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MSS

Member
Joined
May 5, 2012
Messages
5
Hey guys,

I've searched for answers to this question in the forum and couldn't find it anywhere.

I found a killer deal on a JP15 but the preamp and piezo are broken. I'm fine with no piezo but if the preamp is broken is this going to affect the sound when using the two humbuckers? I have a preamp in my effect pedal so is the one in the guitar absolutely necessary?

Thanks in advance for any advice you can give.
 

beej

Moderator
Joined
Aug 16, 2004
Messages
11,306
Location
Toronto, Canada
First off, you do have the option of replacing the preamp. You'd have to send the old one to MM and purchase a replacement. Just something to keep in mind.

It's a buffer onboard, not a preamp. It's needed to reduce treble loss as you turn down the volume (like with any guitar), give a boost when engaged, and to handle mixing the high impedance mags with the low impedance piezo. If that's not of interest, you could rewire it to be fully passive. Wouldn't affect the sound materially.

Another crazy option is to find a third-party preamp to put inside to deal with the mags or piezo. Not that difficult if you're handy. But otherwise probably a challenge.

And yeah ... hope that was a killer deal!
 

MSS

Member
Joined
May 5, 2012
Messages
5
Thanks for your response, Beej.

I'm in Vietnam and the dealer said the the JP15 preamp is very difficult to change and that the luthiers here can't do it (I'm guessing that's why he hasn't had it done already). It would be very costly to send to MM from here.

So if unless it's fixed or wired as passive I'm going to have problems? The piezo system isn't working at all, so mixing the high impedance mags with the low impedance piezo isn't an issue. So the only issue I'd have is I'd suffer treble loss when turning the volume down and wouldn't get a boost from the buffer?

Thanks again for your help. Very much appreciated.
 

beej

Moderator
Joined
Aug 16, 2004
Messages
11,306
Location
Toronto, Canada
I can't imagine it would be that difficult to change, however you would need the new part to do it. (Getting the replacement would be up to you- you'd have to contact Music Man directly. Worth exploring, anyway.)

That said, if you want to just rip everything out and go passive, you certainly can. Should be an easy job.

Yes- no boost, and a wee bit of treble loss when reducing the volume (same as any other guitar without a buffer). But you can get around that by using a treble bleed (capacitor & resistor) if that bothers you.
 

MSS

Member
Joined
May 5, 2012
Messages
5
I can't imagine it would be that difficult to change, however you would need the new part to do it. (Getting the replacement would be up to you- you'd have to contact Music Man directly. Worth exploring, anyway.)

That said, if you want to just rip everything out and go passive, you certainly can. Should be an easy job.

Yes- no boost, and a wee bit of treble loss when reducing the volume (same as any other guitar without a buffer). But you can get around that by using a treble bleed (capacitor & resistor) if that bothers you.

Ok thanks for clearing that up.

I bought it, it’s awesome! Will contact music man about getting the replacement and take things from there.

Thanks again for your help.
 
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