Luke iii boost installation

[luiscesaripad]

Hello! I purchased an LIII boost circuit from a forum member. I want to install it on a HSH silo that i also have Graphtech Piezo saddles and preamp installed on it. I got the both schematics from Music Man CS, but the luke only comes HH or HSS and my guitar is HSH. Is there anybody with great electronic knowledge that could help ? Is it possible to install it in an HSH guitar? Can i power it with the same 9v battery used for the piezo system? Thanks!

 

[beej]

The LIII circuit is a preamp with onboard boost. But you're already running your pickups & piezo through the Ghost preamp. So ideally you'd just want to use one or the other.

The Ghost doesn't have a boost. You could run everything through the LIII preamp instead, but you'll have to work out the wiring to short the mags or piezo depending on how you have the switching set up (i.e. if you have a toggle switch for mag/piezo/both). Shouldn't be too difficult though.

I'm not familiar with the LIII circuit, but you should have a few options in terms of wiring up the pickups to the LIII. If you're not handy with this stuff, you might be better off just taking this to someone.

 

[luiscesaripad]

Yes, but i really like the preamp on my LIII HH. I even changed the stock pickups and installed a pair of Dimarzio Transition Humbuckers in the silo. So now that i got the original LIII preamp, i want to install it in the silo. I notice that my Luke 3 is much louder than my other guitars that does not have preamp. The preamp really opens up the tonal range and power of the pickups and i want it in the silo as well. Do i really need to chose only one of the preamps, the Graphtech or the Music Man? Dos the JP13, 15 only use one preamp for both mag and piezo?

 

[luiscesaripad]

Just to mention, the silo has two separated jacks for mag and piezo and a blend switch.

 

[beej]

Both preamps are supposed to be unity gain. The LIII HBs are going to be louder than what's in the Silo ... but regardless, you could increase the output of the Ghost if you wanted to.

Feeding one preamp into another will just add noise without doing anything, really. If you run them separately, you could use the Ghost to run the piezo and the LIII preamp for the mags and combine them at the output or run them into separate outputs if you want. Voltage wise you'll probably be ok, but you'll drain the battery more quickly, so that's something you'll have to contend with. It's your guitar, but I don't see why you'd want two separate preamps in there.

With the JP series, one output is active (from the preamp) and the other is passive (from the mags) and they have a single preamp (I believe). You could could do that with the Silo as well. You just need to think through how you would want the controls/outputs to function.

The blend control isn't a big deal. You have to have both signals active for that to work (it's an impedance issue with the two kinds of pickups) ... you use a pot or switch to gradually ground the input from one set of pickups at the input of the preamp.

 

[luiscesaripad]

I read the manual of the Ghost preamp, and it says that the ghost preamp can power another active pickups or circuits. I just have to figure out how. I cant get rid of the ghost preamp because it offers and push pull pot for mid cut and a trim pot for the gain of the piezo. So i believe is better to use both, and each jack for each type of pickup. And use the ghost capability to power the LIII preamp. I am cooking my brain...

 

[beej]

Take all of this with a grain of salt because I have no actual experience with the LIII preamp (though I've installed the Ghost system a few times).

The Ghost has an aux power out but you can't draw too much current from it. I would probably take 9V from the power input to the Ghost. But you have to watch how you have the output jacks wired up, so the circuit is completed (and you get power) when you plug something into either output jack (assuming you use a separate preamp for each output).

So ... to do what you want, disconnect the mags from the input of the Ghost preamp and instead wire the output of the pickup selector (what would normally go to the volume pot) to the LIII preamp (basically follow that schematic, removing the volume pot as well, etc.). Then, wire the output of that preamp to the other output jack. You won't have a blended signal, but you'll get buffered/boosted mags at one jack and buffered piezo at the other. (You won't have a passive output, though you could wire something up for that.)

In terms of pickup configuration, what you're sending to the LIII preamp is the output from the pickup selector switch, so the actual pickup configuration shouldn't really matter. I don't know how you have your Silo wired up at the switch, but from what I can see of the LIII (with the 4-pole 5-way), you would change a few wires on the lever to account for volume reduction in the humbucker positions. That's easy to adjust later, though.

Again, I'm just guessing. Doesn't look too difficult, but you might need to play around with it a bit to get it all as you'd like.

 

[luiscesaripad]

Ohhh your advice is perfect! That is exactly what i want. One jack with buffer/piezo and one jack with preamp/boost for the mags. The silo is now with Dimarzio
Transitions neck and bridge and a seymour duncan single coil. They are wired like any other hsh guitar. But i have a push pull pot to coil tap the humbuckers and one mini switch that brings up the two humbuckers in series, giving me the midle position sound of a les paul, and when add coil tap it, the tone is pretty like tele mid position, but the volume drops very much. That is one of the reasons i got the LIII preamp, to balance the volume to match in all positions and settings of the pickups. Thank you so much for you great, very great help!!! Any other advice is very welcome!

 

[beej]

Hey great. With regards to the volume boost from the preamp, you're going to have to experiment a bit when you split the pickups. You would need another set of poles on your push/pull switch when you do this, but you're probably using them all. Something like that might require a 4PDT toggle switch, etc. Again, just guessing. If you don't care about that then it's no big deal. (Personally I like the volume reduction in split/single coil positions.)

Good luck, and please let us know how you make out.

 

[luiscesaripad]

Thanks. I will let you know as soon as i get it installed. Thanks a lot!

 

[luiscesaripad]

Do you think it is possible that the preamp of the Luke 3 could power up the Graphtech Saddles?