Pdf105 and hexpander

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mockchoi
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Pdf105 and hexpander

Post by mockchoi »

I’d been waiting to see if a fly with the Graphtech would come along, because I need a 13 pin guitar backup. I came across a pdf105at a good price and grabbed that thinking it would work.

It’s tighter in there than I’d hoped. Has anyone done this kind of operation? Necessary to route the cavity? I don’t think there’s room for the volume and S1/S2 toggle switch.
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mmmguitar
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Re: Pdf105 and hexpander

Post by mmmguitar »

I’ve done a few Hexpander installs, @mockchoi; if there’s anything I can help with. You can always make a wiring harness out of cardboard/posterboard/whatever you have to test what all can be fit in there without all the spaghetti in the way (any Graph Tech setup is going to be a spaghetti factory by time you’re done, regardless, unless you ziptie everything or actually shorten the wires).
Summary of the Parker Guitars speculator market from 2020 onward: https://en.wikipedia.org/wiki/Greater_fool_theory
mockchoi
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Re: Pdf105 and hexpander

Post by mockchoi »

Thank you, @mmmguitar. Sure I’ll always take help :)

It looks like the best bet may be to move that acoustasonic board to the trem-side of the cavity, and put the jack where the board currently is. I think there should be room for the switch and pot in the empty space; if not I’ll do without the pot. I don’t want to move any existing controls.

Re the Hexpander board. I read the install documentation, which discusses piggybacking that board to the existing one. I watched some install videos though and they did not do this; simply plugged the Hexpander into that open blue and gray harness. Do you have a recommendation? I don’t care about having the guitar signal going through the 13 pin cable.

Thanks :) I may have more questions :)
mmmguitar wrote: Tue Nov 05, 2024 7:52 pm I’ve done a few Hexpander installs, @mockchoi; if there’s anything I can help with. You can always make a wiring harness out of cardboard/posterboard/whatever you have to test what all can be fit in there without all the spaghetti in the way (any Graph Tech setup is going to be a spaghetti factory by time you’re done, regardless, unless you ziptie everything or actually shorten the wires).
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mmmguitar
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Re: Pdf105 and hexpander

Post by mmmguitar »

mockchoi wrote: Thu Nov 07, 2024 8:23 pm I don’t care about having the guitar signal going through the 13 pin cable.
Does your rig/intended setup utilize running 13 pin and 1/4”-outputs simultaneously, or are you exclusively using modeled guitar tones with the 13 pin-out? Depending on your needs, you could make the most of the available space by using a concentric b250k pot for piezo and 13 pin volume, or a dual gang pot for a master volume affecting the magnetic and 13 pin signals simultaneously.

The Acousti-Phonic and Hexpander are designed to be piggybacked so that the piezo signal can be passed through both. Though it may have been omitted in the video, your only 13 pin options are to use both boards piggybacked, or the Hexpander only. Depending on your needs or the synth you’ll be using, you may not even wish to retain the Acoustic-Phonic (which adds more hiss to the signal than, say, a COSM acoustic model processing the Hexpander piezo signal). Also, depending on whether you go with a piggybacked or Hexpander-only setup, the magnetic circuit-in on the Hexpander preamp will require a specific pin layout in its 2x2 quick-connect plug (it’s two different “harnesses” sold by Graph Tech which have only one pin’s difference between them).

One tip I have is that the 2mm pitch pin connectors Graph Tech uses are garbage; and the wires can easily come out of their crimps - So I would suggest to avoid plugging everything in until you have the circuits decided upon and plotted out (which I’m happy to do with hideous, circa-Windows ‘98 Microsoft Paint for your viewing pleasure). I also recommend using some low tack masking tape to hold all the quick-connectors securely into their plugs on the board before you pack everything in to the cavity and screw the cover back on - Otherwise, connections are liable to come out during reassembly and cause you to emit a string of curse words as you recognize that you'll need to take the rear cover back off to troubleshoot something which shouldn't have happened.

Another tip is to repurpose the anti-static bag the Hexpander board comes in by cutting open each end, sliding it over the piggbacked boards before you connect the 13 pin harness from the jack to the Hexpander (after every other connection has been secured), then securing the bag with tape. This will free you up to experiment with fitting the stacked preamp boards into the control cavity wedged between two pots or switches without fear of anything shorting, to potentially afford you more room. Of course, if you prefer it be stuck somewhere away from the other electronics, it’s your project to be as neat or messy with as you like.

Please feel free to post or PM me with any thoughts which come to mind, and to have fun with narrowing down which of the options and possibilities afforded by such gear work for you.
Summary of the Parker Guitars speculator market from 2020 onward: https://en.wikipedia.org/wiki/Greater_fool_theory
mockchoi
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Re: Pdf105 and hexpander

Post by mockchoi »

Well it’s not THE most professional job ever but it gets the job done. I opted to go without external controls and have a guitar with less switches on it than my Fly, but may add them later. Now on to figuring out GR-55 settings for the Graphtech; it’s very different.
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Re: Pdf105 and hexpander

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@mockchoi, here's a helpful GR-55 input settings guide from the vguitarforums I used for my Graph Tech and RMC setups:
As we all know we don’t all have GK-3 pickups installed on all our guitars and some of us have multiple
guitars with different Pickup systems. I will cover some basic principles I have discovered when I
installed a piezo system on one of my guitars.

Through reading the threads on this topic I have found some useful Ideas and discovered some new
ones. The first rule is set up your GR-55 and any other 13 pin synth or processor so that it knows your
guitar. Set the sale length correctly, if you don’t know it you can measure it or look it up on line. Most
guitar sites include the scale length in the details of the guitar. As a rule you should set the correct
pickup type but you can try other types. I use the Fishman setting for my GK-3 pickup; I can EQ it to get a
little better tone from COSM acoustic guitars. The only other setting on the first page that I change is the
Normal Pickup gain, if you dial it back to -4 you will get less noise when using the normal pickups.
The string distance page is only useful for the tone of your COSM guitars and is only necessary if you
select GK-3 or GK-2A pickups. This setting will not affect tracking or dynamics.

Setting your sensitivities is very important and I have read many threads on the topic. The best results
come from setting the sensitivity as high as you can without passing the last dot on the meter. This
includes Piezo pickups as well. I have read many threads that say to set it to 0. This will provide good
PCM tracking but it will lessen the dynamic response of your playing. If your Piezo pickup still glitches we
can fix this on the next page. Remember these concepts w apply for all pickup types. And applying them
will improve your playing experience.

The next page is the Velocity settings. Now here is the revelation I came up with and you will be amazed.
Lower the Velocity dynamics to about 2. Remember when I said we would fix the glitches from the
sensitivity page that’s how you do it. From now on you can set Velocity and play feel per patch in the
Velocity settings. You have 2 settings here in the patch Velocity curve and level velocity sensitivity.
Every instrument responds differently to your paying and you have to set each one a little different to
get the most out of it.

I usually set the play feel on the low side also 2 0r 3 is good d play guitar. This setting can be increased or
decreased in each patch with Velocity curve also.

Low Velocity cut is for those unessential notes from brushing against the strings. Set this above 5 but be
careful because it will cut off any week signal and you will lose some dynamic ability. You can make up
for this by playing every not strong and accurate (if you are anything me this is not possible) or you can
use the legato option. Legato is notes that are tied together (slides, slurs, bends, taps and trills). This is
even helpful for instruments with the chromatic option.

On the Nuance page you can leave it default for piezo pickups but for GK’s I suggest setting the Nuance
trim to 8. This will especially help with triggering drums. For some reason the Ab snare drum needs a
little help triggering and it also helps with other tones as well but the drum kits is where it shows the
most. Drums have fewer editing parameters and they can be tricky. You will need to employ a lot of
palm muting to get an accurate performance.

Always keep in mind when using PCM sounds you are no longer a guitar player you are a synth player
and you will need to learn new techniques to achieve a flawless performance.

The topics covered in this article are purely my opinions and feel free to experiment or use whatever
works for you. Remember every guitar is different and no one setting will work for everyone.
I am ordering an OPT-1 from RMC soon and I will cover my thoughts on what it does and does not
improve. So far everything in my GR-55 is working great without it with the exception of the GR-300
COSM model but I got around that by using the GR-300 PCM.

Side note for Piezo users…. If you use some kind of foam on the other side of your bridge on Les Paul
type guitars it will get rid of that overtone/feedback pitch on COSM guitars.

-Jimmy.
Summary of the Parker Guitars speculator market from 2020 onward: https://en.wikipedia.org/wiki/Greater_fool_theory
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