Pre-EBMM Sabre: Cut/Boost? Phase? No Battery?

[fu22ba55]

(My three switches are PUP selector, phase a.k.a. "suck" (but I kinda like it), and treble boost)

I've searched and read plenty about the Pre EBMM Sabre's electronics, but still have a couple of nagging questions:

1) Are the tone controls boost/cut or boost only? Does anyone have a bonafide, schematic-informed answer to this question? My brain cannot read schematics. I've heard they are boost/cut, but not 50/50, more like 80/20... and there's no center detent. Great.

2) Does the phase switch reverse phase on whichever PUP you're using, or does it reverse the phase of the two PUPs in relation to each other?

3) Does the middle "suck" switch do something different when there's no battery in the circuit? Mine *can* run without a battery, but only when phase selector is in "suck" position. And when doing so, only the volume knob works, tone circuit is obviously dead. So, when running it like this, is it in phase or out of phase? It appears that only the bridge PUP is working when running in this mode.

[SGD Lutherie]

The phase switch changes the polarity of the neck pickup. Pickups are only out of phase when both are used, it's in relationship to the other pickup.

Most of the old preamps were boost only, though the treble controls were said to do both. Don't worry about the lack of a center detent, just turn them until you get the tone you like.

You shouldn't get any sound without a battery, so it must be just a fluke that it works.

[fu22ba55]

Thanks David.

You're info is super helpful and enlightening as usual.

My treble is definitely boost/cut like you say, but it's hard to tell with my ears if the bass is boost only, or if it's cutting as well.

Originally Posted by SGD Lutherie

Don't worry about the lack of a center detent, just turn them until you get the tone you like.

Understood, but I'm kind of OCD about stuff like that... little tape markers on all my amp knobs, etc... especially for recording or when trying to dial in a sound on an amp... I like to know the bass will sound the same the next day or next week.

Can I replace the pots with ones with a center detent? Would I use a standard 500K with detent (if there is such a thing) or something more unique?

Originally Posted by SGD Lutherie

You shouldn't get any sound without a battery, so it must be just a fluke that it works.

Alright... something is definitely "unique" about this one then... someone may have gone in there and gotten creative.

Just checked again:

With no battery in the bass and phase switch in the "out" position, the bridge PU works full bore, loud as heck, and volume pot works. Tone pots don't seem to do anything.

AND when I put the phase switch back in the "in" position, I get a very weak signal, but still audible, both PUPs work, PU selector works, but too low to tell if tone knobs work. Maybe it's just a little bit of phantom-like power coming back through the guitar cable? Using a Boogie D-180 Tube amp.

---

Maybe back in the day someone wired the phase switch to be a deadman switch in the event the battery crapped out?

If that's the case, I may have this thing rewired to use the neck PUP instead of bridge in deadman mode.

Do you know if these PUPs need batteries to work (like the MECs in my Warwick), or will they work if rewired with a passive circuit. The bridge PU clearly works fine without the battery....

And are these old MM PUPs coil-tappable? Or would I be better off with Nordys if I want to get creative with single-coil sounds...

[SGD Lutherie]

Originally Posted by fu22ba55

Thanks David.

You're info is super helpful and enlightening as usual.

My treble is definitely boost/cut like you say, but it's hard to tell with my ears if the bass is boost only, or if it's cutting as well.

You would have to hear the pickup with no preamp to tell.

Understood, but I'm kind of OCD about stuff like that... little tape markers on all my amp knobs, etc... especially for recording or when trying to dial in a sound on an amp... I like to know the bass will sound the same the next day or next week.

Can I replace the pots with ones with a center detent? Would I use a standard 500K with detent (if there is such a thing) or something more unique?

You still don't need a center detent. Just get knobs with pointer lines on them. You also don't know if a center detent you mean anything in the context of the circuit design. It wouldn't be flat, but might be "7" or something.

Just checked again:

With no battery in the bass and phase switch in the "out" position, the bridge PU works full bore, loud as heck, and volume pot works. Tone pots don't seem to do anything.

AND when I put the phase switch back in the "in" position, I get a very weak signal, but still audible, both PUPs work, PU selector works, but too low to tell if tone knobs work. Maybe it's just a little bit of phantom-like power coming back through the guitar cable? Using a Boogie D-180 Tube amp.

It's possible that when it's out it's somehow getting past the circuit.

Maybe back in the day someone wired the phase switch to be a deadman switch in the event the battery crapped out?

That makes sense, but do the pickups sound out of phase when you switch it (with the battery in)?

If that's the case, I may have this thing rewired to use the neck PUP instead of bridge in deadman mode.

You can just wire it as a preamp bypass. I wouldn't do it worrying about battery failure though. Those preamps draw very little current. You could probably have the same battery in there for a year or two.

I've said it here a few times, I've used basses with preamps in them since 1977, and have never had a battery go dead during a gig. I've broken strings, but never had a battery die. I just change them when they are low and check them when I change my strings, or before a gig if I hadn't checked in a while.

You could also wire the switch up for series/parallel or something.

Do you know if these PUPs need batteries to work (like the MECs in my Warwick), or will they work if rewired with a passive circuit. The bridge PU clearly works fine without the battery....

No, they are passive pickups.

And are these old MM PUPs coil-tappable? Or would I be better off with Nordys if I want to get creative with single-coil sounds...

I'm not sure how many wires come off the pickup. They might not be. If you get a three coil pickup like Nord makes you can switch into single coil mode with no hum.

[fu22ba55]

Originally Posted by SGD Lutherie

You still don't need a center detent. Just get knobs with pointer lines on them. You also don't know if a center detent you mean anything in the context of the circuit design. It wouldn't be flat, but might be "7" or something.

Understood 100%

Originally Posted by SGD Lutherie

That makes sense, but do the pickups sound out of phase when you switch it (with the battery in)?

Definitely out of phase.

Originally Posted by SGD Lutherie

You can just wire it as a preamp bypass. I wouldn't do it worrying about battery failure though. Those preamps draw very little current. You could probably have the same battery in there for a year or two.

Understood and agreed.

Originally Posted by SGD Lutherie

You could also wire the switch up for series/parallel or something.

[...] they are passive pickups.

[...] If you get a three coil pickup like Nord makes you can switch into single coil mode with no hum.

To my ears, the preamp seems to be coloring the sound a bit. When playing the bridge PUP with battery out, the tone sounds a little more "honest" if that makes any sense...

I may bypass the preamp, or just rewire it like a Jazz Bass with new pots: V-V-Tone. Then I'd have three switches for tomfoolery.

Thanks for your help David.

[Caca de Kick]

The 2 band Musicmans will still function passive with the battery removed. I have had this with old StingRays, but never tried it with my Sabre, but doesn't suprise me.

As far as middle reference points go for the knobs, I'll share with you what I do with my Musicmans;
I set the knobs where my favorite sound is, then without movint the pot shafts I carefully unscrew the knobs and re-position them so the set screws are pointing straight up at me. That way on dark stages I know where my setting are incase I accidentally bump my knobs.

Pictured below, see how set screws face me....

[SGD Lutherie]

Originally Posted by Caca de Kick

The 2 band Musicmans will still function passive with the battery removed. I have had this with old StingRays, but never tried it with my Sabre, but doesn't suprise me.

It shouldn't work. There is an unpowered op amp between the pickup and the jack. You also have a 25K volume pot at the output which would load the pickup down so much it would be useless. The tone controls are also always in the signal path. Same thing with the Sabre.

Here's the Sabre schematic, but the Stingray works the same way.

[Caca de Kick]

Originally Posted by SGD Lutherie

It shouldn't work.

Maybe on paper, but I've bought several used/vintage StingRays over the years that had a simple on/off switch wired to the battery lead. I don't like this kill switch thing, so I always removed them, repaired the lead, and always had to buy a new control plate because of the resulting hole. Yes the output was low, but still worked...but again it wasn't a sound I cared for.

[SGD Lutherie]

Originally Posted by Caca de Kick

Yes the output was low, but still worked...but again it wasn't a sound I cared for.

OK, well that makes sense then. That was not the tone of the pickup with the preamp bypassed. That was just junk leaking through the unpowered circuit.

So based on that I stand by the fact that it doesn't work... not like bypassing the preamp.

Even EMG's make a feeble sound when unpowered.

[fu22ba55]

Originally Posted by Caca de Kick

I set the knobs where my favorite sound is, then without movint the pot shafts I carefully unscrew the knobs and re-position them so the set screws are pointing straight up at me.

Understood, and thanks for the pic. I already started instinctively using the set screws as a reference, but unscrewing and re-setting them is a neat hack for sure. Better than black tape since you can feel them in the dark.

Re: Passive

Originally Posted by Caca de Kick

Yes the output was low, but still worked...but again it wasn't a sound I cared for.

I wonder if anyone here (or on the EBMM forum) has had any luck gutting and rewiring a Sabre for true passive, eliminating the circuit completely.

Looks like my Sabre electronics are indeed all original, so I don't think I'll mod it afterall, but I'm curious what the difference would be. I can really hear the color of the preamp, and it takes some getting used to.

But if that's the Sabre sound, then that's that.

[SGD Lutherie]

Originally Posted by fu22ba55

I wonder if anyone here (or on the EBMM forum) has had any luck gutting and rewiring a Sabre for true passive, eliminating the circuit completely.

That would be simple, it's no different from any other bass with passive pickups and a preamp. But passive isn't always better, and the preamp is part of that Music Man tone.

[fu22ba55]

Originally Posted by SGD Lutherie

But passive isn't always better, and the preamp is part of that Music Man tone.

This thing is 100% original, down to the strap buttons. (Well, minus the foam mutes. They are long gone.) Sounds like the circuit was not tinkered with after all... I better leave things as they are.

Little bit of ground hum, but no big whoop.

[Caca de Kick]

A few years ago Rudy's Music (in NYC) had a preEB Sabre where someone completely removed the preamp, and installed either 250k or 500k pots.

The thing that was a shame was Rudy's was still asking top dollar as if the bass hadn't been touched, and the rare preamp was long gone.

[vin*tone]

Originally Posted by fu22ba55

And are these old MM PUPs coil-tappable? Or would I be better off with Nordys if I want to get creative with single-coil sounds...

Yes they are. If you pull the pups out you'll see a wire connection on the bottom. I've just done a coil tap mod on mine - running wires from these connections. The phase and bright switches are now single single coil taps. I'm still experimenting with polarities etc.. but so far so good. The tones you'll get are not 'single coil' (as in Jazz bass) sounding. It basically gives you different flavours of 'Stingray'.

OT: I'm a big fan of keeping my basses in as 'original' a condition as possible but my partner has FORBIDDEN me to ever sell this bass so I don't care so much about its resale. The mods I've done are all reversible but I can't see any reason why I ever would.

[fu22ba55]

I spent some time at high volume with this bass last night, dialed in some great tones, and fell a little bit more in love with it.

I snapped a pic of the pre, (attached), and according to the info on Musicmanbass.org (http://musicmanbass.org/mycustompage0019.htm) it's a legit '70 pre, including the older, Tantalum capacitors.

Quote from link above:
"Electrolytic (as opposed to Tantalum) capacitors appear on non-epoxied pre-amps from circa late 1981 (or early 1982) onwards. Audiophiles would argue that the electrolytic has a more mellow and pleasing tone to the ear."

[fu22ba55]

Originally Posted by Caca de Kick

I set the knobs where my favorite sound is, then without movint the pot shafts I carefully unscrew the knobs and re-position them so the set screws are pointing straight up at me.

Caca de Kick,

I might take it one step further and replace the original set screw with a longer one so it sticks up a bit from the knob? That way I'd be able to feel it in the dark for sure...

[Caca de Kick]

Yeah I don't see why not. Should be easy enought to find longer set screws at the nearby hardware store.

[flecktones1981]

Does anyone know of a good replacement onboard preamp for a Pre Ernieball Sabre that will fit in the bass as is. I went to a music store and they said some pre amps I'd have to cut a space in the wood for it to fit.

I have a 79 sabre that got switched to passive, and don't have the original active electronics, but want to change it back!

Also I have it setup for only the neck pickup and want a pickguard to fit over it. Will a stingray pickguard fit it?

[SGD Lutherie]

Originally Posted by flecktones1981

Does anyone know of a good replacement onboard preamp for a Pre Ernieball Sabre that will fit in the bass as is. I went to a music store and they said some pre amps I'd have to cut a space in the wood for it to fit.

I have a 79 sabre that got switched to passive, and don't have the original active electronics, but want to change it back!

Also I have it setup for only the neck pickup and want a pickguard to fit over it. Will a stingray pickguard fit it?

The Stingray and Sabre preamps are identical, except the Sabre has the treble boost, which is easy to retrofit onto a Stingray preamp.

I make a Stingray preamp, and could add the treble boost switch.

[vin*tone]

You mean bridge pickup? The pickups are slightly smaller on the Sabre (IIRC) and I think is in a slightly different location..

You wouldn't want to make it look like a Stingray anyway??! I got a replacement made at Pickguard Heaven..... Pickguard Heaven: Prices - Music Man