Can GK-3 act as a normal magnetic pickup

Started by celemourn, March 16, 2023, 12:23:56 PM

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celemourn

Hi, first post!

I'm planning out a new guitar build, and one of the main things I want to do is to make it essentially just a neck, with no real body, and with the longest possible fingerboard (fretless below 24th). I also want it to be able to work with a synth, which I plan to buy in the future (but later, as they are freaking expensive). So I picked up a gk-3.

I've gather that the signals on pin 1-6 are just plain old analog signals from the tiny humbuckers in the pickup, and so I'm wondering if I can rig up an adapter or cable, possibly with a preamp built in, to combine those six signals and send them out as a regular old magnetic pickup signal that any amp or pedal can use? Does this seem feasible? Is there anything special about pins 1-6 that would prevent this from being done (other than the signal being really weak, because the coils are tiny)? A secondary goal is to also integrate a wireless 5GHz transmitter so I don't have to be bound by a cable when I'm not using the synth functions.

Any thoughts or advice?

EDIT: regarding the fingerboard, I really do want it to go all the way from the nut to the bridge, if possible, hence why I'd like to use the gk3 as the sole pickup, rather than also using a magnetic one. I could use a piezo if necessary I suppose, but that add a preamp that I'd have find a place for, and it's gonna be cramped already, so I would like to avoid it.

sixeight

#1
Technically you can, if you would diy build a circuit that can mix the 6 signals from the gk pickup.

But the sound would be very thin, as the preferred position of the GK pickup is very close to the bridge.

A much better result will come from guitar modeling, which the GR55, GP10 and SY1000 are capable of. Also the older VG8 and VG88 are capable of this, which you can sometimes get cheaply second hand.

celemourn

yeah, my preference will be to just use an SY-1000, but its going to be a while before I can fit that into the budget. I don't mind rolling my own PCB, I just don't know a lot about circuits and analog signals and such. :)

gumtown

Sixeight has covered most of it,
the GK-3 has provision for a normal guitar pickup input, which the guitar/mix/synth switch makes use of both input signals (normal pickup + control voltage for the synth).
I would advise installing a pickup, even a thin type, closer to the fretboard, as the GK must be positioned right next to the bridge, and making a circuit board with axctive electronics to mix the hex pickup signals will take more room than another pickup.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

gumbo

Quote from: gumtown on March 16, 2023, 02:28:16 PMSixeight has covered most of it,
the GK-3 has provision for a normal guitar pickup input, which the guitar/mix/synth switch makes use of both input signals (normal pickup + control voltage for the synth).
I would advise installing a pickup, even a thin type, closer to the fretboard, as the GK must be positioned right next to the bridge, and making a circuit board with axctive electronics to mix the hex pickup signals will take more room than another pickup.

My thoughts exactly... ;)
Read slower!!!   ....I'm typing as fast as I can...

celemourn

Quote from: gumtown on March 16, 2023, 02:28:16 PMSixeight has covered most of it,
the GK-3 has provision for a normal guitar pickup input, which the guitar/mix/synth switch makes use of both input signals (normal pickup + control voltage for the synth).
I would advise installing a pickup, even a thin type, closer to the fretboard, as the GK must be positioned right next to the bridge, and making a circuit board with axctive electronics to mix the hex pickup signals will take more room than another pickup.

What you're saying makes a lot of sense, and I may end up going that route. If I can find a particularly tiny preamp I could use a piezo pickup of some sort.

On the other hand, if I sacrifice the idea of being wireless, the circuit to make use of the GK-3's pin 1-6 doesn't need to be on the guitar itself. I could use a standard 13 pin cable to go to a separate converter box which has 13 pin in, 1/4" mono out.

I really would like to have the wireless functionality though. :D

gumbo

Quote from: celemourn on March 17, 2023, 05:15:07 AMthe circuit to make use of the GK-3's pin 1-6 doesn't need to be on the guitar itself

I think if you try to poke the minuscule signal strength of the Hex Pickup down the 13-pin cable without having first pre-amped it, you just might find it all but disappears in the first two feet of the cable...well, almost......just saying.. :-X 
Read slower!!!   ....I'm typing as fast as I can...

Brak(E)man

Slightly ot but Uli Roth Sky guitars have the neck pickup under the fretboard.
Just a thought.
swimming with a hole in my body

I play Country music too, I'm just not sure which country it's from...

"The only thing worse than a guitar is a guitarist!"
- Lydia Lunch

celemourn

Quote from: Brak(E)man on March 17, 2023, 10:00:51 AMSlightly ot but Uli Roth Sky guitars have the neck pickup under the fretboard.
Just a thought.
I was just thinking about that actually. Part of the concept for the instrument is that past the 24th fret you can use it as a fretless guitar and slide all the way to the bridge, so for that specific function a neck pickup in the normal place wouldn't work, but I expect 99% of the time it won't matter. so having a super thin pickup under the fretboard is definitely viable.

Brak(E)man

#9
Quote from: celemourn on March 17, 2023, 12:00:35 PMI was just thinking about that actually. Part of the concept for the instrument is that past the 24th fret you can use it as a fretless guitar and slide all the way to the bridge, so for that specific function a neck pickup in the normal place wouldn't work, but I expect 99% of the time it won't matter. so having a super thin pickup under the fretboard is definitely viable.

The under the fretboard pickup can of course be placed where a bridge PU would be.
Using the GK as a "normal" PU is feasible but requires a preamp + additional boosters like in the Spicetone 6appeal ( it has two extra boosters ) https://liveweb.spicetone.com/6appeal/features/
in order to make it sound not brittle and thin.
QuoteROOT BOOST is especially useful, if your guitar has a hexaphonic pickup (like Roland GK) mounted on or near the bridge. Pickup near bridge mean thin sound. The Root Boost function recovers the lack of bottom end, amplifying the fundamental frequency range of each string.
I'm guessing it's overkill to try to make the GK into a normal PU, it's probably easier to test a PU under fretboard to see if that functions well enough.

I'm curious since I also plays fretless since a long time back both acoustic and electric with GK and piezo.

What are your  purpose in having the guitar fretless so far up the neck?

I've used fretless electric mandolin and is very difficult to achieve anything remotely musically above the 12 "fret" which would be similar ( but not exactly the same ) as above the 24 "fret" on a normal scale length.
I have a baritone scale 31 frets / octave tuned like a normal scale that's fretless above where the normal 7th fret would be.
(I also have a similar one that's fretted all the way to the 62fret.
It's very close between the tones up there.)
swimming with a hole in my body

I play Country music too, I'm just not sure which country it's from...

"The only thing worse than a guitar is a guitarist!"
- Lydia Lunch

gumtownadmin

You could find a thin toaster or blade pickup, and recess it by the neck to be a 24 th or 25th fret, or somewhere up the playable body/fretboard to be a 36th fret.
Or a pickup recessed below the fretboard to have a thin wooden veneer over it, flush with the fretboard.
Always remember that you are absolutely unique. Just like everyone else.

eUphonic

About the thin tone: it's not only that a GK3 is close to the bridge but also because the six coils have a very low DCR/inductance, giving an ultra high pitched resonant peak... and the higher pitched is a resonant frequency, the lower is the output level with a same magnetic strenght.

FWIW, I share below the frequency response of a GK3, electrically excited while my GP10 was in setting mode (situation where the signal is only buffered and not processed by the unit).



And here is the same thing compared to the GK3 played in chords from unfretted strings to 12th fret, in the same situation of unprocessed signal, direct to the board.



Last but not least, here is the response of a normal bridge humbucker played in the same way in two positions (right screen = the pickup 1 cm closer to the bridge).



Draw your conclusions. :-)


GuitarBuilder

Very interesting!  Can you elaborate on how you electrically excited the GK-3?
"There's no-one left alive, it must be a draw"  Peter Gabriel 1973

eUphonic

#13
Quote from: GuitarBuilder on March 18, 2023, 07:33:38 AMVery interesting!  Can you elaborate on how you electrically excited the GK-3?

Hi,
I've used an ultra-low impedance air coil, as those used here to do thousands of measurements on magnetic pickups these last decades.
It's roughly the same thing than in the figure 11 in the web page below (with the difference that I favor smaller coils):

http://www.buildyourguitar.com/resources/lemme/

GuitarBuilder

Quote from: eUphonic on March 18, 2023, 01:10:55 PMHi,
I've used an ultra-low impedance air coil, as those used here to do thousands of measurements on magnetic pickups these last decades.
It's roughly the same thing than in the figure 11 in the web page below (with the difference that I favor smaller coils):

http://www.buildyourguitar.com/resources/lemme/

Nice! Thanks for the link!
"There's no-one left alive, it must be a draw"  Peter Gabriel 1973