7 String GK Pickup Strategies For Single & Multiscale 7 String Guitars

Started by luca9583, November 22, 2022, 10:22:38 AM

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luca9583

I've been thinking about how to incorporate the GK pickup with various 7 string guitars and thought i'd start a thread. My 6th and 7th strings on all these instruments are tuned to E1 and B0 like a 5 string bass, while the top 5 strings are in standard tuning. As we know, there aren't any Roland processors that can do more than 6 strings.

Here is a 7 string baritone with standard string spacing.

Solution? Simple. Two GK3 kit pickups with two kit boards and 13 pin sockets. One for the top 5 strings (or top 6) going to the VG-99, and the other for the bottom 2 strings (or bottom 6) going to a VB-99. I also discovered while doing this that provided you don't use any ALT tuning, a VG-99 doesn't mind hearing bass tuned strings and can apply COSM modelling to them, it just can't track them for tuning or synth work.

The custom surround/ring for these was made for me by John Procter here in London..it basically screws on top of the humbucker's pickup ring, keeping the GKs nice and solid.

The GK that handles the lower strings had to be wired in reverse at the white board so that i don't need to choose the reverse pickup setting in the VG/VB..this worked perfectly.

luca9583

The next guitar is a custom 7 string with narrower than standard spacing and was the first 7 string i came up with a GK strategy for.

Again 2 x GK pickups but as this was my first experiment, i first tested a GK2A for the top 5 strings, and then got another GK2A for the two low strings without realising it was actually the older GK2.

You can see here that the narrower string spacing means the GKs don't line up properly on all the strings, but actually the crosstalk is low enough to pull off perfect ALT tunings on the higher strings, with only a tiny amount of bleed going into the 5th string's sensor due to the far from less than ideal coverage.

The BKP humbucker actually picks up all the strings fine despite the narrower string spacing.

I'd like to come up with a modded GK solution for this..more on that below.


luca9583

Here is the biggest challenge..a multiscale Agile 7 string (27-30" scale).

For starters, the stock humbucker wasn't long enough to be routed at the correct angle to match the placement of the bridges, so i got a 10 string (yep!) 5" Lace X Bar routed in to correct this. The 5" pickup was the only one that would cover all strings at the correct angle.

Now for the GK challenge. The first attempt was to line up two GKs as follows, but as predicted, there would be too much crosstalk for ALT tunings etc.

The second idea is to angle the GKs at the ideal angle, but that would require shortening the baseplates of the bridges, which we could get away with given that i know the intonation points won't need to go sharper, but that isn't ideal.

That leaves me with coming up with an angled modded GK which is where any input would be really appreciated.

I'd like to take @Yaman's GK individually adjustable pickups mod and apply it to this instrument.

I learned while wiring this first attempt that the audio from each sensor can be wired to either of the two GK kit boards in the guitar..so for example, i switched the wires to the kit's white connector for the top 5 strings so that the two unused sensors aren't wired, and replaced by the next 4 in line.

So i'm thinking that a custom 7 string GK could actually be made so that 7 x separate sensors could be mounted with wider spacing to match the bridge angle, but with the 6th and 7th string sensors both wired to the second GK board that feeds the VB-99. I'm guessing that would mean two sets of ground and shield wires (one for the top 5 and one for bottom 2).

Any ideas and do you guys know anyone who could make the modded pickups for these guitars in the UK?


gearhound22


luca9583

Quote from: gearhound22 on November 23, 2022, 05:17:32 PMThere is a spare pin in the GK 13pin cables iirc too :(

I'm running 2 x 13 pin sockets on all the guitars..one to the VG and on to the VB, and with the Kits i'm only using the volume knobs (no buttons for now, and definitely no pickup mixing etc), so i'm not sure i'd need to use a spare pin, unless your're talking about grounding?

ESQ17

He may be referring to connecting the 7th string to pin 7 which would normally get the summed magnetic pickups output. Or to pin 9 which is not actually connected to anything. It's not a 'spare' per se, but no reason it couldn't carry signal if wired...

Which, unless I've missed something, won't work with either what you're doing, or for a single Boss/Roland input like I'm doing.

In trying to find my perfect all rounder guitar for a GK setup (and dear Lord, the end result had better be worth it) I gave a serious look at slotting the Floyd baseplate on my Jem 7 string and using Graphtech Saddles/preamp/traction setup to my SY-1000. Leave Drop A (Low string) piezo unplugged and only use the standard tuned strings when alt tuning. There are... challenges with this. Not least of which is finding a machine shop willing to drill 7 2mm x 6mm slots for the wires into a hardened steel baseplate.

I'm probably still going to try it down the track, but think I'm going to wuss out, buy a PRS Floyd SE (25" scale, 24 frets, locking trem, ebony fretboard and 'one look suits any gig' aesthetic, it's as all rounder as I can come up with that isn't megabucks), drop a Graphtech loaded floyd kit in it and do the 7 string next year.

And if the 7 does work, then I'm gonna follow Elantric and shoehorn a FTP in there as well.

And it will be called Conner McCloud, as I will need only one... :)

Good luck on your builds, I'm now watching with interest.
ESQ... Exclamation, Statement, Question. The only things a working musician really wants to hear.
Exclamation: "That sounded great! Statement: Here's some money for you. Question: Same time tomorrow?

gearhound22

Quote from: luca9583 on November 23, 2022, 05:24:08 PMI'm running 2 x 13 pin sockets on all the guitars..one to the VG and on to the VB, and with the Kits i'm only using the volume knobs (no buttons for now, and definitely no pickup mixing etc), so i'm not sure i'd need to use a spare pin, unless your're talking about grounding?

Just saying they wasted a pin on a potential 7th string input :(

luca9583

Quote from: gearhound22 on November 25, 2022, 03:07:05 AMJust saying they wasted a pin on a potential 7th string input :(


Indeed! Hard to believe they still haven't come up with a modular pickup system and processor to add more strings, especially given some of the instruments/market that tends to be interested in GK stuff.

admin

Quote from: gearhound22 on November 23, 2022, 05:17:32 PMThere is a spare pin in the GK 13pin cables iirc too :(

Unless it's newer than 2004

At that time the GR-20 and GK-3/GK-3B started to use Pin #9 as a Control Voltage to reflect current positioning of the three way "Guitar/Mix/GKSynth" switch.

Details
https://www.vguitarforums.com/smf/index.php?topic=5259.0

luca9583

@ESQ17 have you thought about Cycfi pickups (or an extra single string pickup for your low A) for your 7 string and running the low A string only to a GP-10? You could use the GP-10 for Cosm sounds of that low A (these should work if you don't ask tbe GP-10 to pitch shift it), and then run the GP-10 into a programmable pitch shifter to achieve alt tuning on that string.

Even the Cycfi direct to a pitch shifter would work well.

After that, just sum the top 6 strings from the SY1000 with the processed 7th string with a mixer, or even feed the processed 7th string into the SY1000 and sum it in there.

luca9583

Even with the availability of an extra pin of a 13 pin socket, it's of no use if there's no preamp available for it and no V guitar processor that will accept a 7th string, so until Roland and Boss agree to cater for more than 6 strings, it's gonna be a case of using two separate GK lines into two separate processors.

luca9583



I took the plunge and chopped up a GK3..wired up a single mini humbucker to the GK preamp and sure enough it works perfectly.

Having just had the guitar set up, i can see that i just need to replace all the bridges with ABMs as i did for the lowest string, because by mounting the ABMs so that their edges are much closer to the intonation points, the intonation points would leave plenty of space to mount a mini GK for each string.

Once that is complete i'll just need to get a mini housing made for each mini GK so they can be mounted properly.

So a modular GK setup appears to be possible.


luca9583

Quote from: admin on December 05, 2022, 10:56:14 AMWhat's an "ABM"?


Ah sorry yeah ABM is the brand of the chrome individual bridge i had mounted on the 7th String. The travel of the saddles on these allows you to get the saddle quite close to the edge (compared to the stock bridges on the strings here).

https://abm-guitarpartsshop.com/ABM-GUITAR-PARTS/Single-Bridges/Guitar/ABM-3210:::256_3_45_144.html?language=en

I actually thought about getting the ABM piezo bridges, but saw that many users here prefer the tone and separation of the GK over a piezo, and a 7 string guitar would require 2 x Graphtec systems.