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Why No Replacement Piezo Elements For Jtv69?


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#121 psarkissian

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Posted 07 March 2014 - 12:05 PM

Take it to a Line 6 authorized service center that knows the JTV's.

Piezos can be a touchy thing.


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#122 snhirsch

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Posted 07 March 2014 - 03:22 PM

I'm always surprised to hear reports of behind-the-saddle ringing on a JTV-69.  I've plucked the free portions of the strings with a jeweler's screwdriver and hear essentially nothing but the tick of the blade hitting them.


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#123 paulm_80526

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Posted 08 March 2014 - 06:06 AM

In the case of my JTV with the Graph Techs, the entire saddle body is "ringy", not so much the string behind the saddle. I posted a video on YouTube.

 

In the case of the Parker Nite Fly, it's definitely the string, though. Common problem. I have a friend with a Nite Fly that has the same issue.


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#124 paulm_80526

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Posted 08 March 2014 - 09:06 AM

Take it to a Line 6 authorized service center that knows the JTV's.

Piezos can be a touchy thing.

 

 Not sure a Line6 Service person would mess with my JTV now that I've swapped out the piezos. Plus I'm having fun experimenting at this point :-)  I'm happy enough with the sound now, but will continue tweaking.

 

On the piezo thing, there's some interesting stuff on the web. E.g.,

http://www.acs.psu.e...rs/pickups.html

http://en.wikipedia....iezoelectricity


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#125 psarkissian

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Posted 10 March 2014 - 07:20 AM

"Not sure a Line6 Service person would mess with my JTV now that I've swapped out the piezos"---

 

Being the JTV service guy at Line 6, yes,... I would,... but I don't know if it would be warrantied at this point.

But I'd service it anyway. I'm here for when a teak goes wrong as well as the usual JTV servicing,...

and unfortunately, I see plenty of those tweaks go wrong.

 

Please tread with care, it's not our father's old hollow body archtop. A JTV is a whole other kind of beast,

stroke and cuddle under the chin with care.

 

 


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#126 cruisinon2

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Posted 10 March 2014 - 11:04 AM

 

 

Being the JTV service guy at Line 6, yes,...

 

 

Please tell me you're not the only one.... ;)

 

And since you've unveiled yourself...any thoughts on the crosstalk thread? I saw you posted in that one too. I'd love to figure out if my drop D issues are curable, or if it's peculiar to the way I play and would plague any JTV I tried...


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#127 paulm_80526

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Posted 10 March 2014 - 07:33 PM

"Not sure a Line6 Service person would mess with my JTV now that I've swapped out the piezos"---

 

Being the JTV service guy at Line 6, yes,... I would,... but I don't know if it would be warrantied at this point.

But I'd service it anyway. I'm here for when a teak goes wrong as well as the usual JTV servicing,...

and unfortunately, I see plenty of those tweaks go wrong.

 

Please tread with care, it's not our father's old hollow body archtop. A JTV is a whole other kind of beast,

stroke and cuddle under the chin with care.

 

Not looking for and tweak rectification at this point, but I appreciate the offer!

 

What would be interesting to me would be some practical information about the JTV-69 piezo bridge. E.g., What changed between the original version of the JTV-69 Bridge (the one I have) and the current version (which I'll have soon, hopefully)? I know the PCB was moved to the backside of the block, but anything else? Do the saddles still have pointed adjustment screws and etched tracks? Also, I was wondering about your thoughts on "chassis ground" vs wired ground. Have you seen many instances where the LR Baggs "chassis" ground have become more-than-low-Z? What would one do to fix that? Also, what steps would you take to dial in a piezo saddle (either LR Baggs or Graph Tech Ghost) to get the best tone with minimal ringing?

 

Just FYI, I have 4 Variaxes. (2) 700s, (1) JTV-69 and (1) JTV-59. Love 'em all! Also have a DT-50, Amplifi, POD XT, POD X3 Live, and multiple DL3s.. Built my first guitar amp at 15 using SWTPC preamp/amp and some custom circuitry (sadly... 40 years ago), and love experimenting. I appreciate robust design and information; less interested in cuddling :-)


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#128 snhirsch

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Posted 11 March 2014 - 03:27 AM

In the case of my JTV with the Graph Techs, the entire saddle body is "ringy", not so much the string behind the saddle. I posted a video on YouTube.

 

I'm a bit puzzled by the lengthwise position of those bridge pieces.  Is that really where they ended up when you adjusted the intonation?  Modern string sets with solid 3rd strings almost always require a distinctive 3-slanted + 3-slanted pattern where 6th and 3rd string are furthest from the nut, then 5th and 2nd, etc.

 

Also, the "clacking" you demonstrate in the video suggests that the bridge pieces are too tight against each other laterally - so when you loosen one screw it cannot twist enough to settle tight against the plate.  Is there any daylight at all between the pieces?  The original Variax pieces have about 1/64" of daylight between them.  I'm not sure what material the GraphTechs are made of, but you may want to consider grinding a bit off the sides to open some clearance.  They do say not to file the actual saddle area, but I doubt the pizeo element extends to the sides. 


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QSC K10 FRFR

 


#129 cruisinon2

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Posted 11 March 2014 - 03:52 AM

I'm a bit puzzled by the lengthwise position of those bridge pieces.  Is that really where they ended up when you adjusted the intonation?  Modern string sets with solid 3rd strings almost always require a distinctive 3-slanted + 3-slanted pattern where 6th and 3rd string are furthest from the nut, then 5th and 2nd, etc.

 

Also, the "clacking" you demonstrate in the video suggests that the bridge pieces are too tight against each other laterally - so when you loosen one screw it cannot twist enough to settle tight against the plate.  Is there any daylight at all between the pieces?  The original Variax pieces have about 1/64" of daylight between them.  I'm not sure what material the GraphTechs are made of, but you may want to consider grinding a bit off the sides to open some clearance.  They do say not to file the actual saddle area, but I doubt the pizeo element extends to the sides. 

 

Unless one really knows what they're doing, jury-rigging stuff that wasn't designed to work together is at the very least a pain in the arse, often more trouble than it's worth, and sometimes worse than having done nothing at all. Hats off to anyone for whom this kind of surgery is a walk in the park, but for me it's starting to seems like the JTV/Graphtec combo won't be an option. I can strip wires and solder, but I draw the line at grinding metal. I think I'll stick with what I got...limitations and all...Just don't see it ending well.

 

Or I'll buy an 89 and put the wrap-around Graphtec bridge on it...that shouldn't require a welding torch or anything, right? ;)


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#130 paulm_80526

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Posted 11 March 2014 - 04:50 AM

I'm a bit puzzled by the lengthwise position of those bridge pieces.  Is that really where they ended up when you adjusted the intonation?  Modern string sets with solid 3rd strings almost always require a distinctive 3-slanted + 3-slanted pattern where 6th and 3rd string are furthest from the nut, then 5th and 2nd, etc.

 

Also, the "clacking" you demonstrate in the video suggests that the bridge pieces are too tight against each other laterally - so when you loosen one screw it cannot twist enough to settle tight against the plate.  Is there any daylight at all between the pieces?  The original Variax pieces have about 1/64" of daylight between them.  I'm not sure what material the GraphTechs are made of, but you may want to consider grinding a bit off the sides to open some clearance.  They do say not to file the actual saddle area, but I doubt the pizeo element extends to the sides. 

 

Hadn't adjusted the bridge for intonation when I made the video. Was mostly interested in demonstrating the clacking or ringing. Have done that since, though, so now a D chord is tolerable 12 frets up :-)  The intonation adjustment had no effect on the clacking.

 

Very good theory on the cause of clacking. Turns out, though, that there is a gap laterally between the GT saddles, Definite daylight. So I don't think it was a "floating screw" due to the saddles not being able to rotate due to lateral contact when the set screws weren't even. What I'm thinking is that the long tails of the GT saddles may be riding unevenly on the bridge plate, with one side being forced down by the screw. It's hard to see if this is what's going on as the ridge at the back of the bridge obscures the tails. The original saddles keep the screw pretty much parallel to the bridge plate.

 

Anyway, as I said in the post above, the sounds is actually pretty good now that I've adjusted everything. I definitely happier than with my failing original bridge, and will play out with my JTV-69 again. There is still a tiny amount of piezo ring in some of the sounds, but certainly tolerable. I will do an A/B comparison for sure when I get the new LR Baggs bridge from Full Compass, and post the comparison.


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#131 paulm_80526

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Posted 11 March 2014 - 05:02 AM

Unless one really knows what they're doing, jury-rigging stuff that wasn't designed to work together is at the very least a pain in the arse, often more trouble than it's worth, and sometimes worse than having done nothing at all. Hats off to anyone for whom this kind of surgery is a walk in the park, but for me it's starting to seems like the JTV/Graphtec combo won't be an option. I can strip wires and solder, but I draw the line at grinding metal. I think I'll stick with what I got...limitations and all...Just don't see it ending well.

 

Or I'll buy an 89 and put the wrap-around Graphtec bridge on it...that shouldn't require a welding torch or anything, right? ;)

 

:-)   Probably no welding required, and I don't think any grinding either! There is lateral separation between the GT saddles.

 

I understand and respect your position on getting something known to work. Depends on your end game, of course. For me it's really fun to try new things and learn along the way. No one "really knows" what they're doing until they've done it, and usually more than once. E.g., Line6 seems to be continually updating released designs to make them better, as they seem to have done with JTV-69 bridge.

 

The sound is actually pretty good now that I've adjusted a few things, BTW.  As I mentioned in another reply, I'll post a comparison when I get the replacement bridge from Full Compass.


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#132 snhirsch

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Posted 11 March 2014 - 05:03 AM

 What I'm thinking is that the long tails of the GT saddles may be riding unevenly on the bridge plate, with one side being forced down by the screw. It's hard to see if this is what's going on as the ridge at the back of the bridge obscures the tails. The original saddles keep the screw pretty much parallel to the bridge plate.

 

Are you saying that the trailing edge of the new pieces might be in contact with the plate?


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PRS Custom 24 (1990) w/ GK-3 Hex PU

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QSC K10 FRFR

 


#133 paulm_80526

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Posted 11 March 2014 - 05:58 AM

Are you saying that the trailing edge of the new pieces might be in contact with the plate?

 

I think that might be the case for some of the middle saddles, but hard to see. I've adjusted the overall bridge height to keep the outside saddles as low to the bridge as possible to minimize the intonation screw angle. On the Low-E there is a measurable gap between the bridge and the exposed tail.  But, the middle saddles have to be adjusted higher due to the curve of the fretboard, of course, and they could be touching.

 

Now that I'm back at my guitar, though, I'm not sure I'm seeing a strong correlation of the ringiness to saddle height above the bridge. So that may not be it...


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#134 Charlie_Watt

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Posted 11 March 2014 - 06:15 AM

How much did you have to adjust the string volumes to get them at the same levels of the old piezos?  When I did my 500 I had to go down to about 50%.   Full volume sounded terrible.


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#135 paulm_80526

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Posted 11 March 2014 - 06:24 AM

How much did you have to adjust the string volumes to get them at the same levels of the old piezos?  When I did my 500 I had to go down to about 50%.   Full volume sounded terrible.

 

About the same for the JTV-69, although I'm at Work, not Workbench right now :-)

I'll check and respond with numbers tonight.


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#136 psarkissian

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Posted 11 March 2014 - 07:51 AM

Yes crusinon2,... I'm it. Would've thought the "US Service Technician & Moderator" was the dead giveaway.

 

The crosstalk issue,... a combination of playing technique and/or set-up.

It's usually good to have the set-up checked by a local guitar tech in your area,

who is authorized Line 6, and knows JTV's. Local, because climate will affect 

the set-up.

 

"I know the PCB was moved to the backside of the block, but anything else?"--- No. If there was anything else, they haven't told me yet.

 

"Unless one really knows what they're doing, jury-rigging stuff that wasn't

designed to work together is at the very least a pain in the arse"--- Right you are. Seen my share of Frankenstein'ed JTV's. Not always pretty, which is why they come across my bench in the first place.


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#137 paulm_80526

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Posted 11 March 2014 - 09:44 AM

Wow - you're it for the US. Hats off to you - I'm sure you've seen some interesting... opportunities!

 

Quick question then, and not sure if you can answer this or not. Have you seen a Graph Tech retrofit for the JTV-69 that worked well, after you got things straightened out? I know you can't recommend that or suggest that anybody do it, but I'd be interested to know if there is an existence proof, in your opinion. I'm pretty happy with mine now, but interested in your opinion as well.


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#138 cruisinon2

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Posted 11 March 2014 - 09:56 AM

Yes crusinon2,... I'm it. Would've thought the "US Service Technician & Moderator" was the dead giveaway.

 

 

OK...really no need to get testy. I'm neither an imbecile, nor illiterate. I see your title now, and I saw it before. The title alone doesn't necessarily preclude there being more than one of you. And frankly, it surprises me a bit that they would dump the load of repairing every JTV in the country on one guy. That's all I meant. Would have thought the smiley face in my other post was a dead giveaway.


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#139 psarkissian

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Posted 11 March 2014 - 11:49 AM

No worries, I'm not testy. I am sometimes in a hurry to get these responses out and though

I'm good with guitars, my typing skills can use some augmenting. "That's all I meant..."--- I figured

as much. Ah yes, the smiley face,... :)

 

They thrust this upon me because I asked for it. They know how much I like working on these.

There are also a number of Line 6 authorized service centers in America that are capable, so

I get some help. And there's my counterparts in the UK taking care of the Euro Zone. :)

 

I also own a 69 and two 59's. :) :)


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#140 cruisinon2

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Posted 11 March 2014 - 12:12 PM

No worries, I'm not testy. I am sometimes in a hurry to get these responses out and though

I'm good with guitars, my typing skills can use some augmenting. "That's all I meant..."--- I figured

as much. Ah yes, the smiley face,... :)

 

They thrust this upon me because I asked for it. They know how much I like working on these.

There are also a number of Line 6 authorized service centers in America that are capable, so

I get some help. And there's my counterparts in the UK taking care of the Euro Zone. :)

 

I also own a 69 and two 59's. :) :)

Fair enough...all good. :)


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#141 Charlie_Watt

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Posted 11 March 2014 - 12:34 PM

Glad to have you contributing here, psarkissian!!!


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#142 psarkissian

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Posted 11 March 2014 - 12:54 PM

  :)


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#143 paulm_80526

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Posted 11 March 2014 - 04:49 PM

How much did you have to adjust the string volumes to get them at the same levels of the old piezos?  When I did my 500 I had to go down to about 50%.   Full volume sounded terrible.

 

Just checked my settings. I set them by comparing the magnetic pickup volume to the equivalent Spank models. From low to high: .49, .53, .54, .56, .59, .56. The piezo-based models are still a bit hot relative to the mags with these settings, but that's OK - helps drive the front end of my amp a bit more.

 

So... pretty close to where you ended up. Not distorting as far as I can tell, or if it is... it sounds good :-)


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