Gibson EB-0 Lo Z Christmas project

[amptech]

At last, my first Lo Z project. Mentioned before in Lo Z threads, this is a straight one pickup EB-0 project, and
the ´core´is a nice 1967 body bought naked on ebay recently. It is really a combined project, it all started when I bought
a set of Lo Z pups (4) listed as ´gibson bass recording pickups not working´. It turned out to be guitar (les paul) pickups, but two of them were in perfect working order! The ´strongest´of them read 15dc ohms, but had a broken ear. The other working unit had some epoxy smear underneath. The other two looked perfect, but had open coils. Researched a bit, and found them all to be ex-gibson employee stuff- but the previous owner thought they were all broken and sold them cheap.
It will be fun to install NOS pickups, I´ll be the first to wear the black plastic..

After getting really comfy with EB0/3 basses from the 60´s, I noticed some difficulties playing my Fender P fretless.
This would be a good excuse to buy yet another project, but space is becoming a problem. So i will combine the two projects, I can always refret if I don´t like my LoZ fretless.

Well, the body arrived, and it was not as good looking as it seemed to be on ebay, but it was cheap. On the other hand, unbroken headstock and solid neck/body joint. It was sanded down at some point and clearcoated, seems to be floor laquer painted on with a too big brush. Same with the fretboard, it had a thick smear of laquer, painted over a well used and incredibly dirty piece of rosewood! The frets almost fell of the instrument.

I top mounted the pup on my ´67 EB-3, and spent an evening looking for the sweet spot. My sweet spot, that is,
and it ended up somewhere between the neck pup and the handrest.

So I needed to fill the mudbucker/neck wire routing, and all screwholes. I´m going for my first polaris white gibson, and
for the first time I´m going to follow all necessary steps to get a decent finish..

Here it is:

]

[Granny Gremlin]

Good luck.  I'm sure that'll look and play sweet when done... too bad about your unfortunate choice of pup location though 

[amptech]

Good luck.  I'm sure that'll look and play sweet when done... too bad about your unfortunate choice of pup location though  

Thanks. I did think of doing pickguard in the style of the P90 single pup les paul special.
But to challenge myself both on woodworking and finishing, I decided to go non-PG.
If I screw up the wood/finish, I will have to make a PG though.

I am comfy with the pup placement, as I play fingerstyle in the neck area. Think it looks OK too.

Here´s some pics for those who might have interest in such a project (sorry for the large pics):

I always make some plugs when I remove wood. Useful for screwholes.

It´s gonna have a solid finish, but I´m trying to learn how to ´hide´wood finish repairs

And the fretboard laquer:


Repaired the broken ear of the pup with epoxy. I cut an ear off one of the non-working pups..
]

[Basvarken]

Nice project!

[Granny Gremlin]

Good repair job on that pup!

[Highlander]

Very neat...

[chromium]

Nice project!  That'll look, and likely sound great with the lo-Z pickup.  I don't know how you guys find these white-covered ones?! (nice score)

With having to plug such a large route for the old pickup, will you have to veneer the front of the bass? or are there ways to prevent the grafts from telegraphing through the new finish?

[amptech]

Nice project!  That'll look, and likely sound great with the lo-Z pickup.  I don't know how you guys find these white-covered ones?! (nice score)

The 4 pups i bought were all black. What you see in the first picture is just the ´template ´that Rob kindly dug up for me.
Never even seen a white one other than the pictures here.

[/quote]With having to plug such a large route for the old pickup, will you have to veneer the front of the bass? or are there ways to prevent the grafts from telegraphing through the new finish?
[/quote]

Don´t really know yet, I did plug a hole once (!) on my EB0/6 project - but it´s difficult to hide in a transparent finish.
I did manage to match the colour, but didn´t match the grain, and did´nt use grain filler. It´s level, but not good looking.

I have tried to level all plugs, and match the growing direction of the grain. Got me some grain filler and sanding sealer, we´ll see how it turns out- been reading a lot about finishing lately. It´s already better than what I´ve done before, using the correct sandpaper grades for different woods, never thought of it! When I see the finishes I´ve done now, I just see why they look crappy - have to do it all over:-)

Here she is; routing,  plugging and main sanding complete.



As i did the routing, It was frightening to see how deep it had to be. There´s gotta be some adjustment space, and there is now solid wood no thicker than in the ctrl. area under the pickup. I wonder how deep it would have to be if i used a bass pickup? The guitar pup is 32mm high.

While I´m at it, here´s a shot of the butt end of the instrument, I´m going to have an XLR out for the Lo Z, and use a transformer to a normal jack - I think it will look best with a normal EB0 ctrl. layout. The two small wood plugs to the right is to stabilize the ´typical input crack ´repair.

[Chris P.]

Cool! I also have an EB0-body around somewhere.

[dadagoboi]

Looking Good!

[Granny Gremlin]

The XLR out will be a bit of a problem in that the pup output is single-ended and anything with an XLR input is balanced.  Depending on the input section there can be a significant level drop (and therefore increased noise when you turn up the gain to compensate).  I assume you are not planning to use an XLR plug other then to the transformer/cable you're making, but there is an opportunity to make things better here.  Using a simple 1:1 transformer inside the bass (a local surplus store here has them real cheap, they're not super top quality, but this is such a low level application it shouldn't matter much... I actually grabbed one of those to play around with and could send it to you for the cost of shipping - it's about half an inch cubed in size) can balance the output for you.  This will do a few things (which may or may not be important or useful to you):

1) provide true universally problem-free Direct Injection without a DI - i.e. input into any mic level device.  ... then plug the thing into a vintage Ampex tube preamp and get yer James Jamerson on (I do this with my Triumph and despite the loZ pups, have to use the HiZ output and a DI for optimal results).
2) increase noise resistance (common mode rejection! which I'm sure you know all about). You can then just use any passive DI (backwards) to plug into a regular amp (or, as Rob would likely say, skip the expensive DI  and just turn up the input gain - I find that this approach is not that great with all amps, especially old tube amps, and you'd still need an XLR to 1/4"TS "winkie", which you can make or buy in barrel form, at least locally here, for about $5).  I can get barrel style Z converters (DI with no ground lift or passthru output) locally for $7-10.
3) isolation even when running LoZ (not using the Lo to Hi transformer)

I am also very curious as to what you're planning for the circuit - or are you going pup direct to jack?


Anyway, looking good so far (nice job on the plugs and routing - don';t think the plugs will show after finishing - solid/opaque white right; no sweat).  I was gonna say looks like you need some fret leveling if not a refret, but I see in the latest pics you pulled the frets so good on you for going the full 9.

[Grog]

Nice Job!! I've been contemplating doing something similar with my Les Paul Signature pickup. The Les Paul Signature guitar & bass, both have a balanced line out (1/4 stereo jack) on the bout of the guitar. A store bought 1/4 stereo to female XLR jack works well with the LP Sigs. I have more than enough parts to build a few basses, but no body.............

[amptech]

The XLR out will be a bit of a problem in that the pup output is single-ended and anything with an XLR input is balanced.  

Well, there is still a regular ac signal we´re dealing with , and I´m going to have a very simple cct applied here.
There will be volume and tone, and a Lo to Hi Z transformer. It will be like the triumph bass, without all the controls. (The Triumph has both   hi and lo Z balanced / switched, hasn't it?)

A regular microphone is ´single ended´well, you still run the ac signal through XLR with separate shield (or through a transformer in the mike)

I´m not going to have any hi/lo switch, but I will be using a stereo jack for the hi Z out just to separate ground from the XLR connection.
I can post the schematics tomorrow, have to go to bed now..

[Granny Gremlin]

Yeah, do post a schem when you can, thanks.

I highly recommend not only a typical tone (treble cut) but also the bass tone as on the Triumph.... Though with a geetar pup in not neck position on a bass this may be less useful than either bass version in neck position on hot coil tap or geetar version on an actual guitar in neck position... so nevermind just thinkin out loud. 

[Basvarken]

2) increase noise resistance (common mode rejection! which I'm sure you know all about). You can then just use any passive DI (backwards) to plug into a regular amp (or, as Rob would likely say, skip the expensive DI  and just turn up the input gain - I find that this approach is not that great with all amps, especially old tube amps

My Ampeg V4B doesn't have a gain control. Just volume. And I just crank it up some more tho get the desired increase in volume.
Makes the power tubes work harder. Not the pre amp tubes.

When I'm running lo-z into my Orange I don't dial in more gain either. I just turn up the master volume. Again making the power tubes work harder. Not the pre-amp tubes.


But I got to admit that I haven't been running Lo-z a lot lately. I use the external impedance transformer most of the time.
The transformer has an XLR in and 1/4 jack out.

I'm not sure I understand why you guys would want it the other way around?

The big advantage of the lo-z output is that the signal stays clean all the way to the amp or to the board. No matter how long the cable is going to be.
No need for a balanced signal. The signal is pure and good as it is.