6 string bass with GK internal mods

Started by gumtown, April 25, 2013, 02:05:40 AM

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gumtown

Here is my latest bass, just a cheapo new 6 string bass ($160).
amazing for the price, as the neck is good and straight, intonation spot on.
I expected the stock passive pickups to sound like poo, but they have a nice beefy tone,
and I have a soft spot for block inlay fretboards.

The GK install is a hybrid of a GK-3B pickup and th e GK-Kit-GT3 guitar kit.
First i modified the gK-3B pickup from side entry in the middle to bottem entry at one end.
The plastic backing is so soft, i used a steak knife to make a circular hole and squared one end for the plug to fit through.


Then installed the Pickup, with diagonal drilling a 6mm hole for the pickup wire.
The GK socket was going to be tricky i thought, covered all areas to be drilled with electrical tape to minimise finish chipping.
but with a sharp drillbit and many holes, i managed to route out a snug fitting GK socket profile.
Also installed the led on the side next to the GK socket.


Then drilled the button holes and selector switch holes, i used the second tone pot hole and knob at the end for the GK volume.
Note* I should have cleaned the bass of the tape residue before taking the photos


And here it is finished and working first time.


Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

gumbo

Beautiful work, gt...

...look forward to hearing some sound samples down the track!

Regards from the West Island   ;D

gumbo
Read slower!!!   ....I'm typing as fast as I can...

Elantric

#2
Very Clean install Gumtown!

QuoteThe GK install is a hybrid of a GK-3B pickup and the GK-Kit-GT3 guitar kit.

Which I'm sure you modified to GK-3B Input gain specs?
https://www.vguitarforums.com/smf/index.php?topic=73.msg3281#msg3281

Might be handy for a full GK-3 to GK-3B BOM (Bill of Material) change, by swapping a few input opamp feedback Resistors and the Pin#9 Control Voltage resistor ladder.
As we know running a straight  / stock GK-3 or GK-Kit Internal which is designed for guitar use WILL compromise your Bass's headroom and dynamic range

aliensporebomb

What bass was this and where did you get it?  I've been looking for one to replace the one that had a twist in the neck that would be "cheap but playable".

Really nice job!
My music projects online at http://www.aliensporebomb.com/

GK Devices:  Roland VG-99, Boss GP-10, Boss SY-1000.

gumtown

Haven't noticed any limit in the dynamic range or headroom (+/-7volt GK supply rail for the preamp should provide plenty of headroom),
and the GR-55 doesn't seem to care the GK switch control voltage isn't correct.

If the control voltage was importaint,
Roland should have made the GR-55 so it could switch guitar/bass mode automatically depending on what was plugged into it.  ;)
With this bass I am only going to use it for modeled tone only and PCM synth anyway.

As far as I can tell the only difference in the GK-3 and GK-3B is just the control voltage and the pickup,
inside the GK-3B pickup the coils seems to be the same size as the GK-3,
except they are on two separate circuit boards which can slide to adjust for different string spacings.

So far I have only tested it with headphones, things may be different with more serious amplification.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Elantric

Quote
As far as I can tell the only difference in the GK-3 and GK-3B is just the control voltage and the pickup

The individual String Preamp Buffer OpAmp Feedback resistors are different value

GK-3 = 10K


GK-3B - 22K


gumtown

Quote from: aliensporebomb on April 25, 2013, 01:04:41 PM
What bass was this and where did you get it?  I've been looking for one to replace the one that had a twist in the neck that would be "cheap but playable".

Really nice job!

Local E-Auction - here are the selection of basses they do
http://www.trademe.co.nz/stores/so-music?cid=1321

and this is the one i got (1 $NZD = 0.85 $USD)
http://www.trademe.co.nz/music-instruments/instruments/guitar-bass/bass-guitars/auction-585374750.htm


I guess they import them from China, the quality of most of their stuff seems reasonably good, playable atleast,
I like some of the double and tripple neck guitars they have (as a novelty idea).


or a "Popular style" guitar like this for USD$168


I am sure they won't last because something has to be wrong with them at this price.

Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

gumtown

Quote from: Elantric on April 25, 2013, 01:15:58 PM
The individual String Preamp Buffer OpAmp Feedback resistors are different value

GK-3 = 10K


GK-3B - 22K

That must be why I had to bump the string sensitivity levels up a bit higher than 'usual'.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

fokof

Nice & clean job !

I'm GAS'ing on a 6 stringer for while , I might jump the bandwagon this year.

I only have 5 strings.....