Controlling JTV guitar models and settings via MIDI

[rockmancentral]

So, I've spent the last several days reading over the forum and the internet about controlling a JTV guitar (guitar models, tunings, mags vs models, etc) using MIDI... specifically SYSEX messages, though regular patch change commands would be easier.

 

I've seen where people have built a cable to convert the VDI interface to work with standard MIDI connectors.

I've seen people "claim" to have figured out the SYSEX messages to change models, tunings, and even switch between mags and the piezo models (though, that user never seemed to respond when asked for that documentation).

 

Is anyone willing to share that info and/or how they made it work?

I'm a software engineer and can handle building simple electronic circuits, so I'm ready to go down the hole of getting a MIDI SYSEX monitoring software going to sniff out the messages, but it would be nice not to have to reinvent the wheel if someone has already gone down that road.

 

I also have a Raspberry Pie 4 that I'm looking at adding Windows 10 ARM OS onto and am wondering if anyone knows if the Workbench HD software will run on it?

Can the Workbench software respond to incoming MIDI commands (SYSEX or Regular MIDI patch changes) to change models, tunings, etc on a JTV guitar?

 

I also saw the RackVax, but the page seems to be down now.

It also seemed to be the older Variax guitar guts, not the newer JTV guts.

Has anyone tried taking the guts out of a JTV and doing the same thing?

 

 

[psarkissian]

1) Rack Vax is no more. They wanted us (and me) to take care of support for them, but I already kept busy servicing our own Variax products.

2) Parker Fly is iffy, trying to use MIDI with a Variax.

3a) Doing transplants is something for those with intimate knowledge and experience with this product. 3b) Line 6 does not support modifications to its product.

      3c) If you were to mod it or do a transplant, something went wrong, and you sent it to me to be repaired, I'd have to send it back untouched.

      3d) I have done transplants. But they were for high profile artist endorsers, as a favor to the endorsers and the execs here.

      3e) We don't have a custom shop for this.

 

MIDI SysEx is for updating Flash and using the Workbench HD app. Claims of success have been limited as what can be accessed is limited.

"... have a Raspberry Pie 4 that I'm looking at adding Windows 10 ARM OS onto and am wondering if anyone knows if the Workbench HD software

will run on it? " --- as far as I know,... no, it won't. AS far as I know for the query after,... no it won't.   ---- Lots of proprietary stuff, not made to be messed with like that.

 

 

[rockmancentral]

Thanks for the response.

 

Sorry if I touched a nerve..... I'm sure you've answered that question a million times, probably for people that know nothing about electronics, software, etc.

And please don't take any of these questions as a "dis" on the products as they currently are.

I really do like both of the JTV's I have as they are now.

 

As a software engineer and armature electronic tech, my mind is always thinking about logic and the flow of data/signals.

It's just in my nature to look at something and think, "What if I ...." to see if I can "functionalize" something for reuse beyond it's current limitations.

It goes without saying that I understand the risks and wouldn't hold Line 6 accountable for my mistakes.

I wasn't looking for "support" so much as just asking for your experience, gotcha's that I should look out for if I choose to go down that road, etc.

 

Like when you said that DiMarzio Super Distortion Pickups would sound "dark".

That's good to know in advance, and it let's me know there could be an issue and I may decide not to go that route.

Or, I may decide that I will try to compensate for that by EQ'ing the signal, or as I said, just not feed it to the JTV mainboard at all for processing.

And yes, I understand the caveats that creates (how do I handle volume, tone and pickup selector!).

 

As for transplanting the JTV guts out of the guitar, yeah, obviously it's a lot of work and things could definitely go wrong.... I understand that.

At the same time, as long as all the wiring stays the same, with only absolutely required changes (ie- running the piezo pickup lines outside of the guitar to feed the processor), I don't see any reason why it shouldn't work.  I understand the piezo wires probably shouldn't be run all the way to the floor or a rack 50 feet away, but 6 inches outside of the guitar shouldn't be a problem if done carefully.  The fact that you've done it confirms that it's possible.

 

Anyway, I'm new to the Variax and though I love it already, there's just a few limitations for my playing style and such that I'm looking for ways to overcome.  But as the guy that ends up with these projects on your workbench, I get why you would want to discourage it.

 

Peace!

[psarkissian]

Touch a nerve? No.

Million times,... more half a million,... no problem, it's why I'm here.

A "dis"? No.

Just want you to be informed, it's what I'm here for.

"...  to see if I can "functionalize" something for reuse beyond it's current limitations. " --- Not a god idea, as this our products

don't take kindly to mods beyond what they were designed for. As far as "gotchas",... changing tuning machines or pick-ups is one thing,

tampering with the programming is a bad idea.

 

And L6 takes a dim view of program hacks, as they guard their IP. Best not to go down this road.

 

When using 3rd party pick-ups, use those with a DCR (DC bulk resistance) between 6k-Ohms and 8k-Ohms. Use the pick-up wiring diagrams

in the Line 6 Knowledge Base. Magnetics don't get processed in mag-mode, only the piezos do, but the signal runs thru the board,... so don't

mess with that. Don't disconnect the mags, it messes with the modes,.... can't elaborate further on that.

 

Misunderstood,... I've done transplants, but never run piezo wires out beyond a few inches to do lefty conversions for the likes of guitarist and

L6 endorser Carlos Rios (Stevie Nicks, Chick Corea). Yes, I know the pitfalls of transplants, so I discourage them to all but a few very experienced

people with intimate knowledge.

 

One guy took a Variax bass, transplanted it in a custom body. The electronics didn't fit, so he took off half the case, thought he got all the ground tied off.

It didn't work,... the case being half apart threw off and changed the reference point of all the ground planes. Don't know if he ever got it working again.

 

Line 6 won't support mods of its product. I'm not allowed to walk people thru mods or transplants, I can just point out the pitfalls, the rest is up to all of you out there.

Best of luck.

 

[rockmancentral]

I wouldn't try to "hack" the program.  I was more talking about reading the SYSEX messages that the Workbench software sends to the Variax through the VDI cable and just trying to send the same signals from another source (midi pedal, Cakewalk Sonar, etc) to get the Variax to do the same thing.  Sounds like a stupid analogy, but think of Mathew Broderick in "Wargames" when he records the signals from the doors security keypad onto the mini tape recorder, then plays them back afterwards to open the door.  He couldn't get to the keypad, but he was able to send the same signal anyway to get it to open the door.  The lock didn't know or care where the signal came from..... it just heard "boop boop boop, beep beep beep" and did what it was told. 

 

"When using 3rd party pick-ups, use those with a DCR (DC bulk resistance) between 6k-Ohms and 8k-Ohms. Use the pick-up wiring diagrams

in the Line 6 Knowledge Base. Magnetics don't get processed in mag-mode, only the piezos do, but the signal runs thru the board,... so don't

mess with that. Don't disconnect the mags, it messes with the modes,.... can't elaborate further on that."

 

OK, but my favorite pickup doesn't come in that range, so what am I supposed to do?  Put a pickup in there that sounds like crap to me when I play it as a mag pickup just so it doesn't mess with the Variax circuit, even though the Variax doesn't even use it?  If it was easier to cross reference pickups to find something that is going to have the same tone and power but work in the range you specify, that would be helpful.  I don't know of such a cross reference chart.... do you?  Is it possible to add a resistor in parallel to the mag pickup to lower it's DCR to the required range?  IE- slap a 19 k resistor in parallel with a 13.5 k pickup and it's around 8k.

 

I love the tone of the Bridge P-90 in the 59-P, but the noise is pretty bad!  Which is the main reason I want to switch them out, and since I discovered that my favorite pickup, the DiMarzio Super Distortion comes in a P-90, I'm good to go!  Or so I thought!  (Too bad Tom Scholz didn't have that option when he had to replace his P-90's in his '68.... ended up routing it out for a humbucker!).

 

"Yes, I know the pitfalls of transplants, so I discourage them to all but a few very experienced people with intimate knowledge."

 

Yeah, well HOW do we gain that "intimate knowledge" without actually doing it?  I wanted a Hyperspace Pedal so I could do all the spaceship effects from the Boston albums when I play my Boston covers.  I had to experiment until I figured out how to make it work, which I eventually did.  Now, I'm pretty much the resident expert on how it works.

 

BTW, what I was envisioning was basically putting the mainboard and model/tuning selectors into a small box that I could attach to my guitar strap or whatever.  Run the piezo signals (along with the volume/tone/pickup selector?) out through an 8 or 13pin cable maybe 6" long that plugs into the box.  It's not rocket science... all I'm talking about is changing the physical geography of where the processor board is located.... the wiring would essentially be exactly the same.  From there, it would be easy to add a piezo bridge to any guitar and feed it out the same way to the processor.

 

[psarkissian]

SysEx is for data comm When using Monkey and Workbench HD. Trying to go beyond the narrow applications invites trouble.

Some of our products, such as floor effects and floor controllers have some MIDI CC capabilities more useful MIDI controlling.

Variax was never designed to do that. Being a guitar, there's only so much space and therefore only so much memory, and it's all

used for modeling and not much for controlling.

 

Regarding pick-ups,... with passive electronic guitars, one can take a orange chicklet capacitor and change values to match however one wants.

These are the other way around. The control and  board circuitry are fixed and matched, and that determines the DCR range that can be used.

There is no chart. The DCR range is what we use so that it impedance matches the circuitry, so everything is a balance of circuitry, just as a guitar

set-up is a balance of tensions int he mechanics of it.

 

DiMarzio Super Distortion, one of my faves,... but not in a JTV. Too dark of an EQ tone, lose all the highs and bite of a Super-D.

 

Some out there have lots of experience with guitars to begin with,... old timers like me, from the classic rock days, crewing for a classic rock band,

and cooking up crazy circuitry. We know the in's and outs and been doing this for decades. So adding quirks of JTV's is not a problem to jump into.

Maybe four to six guys in North America I trust to do a mod or transplant without mistakes. I don't know about ability of others. 

 

The box,... potential grounding and impedance issues, even if the wiring is the same, all, all the ground planes must be maintained. 6" is a 

maybe length. If one is out of place, it can shift the other ground points,.... that is the trap of dealing with mixed signal devices. That guy with

the Variax bass transplant didn't understand that, even after explaining it to him, so he could never get his bass to work after the transplant.

 

 

[rockmancentral]

I just can't seem to cut a break due to the limitations of the JTV Variax I keep running up against.

The pickups I could handle, but not being able to put a Sustainiac in there or control the models/tunings via MIDI is kind of a deal breaker for me.

Shame though... I do like the guitars themselves..... very pretty!

 

I guess I'll have to settle for playing my Gibson Collectors Choice #10 now that I've found a way to add a Stetsbar tremolo and a Sustianiac (using potentiometers with Push-Push switches instead of drilling holes for toggles).  I've also discovered the Boss GP-10, and it looks like it'll fit my needs better than the JTV Variax.  

ie- acoustics and alternate tunings accessible via MIDI, usable on any guitar just by moving the GK-3 from one guitar to another.

 

[psarkissian]

Limitations? These do more than just about any guitar out there.

MIDI MMC controlling might be useful in conjunction with VDI and a floor effects that has more in the way of MiDI MMC.

 

[rockmancentral]

Yes, limitations.

• Limited on controlling Guitar Models via MIDI
• Limited on controlling Guitar Tunings via MIDI
• Limited on what mag pickups I can use
• Limited on the ability to use a Sustainiac

MIDI control is very important to me because I don't want to stop playing, even for a second, to change my guitar model or tuning.... I need my transitions (guitar model, amp model, tunings, effects) to be seamless with the touch of a single footswtich on my Kemper Stage, so MIDI integration is a must have.  Yeah, I know I could get that with a Helix, but I prefer profiling technology over modeling technology.

 

I've been hard pressed to find a pickup, especially a humbucker P90, that fits your DCR requirements in the tone characteristics I prefer.  I've even reached out to DiMarzio tech support.

 

No Sustainiac is another deal breaker for me.  There are places in the music I play where I need to be able to get consistent feedback or infinite sustain.  Not being willing to hack up my CC#10 to add toggle switches or a tremolo is the reason that wonderful guitar has been mostly sitting in the case unplayed because I can't use it due to those limitations (which I now know I can rectify, so it will become my go-to guitar).

 

In the end I really only needed the Variax for tuning down a couple steps for a song or two and for the acoustic sounds for a few parts.  Having the rest of the features are nice to have and may come in useful in the future, but not at the expense of the things I need my guitars to be able to do.  Like I said, I can accomplish that with a Boss GP-10 and I can use it on all my guitars (no limitations!) simply by moving the GK-3 from one guitar to another.  I don't have to transplant the guts of a Variax to a box because it's already IN a box and can stay on my pedalboard, where it belongs.

 

Don't get me wrong, I love the JTV guitars and the concept, I've wanted one for a long time.  And I finally bought 2 of them!  But I didn't realize I was going to be told I couldn't trick them out the way I need to be able to to play the music I play. 

 

 

 

[psarkissian]

" I didn't realize I was going to be told I couldn't trick them out the way I need to be able to to play the music I play. " --- For that,

it would require a custom guitar and some custom mods to do that.

 

[rockmancentral]

Adding a Sustainiac isn't really much of a "customization"..... really just changing a pickup and adding the processor board.  Several people, including the Sustainiac manufacturer, have said they've added Sustainiac's to JTV guitars with no issues, and are even able to use it with the modeled guitars with great results, saying the tracking is great.  You are pretty much the ONLY person telling me it won't work.  Whether that's because you've seen some really bad results from people doing it or you just don't want to get one of my guitars on your bench if I botch the job, I don't know.  But, like I said, it's a deal breaker for me so I'll most likely be letting both the guitars go in favor of the GP-10 (which will save me money in the end anyway since one GP-10 is a LOT cheaper than 2 JTV guitars and all it was going to cost me to trick them both out with pickups, Sustainiacs and tremolo's)).

 

Changing a pickup isn't usually a big deal either.  Given the ranges of most humbuckers on the market, it seems like it would be a smart marketing move to modify your circuitry to be able to handle larger DCR rated pickups (which are the average out here) rather than tell people they can't use their favorite pickups in your guitars.  But, that's just the business half of my degrees talking.

 

Same for the MIDI control.  Even if you built your own proprietary converter box (and sold it for a couple hundred bucks) so people could set it up in Workbench and then use it via MIDI to control the guitar like you can with the Helix, I think you'd sell more JTV guitars.  Maybe your marketing team already did the research for that and decided you sell more Helix's by limiting it than you would JTV guitars by opening it up?  As a consumer, I still think it's a turnoff though.

 

Anyway, I appreciate you taking the time to answer my questions, even if the answer always seemed to be "No you can't".

[soundog]

I, too, want MIDI control for my Variax.

 

Plain and simple.

 

It makes sense.

 

It's easy. You have all the technical hooks.

 

Just do it.

 

If it requires a little box doo dad, I'll buy one.

[psarkissian]

X3 Live, HD-500X or Helix, using Preset Force mode.

 

[rockmancentral]

Or, buy a Boss GP-10 and a Roland GK-3 and then you are no longer tied to a single guitar for modelled guitar sounds.

[psarkissian]

GP-10 digital audio is 24 bit resolution at 44.1kHz sampling rate. Using a 96kHz sampling rate would be better for a 24 bit system. 

 

[rockmancentral]

Considering CD's are only 16 bit @ 44.1khz, I'm not overly concerned about the sampling rate.

The samples I've heard sound pretty amazing, especially the nylon string guitars.

Besides, 96khz creates HUGE file folders!!!!

Especially if I decide to record each string raw to it's own track for re guitar modelling later, as you can do with the GP-10!!!

 

FWIW, I'm just excited that I'll be able to play my Gibson guitars and use the modelling from the GP-10!!!!

[psarkissian]

If that works, use it.

There is a risk of what I call "scrunching",... trying to pack a lot of audio data into a lower rate sample interval.

Scrunching can lead to regular data errors, jitter errors, and an area I've been researching the last few years,...

risk of uncertainty errors (offsets and and jitter affects due to data-to-clock uncertainty) where data doesn't know

which clock cycle it belongs to.

 

I'm a High Resolution Audio (HRA) guy myself.

 

[cags12]

Totally agree about the limitations. The only reason why I still do not own a Variax. Funny I keep coming to these forums when I feel I do want one but then in remember about all these limitations. 

Let me tell you a hopefully quick  story:

 

6 years ago I decided I wanted a guitar that could do everything and naturally thought about the Variax. My biggest gripe was the aesthetics of the guitars, I simply disliked them completely (maybe except the shuriken).  So I decided going the transplant route. However during my research I discovered the now discontinued Antares ATG system which is basically the same as the Variax in terms of overall functionalities (some pros and cons on both systems). There were more Pros in the end. The biggest one was they offered a luthier kit so I could install in my guitar of choice at a fraction of the price it would const a Variax transplant or full guitar. Long story short I bought 4 of their systems and have installed in multiple guitars specially in my PRS with zero permanent modification (yes, zero routing).

Some of the Pros (hardware-wise):

 

- Can install in any guitar of choice 

- Low footprint PCB (credit card size) 

- Can use any type of pickups and even a sustaniac. (Adrian Belew actually moved  to the ATG platform from the Variax)
- Can be controlled with MIDI (wired or wireless) 

- Not a closed ecosystem product

- Piezo or Magnetic Hex options

 

Of course the Con is that it has been discontinued and suffered from bad marketing and inexperienced company in the guitar industry.  

 

If only Line6 expanded the vision of the Variax to be more like an open platform, it would sell more for sure. It would quickly get me at least. Like the OP I have also embraced Roland/Boss GK products over Line6 because of the same.