SG-Bass: pickup cavity and stiffness of neck joint

[Beate Ritzert]

One of my current projects is an SG-Bass. 76 cm scale, vintage Framus neck from a J-375 bass, multilayered Beech (bolt on, really stiff, well shaped and incredibly cheap), Alder body, Hipshot Supertone bridge, Schaller M4-2000 tuners, black nylon tapewounds. Pickups and positions are still unclear. Electronics probably DIY active with 2 BF245 JFETs, or for the fun of it, an ECC81/82 tube if i get that working reasonably at, say, 22 V.

I started this project because i would like to play an SG bass with considerable faster and more direct response as my (pretty decent) Epiphone EB-3 shortscale - at least comparable to that of my RD inspired shorty with the same Framus neck. And, of course, for the fun of building an instrument.

Now my question:

If i use a sidewinder (possibly an ARTEC, which i do already own and consider modifying) and put that into the "original" position, the pickup cavity would be located immediately adjacent to the neck joint, and it would be pretty large. I am somewhat afraid that such a position would already weaken the structure of the body a bit and i would start noticeably losing attack.

What Do You think? Should i better place the pickup cavity a few cm away from the neck joint?


Thanks

Beate

[Mark Swanson]

I would move it back as you said. I think that it would really help out the neck joint, and the relatively small distance you would be moving it won't make hardly any difference in the tone of the pickup. But, a weak neck joint can really sap the tone! So moving it a bit is a good idea.

[Art Davila]

I have had this discussion with a guy who does cnc bodies and asked him to make me a second body because I believed that having the neck pocket connect with the pickup pocket made the body less resonant.
He disagreed, but as I was paying for it, he re worked the design and moved the pickup cavity 5/16's down from the neck joint cavity.
Both bodies were mahogany and weighed nearly identical. I do not remember the weights as this was 1 yr ago and sold both guitars.
Both used Ibanez necks and I installed threaded inserts, so I can use machine screws instead of wood screws.
I had a friend run both guitars thru several songs and even removed the necks to switch them to the other body.
The result was we both noticed a slight more resonance and sustain from the guitar body which did not end in the pick up cavity.
The tone from the pickups were pretty much identical.

[Beate Ritzert]

Thanks. I think i will place the pickup a few cm away from the neck, maybe in the same distance to the neck as with my Epi instead of the original position - the Epi has two frets more. Now the decision on the PU itself is still open: apparently my sidewinders have a pretty smooth attack (eddy currents?).
One option i am still thinking about is making my own Low-Z humbuckers.

Beate

[Hans Bezemer]

I've build a couple single loop low-Z pickups and they sound pretty well.
The concept is very simple: a single loop around a magnet and a current transformer to transform the signal to mic-level.
One of the advantages is that you only need to drill a hole for the current transformer, but no cavity.
Downside is that you need a mic--> line converter.
It's the concept that Lace uses with their Alumitone pickups.

Here's some background info:
http://music-electronics-forum.com/t5447/

[Beate Ritzert]

Hans, this pickup sounds really good when its lear. A lot better than the more conventional Low-Z i made by rewinding a cheap and crappy Tele neck pickup i discussed here: http://music-electronics-forum.com/t308 ... post276487 (unfortunately the pictures i uploaded into that forum are gone).

I just measured the available height: 8-9 mm in the neck position of both my EB-3 and my RD bass (same bridge and neck as in my current project). Should be sufficient for conventional but flat Low-Z-designs even if i avoid the cavity at all.

But that brings up another idea - do You think it is possible to build the single loop pickups "around a soundhole"? I am still thinking on a possibility to convert the the pickup holes of that guitar (http://www.mimf.com/phpbb/viewtopic.php?p=15182#p15182) into soundholes while retaining two pickups.

[Hans Bezemer]

Beate,
I don't really understand what you mean by building a pickup around the sound hole. But you can shape the single loop any shape you like as long as it is around a magnet. I've made several by routing a groove in a piece of plywood.

As you see these are two pickups, one for the bassside, one for the trebleside. The loop is made from common electric wire.
I've also made a humbucking version but I didn't noticed any big difference, so I stick to the single coil version.

If your willing to step away from regular guitar pickups, you could consider to use your strings as a pickup.
In a nutshell you make a loop with two adjecent strings or from one string and a common ground return (which basically means that you must have a conductive nut connected to your trussrod and your trussrud connect to your string.)
This concept is used in a commercial product called: Stringamp.
Here's someone using this concept on his bassguitar: http://www.youtube.com/watch?v=Lj5knLzVSns
For background info see: http://music-electronics-forum.com/t14952/
Right now I'm experimenting with this pickup design and it sounds promising. One of the advantages is that you can design a polyphonic pick up.

[Beate Ritzert]

Beate,
I don't really understand what you mean by building a pickup around the sound hole.

I would like to build the pickup onto or into something like a humbucker frame and retain the interior of the pickup openings as soundholes (of a thinline archtop).

[Mark Swanson]

I can see that, it would be a cool idea and a design challenge.

[Hans Bezemer]

Ok, I get it. Yeah that would be a cool idea.
Making the loop would not be a real problem, but getting a small / thin but still powerfull magnet might be the bottleneck.
The desired width of the pickup must be around 5 - 6 mm / 0.24 inch?
Maybe a slimmer version of this design could work: http://music-electronics-forum.com/t5447/#post173977

Hans