Gus's Byzantine Fly Mod

[Augustonian]

Howdy folks. I'm currently getting ready to mod a fly. Me being me, I'm researching all my options which I'll write up here. This is mostly for me to organize my thought, but if you guys either get inspired or have some insight then that's all the better. This will likely change up until I throw everything into the guitar itself.

The main issue is only so much space, and only so many controls. If I can, I'll do this without making the guitar Swiss cheese. It's a mix of aesthetics and ease of use, but it will make my life harder. Basically, I am focusing on a few ideas: ease of use, small footprints, and feature set.

So let's get to it. I want the following in my guitar:
1. Magnetic pickups
2. Piezo Pickups./Midi
3. Sustainer

1. The magnetic pick up(s) are the simplest of course. I only need a volume, tone, and PU selector. Given there will be a sustainer, I will skip the middle coil split switch position of the fly. I have 3 positions however, so maybe that will become something else. Anyway, that's two pots and switch. No boards, just wires.

2. The piezos and midi are kind of related. For now, I'm considering the following options
a. RMC Polydrive: Piezo + Midi. Includes the usual synth controls (program change, synth volume pot, mix switch) as well as a mix pot for the piezo. volume and tone are placed downstream before the output jack. Seems like it assumes a mono output by design. Seems like RMC wants piezos replaced along side the purchase of the board.
b.Graphtext Hexpander. Similar to the RMC but built modular. Instead of a blend knob there is a piezo volume. Works in stereo. Seems a little chunkier than the RMC.
c. Fishman Power chip + some other midi. The other midi could be a Roland GK internal Boss GK5 torn down and installed internally, or a Fishman Tripleplay given the same treatment.

3. The sustainer has fewer variables and is well documented. Complicated and requiring the most work on the body to accommodate. The only controls I'll be using are the on/off and the harmonic mode control (I don't use mix mode).

I need to go through the control options as they relate to what the guitar has in it already, but that'll be an additional post. Feel free to tear into what I have here.

[jb63]

Have a look at the first one here. (Black 1996)

This was the first fly I modded and may help with plotting your controls.

viewtopic.php?t=799

[Augustonian]

Have a look at the first one here. (Black 1996)

This was the first fly I modded and may help with plotting your controls.

viewtopic.php?t=799

I was looking at those before I ended up taking the plunge actually. They look like great pieces.

[Augustonian]

So yesterday, I put all of the possible components. Today I'm going to boil down all the controls. Ideally, I'll have all the controls set up without having to drill anything. That may change, and this post is the most likely to include change, but speculation helps get me started. Here's the original control layout:


One thing you might notice in my last post was that the controls are basically the same across most options:

• All piezos I'm considering have a pot and a switch, when including optional controls.

• All 13 Pin midi solutions have exactly the same controls. I'm only looking at the volume, and Midi/Mag switch

• The oddball midi solutions (tearing apart a shell for the circuit board inside) all need an output or a jack of some kind.

Essentially, without knowing which solution I use for each component, I can move ahead planning, knowing generally what I will have control-wise.

In addition,

• The mag pickups have volume, tone and a selector

• The sustainer needs an on switch and something to control the harmonic mode (pot, or switch)[\list]
  
  If you're keeping count, that's a little control heavy:
  Piezos: 1 pot 1 switch
  Midi: 1 pot 1 switch
  Sustainer: 1 switch, probably 1 pot
  Pick ups: 1 switch, two pots.
  
  If I cut out the mix switches, that's 4 pots and 2 switches which is quite manageable. However, I do want those two switches in there eventually.
  
  So my layout is currently
  3. Volume
  3.I (the switch on 3) will be the sustainer on/off
  2. Tone
  1. Midi volume/ Piezo blend or volume. The concentric pot for this will probably be hard to source, and I need to research what will work. I may need to tear apart a pot or two to get something that works.
  I PU select
  II Midi/Mag/Piezo Switching with this crazy switch.
  
  Over the next week or two I'll be scouting parts and probably make a block diagram or such for wiring.

[mmmguitar]

Ideally, I'll have all the controls set up without having to drill anything.

Though I hope that remains the case, I suggest being mentally prepared to find you have to shallow out the internal side of the potentiometer shaft holes with a forstner bit to get a fastening nut over the first thread of what was supposed to be a pot shaft of sufficient length; as Fly tops can be surprisingly thick in places.

Midi volume/ Piezo blend or volume. The concentric pot for this will probably be hard to source

If you happen to go with MIDI/piezo volume, I put these Alpha B250K concentric pots in my Flys utilizing the GraphTech Hexpander/Acousti-Phonic stuff.

Are you planning to use a dual 9 volt setup to power the piezo and Sustainiac? As detailed in the thread for my Supreme, I ended up adding a new battery rout to afford some much-needed space in the main cavity - If I was to use a dual battery setup similar the Belew DF842AB, I'd basically have to reposition everything in the cavity to accommodate another battery (perhaps even replacing the Hexpander with a RMC board).

[Augustonian]

I suggest being mentally prepared to find you have to shallow out the internal side of the potentiometer shaft holes with a forstner bit

Noted: yeah I am very fond of planning for the best and preparing for the worst. Good tip.

If you happen to go with MIDI/piezo volume, I put these Alpha B250K concentric pots in my Flys utilizing the GraphTech Hexpander/Acousti-Phonic stuff.

Yes, I think this is going to depend on how I end up wiring it all. This is a good shout to start, I've also got some of these lying around. We'll see what happens when I pick my piezo/midi system though.

Are you planning to use a dual 9 volt setup to power the piezo and Sustainiac?

Yeah, this is currently one of my questions marks. In your wiring, does the 13 pin power the hexpander with the Sustainer having battery power? Or is it shared/something else? I wasn't aware of that guitar (looks beautiful) but that is very helpful though I've only skimmed so far. It's honestly remarkably similar to what I want to do, even including a freeway switch. Could you talk more on the PU selector wiring?

[mmmguitar]

In your wiring, does the 13 pin power the hexpander with the Sustainer having battery power? Or is it shared/something else?

It's the former. I had once planned to make a breakout box similar to the Belew's; in which the Sustainiac would be powered via a regulated 9 volt supply sent up pin 9 of the cable - But it became apparent in the brainstorming stage that the sustainer effect would likely cause the cable shield to radiate oscillating noise into the crucial signal-carrying wires; and necessitate fabricating a custom cable just to get the setup to the point of being usable. I know I could snake a dedicated power supply around the 13 pin, as well - But I'm not yet tempted to complicate things beyond the onboard 9v alkaline battery setup.

For reference, this is the Belew pin routing:
download/file.php?mode=view&id=2237

Could you talk more on the PU selector wiring?

It's the basic 3x3 03 FreeWay wired according to their H-H hum/split diagram, with the exception of the Sustainiac's purple "humbucker voicing" wire being soldered to the N1 contact on the pole shunting connections to ground for hum/single switching (in their diagrams, it's pole "B"). If, for example, you soldered the yellow "sustainer on" wire to the M1/M2 contacts on the B/ground-shunting pole of the switch, then you'd have the following selections:

1. Neck humbucker---4. Neck single
2. N+B parallel-------5. Sustainer on
3. Bridge humbucker--6. Bridge single

Of course, a selector switch with more than two poles would afford the additional options you seem to want (e.g. piezo+mag combinations, selecting between fundamental and harmonic feedback modes on the switch, etc.) - Just more food for thought. Also: You'll likely need to take a dremel sanding barrel to the wall of the control cavity to make room for whichever FreeWay footprint you settle on - I've had to do so with every era Fly I've owned, in lieu of relocating the selector switch to a different mounting hole.

[Augustonian]

It's the former. I had once planned to make a breakout box similar to the Belew's; in which the Sustainiac would be powered via a regulated 9 volt supply sent up pin 9 of the cable - But it became apparent in the brainstorming stage that the sustainer effect would likely cause the cable shield to radiate oscillating noise into the crucial signal-carrying wires

As in, you were replacing the variax supply in favor of the Sustainer? Yeah, the 13 pin connections are obnoxiously shielding free it seems. That being said, I may put a piezo power on some unused pin and built a breakout. I would only do this if the install I did required a second battery though.

... FreeWay wired ...

Yeah I tend to prefer to use the second axis as a single control: for example I would likely wire it so pushing it away from me turns on the sustainer. Oe adds Piezos in, etc.

For mine, I was thinking of using a 3x 08 to control Midi, mag and piezo on states. However, there are 7 states and 6 positions so I'd have to give one up. Likely this choice will depend on if the piezo system has stereo switching incorporated. From what I can tell, the Poly drive doesn't. Anyway, I'll chew on this as I plan.

[mmmguitar]

Likely this choice will depend on if the piezo system has stereo switching incorporated. From what I can tell, the Poly drive doesn't.

That reminds me to ask if you intend to run TRS and 13 pin-outs simultaneously? I ask because, supposedly, the hex pre pin 7 input for the mag signal will trigger a piezo pre's "smart switching" to sum the mag/piezo signals to mono via the jack "tip" output wire (which should be the only output connection jumpered to the pin 7 input) - even when a TRS plug is inserted and passing along the "ring"/piezo signal.

I never use this setup, myself - But I recall reading about some unhappy Mojo MIDI owners who were informed that they had to add an additional switch (interrupting the pin 7 input connection) to get the dual TRS/13 pin signal routing they'd envisioned.

[Augustonian]

you intend to run TRS and 13 pin-outs simultaneously?

Yeah I thought about that a bit. I usually split up the piezo and mag when I'm recording so I can get the full spectrum of the piezo, but I don't think I would need to in a more live situation. This is where the thought of using the GK5 actually came from, as they would be entirely separate. This would come at the cost of an extra battery though, unless I figured some other wacky solution.

In general I probably won't try to have my signals be so separated. If I really wanted, maybe I could repurpose another 13 pin output that I'm not using and use my currently imaginary break out box to get that signal on its own.

[Augustonian]

So I have a draft of my wiring, it is fairly simplistic, I am ignoring anything about grounds other than they exist and need to be wired to at some point. The pot controls are simple: mag volume(with sustainer on/off), tone(with what I believe to be harmonic mode control skipping the mix mode as mentioned)*, and blend with the piezo. Currently, my thought is to use this guitar exclusively with the 13 pin + a breakout box for the additional wires I've stolen from the normal Roland wiring. The breakout box will have piezo out (maybe also mag out? seems like a bit much) and a power supply for the piezo.

I've also noticed, I left out the switch for the sustainer: I'll probably add something for this on the 13 pin.

*I basically guessed at the wiring for the pot-free control. I'll ask Alan in between him telling me how hard the Fly install is. The random pot on the brown wire is a carryover from whatever I thought was gonna work.



The PU selector is picutred as a freeway but is functioning the same way as a normal gibson switch. The second freeway switch is the 3x3-7, which is wire to control the piezo an mag as written in the powerchip manual. The synth volume also goes through here. This is the normal wiring on the right hand side of the GK kit wiring. The left requires a second throw. I still have some questions as to what this may affect (5 pin midi output: will it still be on, or will the unit set external synth volume to zero as well?)

Anyway, I'll review this well before I rewire everything and likely make a few more drafts, particularly once I get the wiring from Alan.

[mmmguitar]

I forgot to mention this before, @Augustonion: I encourage you to also share this project with the vguitarforums community; as the regulars there are specialists with decades of firsthand experience in planning and troubleshooting such mods (Apologies if you already post there - I didn't see an "Augustonion" in the members list).

So are you settled on using a particular GK iteration between the internal "3" or a modified "5" - Or is this still in the brainstorming stage of just seeing how the Sustainiac/Powerchip/GK3 circuits might theoretically integrate before you assemble the hardware? Also: The "I'll ask Alan in between him telling me how hard the Fly install is" comment very much spoke to me.

[Augustonian]

That's a good idea; I'll throw this to them to see what they think, particularly the GK portion.

This comes from a handful of things:
1. The GK5 cabling is apparently unshielded (in classic Roland fashion), so running that with a cable in addition seemed like a bad idea at worst and inconvenient at best.
2. The best midi tracking comes from hex pickups, based on what I've read.
3. The RMC polydrives is not only expensive (600 including piezos: I'm still a grad student!), but adding in the replacement pieces would lower the bridge height => that bending the bridge is more likely to cause a crash.

Asking "what is the best day to day solution for the money" led me here.

Now, all that being said, I haven't shipped any parts yet so I still consider myself in the brainstorming stage. I started here because this seemed like one of the most complex choices, and I can essentially move some stuff around to get the other install options I've listed.

And yeah to be honest, I'm not sure how much I should tell Alan other than the normally requested info. To quote just about everyone who installs sustainers on flys, this isn't for the faint of heart. Adding hexaphonic gk connections and then modifying them doubly so.

[Augustonian]

I'm back with another schematic:


This is really similar, all the same control options, but with the RMC Polydrive as the piezo and midi. The advantage is the small size, and the wiring simplicity. Here I can get away with 1 battery with no breakout box. The extra advantage there is that the breakout box ends up requiring a second 13 pin cable which is money and, depending on length, tone.

I have been a bit lazy here: my switch wiring is not super clear. I plan on using a freeway 3x3-07 (see schematics here: https://www.freewayswitch.com/schematics-toggle/) and grounding each signal: the mixed piezo, the mag signal, or synth volume. This is the exact same wiring equivalent as the Roland board (set volume to ground, as if you rolled the vol pot to have 0 volume.) Technically, it should go to 7, not 5 but they act in the same way.

For now, this is the best option other than cost. I've got the guitar now and seeing the spacing for the bridge, I'm not too worried about the bridge crashing in the lower position that the RMC piezos demand. It's a big "we'll see."

Between this and the other option above it comes down to the following:
-Midi tracking quality, generally accepted answer seems to be Roland is better
-Size in guitar
-Complication of use
-Cost for the install and equipment paired with it

There is a hanging question on how good the modelling with be with each. As I understand it, the modelling takes the tone from the source (Piezo or mag hex) and "flavors" it corresponding to the patch. From Vguitar it seems like the acoustic patches are good on piezo and the electric patches good on mag (no surprise). For some of the synth patches, I'm curious if it makes a real difference?

Anyway, I've gotta price things out so I can push myself one direction or another.

[mmmguitar]

the breakout box ends up requiring a second 13 pin cable which is money and, depending on length, tone.

Though true, I also wouldn't be too concerned with tone-suck in the bigger scheme: The "tone" is already compromised by way of the buffering from the Sustainiac preamp and piezo preamp, as well as the synth unit's A/D preamp input makeup gain settings compensating for the pin-7 wire being high impedance by design. Having compared the guitar signal tapped off at each of these points, I regard each one as being a step further from that "passive" sound I prefer - But that's the give-and-take nature of the tech we're working with. I made my peace with it by designating the Parker to be the super-versatile processed guitar (with my favorite passive guitars constrained to sounding like themselves).

I made a low resolution webm to demonstrate what I mean about the signal path: Every clip is technically "Guitar pickup straight into amp, with no noise suppression." However - despite detail being lost in the course of the audio having been bounced to 44.1kHz and compressed by a codec -, obvious differences in amplitude and signal noise can be heard as the guitar's bridge pickup and piezo element signals are processed through the various gain stages.

There is a hanging question on how good the modelling with be with each. As I understand it, the modelling takes the tone from the source (Piezo or mag hex) and "flavors" it corresponding to the patch. From Vguitar it seems like the acoustic patches are good on piezo and the electric patches good on mag (no surprise). For some of the synth patches, I'm curious if it makes a real difference?

To paraphrase something VJ and I have said in various threads: Electromagnet-generated waveforms and piezo-generated waveforms seem to sound best when we're not trying to make one sound like the other - So I would agree with the vguitar sentiments regarding transducer-specific modeling. All things being equal*, the COSM synth (GR-300 emulation via DSP) patches sound fine driven by either (with crosstalk addressed in the unit's input settings being a bigger factor in performance), and the fidelity of the "synth" stuff consisting of layered samples is a matter mostly to do with calibrating those input settings for accurate triggering and minimized crosstalk. To reiterate previous assertions: The GK pickup is far from perfect - But the Roland synth units are designed with them in mind. Any non-GK transducer (such as a piezo-based hex system) require somewhat more in-depth calibration to achieve comparable performance (Jimmy from vguitarforums wrote a guide summarizing these considerations in a GR-55-specific document I have attached to the end of this post). Here's a vguitarforums thread discussing "optimal" input settings, as well - The consensus seems to be that, no matter which gear choices you've arrived at, there's an upfront learning curve to mating your chosen unit with your chosen transducer setup before anything can be considered "optimized."

Do you see yourself using the guitar moreso for sample triggering (whether via internal unit sounds or MIDI conversion), or COSM modeling?

*The COSM GR-300 emulation Roland uses in their recent synth units is actually quite susceptible to mistriggering due to a sensitivity to subharmonic artifacts in the input signal. In the case of the GR-55, people such as Richard McClish and Wayne Scott Jones produced aftermarket subsonic filter boards to mitigate this issue. Subsequent Roland synth units implemented a digital high-pass filter at the input stage to address this known issue.

Hexiphonic settings.pdf

(124.41 KiB) Downloaded 77 times

[Augustonian]

I also wouldn't be too concerned with tone-suck in the bigger scheme

Fair enough; I haven't gone in and done an FFT of the preamp of my sustainer buffered and unbuffered with and without large cables, I'm probably too in the weeds there. I was more trying to avoid having a ten foot 13 pin cable, a breakout box, then another ten foot 13 pin cable wrapped together under my pedalboard or something.

For shits, I plotted the amplitudes:


This of course doesn't show what frequencies are affected and how, but it's fairly dramatic to see the volume change as well as hear it.

Anyway, knowing that it's really down to fine tuning, I can definitely deal with that. Also, the filtering board is helpful to know about if I get onto the 55.

As far as COSM or triggering, I'd like to be doing a bit of both. Out of laziness, I'd like to be able to do pitch->midi when putting down tracks. Live, I likely would use COSM synth patches instead. I am more in favor of optimizing for COSM because of that. Though if I had good enough tracking/latency I may use the pitch->midi and slap my Hydrasynth to my pedalboard, but I'm not holding out for it.

[Augustonian]

@mmmguitar, let me know if this is a hassle, but could you check where the Sustainer 10 pin green wire on your Belew routes to? I've been going back and forth asking Richard if the polydrive has any switching when only the 13 pin is plugged in, but he is really dancing around the question.

[mmmguitar]

@mmmguitar, let me know if this is a hassle, but could you check where the Sustainer 10 pin green wire on your Belew routes to? I've been going back and forth asking Richard if the polydrive has any switching when only the 13 pin is plugged in, but he is really dancing around the question.

I already know where the green wire goes (and will elaborate below).

Now, firstly: What kind of "switching" are you wanting when the 13 pin cable is connected to the PolyDrive? If you end up going with one, I'll be happy to get under the hood of my Belew and map out the pertinent connections, should you hit a wall. But given what a nightmare it was for me to remount the PolyDrive in that particular guitar after swapping out the bridge pickup, I admit to hoping it doesn't come to that.

Because the 10 pin green wire toggles the preamp on and off when sent to ground, a simple SPST switch between it and the ground lug of your output jack(s) effectively acts an on/off switch preventing battery current from being drawn while a cable is plugged in to the guitar. Switch or no switch; if you solder the path of that green wire to the common ground lug on your 1/4" jack, then jumper it to the grounding terminal on your hex preamp board (the MAG GND terminal, in the case of the PolyDrive), a cable inserted into either jack will activate the Sustainiac preamp by complete that wire's path to ground.

In the case of my Supreme, I originally aped the Belew by having the switch on the rear cavity cover, before moving the green wire to the switching hex vol pot on the face of the guitar in a subsequent revision (my next revision will be to have a 250k logarithmic push/pull for MIDI volume, sustainiac power on/off, and routing the bridge pickup hot wire directly to the jack to bypass the Sustainiac when it's "off"):

In the case of the Belew Fly, Dennis Anesi has the green wire soldered to what is essentially still a SPST interrupting its path to a common grounding point (I haven't traced its path, but there would obviously be continuity between the output of the SPST and the ground terminal of the PolyDrive required for it to work). It's a fancy LED switch mounted on a PCB assembly Dennis fabricated to also mount a Variax component - But it's functionally a SPST for that green wire along its path to ground, nonetheless.

In the below belew, you can see where the PolyDrive MAG GND terminal seems to be used as a common for several components (I'm assuming signal from the Sustainiac's 10 pin green wire has found its way there):

[Augustonian]

So I'm hoping to be able to avoid the switch the Belew has. I just needed some confirmation the preamp wouldn't sit there and eat batteries when the guitar was unplugged.

... hoping it doesn't come to that.

I don't think it will come to that, what you've given me is helpful enough to make me confident it should work as I expect.

Also, putting together cost estimates, thinking about repairs and comparing usage, I'll most likely go for the polydrive. I would also consider the Graphtech, but this guitar will be used for recording. Low noise is helpful, and the space saved will make it easier to do repairs or change things after the fact.

[mmmguitar]

I just needed some confirmation the preamp wouldn't sit there and eat batteries when the guitar was unplugged.

I get what you mean, now: You’re referring to standby power, and a switching jack to prevent current draw.

I’ve never actually tested this; because the official disclaimer from Alan Hoover is that you need either a switching output jack or a minimum SPST switch to prevent the Sustainiac from draining power in standby mode (activated by the green “standby” wire being grounded).

Whether the preamp will consider itself grounded without being passed down a cable plug, I can’t say. Being as I planned my Sustainiac/13 pin builds around emulating the Belew from the get-go, I’ve always erred on the side of using a switch for the Sustainiac standby wire, and all of my Flys have had switching 1/4” jacks leftover from the Fishman preamps (which I run in mono, but sill utilize the switching “sleeve” jack lug for the Sustainiac standby wire (note that this is unnecessary for 1/4” sustainer operation if you have a separate switch - I merely use it because it’s there).

I’d recommend moving forward with some sort of functional on/off switch in mind, and reaching out to Alan to confirm whether or not the battery will drain without a cable plug inserted.

Here’s the pertinent Sustainiac FAQ entry:

27) Q. The Stealth PRO uses a stereo output jack to connect/disconnect the battery. I already use such a jack for my internal guitar preamp. Can I leave this out of my Stealth PRO installation?

A. For the Sustainiac Stealth PRO sustainer, the battery lockout can be omitted. The stereo jack simply connects a wire to ground, which can be worked around by simply permanently connecting (soldering) this wire to ground. No battery standby current is drawn until the power switch is pulled on. Of course, you have to remember to turn the sustainer off, because a 9v alkaline battery will be drained in about 20-50 hours.

However, for the Stealth PRO, the battery lockout not only places the sustainer into a standby condition (no current drawn), but it also turns on the low-noise preamp circuit which is what makes the driver work like a pickup when the sustainer is off. This preamp draws about 2.5 milliamperes (ma) of current from the battery. For a typical 500ma 9v alkaline battery, this works out to about 200 hours of battery life on the preamp. So, if you do not use the battery lockout on the PRO, you must have some means of disconnecting the preamp (disconnecting the lockout wire from ground) when the instrument is not in use. A separate switch would be the only other practical solution, if you have a convenient place to put one.