looks like that's close enough to standard J pickups that I should be able to come by something at a reasonable price if it turns out that way.

 

Yes, this is the bass I defretted. It was never my intent to get involved in the electronics. I was satisfied (or ignorant) until I heard some live fretless that sounded amazing. This has always sounded fine, to me, but it would be nice to have that extra somethin' somethin'.

- Matt W.
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Ah...I was afraid that might be the case. Are the existing pups P, J, or humbucker? Check Ebay and InstrumentExchange.com...you should be able to find some of the better pups used for a decent price.

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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They are J style. I'm already on the 'bay taking a look, and searching the house for excess items that can be used to pad the PayPal account. ;)

 

I'm conviced the preamp is only there so they could market the bass as active, along the lines of the original Tobias basses, rather than as just a fancy looking J-bass clone. The tone and output seems virtually the same with the preamp bypassed.

 

PS - basstatsers.com is short on pickup samples. Is there a good site that has a variety of samples of pickups?

- Matt W.
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Hey Matt:

 

There was some fellows site that someone listed once that had quite a few J-pickup samples...I'll try to find that thread.

 

Check here...there's a couple or three J pickups listed...

 

http://www.bassgear.com/

 

Also, there's a few sets of J pickups listed on Talkbass.com ForSale forum here:

 

http://www.talkbass.com/forum/forumdisplay.php?f=129

 

HTH,

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Dave, you're being awfully helpful. Thank you!

 

I posted a question to the TalkBass seller under my other online alias. If they fit, I'll probably bite. That just happens to be the model I was favoring based on eBay prices and a few reviews. The price is fair and battle scars don't matter so much.

 

edit... then I listened to the samples. I like 'em!

- Matt W.
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Model Js arrive. Less w00t.

 

On both pickups the coil under the D & G strings seems dead. I hooked up the neck pickup and had only two strings speaking. A little tapping with a screwdriver confirmed that the polepieces on the high side have virtually no magnetic pull, while the low side draws the screwdriver in like an Imperial tractor beam. While I haven't fully installed the bridge pickup yet, it performs identically in the screwdriver test.

 

What's up with that?

- Matt W.
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i know dimarzio ultra jazz pickups are side-by-side humbuckers. i assume model J pickups are, too. it appears both coils have demagnetized.

 

contact the seller. if the pickups are under five years old, and if the receipt still exists, dimarzio will replace them for free. maybe they were sold because of the dead coils (probably), or maybe it's a mistake (probably not). either way, that kind of thing shouldn't fly on talkbass.

 

robb.

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Matt...if you bought these from a seller on TalkBass, then he should have a motivation to make things right...there's a feedback system on TalkBass (somewhat similar to Ebay, but looser controls). Most people are honest and I'd imagine this is simply an oversight, so contact the seller and work out a return.

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Robb and Dave, thanks for your comments. Fortunately this turned out fine with a little thought.

 

Part of my problem was that I started a project that I had little understanding of too late at night. In desperation, I cried "wolf."

 

These pickups have exposed magnets on the bottom; during shipping a few of them broke loose from the hot glue that had become too old to secure them. I put them back on without giving much thought to polarity, as long as they didn't repell, ignorant of the fact that there is a right way and a wrong way.

 

After stewing for a couple days I took a moment to fiddle with them and find a position that gave me magnetism through the poles. What do you know, they work now.

 

About feedback on TB, I had already left him a positive feedback. The sale went down very well; he shipped the next day, his communication was good - it was a good transaction. I don't think he could have anticipated that the glue would fail. I let him know that it did, but it was negligible at the time - I thought I fixed it...

- Matt W.
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The installation is complete, for the moment. I went ahead and hooked up the Dimarzios to the preamp. With everything falt, the difference between having the preamp in the path and bypassing it bypasses is negilgible. With the preamp I can make a few minor adjustments and get closer to what I'm looking for.

 

Next: pots, or strings, or both.

- Matt W.
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I'm doing something similar on my Jazz fretless. I heard Q-tuners on a sampler and thought: wow that's the sound I want. I have ordered the PUs. Last night I got exactly the same sound with my stock Fender PUs albeit with an Audere pre-amp. Nevertheless, I have ordered Q-tuners and Nordstrand SEs and will post the sound clips when I am done!

 

Last night my fretless tone got a few comments. Last week I played through a Ampeg SVT + 8 x 10" rig and got an URBy tone! The bass amp really does make a collosal difference to tone - particularly with fretless. I know it's stating the bl**ding obvious but ...

 

Davo

"We will make you bob your head whether you want to or not". - David Sisk
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  • 1 month later...
Originally posted by Davo-London:

I'm doing something similar on my Jazz fretless. I heard Q-tuners on a sampler and thought: wow that's the sound I want. I have ordered the PUs. Last night I got exactly the same sound with my stock Fender PUs albeit with an Audere pre-amp. Nevertheless, I have ordered Q-tuners and Nordstrand SEs and will post the sound clips when I am done!

Any update on that yet, Davo?

 

There's an update to my Dimarzio story... I had been playing mostly with one pickup or another until this weekend when I centered the blend knob and played some long notes across all four strings... Suddenly the D and G strings sounded very weak, all treble and no bass, while the E and A were solid. Quick twiddling of the blend knob confirmed that the pickups were fine solo. I grabbed a magnet off the fridge and quickly determined that the polarity of the bridge pickup was the same across all four pairs of poles (lets call that one South), but the neck pickup had North under E and A with South under D and G. I failed to consider polarity (again) when I reassembled the magnets onto the pickups. So after a bit of surgery to re-align the magnets under the neck pickup I got it back together with the neck poles all going North. Now these pickups really thump.

 

I assume that what I have done is right. If I set up both pickups so all the poles go south, that would result in four strings with weak output, right?

 

FYI - I still intend to remove the preamp and go with V/V/T/T controls; that's on hold since I have another project in the works I'll order all the pots at once after we rebound from the holidays.

- Matt W.
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Nice work, Matt...I had no idea that pickups had polarity to begin with (guess I should've figured they did though). I would imagine that it doesn't matter whether they face North or South as long as they all face the same direction.

 

Dave

Old bass players never die, they just buy lighter rigs.

- Tom Capasso, 11/9/2006

 

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Matt

 

see my other thread about Q-Tuners versus Norstrand.

 

Q-Tuner versus Nordstrand

 

My overall conclusion, which Alex no-doubt would have told me in the first place was, the tone is in the wood. So by all means replace and improve the PUs and pre-amps etc, but at best you'll get tone-wise is what is inherent in the wood.

 

FWIW I prefer master vol/blend to vol/vol so that you can turn the volume off between sets/songs etc without disturbing the tonal set-up between the PUs.

 

Davo

"We will make you bob your head whether you want to or not". - David Sisk
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