GraphTech Ghost System problem

B

Briancch

Member
Hey guys...know some of you are long time GT Ghost system user....just installed Ghost saddles with Acousti-Phonic preamp on my guitar

Right now the guitar is wired based on this diagram without the piezo volume
https://cdn.shopify.com/s/files/1/2372/8913/files/acousti-phonic-kit.pdf

However, I notice there is piezo signal bleed when I switch to magnetic? What are the possible causes on this issue? Everything is shielded and wired properly.

Possible reasons?
- a defective Quick Switch or preamp?

I don't actually need a blend function, it's always piezo or magnetic. Would a two way on/on switch fix this issue?

Cheers
 
I purchased a Lifeson LP back in 2015 that has the Ghost System on it, and after installing a set of Motor City Hot Head mag pickups, they really never sounded right. First I changed the switch wiring to what I thought would totally separate the two systems, but after looking some more, saw that the mag wiring was still going through the board, and it still sounded ”off” on the mags. Ended up completely rewiring it to where the mag system was totally separate from the Ghost system, and you now have to change input jacks according to which system you want to play through ( of course having the Axe Fx I can have both hooked up at once and choose between them with the fc-12).

I know this doesn’t do a lot of good for diagnosing your issue, but might give you another idea as far as separating them. Both systems really sound great now, and it has become one of my favorite guitars. Good luck!
 
I can't think of a reason for the signal bleed. Then again I'm too chicken to do any aftermarket mods myself. I always have them done by a tech I trust. Anyone local you could have sanity check it for you?
 
I am using the Ghost saddles with the Acousti-phonic preamp and the hexpander for 13-pin MIDI output on a American Deluxe Strat. I am not having that issue. I can separate Magnetic from Acoustic. Have you checked that the 3-position switch doesn't have a bad contact?
 
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Piing said:
I am using the Ghost saddles with the Acousti-phonic preamp and the hexpander for 13-pin MIDI output on a American Deluxe Strat. I am not having that issue. I can separate Magnetic from Acoustic. Have you checked that the 3-position switch doesn't have a bad contact?
Click to expand...
Yea..I got other guitars with Ghost saddle/ preamp and none of them has such issue:tearsofjoy:. Just tested with another preamp and the problem is still there ...so likely it's the problem of the toggle switch?
 
I didn't use the Graphtech schematic where mags go throughthe PCB because it adds noise.
I used a Switchcraft 14b stereo jack but I had to correct the schematic:
Acousti-Phonic with 14B stereo Jack - CORRECTION.jpg
 
One other thing I forgot to mention is that before separating the two systems, the battery for the piezo system didn't used to last very long.......
now seems to last forever.
 
I've been having noise issues with my build as well. I built an electric with this system and have always had issues with a stereo plug and splitting the two pickups. I will be trying this fix shortly. I also have huge noise issues if I plug my Sennheiser wireless with a mono plug into the system. I had to make a stereo plug with the ring disabled going to a mono female jack and I plug my wireless into that. No noise but then I can't use the piezo this way. So, how does it work when you split the two? Also, when using the stereo split, can you still use the toggle switch?
 
You need a switch plus the stereo jack. Otherwise the Graphtech will not work correctly, either it sucks or it will eat your batteries if you store your guitar without unplugging.
I still think it is one of the best sounding piezo preamps though.
 
Again not an answer. I didn't care for the mag going through the Ghost preamp so I added a second jack and just use two outputs and let the Axe FX do the switching between the two.
 
With the schematic I provided, the mags don't go through the Ghost preamp either.
But I also used two output jacks on my Larkins.
 
Just chiming in with a similar solution. I used a push/pull pot that switches between magnetic and piezo, I also don't run magnetics through the PCB and never attempt to blend, one or the other and just the one output jack.
 
So that worked great! Thanks for that MisterE! No more hum. So, now I need to switch between the 2 pickup systems with a foot switch. I realize you guys here are using Fractal stuff, which may happen, but how do others switch? I obviously have the mini toggle switch but I'd prefer a footswitch and leave the toggle switch in the middle using a TRS cable out.
 
Johan Allard said:
Just chiming in with a similar solution. I used a push/pull pot that switches between magnetic and piezo, I also don't run magnetics through the PCB and never attempt to blend, one or the other and just the one output jack.
Click to expand...
Do you get a pop when using the push pull? I thought that was the side effects of bypassing the preamp.
 
warlockII said:
Do you get a pop when using the push pull? I thought that was the side effects of bypassing the preamp.
Click to expand...
Not pop at all. I did try at one time to also connect the piezo power to the push-pull, thinking that if the piezo is disengaged, there would be no need to power it so it would (almost) never run out of battery, you could leave everything plugged in and so on. With that configuration I got a pop since switching to the piezo would also turn on the piezo. But with everything turned on when the guitar cable is plugged in as all standard piezo's are configured, there's no pop whatsoever.
 
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