Upgrading Variax piezos?

Started by Infi-del, September 24, 2015, 09:51:25 AM

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Infi-del

I am always looking to upgrade or modify my guitars to get the most out of them. I'm getting a JTV-89 in a trade shortly and I've read some opinions that the transducers are not of the highest quality. Whether or not that's true it raises the question is it possible to upgrade with them "Better" different pieces? Like maybe something from Fishman or LR Baggs? Are there any upgrades out there for the variax pickups? Is it even worth considering? Just wondering.
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Infi-del

Like say with something like an LR Baggs T-Bridge. If the threads matched you could just transplant the saddles it seems. But even if you had to bolt down the entire bridge... you could always add like a Gotoh tailpiece for your strings.

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Elantric

#2
Here are some facts about piezo pickups in a Tune-o-matic bridge

* Most are designed to for adding an acoustic sound to an electric guitar

* Most suffer from mechanically induced adjacent string "crosstalk" - which means pluck the "D" string and you will hear 30% of this signal in both the "G" string piezo saddle and "A" string piezo saddle - this has little consequence for 90% of piezo users who simply feed a mono piezo EQ preamp, but this mechanically induced adjacent string "crosstalk"  is key source for major problems for all Hexaphonic DSP Alt Tuning systems. (Variax, GR-55, GP-10, VG-99, Antares ATG, etc) Warbles, and out of tune notes result when  "mechanical vibration crosstalk" exists.

Suggest read this thread for more details

https://www.vguitarforums.com/smf/index.php?topic=5043.msg34299#msg34299

Infi-del

Quote from: Elantric on September 24, 2015, 11:07:21 AM
Here are some facts about piezo pickups in a Tune-o-matic bridge

* Most are designed to for adding an acoustic sound to an electric guitar

* Most suffer from mechanically induced adjacent string "crosstalk" - which means pluck the "D" string and you will hear 30% of this signal in both the "G" string piezo saddle and "A" string piezo saddle - this has little consequence for 90% of piezo users who simply feed a mono piezo EQ preamp, but this mechanically induced adjacent string "crosstalk"  is key source for major problems for all Hexaphonic DSP Alt Tuning systems. (Variax, GR-55, GP-10, VG-99, Antares ATG, etc) Warbles, and out of tune notes result when  "mechanical vibration crosstalk" exists.

Suggest read this thread for more details

https://www.vguitarforums.com/smf/index.php?topic=5043.msg34299#msg34299

Do fender style bridges with the sort of free floating saddles do better with crosstalk and such? Or is it just the nature of the beast with these types of guitars. I don't plan on running my 89 through anything but my HD500X and maybe a few select pedals. I don't own any synth type processors like the GR-55 or anything... YET lol.
My ebay user name is Doom_Enterprises you can see my feedback here... http://feedback.ebay.com/ws/eBayISAPI.dll?ViewFeedback2&userid=doom_enterprises&ftab=AllFeedback

Elantric

#4
From Experience -


* RMC Piezos provide the lowest mechanically induced adjacent string "crosstalk"

* GraphTech Ghost Piezos provide the Highest mechanically induced adjacent string "crosstalk"


For further reading on Peizo PU design and hurdles,  read the
Interview with Richard McClish of RMC Pickups
https://www.vguitarforums.com/smf/index.php?topic=8187.msg58112#msg58112

QuoteCrosstalk and Bleedthrough: RMC Piezo vs. GK-2A Magnetic

GK PICKUP - ELECTRICAL

The GK pickup is sensitive to the vertical vibrations of the string above it and also to the mostly-horizontal vibrations of the adjacent strings (about 40dB softer than the string above it) partly because they are at about 10 times the distance from the pickup and they also carry the magnetism of nearby mono pickups while being parallel to the monitored string which naturally tends to increase the leak into the monitored string. There is also an electromagnetic influence of steel springs and screws on the extreme string pickups, especially if those parts have touched magnets prior to being mounted in place (repairmen often use magnets to keep small parts together).

GK PICKUP - MECHANICAL

Mechanical crosstalk tends to occur as a function of the accelerated mass of the pickup being displaced with respect to the portion of the bridge supporting the strings.This occurs to different degrees with double stick and screw/spring mounting.

RMC - ELECTRICAL

Separate fully shielded transducers and separate shielded cables reduce electrical crosstalk to unmeasurable levels. The impedance of Poly-Drive string buffers is about 10 ohms, producing extremely low crosstalk levels in the DIN-13 cable (well below -90dB up to 1KHz).

RMC - MECHANICAL

The RMC tends to leak as a function of the combined string mass and string support mass being accelerated by a motion of the bridge caused by the vibration of another string on another string support. That's why I was asking about immobilizing the bridge. The more massive and solily attached the bridge assembly, the lower the crosstalk level. This would tend to rule out acoustic instruments with piezos as good MIDI controllers. The fact is that they perform quite well because the mass of the top is much greater than the combined masses of a string support and the adjacent portion of an elastic string.

However, depending on the type of instrument and hardware used, there are other factors that can substantially increase mechanical crosstalk such as:

    The portion of string between the bridge and the tailpiece. The string has stiffness and there will be pivotal movments of the string over the string support, especially with strings of large diameter. This is often a real offender and I suggest damping this portion of the string on instruments with Tune-O-Matic bridges in order to reduce ringing and crosstalk.
    Tailpiece wobble in archtops and the like. Same problem and really obnoxious in the low and mid frequencies, especially with wooden tailpieces held by a wire loop around an endpin. Block the tailpiece and damp the strings.
    Poor coupling between the saddle and the bridge. This would tend to show up as crosstalk at specific frequencies. The coupling can be substantially improved by putting a small dab of super glue or Loctite between the mating surfaces, using the point of a pin as an applicator.
    An associated resonating member such as an intonation screw, a spring or a combination of such parts. These would also tend to show up as one or more peaks in the spectrum so their influence on tracking may be insignificant although they will show up on a "scope" output waveform.
    A resonant truss rod (not necessarily loose or rattling, but with a significant undampened free length). This is also a resonator and in extreme cases can cause a wolf tone. Tap on the neck to hear this one.
    A poorly glued nut. The crosstalk level will change on the open strings when you touch the nut with a hard and heavy object.

It's also very important to realize that the mechanical crosstalk level is typically five times higher in the mono sum signal than in any given string signal. That's a 16dB difference in favor of good tracking.