Question Active Circuit in JP13 & Pickup Swap

[mandoismetal]

Hello all,

First post here. I just recently bought my first EB MM guitar! I love the way this thing plays. However, I think I prefer the sound of JP's previous Dimarzios better.

Does anyone know if the preamp on the JP13 can be "skipped" in order to have a fully passive CL/LF set?

Will this affect any other features like the piezo and the coil tap?

Thanks in advance!

 

[dedeman]

I do not have that JP13 model but most definitely the booster preamp does not affect the signal if it is not engaged (switch pot in UP position), although it might drain a bit of battery if instrument cable is inserted in any of the jacks in the guitar. And from what i know, the preamp will only be for magnetic pickups, not for piezos, which have their own preamp. An inside picture would be more relevant...

But anyways, I wonder why would you not like the preamp as a feature? It sounds bad? How are you using it? I have a JP11 and I wish I'd have a preamp in it, as some other Luke guitar have... and as JP13 have. I am looking for an aftermarket onboard preamp but I can't find anything but EMG which have a different philosophy - they are made with cheap OPAMP integrated circuits not with FETs which I understand are more desirable sound wise.

An onboard preamp might help lower a high gain channel on an amp which would help get a less saturated and compressed heavy overdrive distorsion, while still getting the aggression and "umph". In fact, most players use overdrive pedals in front of amp for the same purpose, but having a boost in the guitar itself, I find it more appealing, because when switching from drive to clean there is no need to step on the overdrive to take it out as well. And of course, the flavor is different with a clean booster instead of an overdrive pedal.

 

[beej]

I'm sure you could wire it up for a passive out, but it would be somewhat of a project- I wouldn't suggest it unless you're handy with a soldering iron and don't mind digging in to it.

Really, there's no advantage to passive except that you'll be more susceptible to high-end roll-off due to cable capacitance, something you can easily adjust by wiring in a capacitor or two. (The preamp is a buffer.)

That said, if you really don't like the pickups, there's no reason not to swap them out.

 

[dedeman]

But I believe the sound path from pickups is "passive" to the output, unless the preamp is engaged... the switch should do the routing through preamp or by-pass.

 

[beej]

I haven't seen the schematic, so take this for what it's worth, but that was not my impression from earlier posts. Best to ask AJ or somebody in the know then.

 

[killerburst]

I know on the Luke 3 the preamp is always in the audio path and the battery is required for output. Switch toggles between unity gain buffered output and boosted output. My presumption is it's the same for the JP13 but you can test it easily by removing the battery and seeing if you get any output.

 

[mandoismetal]

Thanks all for the feedback.
First, battery is needed for output even with the boost disengaged.
Second, I'll probably leave it as is and try to trade for a JPXI or JP12. I feel the preamp (with boost disengaged) adds a bit more flavor to the signal than I previously thought. I'm not sure if it is a combination of the preamp and the new pickups, but the the tone feels a bit more muddy/bassy and stiff. I've tried to compensate the EQ in my amp with some minor success.
I originally wanted a JPXI or JP12, but I found this guitar locally at a very good price so I went for it lol.
Thanks again for reading!

 

[dedeman]

Could you take a picture inside and share it here? I think there might be a way to bypass the preamp if you're not content with it.

 

[Tis BOOLsheet]

Thanks all for the feedback.
First, battery is needed for output even with the boost disengaged.
Second, I'll probably leave it as is and try to trade for a JPXI or JP12. I feel the preamp (with boost disengaged) adds a bit more flavor to the signal than I previously thought. I'm not sure if it is a combination of the preamp and the new pickups, but the the tone feels a bit more muddy/bassy and stiff. I've tried to compensate the EQ in my amp with some minor success.
I originally wanted a JPXI or JP12, but I found this guitar locally at a very good price so I went for it lol.
Thanks again for reading!

Warning: i believe the necks on the JPXI and JP12 feel quite different from the JP13. Make sure you are okay with that!

 

[beej]

I'll bet the farm that the preamp doesn't add anything to the tone (except preventing high-end roll-off with a long cable).

You probably aren't bonding with the pickups (which are easily changed). Or just the sound of that particular guitar (not so easily changed).

 

[dedeman]

I've found an interesting onboard booster preamp which is a retrofit for JPXi model. It is interesting.

 

[beej]

No kidding? That's very cool.

 

[dedeman]

Yes indeed.

 

[billy carr]

I'd like to add that to my jp6, or an AL. If it compares to what ebmm puts in the luke3s, I'm sold.

 

[GoKart Mozart]

Woah...that's definitely cool. Someone be the guinea pig and let us know how it works!

 

[mandoismetal]

After spending about a month tube rolling my Mark V, I feel in love with my JP13 all over again!

This guitar is staying with me forever lol. I guess I just had to realize that it would be different and that different does not mean bad.

Thanks for all the suggestions and feedback!