Active pickup output 'halved' after installing Roland GK-3 kit.

Started by Kitko, January 20, 2016, 04:14:07 AM

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Kitko

I recently had a Roland GK-3 kit installed into my Ibanez RGA72QM (http://ibanez.wikia.com/wiki/RGA72QM) - by an experienced luthier. By experienced I mean experienced in guitar synths related stuff (even his own nylon acoustic has a 13-pin connector).

This was, however, his first intallation of GK-13 on a guitar with active pickups (the Ibanez has a pair of stock humbuckers powered by two 1.5V batteries.

The synth works fine, the guitar's pickups switch on BUT... their output seems halved. It's not just when using the GK-3, though. When I plug the guitar directly in the guitar processor I used it with prior to the GK3 transplant (no GK3 situation, just guitar jack out), instead of a meaty distortion I'm used to, I'm getting a mild overdrive.

The weird thing is that the volume pot controlling the guitar's humbuckers seems to do nothing for the first half of the travel. It's like the portion of the signal is getting lost somewhere.

Any help will be MUCH appreciated.

Thanks.
Boss SY-1000
Roland VG-99
Boss RC-600
Roland FC-300
Ibanez RGA 7 with GK3
Ibanez RGA 72QM with GK3 kit
Ibanez RGA 121 Prestige JD Craft

Elantric

Common problem when installing GK-3 internal on guitar with active PUs

It's important to use a 1/4"  switching output jack that removes the normal guitar output signal from getting loaded down by the Opamp buffer (locate IC4A in circuit below) in the GK-KIT-GT3 internal kit. WHEN THE GUITAR IS USED WITHOUT GK 13 CONNECTION

Review this post.
https://www.vguitarforums.com/smf/index.php?topic=73.msg73532#msg73532



I use these  DPDT Switched 1/4" jack  - they used to be at every Radio Shack store, but those days are over.

When you insert a 1/4" guitar cable This jack allows the internal active Ibanez electronics to be turned on, and their signal removed from the GK-3 circuit - essentially placing the guitar back to "stock" to prevent GK-3 circuit interaction that occurs with some active PU systems.

You might have to resort to using 2 cables from the guitar ( 1/" cable for normal PU's & GK 13 pin for divided Synth PU only )   
http://smallbear-electronics.mybigcommerce.com/1-4-stereo-isolated-dpdt-switch/

Kitko

Thanks, Elantric, for a fast reply.

In my brain, which is fried after I visited a dentist today, it kind of raises even more questions. You see, I'm also getting the 'diminshed' pickup signal even when using the 13-pin cable only and mix the guitar PU's with the GK3.

And the should not be happening, right?

I tried using a dummy guitar jack (patch cable) when I got the guitar home few weeks ago, but that did not help, but I do have a cicruit breaker Planet Waves cable... Unfortunatelly, I won't be able to try this for another 24 hours...

I'll also compare your schematics with the one that came with the pickup, but I'm sure it included the variation for active pickups.
Boss SY-1000
Roland VG-99
Boss RC-600
Roland FC-300
Ibanez RGA 7 with GK3
Ibanez RGA 72QM with GK3 kit
Ibanez RGA 121 Prestige JD Craft

Elantric

#3
QuoteI'm also getting the 'diminshed' pickup signal even when using the 13-pin cable only and mix the guitar PU's with the GK3.

And the should not be happening, right?


The official GK-KIT-GT3 install procedure will render your guitar exactly as you describe.

That's why I never follow the factory method

Instead,  I use the method described in my prior message -with a 1/4" Switching output jack


Show this to your luthier


and
Review the Schematics thread
https://www.vguitarforums.com/smf/index.php?topic=73.msg73532#msg73532

Kitko

I may need to show that to another luthier as that one lives about 200 miles from my place :)

I seriously consider replacing the active Ibanez pickups with passive EMG H4s - providing they solve my problem.

Seriously... would that rectify the issue?
Boss SY-1000
Roland VG-99
Boss RC-600
Roland FC-300
Ibanez RGA 7 with GK3
Ibanez RGA 72QM with GK3 kit
Ibanez RGA 121 Prestige JD Craft

Kitko

So I reviewed about 50 pages here on the forum trying to get my head 'round the problem with active Ibanez pickups...

It reaffirmed my status of one who's hopeless when it comes to DIY electronics and soldering.

So, with my current situation being:
- 50% of normal PU signal strength available in MIX position
- 50% of normal PU signal strength available on the guitar's out jack (with synth out)

the available solutions are:

a) install switching jack
b) replace active pickups with passive pickups

Correct?

I managed to find this switching jack - Elantric, is this what you had in mind?
Neutrik NJ5 FD-V
http://www.thomann.de/gb/neutrik_nj_5_fdv.htm
spec sheet: https://images6.static-thomann.de/pics/atg/atgdata/document/specs/268785_zeichnung.pdf

I am still more inclined to invest in passive pickups as that would, I believe, simplify the wiring.

Big thanks to everyone here who's helping novices like me to get thru!
Boss SY-1000
Roland VG-99
Boss RC-600
Roland FC-300
Ibanez RGA 7 with GK3
Ibanez RGA 72QM with GK3 kit
Ibanez RGA 121 Prestige JD Craft

Tony Raven

Sorry, late to the party again. :(

Unless you really loathe (loathed?) the stock pickups' sound, IMO ripping 'em out sounds :o drastic.

IMNSHO, your "experienced" luthier shoulda known that the GK's buffer would NOT play well with a powered EQ.

Have you tried just entirely disconnecting the active circuitry from the GK-KIT circuit? You give up the "pass-thru" via the GK cable & have to run a 1/4", but it keeps surgery to a minimum. Looks like you'd only have to pull the two-pin CN5 plug.

Kitko

@ Tony,

No worry, I let it simmer as I've done some research and took the guitar apart. This led to 'amazing' discoveries.

1. There was 2-way EQ switch that cut/boosted trebles. That switch was moved to the control cavity and left in the 'no-boost' mode, which did not help.
2. The switch sort of pressed against some other element in a tightly packaged cavity and that caused the partial loss of the signal.

So, once I pulled it out, still on wires, and flipped the switch, I got full stock PU signal :) I'm taking it to another luthier, he lives closer, and have him remove the EQ switch completely.

So:
a) The Roland's schematics was correct.
b) The connection was made correctly.

It seems it was a rather unfortunate turn of events that happened once the cabling in a tight cavity 'settled'.
Boss SY-1000
Roland VG-99
Boss RC-600
Roland FC-300
Ibanez RGA 7 with GK3
Ibanez RGA 72QM with GK3 kit
Ibanez RGA 121 Prestige JD Craft

Kitko

Update:

I finally got to removing the EQ switch from the guitar and reconnecting it all.

Perhaps the most important finding is:

If you have an active guitar (properly made with the active electronics being switched on by inserting the cable's jack), you can absolutely trust the Roland GK-3 internal kit user manual and connection schematics.

Boss SY-1000
Roland VG-99
Boss RC-600
Roland FC-300
Ibanez RGA 7 with GK3
Ibanez RGA 72QM with GK3 kit
Ibanez RGA 121 Prestige JD Craft