Indiviual String Pickup

[billm90]

I basically have 6 individual pickups I plan to run for a midi set up.

I am wirring these up into a gk2a instead of the magnetic pickup it came with, because I am using it on a nylon guitar. The basic idea was to build something like a DIY godin nylon midi guitar.

I would also like to run the 6 indivual pickup leads to a 1/4 mono jack to run all of the together to a standard guitar amp.

If I split the wirring and sum at the 1/4 jack, it cause the individual midi wires to have all strings signals. basically it wont work.

I need a way to seperate the summed values from the individual values.

I was wondering if a diode can be put on the seperate 6 wires for each pickup befor the 1/4 jack.

I guess diodes are considered 1 way valves for electricity. but I tested one that is silicone, and I cant get an ohms reading any which way I try. I dont even know if they need a voltage to work, or if it is possible to work on pickups.

I am also trying to avoid running several switces to deal with this. I want the guitar body to be plain. unless there is some sort of single switch that can do this job. I dont plan on even having a volume knob on the guitar.

[David Schwab]

You need to run a separate line for each pickup to use it for MIDI. You can't run them to a 1/4" jack. Look at the jack used on the Roland units. You need something like that.

You also need a way to stop from having cross talk between strings, if you are using piezo pickups. Each pickup will need it's own preamp before it goes to the MIDI converter to convert the impedance. The MIDI unit is expecting very low impedance coils, not very high impedance piezo sensors.

Diodes wound clip (distort) the signal, and wont give you any isolation. You wont get an "ohm" (resistance) reading through a diode, and also you wont get a resistance reading on a piezo pickup either.

What you are trying to do is pretty complicated, especially if you are unfamiliar with electronics and piezo bridges. You'd be better off to buy a MIDI unit for a nylon guitar.

[billm90]

basically what I have done, and I already tested on a few junk guitars, is make a midi nylon guitar.

Godin or the carvin NS1 are examples.

I cut 6 piezs buzzers into strips and put one on each string. cross talk is very minimal. there is a tiny bit, but really not much. I have through about trying to cut slots between each pickup.

I have a gk2a pickup for my vg-88.

I disconnected the magentic pickup and I wired my 6 seperate piezos into the g2ka unit, where the magnetics once went. it does work... I just have bugs to work out.

My goal was to be able to run the piezos thru a normal amp as well.

the G2Ka has the selector on it for electric, synth and both. if I could get the 6 wires summed to run to the electric input, I could mix the midi and nylon sounds together. I dont think this is ever going to happen.

with there being nothing I can do to disconnect the sumed value of all 6 piezos from the midi, I guess I am forced to run a series of switches to disconnect the sumed at a 1/4 jack. (I have already done this with a mini dip switch that has 8 switches)

on a side note. I already converted my g2ka to acept 2 phone lines. this way I can quickly connect the magnetic or my diy piezo pickups. all I have to do is move the g2ka module from guitar to guitar. I would of used ether net for one nice neat chord, but I cant find the female connectors. so phone cables it is.

After getting my guitar back together last night I am having pickup issues on the high e string. I think I am going to need to build a new bridge (classical style) I think I may fit 12 piezos to it. this way 6 can go to midi, and the other six can be summed to a 1/4 jack.

Last night I went ahead and installed an under saddle acoustic pickup, this has issues on the low E. I think the bridge I built has issues. It must be uneven with all the wires. I basically glued the piezos to a bridge, and then expoxied the whole thing and sanded it back down so none of the wires come loose.

Thanks for the info on the diodes.

[curtisa]

To sum all the six outputs while leaving them available for MIDI processing requires use of an opamp summing circuit, basically a simple mixer - each of the 6 outputs get summed into one signal which prevents cross-loading back into the MIDI circuitry.

Here you go, can't get much simpler than this. Just add a power supply:

http://devices.sapp.org/circuit/mixer/

Google and ye shall find.

[billm90]

To sum all the six outputs while leaving them available for MIDI processing requires use of an opamp summing circuit, basically a simple mixer - each of the 6 outputs get summed into one signal which prevents cross-loading back into the MIDI circuitry.

Here you go, can't get much simpler than this. Just add a power supply:

http://devices.sapp.org/circuit/mixer/

Google and ye shall find.

Thanks

I have googled for days.... I guess you sort of need to know what you are looking for to find it.