Using GK input to power Fernandes Sustainer

Started by Phil John, July 26, 2013, 07:32:37 AM

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Phil John

Hi,

I've got an Ibanez RG1520 with the piezo GK pickup. I want to fit a Fernandes Sustainer in the neck position. The sustainer circuit board requires a PP3 (9V) battery. I was just wondering whether anyone had tried running any additional circuitry from the 7V supply on pin 12 of the GK connector?

I only need it to work when the GK is connected, so I'm hoping to do away with the battery.

Any thoughts?

Elantric

Use a separate Internal 9V Battery to power your Sustainer - There is not enough reserve current in the Roland +7.5V Rail (supplied by the Host Roland Processor via 13 pin cable) to power the GK 13 pin hex preamp  - AND - a Fernandes or Sustainiac Sustainer.   

Phil John

Thanks for the advice. That's a real shame though. :(

I fitted a Fernandes Sustainer and a GK2 to my previous guitar and the combination was fantastic. The only problem was that the battery powering the sustainer would go flat. I even inserted a switch in the DC power line, but I'd forget to knock it off and it would go flat. I was really hoping to do something a bit more efficient this time, particularly as I want to minimize the amount of routing I need to do to the guitar cavity.

gumtown

The GK supply could be used to electronically switch your battery supply, so the sustainer power switches off automatically when the GK power is removed.
The internal GK Kit3 has this feature built in for switching active pickups,
and since this is in the DIY section, you may have some knowledge on fitting a MOSFET switch for the sustainer battery supply.
Perhaps look at lithium/ion or lithium/polymer type rechargable batteries.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Machh_2

Quote from: gumtown on July 27, 2013, 02:35:34 AM
The GK supply could be used to electronically switch your battery supply, so the sustainer power switches off automatically when the GK power is removed.
The internal GK Kit3 has this feature built in for switching active pickups,
and since this is in the DIY section, you may have some knowledge on fitting a MOSFET switch for the sustainer battery supply.
Perhaps look at lithium/ion or lithium/polymer type rechargable batteries.

Li-ION or LIPO batteries is the best option to suply the circuits, but needs a dedicated charge device, cuz LI-ION/LI-PO batteries needs charge and balances the cells at same time, or the batteries will explode (i have done this experience...), the LI-XX charges have a internal delta-comparator to measure current and voltage charge...but, at the end ,is very good option.
You also can try use a DC-DC converter to use the gk 7V to lift to 9v...
see the link :
http://www.aliexpress.com/item/5-PCS-LOT-DC-Buck-Converters-Input-7-35V-to-Output-1-25-30V-3A-DC/555507128.html

or some like that...

drjoness2001

I am using a Sustainer with a GK-3 guitar.

I tried different approaches, including using an external 9v supply and using pin 9 to carry to current, which resulted in some slight ground hum.

Currently (so to speak), I wired the Sustainer as per the instructions, and use a dummy 1/4" jack to power the Sustainer when I need it. I tried using the internal MOSFET switch (CN6) to turn the Sustainer electronics on and off. Here was my problem: even when the Sustainer is off, the 9v still draws a small amount of current.

So I would be working all day on stuff that had nothing to do with the Sustainer, and when I did need the Sustainer, the battery was dead ("flat" like my vocals).

So now I only plug in the dummy 1/4" jack when I plan to use the Sustainer, or need the humbucker signal to the GK synth.

Brak(E)man

Quote from: drjoness2001 on July 27, 2013, 04:19:19 PM
...

So now I only plug in the dummy 1/4" jack when I plan to use the Sustainer, or need the humbucker signal to the GK synth.

+ 1
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

Elantric

#7
Quote from: drjoness2001 on July 27, 2013, 04:19:19 PM
...

So now I only plug in the dummy 1/4" jack when I plan to use the Sustainer,


+2

gumtown

Quote from: Machh_2 on July 27, 2013, 07:44:20 AM
You also can try use a DC-DC converter to use the gk 7V to lift to 9v...
see the link :
http://www.aliexpress.com/item/5-PCS-LOT-DC-Buck-Converters-Input-7-35V-to-Output-1-25-30V-3A-DC/555507128.html

or some like that...
I don't think the GR/VG main unit would supply nearly enough current to charge a LI-PO or LI-ION battery, 200 mA is about the limit and the GK uses half of that.
Any current in your GK cable will also introduce hummmmmm. (using the common ground for signal and power)
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

Phil John

QuoteSo now I only plug in the dummy 1/4" jack when I plan to use the Sustainer

Nice idea. I may still go with the battery, but that's an option. Thanks.

Machh_2

Quote from: gumtown on July 28, 2013, 04:43:19 AM
I don't think the GR/VG main unit would supply nearly enough current to charge a LI-PO or LI-ION battery, 200 mA is about the limit and the GK uses half of that.
Any current in your GK cable will also introduce hummmmmm. (using the common ground for signal and power)


Batteries Lipo / ION carry any current, up to the rated current of own battery, the issue is the time it takes to load and balancing of the cell LIPO / ION ... without balancing the battery you condemn it the same day you purchase.
I think it is not worth it ...

[] 'S

Machh







MarkFrancombe

I have made an extra jack socket on my guitar especially to send 9vs to the Fernandez, and an axtra jack cable that is wored to a 9v supply at the other end.. Works a charm, no hum, (I think as its shielded seperatly its OK)

M

MikeTranch

just a late p.s. to the topic of powering fernandez sustainer guitar from GR-55:

I did this, going back to the wall wort side of the GR-55, I tapped in there, put an inline fuse, 1A Fast, then 22 gauge wire run along the outside of the GR13pin cable, into a TRS plugged into the guitar.  The TRS plug was added to replace one end of the Roland supplied 1/4 to 1/4 cable.  Inside the guitar, the battery connector was shorted with a 1A fast blow fuse.  The net result is the sustainer is powered when ever the wall wart is plugged into.  Note the slice was on the wall wart cable, so keeps the main rig like new.  As an aside, it was fortunate that voltages and polarities of the GR and the fernandez were the same, allowing one supply to be shared.

The single power supply worked great; the wall wart has enough current capacity to power both, no problem.

But one other problem I had was using the sustainer on, with the GR synths, would produce false notes on adjacent strings.  I deduced this was because the sustainer drives all strings, and that coupled into the hex GR PU, causing extra, false notes.  With the sustainer off, the synths were fine.  And since then, I found info on this forum about nuance, etc., so I may have to go back and give it another try.  Better right hand technique, palm muting, would probably help too. 

In the meantime, I mounted the GK-3 on my LP, and the natural sustain of that ax works great with the synths