VGuitar Forums

Please login or register.

Login with username, password and session length
Advanced search  
Pages: [1] 2   Go Down

Author Topic: 13 Pin to FTP adapter  (Read 2889 times)

0 Members and 1 Guest are viewing this topic.

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
13 Pin to FTP adapter
« on: April 21, 2013, 02:29:52 PM »

Got my FTP 4 days ago and I have to say it's fantastic. besides a few gripes with the mounting (doesn't fit on my strat with any of the brackets and can't fit on any of my LP's due to the pickup ring which I believe is a pretty common issue).

Anyway besides the above it is truly revolutionary so I immediately ordered a second and started tinkering with this because I really don't like mounting mechanism.  I have 3 guitars with Graphtech piezo's and preamps.

At first I hooked the piezo's directly to the triple play circuit, the results: the signal on the 2 bass strings was too weak. It still worked but even with the sensitivity all the way up to 16, the bar would only go about 40%, this didn't seem acceptable.

So next I hooked it via the 13 pin jack using a battery to power the pre-amp, results: Signal was now too high, I turned down sensitivities to 1 and still everything was getting in the red. As a last resort before giving up I switched the Traktion Switch (on the graphtech 13 pin jack) to the axon position, this seemed to cut the output a bit and bring everything more into range.

So far it seems pretty usable. I haven't done a side by side comparison, when I get the second unit in a few days I'll put both on the same guitar and see how they compare. Ideally if it ends up working , it would be really useful so I can easily switch the same unit between any of the guitars without any mounting etc.

Just thought I'd post this in case anyone else has been trying some mods.



Logged

thebrushwithin

  • Senior Member
  • ****
  • Karma: 6
  • Offline Offline
  • Posts: 406
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #1 on: April 21, 2013, 03:02:57 PM »

Wow! I could not pull anything like this off, but I hope you find a way, cause it will then allow you to track while a sustain mechanism is engaged. Piezos track the best anyway, in my experience.
Great work, and good luck!!!
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #2 on: April 21, 2013, 03:19:08 PM »

the tracking seems as good as with the original pickup (not really much room to improve but not had enough time to really test properly) but since the signal from the piezo's is either too weak (without the pre-amp, something to do with impedance but I don't really know the electronics stuff ) or a bit too strong with the preamp(it doesn't over load but at very soft picks it is still above 50%) I'm concerned about the dynamic range, I think that the difference between the loudest and softest notes with the piezo is more restricted.

I'm hoping to get my second unit and plug this to the 13 pin jack and also mount the pickup and compare the midi from the exact same playing. I'll be happy if It's 90% as good as with the original pickup as thats still 1000% better than any of the previous midi solutions I've tried and it can be easily moved.
« Last Edit: April 21, 2013, 03:31:50 PM by utensil »
Logged

musicman65

  • Senior Member
  • ****
  • Karma: 26
  • Offline Offline
  • Posts: 986
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #3 on: April 21, 2013, 09:30:10 PM »

Utensil,

great work! I'm glad to see the signal is slightly too hot. Its easier to attenuate then boost!

I wonder if paralleling (splitting) the 13 pin output signal into a VG/GR input device and the FTP would reduce the signal....it should attenuate it since the FTP's input impedance would be in parallel with the VG/GR circuit. If that worked, I'd split the signal offboard the guitar and keep using all my 13pin guitars with no mods and better midi triggering. Best of both worlds except the wireless....to me, better tracking and keeping my VG99/KPA setup is the ultimate.

                  |---->VG/GR
GK 13 pin---|
                  |---->FTP

bd
« Last Edit: April 21, 2013, 09:34:08 PM by musicman65 »
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #4 on: April 21, 2013, 11:23:12 PM »

I wonder if paralleling (splitting) the 13 pin output signal into a VG/GR input device and the FTP would reduce the signal...

I have a GR-55 I could try splitting it with but can't say how it would work without trying it cause It's really beyond my very basic understand of this stuff. I will try it to make a splitter to try it.

But overall What I had in mind was to be able to plug the FTP via 13 pin so I can easily move it from guitar to guitar without any mounting issues etc. If I could also get it to work with the GR-55 simultaneously it would be great but I would want to be able to use the FTP on it's own too since I see it as being my main piece of gear now.

Any other way I can attenuate the signal, Is there any small circuit available with multiple attenuators. I was thinking I could get some kind of volume control circuit used in 5.1 or 7.1 surround systems and use it control the overall reduction in level. Any idea if this would work?
Logged

Elantric

  • Global Moderator
  • Senior Member
  • *****
  • Karma: 232
  • Offline Offline
  • Posts: 12747
    • Elantric's Tips and Blog
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #5 on: April 22, 2013, 09:08:07 AM »

For best results for mag Hex PU systems use one hex PU


                           |---->GK-3 -> 13pin
One hex PU 8 pin---|
                           |---->FTP controller > wireless


If its a piezo based system (RMC, Graphtech)

                  |---->VG/GR
GK 13 pin---|
                  |---->13pin in >Custom Adapter with Passive Attenuator & 8pin Out > FTP Controller

« Last Edit: April 22, 2013, 10:20:50 AM by Elantric »
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #6 on: April 22, 2013, 11:22:45 AM »

For best results for mag Hex PU systems use one hex PU


                           |---->GK-3 -> 13pin
One hex PU 8 pin---|
                           |---->FTP controller > wireless


If its a piezo based system (RMC, Graphtech)

                  |---->VG/GR
GK 13 pin---|
                  |---->13pin in >Custom Adapter with Passive Attenuator & 8pin Out > FTP Controller

For Piezo based which passive attenuator would work, I've been trying it without the attenuator(s) and the 2 bass strings are just too hot so it's giving a lots of false notes

Logged

Elantric

  • Global Moderator
  • Senior Member
  • *****
  • Karma: 232
  • Offline Offline
  • Posts: 12747
    • Elantric's Tips and Blog
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #7 on: April 22, 2013, 11:24:37 AM »

Quote
For Piezo based which passive attenuator would work, I've been trying it without the attenuator(s) and the 2 bass strings are just too hot so it's giving a lots of false notes

http://en.wikipedia.org/wiki/Attenuator_%28electronics%29

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #8 on: April 22, 2013, 11:59:53 AM »

Most of it makes sense to me but I don't think a diy 6 channel attenuator (made by me) would be all that portable. Was hoping to buy some kind of small circuit board or a dual channel ones , the goal to keep it very small , do these exist? if so any suggestions for online stores?
Logged

admsustainiac

  • Site Administrator
  • Senior Member
  • *****
  • Karma: 12
  • Offline Offline
  • Posts: 477
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #9 on: April 22, 2013, 12:06:57 PM »

Pure DIY

Logged

musicman65

  • Senior Member
  • ****
  • Karma: 26
  • Offline Offline
  • Posts: 986
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #10 on: April 22, 2013, 04:24:58 PM »

A miniature trim pot makes a great passive attenuator. Six mounted on a tiny circuit board would allow each string to be adjusted perfectly. I've seen them as small as maybe 4mm x 8mm with a tiny screw to adjust. They are quite common.

bd


Logged

musicman65

  • Senior Member
  • ****
  • Karma: 26
  • Offline Offline
  • Posts: 986
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #11 on: April 22, 2013, 04:36:56 PM »

Elantric,

I agree with your diagram 100%....but, for me, I would like to keep my array of GK enabled axes unmolested.

The 13 pin GK output is buffered and may be way to hot. I am not sure what the gain is on the GK circuit, any idea? Or is it primarily a current follower (gain of ~1) that lowers the impedance?

The method you show for Piezo with an attenuator board/splitter would be better for me since I want to retain my hardware modeller and VG stuff.

I would lose the FTP onboard controls but, in hardware mode, would I need those buttons for real time adjustments? Can midi commands recall settings in the FTP? Maybe I should wait for a floor controller model.....

bd
Logged

Elantric

  • Global Moderator
  • Senior Member
  • *****
  • Karma: 232
  • Offline Offline
  • Posts: 12747
    • Elantric's Tips and Blog
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #12 on: April 22, 2013, 05:40:24 PM »

Quote
The 13 pin GK output is buffered and may be way to hot. I am not sure what the gain is on the GK circuit, any idea?

Search is your friend

(click the attachments here)
http://www.vguitarforums.com/smf/index.php?topic=73.msg3281#msg3281

Elantric

  • Global Moderator
  • Senior Member
  • *****
  • Karma: 232
  • Offline Offline
  • Posts: 12747
    • Elantric's Tips and Blog
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #13 on: April 22, 2013, 05:47:20 PM »

But I would prefer a method where I could feed the 13 pin gear along with the wireless MIDI from FTP.

                           |---->GK-3 -> 13pin
One hex PU 8 pin---|
                           |---->FTP controller > wireless MIDI

and the "Y" Adapter could be very straight forward.

Mount one hex PU of choice( FTP, GK-3, GK-2A, G1D, PU100, AIX-101) Let the stock Hex PU Cable be the input to the Custom Mag Hex PU "Y-Splitter" to feed two targets.
 
On this  Custom Mag Hex PU "Y-Splitter" there MUST be 12 "coupling capacitors": 
* Six Caps to feed the Hex PU String Inputs on FTP Controller.
* Six Caps to feed the Hex PU String Inputs on the GK3 preamp target.
The 12 Capacitors are required to prevent DC voltage interference and offsets between the two different systems.
Small Surface Mount caps are available, but must be of adequate capacity to pass the low fundamental frequencies of the Guitar.

http://en.wikipedia.org/wiki/Capacitive_coupling





« Last Edit: April 22, 2013, 06:45:09 PM by Elantric »
Logged

musicman65

  • Senior Member
  • ****
  • Karma: 26
  • Offline Offline
  • Posts: 986
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #14 on: April 22, 2013, 07:25:32 PM »

Elantric,

thanks for the link. The NJM2068V op amps look like they have an inverted gain of 12.6 in the GK preamp circuit. I was was hoping for unity gain. This means a splitter would need attenuation down to 8% to get back to the same output as the raw GK pickup if interfacing to the FTP on the other end of the GK cable.

I like your method but $399 per guitar has me looking for a way to leave the FTP in place while switching guitars.

Would you mount the FTP controller inside your guitar making it dedicated to that Axe or make an external pigtail so you can move the wart?

Btw, with proper sizing, the coupling caps could help reduce false triggers from lower frequencies since the caps will roll off lows at 3db per octave...unless you want more by making a true filter with extra components...FTP may handle this already.

bd
« Last Edit: April 22, 2013, 07:30:23 PM by musicman65 »
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #15 on: April 22, 2013, 11:17:02 PM »

A miniature trim pot makes a great passive attenuator. Six mounted on a tiny circuit board would allow each string to be adjusted perfectly. I've seen them as small as maybe 4mm x 8mm with a tiny screw to adjust. They are quite common.

bd

Thanks!, I didn't know what these were called, I was googling mini pots, micro volume control, passive attenuator and never found the right term. It's so often that I am actually looking for the right name to search for. Anyway this is pretty much what I had in mind as I can keep it small even by doing myself. Any suggestion for what value trimpot to try. Would a 10k trimpot sound suitable. With my limited understanding a higher value may be need but 10k seem really easy to find so curious if these may work.



Logged

musicman65

  • Senior Member
  • ****
  • Karma: 26
  • Offline Offline
  • Posts: 986
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #16 on: April 23, 2013, 12:02:57 AM »

Hard to say for sure without knowing the input impedance of the FTP preamp. If you are attenuating the 13 pin out signals then yes, 10k should work. Elantrics point about using a coupling cap per circuit to isolate the GK's +/-7vdc from the FTP's DC supply is important as well.

bd
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #17 on: April 23, 2013, 04:43:50 AM »

I think unlike many others I'm not too interested in both systems working simultaneously (a little over my electronic skills). I would be happy if the FTP worked with my guitars with 13 pin internal installations (I'd mount the FTP on a strap).Right now, I don't know if the battery that's driving the hexpander pre-amp is interfering with the FTP but it seems to work *Almost* as well as with the FTP mag pickup. could it screw up the FTP battery or controller?

The issue is too many accidental note triggers from the low E and A strings .(it's still miles ahead of the GR-55 and Axon in terms of usability, If I hadn't experienced the proper FTP performance I would be happy with it).

I would ideally like to lower the output of the 6 pins to the FTP so I can reduce it from there and then set the FTP sensitivities to midrange rather than all the way down as present.

I picked up 6 10K trimpots (hard to find where I live, had to dig through 5 trashbins of various misc components.). If I get a chance today evening I'll try and rig it up and see if it's an improvement. I also got my second FTP today so I can mount both systems on the same guitar and record the same part to different tracks and compare. I don't think it's will improve on the original's performance as I think a lot of brainpower went into optimizing with the mag output which is probably why even the Godin Session Custom doesn't use piezo's.







« Last Edit: April 23, 2013, 04:59:11 AM by utensil »
Logged

thebrushwithin

  • Senior Member
  • ****
  • Karma: 6
  • Offline Offline
  • Posts: 406
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #18 on: April 23, 2013, 06:26:55 AM »

If memory serves me, I thought the Graphtec system already has 6 trim pots on the hex pander board, but I may be mistaken.
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #19 on: April 23, 2013, 08:45:11 AM »

The graphtech hexpanders I have , only have the pins for the various strings, switches and volume pot. I checked the manual and the volume pot seems to send a control volume signal to receiver rather than reducing the signal from the output. I think the acoustiphonic chip which optionally accompanies the pre-amp has a trim control but I think that is only for summed output and either way not required for the 13 pin functionality so I never got it.

Logged

Elantric

  • Global Moderator
  • Senior Member
  • *****
  • Karma: 232
  • Offline Offline
  • Posts: 12747
    • Elantric's Tips and Blog
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #20 on: April 23, 2013, 10:15:45 AM »

Quote
I think unlike many others I'm not too interested in both systems working simultaneously (a little over my electronic skills). I would be happy if the FTP worked with my guitars with 13 pin internal installations (I'd mount the FTP on a strap).Right now, I don't know if the battery that's driving the hexpander pre-amp is interfering with the FTP but it seems to work *Almost* as well as with the FTP mag pickup. could it screw up the FTP battery or controller?

The issue is too many accidental note triggers from the low E and A strings .(it's still miles ahead of the GR-55 and Axon in terms of usability, If I hadn't experienced the proper FTP performance I would be happy with it).

I would ideally like to lower the output of the 6 pins to the FTP so I can reduce it from there and then set the FTP sensitivities to midrange rather than all the way down as present.

I picked up 6 10K trimpots (hard to find where I live, had to dig through 5 trashbins of various misc components.). If I get a chance today evening I'll try and rig it up and see if it's an improvement. I also got my second FTP today so I can mount both systems on the same guitar and record the same part to different tracks and compare. I don't think it's will improve on the original's performance as I think a lot of brainpower went into optimizing with the mag output which is probably why even the Godin Session Custom doesn't use piezo's.



If you are not sure of what you are doing in electronics, be prepared for damage or smoke.

Piezo pickup saddles are very high impedance.
If you look around, some Piezo PU models may actually work without a preamp, but use a 10 Megohm Volume pot, thus an Active Piezo preamp is employed.

Preamps designed for Magnetics PU's (like the FTP) are not compatible with Piezo PU's. A separate Active Piezo Preamp is required.
 

Roland uses a bi-polar +7V and -7Volt power rails for audio signals to swing above and below the Analog Ground Reference.
Be aware that 90% of the other Guitar preamps you encounter will be run from a single +9V battery and employ a "Virtual Ground" which measures +4.5V DC Offset from Ground

Its these offset voltages on the third party preamps which must be blocked by coupling capacitors.

   
 
« Last Edit: April 23, 2013, 10:19:14 AM by Elantric »
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #21 on: April 23, 2013, 04:00:44 PM »

Yep you're right, I've burned out a few things already (one hexpander was particular regretful), Most elementary mistakes which I wish I would have taken some time to read up on (I usually try to now).This forum is a real strong starting point for me to find things to read up on in regards to electronics. I really have had a lot of enjoyable projects as a result.

I was really looking forward to the FTP. My plan was to put piezo's and hex magnetic pickups on all my guitars and have them output to a 15 pin jack (VGA) so that any future guitar equipment would be easily attached/swapped. So all pre-amps etc would be outside of the guitars and shared. I think this would make the most sense as really the guitar is really just an interface and should be kept as general as possible with just the sensors in it, the processing etc should be external.

Of course now I actually have the FTP and I would be satisfied to just have it work via the 13 pin as that covers my needs.

I also think so far results today are encouraging. I didn't have time to rig up all six 10 k trimpots but I did just the problematic low E string and it's now very controllable and tracks excellently ( I have the FTP software sensitivity set to 7) and the dynamic range is as good as the magnetic.

I'm going to try and finish it tomorrow and do a final test and will report back.

Logged

Elantric

  • Global Moderator
  • Senior Member
  • *****
  • Karma: 232
  • Offline Offline
  • Posts: 12747
    • Elantric's Tips and Blog
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #22 on: April 23, 2013, 04:23:07 PM »

Quote
I was really looking forward to the FTP. My plan was to put piezo's and hex magnetic pickups on all my guitars and have them output to a 15 pin jack (VGA) so that any future guitar equipment would be easily attached/swapped. So all pre-amps etc would be outside of the guitars and shared.

Great idea, but in practice only applicable to a New age'r who enjoys clean Acoustic type tones at low volume or at home, and never uses any high gain tones in the realm of heavy Rock , Blues, Metal, etc using these same Hex pickups


Been there done that - if you employ a cable longer than 1 meter (approx 3 feet) between your passive non buffered Hex PU (Mag or Piezo) to feed a remote box with GK-3 Pre-amp, Variax Board, or FTP Controller - expect huge noise and feedback problems as soon as you engage a heavy Metal High gain patch on a GR-55 or VG-99.

Add a live show with added EMF Noise from stage lighting dimmers, or Ice Machine -  forget it!

There is a valid engineering reason why Active preamps on board the guitar are preferred. The sooner you can convert a high impedance source to Low impedance, the better things get to drive longer cables runs with more immunity to background EMF sources and noise. Make it differential balanced with 0.775Vrms  = +4db referenced = total pro.


 
« Last Edit: April 23, 2013, 07:14:47 PM by Elantric »
Logged

musicman65

  • Senior Member
  • ****
  • Karma: 26
  • Offline Offline
  • Posts: 986
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #23 on: April 23, 2013, 06:14:53 PM »

Yes....low impedance, higher current output like the GK circuit is the key to noise immunity as Elantric mentioned. This is why having a splitter with attenuation on the other end of the GK cable won't have the noise issues and give you the signal you want.

bd
Logged

utensil

  • Senior Member
  • ****
  • Karma: 0
  • Offline Offline
  • Posts: 173
Re: Fishman Triple Play 13 pin MOD experiments
« Reply #24 on: April 24, 2013, 04:03:06 PM »

Ok so rigged up all 6 trimpots (it aint pretty but it functions correctly, pic attached). So one triple play via 13 pin with battery and trimpots and second triple play directly on same guitar. Verdict: Can't seem to get the same performance from the piezo path.It's 90% there but still missing something.

All the sensitivities are in the right range (I have the FTP app set to midrange for all the strings). False notes are now in control but I think it's the release and the dynamics that is just much better with the original magnetic pickup. It's that final 10% that really makes me forget I'm playing synth. It's like the volume curve matches the acoustics of unamplified guitar much more closely when using the original setup

Anyway I'm kinda out of ideas of how to improve this any further as I'm sure there's ways I could mess with the frequency curve to approximate the magnetic (which I assume is optimal), but now I'm leaning in another direction.

I'm thinking to mount magnetic pickups on the 3 guitars and have a common output to the FTP controller. Since I'd mount the controller on the strap I think that the issues with interference and cable length should be minimized.
Logged
Pages: [1] 2   Go Up
 

Blog