Don't know if these are usable for your application, but they are cheap for 2 more days. Electronic Goldmine is a surplus dealer, so these may be old. I have been getting parts here for 30+ years, so they are legit.
https://theelectronicgoldmine.com/products/g12786d
https://theelectronicgoldmine.com/products/g12786d
Of interest is whether I could do the "Linkwitz" mod on these. Ebay has them for a competitive price, free shipping - and a lot more time to think about it. Thanks for bringing it here!
I spent a few hours this morning tinkering with a guitar, an amp with clip leads on the input, some Amazon sourced Neodymium magnets, and a bag full of ferrite inductors trying to find some combination suitable for use as single string guitar pickup. Some worked poorly, some worked pretty good, but magnet and coil position are pretty critical, so I decided something better than masking tape and clip leads is needed for serious experimentation. I put the experiments on hold and went outside to mow the lawn.
Somewhere in my third hour of arguing with an overgrown yard and a cantankerous weed eater, two functional brain cells crashed into each other, and a dim-witted idea was born. Why couldn't a hex pickup be made with a magnet and six hall effect sensors. After feeding my face I fired up the PC and discussed the idea with Google. It seems that this idea was patented back in the 70's. Further digging reveals that there are valid technical reasons where just a simple hall effect sensor will have poor frequency response. It seems that the idea gets brought up every year or two but doesn't seem to make it to the "real product" stage. Several random different search terms brought me to a post here on diyAudio........
It seems that I have been here before, over 12 years ago. See post #6 here:
It said:
OK, next new idea for cool and unique guitar pickup......a magnet and a Hall effect sensor chip.....or six. I built one and it does work, but isn't quite right yet.
I guess that it never became quite right, or I lost my patience. Anything I did in 2012 could be anywhere including the trash, especially if I had abandoned the idea. Guess I'll just have to try it again. Some Amazon quality hall effect chips will be here Tuesday, maybe.
Somewhere in my third hour of arguing with an overgrown yard and a cantankerous weed eater, two functional brain cells crashed into each other, and a dim-witted idea was born. Why couldn't a hex pickup be made with a magnet and six hall effect sensors. After feeding my face I fired up the PC and discussed the idea with Google. It seems that this idea was patented back in the 70's. Further digging reveals that there are valid technical reasons where just a simple hall effect sensor will have poor frequency response. It seems that the idea gets brought up every year or two but doesn't seem to make it to the "real product" stage. Several random different search terms brought me to a post here on diyAudio........
It seems that I have been here before, over 12 years ago. See post #6 here:
It said:
OK, next new idea for cool and unique guitar pickup......a magnet and a Hall effect sensor chip.....or six. I built one and it does work, but isn't quite right yet.
I guess that it never became quite right, or I lost my patience. Anything I did in 2012 could be anywhere including the trash, especially if I had abandoned the idea. Guess I'll just have to try it again. Some Amazon quality hall effect chips will be here Tuesday, maybe.
There are already individual string guitar pickups for midi guitar. https://jamstik.com/products/replac...6e08cd7450cbbdddc64c6cf2e8891f6d48747c6d56d2c
Local preamp at guitar schematic:
Schematic from: https://www.vguitarforums.com/smf/index.php?topic=73.0
Local preamp at guitar schematic:
Schematic from: https://www.vguitarforums.com/smf/index.php?topic=73.0
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I haven't looked into the Jamstik stuff since it is beyond my budget. I do have a Roland GI-10 Guitar to MIDI interface which includes the GK-2A hex pickup. This unit is from the mid 1990's and is far from perfect. Your schematic is from the GK-3 which is very similar.
I had the GK-2A on an old UNIVOX branded Mosrite clone which was fitted with fairly heavy strings for several years. I had to place the divided pickup very close to the strings to get good tracking. The picture shows that it was a bit too close though I used that guitar for about 15 years until I wore the frets down.
This system and some of the newer Roland stuff did not make the individual string outputs available to the user, though many achievable hacks were published to do this. Some people who did this reported usable audio, some said that it was distorted or muffled. Since the original intent for this system was to provide a MIDI output from a guitar, clean audio was likely not a priority, or even a consideration, as the system left the guitar's audio output unchanged.
I have tinkered with DIY pickups and guitars for years until my career came to an abrupt halt and I had to pack up everything I wanted to keep and move it 1200 miles. I'm just now restarting that guitar making stuff that got boxed up 11 years ago.
I had the GK-2A on an old UNIVOX branded Mosrite clone which was fitted with fairly heavy strings for several years. I had to place the divided pickup very close to the strings to get good tracking. The picture shows that it was a bit too close though I used that guitar for about 15 years until I wore the frets down.
This system and some of the newer Roland stuff did not make the individual string outputs available to the user, though many achievable hacks were published to do this. Some people who did this reported usable audio, some said that it was distorted or muffled. Since the original intent for this system was to provide a MIDI output from a guitar, clean audio was likely not a priority, or even a consideration, as the system left the guitar's audio output unchanged.
I have tinkered with DIY pickups and guitars for years until my career came to an abrupt halt and I had to pack up everything I wanted to keep and move it 1200 miles. I'm just now restarting that guitar making stuff that got boxed up 11 years ago.
Attachments
Hopefully you wont be as rudely interrupted, as time goes on. It'll be interesting to read about what you come up with.
I bought some of the better PLL chips; only 5 to a pack. I need to order again if I expect to use them with a hex pickup, plus spares. Came surprisingly fast from overseas; hand delivered to my door by a young lady with a car full of packages...
In a hex pickup driven application, one would think that the capture range on these could bet set to only comprehend the range of the string. IIRC, the minimum frequency can be set, so why not simply tune that to the open string frequency? Now it cant go below. The capture range above could be set to however high up the neck you want to go and I bet a there's a lot of mileage lead-wise even keeping the range on each string below the problematic octave.
Better than what I once tried decades ago, having one PLL try to track all six strings... It would do it, but required you to play ultra-clean, including picking wherever dead center was on the fretted string you expected it to track. Heck I even went as far as a tracking bandpass filter upstream, thinking "the probability of the next note is within the filter's pass band anyway".
Maybe would have worked a lot better splitting frequency capture duties across all the strings. Alas, it's probably an effort I'll never get to and my time is likely better spent learning how to use my looping pedal effectively. The impressive guy tells me the hardest thing is turning it off, still keeping time and finishing the song "manually".
Which ones. Most of my PLL experiments from about 2010 used the CD4046 / MC14046 chip. A single guitar string spans just under two octaves. There are many different versions of the 4046 PLL chip but all will do two octaves. I was attempting to make the VCO track one volt per octave so that the PLL would directly make CV for a synth. I never got it to work. If the VCO's range is expanded to cover the whole guitar (about 4 octaves) the opportunity for locking onto a harmonic greatly increases. I spent far too much time tinkering with PLL's, and I may go back there as better chips exist today, and I know a whole lot more about PLL's and frequency synthesizers, but from an RF (100 MHz to 2 GHz) perspective.
I made crude "computer music" from my SWTPC MC6800 computer in the 1970's. This was an 8 bit machine that ran at a blazing 921.6 KHz. I have tinkered with computer music ever since. Small form factor "maker boards" have also advanced in power, price, and bit depth so that realistic music synthesis is now easy and cheap. I have built 3 working "virtual analog synths" with the Teensy series chip sized boards using their drag and drop audio library. This where I plan to send the output of the hex pickup.
74HCT9046 Just spent another $18 for a second set of 5. Shipping about 3X the cost of the chips.
Here's a repeat of an earlier attempt, this time using an AudioTechnica electret capsule microphone, instead of a Shure dynamic. Seems to work better, less prone to vibration pickup.
This is all to try to meet a challenge from another player; a guitar mounted pickup system that sounds like a stand mic'd acoustic tone. He seems currently content with his soundhole mounted mag pickup on his steel core strings, but hasnt yet committed to a drilling out the tail block. I like nylon.
- A round foam plug is velcro'd to the side of the guitar; that way I can remove it fairly easily. The curve of the guitar body is a pretty stiff mount point. I stand when playing on stage, otherwise there'd be leg interference in a seated position.
- The gooseneck arm is an ebay purchase (https://www.ebay.com/itm/186885465340) - it grips the end of a wood stick suspended within the foam plug.
- The mic is an AT 831A, also an ebay purchase.
- The mic is suspended in some kind of filter media, in an attempt to avoid blocking its side ports
- The mic can be easily adjusted to pick up more toward the bridge, or more toward the sound hole. Response is more bass up by the soundhole, however likely more prone to feedback when playing live.
- The velcro adhesive interacted with the guitar's top finish, when I had the cable from the hex pickup attached. It's my Franken-guitar, that I try out different pickups on.
This is all to try to meet a challenge from another player; a guitar mounted pickup system that sounds like a stand mic'd acoustic tone. He seems currently content with his soundhole mounted mag pickup on his steel core strings, but hasnt yet committed to a drilling out the tail block. I like nylon.