EH rackmount guitar synth-any builders?

[loss1234]

hey there

i just completed this:

http://img.photobucket.com/albums/v317/StephenGiles/EH_sine.gif

its basically a basic version of page one from the EH guitar synth on mark hammers great page.


i am trying to figure out if what i built sounds the way it should and also trying to figure out if i might be able to take the output from this and interface it with other projects that dont have such good fundamental detection,etc.

anyway, has anyone around here built this? any advice?

thanks

[ianmgull]

wow. Sounds interesting. So this just outputs a square wave?

[loss1234]

well check out this link for more
http://hammer.ampage.org/files/EH-Guitar-Synth.ZIP


...but yes, a well tracked square which is then used for f to v applications. (i hope)

[snufkin]

do you have a layout ?  i guess its simple enough to bread board

i have a partly populated penfold p2v board but i suspect it will only be good for unusual sounds

[loss1234]

no layout sadly

and even page one filled a major sized breadboard.

thats the reason i am asking if anyone else has had luck because before i comitt three more breadboards, i want to be sure i have the first page working right.

anyhow, where did you get a board for the penfold p to v? i would love to get one of those


thanks

[snufkin]

i etched it from the article on ampage

there's a guy on the electro music forum who made one and posted sound clips and it actually worked ok for him

[Paul Perry (Frostwave)]

What is going on there? Low pass filtering and a LOT of compression? If so, there MUST be an easier way, but I wouldn't want to second-guess Howard Davis, the original designer.

[loss1234]

yeah i think i have given up on this one for now. its just too big. and this is before it even gets to the F TO V portion. there has to be another way.

which part does the compression?

thanks

[Rodgre]

It's just too bad that there isn't some $45 one-stop-shop IC made in china that simply converts pitch to a reliable voltage. Someone needs to get on that right away! I'm sure there are at least 15 or 20 of us that would love to see that.

The more I play my Roland GR-300, the more the whole process of guitar-to-control voltage seems like so much fun!

I'll have to put it online when I think of it, but I have a schematic that Paia sent me with my Gnome kit that I never finished back in the mid-80s. It is a Guitar interface for the Gnome. I am really foggy on it, but I'm recalling that it was simply some sort of square wave fuzz which could be run through the Gnome, and it also generated a trigger signal. No real guitar-to-oscillator control though.

Roger

[Processaurus]

You could make a great, cleaner sounding octave up by using the squaring technique (rather than FWR) after your guitar to sine wave converter.  I've wanted to try that on my deluxe octave multiplexer, which has that same circuit in it.

[Paul Perry (Frostwave)]

It's just too bad that there isn't some $45 one-stop-shop IC made in china that simply converts pitch to a reliable voltage.

Well, you can do it for 45 cents - unless you insist on playing guitar. The very erratic guitar note, that's the problem. And chords. 

[StephenGiles]

You could make a great, cleaner sounding octave up by using the squaring technique (rather than FWR) after your guitar to sine wave converter.  I've wanted to try that on my deluxe octave multiplexer, which has that same circuit in it.

In that case, you are but a short leap from a half decent tracking VCO if you look at the circuits on Mark's site. The squarewave output from the 311 is fed to the f to v generating  circuitry consisting of VCO3 (running at 2 x guitar frequency) and the network around the 2 x 4047s, which I imagine generate positive and negative pulses and when averaged off, produce the necessary voltage increments.

[StephenGiles]

I dusted my old EH Guiltar Synth veroboard this afternoon - literally, with a feather duster and 19 years worth of dust half came away!!

I connected up to a couple of PP3 batteries - they don't give nearly enough jump to the 20 or so ICs which need a dual 12v with a bit of oomph, but after jiggling about for half an hour I got an output from the Adaptive Filter thusly, which I've left in wav format.

http://www.4shared.com/file/48779574/7a95f1ff/EHfund_gen.html

......which, if you play through Windows Media Player with the visuals set to scope, you see a nice sinewave appearing. We are booked for Argentine steak soon but I'll see what else I can get working. The squarer is next and if I have any 4030/4070, the frequency doubler. After that I need to sort out a bird's nest around the P to V circuitry.

Did your'n sound anything like this loss1234?

[loss1234]

damn, yeah it did sound kind of like that (although a bit noisier if i remember correctly) but the squarer was MUCH  harsher.

i think i got scared off because i stupidly thought it was JUST supposed to sound like a square wave tone, not a guitar that is sine ish.

so maybe i built it right after all?

well i might rebuild it then.

do me a favor, when you get the time post the square wave sample and then i will know for sure if i was on the mark.

if i was, then i really just need to buy some more breadboards as i used up a giant one just for page one.

thanks a lot for doing this

[loss1234]

prcoesasuaraus: what do you mean by the squaring technique? do you mean simply sqauring like in a fuzz? i would love to be able to do a non distorted octave up.

[StephenGiles]

You could make a great, cleaner sounding octave up by using the squaring technique (rather than FWR) after your guitar to sine wave converter.  I've wanted to try that on my deluxe octave multiplexer, which has that same circuit in it.

Please tell me about it, do you have a circuit I could try as I seem to have the only working EH Fundamental Extractor on the entire planet!!

[Processaurus]

Here's some Squarers.

• JC Maillet's:
  http://www.lynx.bc.ca/~jc/pedalsHarmonic.html
• Geofex (I made this one and it worked, but had low signal output.  Needs tweaking):
  http://geofex.com/Article_Folders/jfetdoub/mudoubler.htm
• Johann Burkard's (looks the simplest, uses a modern IC):
  http://www.diystompboxes.com/smfforum/index.php?topic=53166.0

Supposedly any ring modulator works as a squarer if both the carrier and modulator are the same.  The lovetone ringer stinger has that footswitch that is octave/ring mod, that must hook both carrier and modulator together.  One problem of that is sustain, as the dynamics are squared as well, so something compressed would be ideal, like the EH fundamental extractor, you guys would probably know better, I believe it is a compressor and tracking filter.  When I had a deluxe octave multiplexer apart and hooked that "sine" output up to an amp to play with it, I thought I would get synthesizer perfect sinewave, but it sounded more just like incurably muddy, muffled guitar.  Similar to Stephen's sample, which is really interesting as you can hear the filter tracking, I don't recall mine being quite as heavily filtered (though who knows if it was working 100%).  Also, it was quite noisy from the compression.


Here are some notes and scope pictures on the EH deluxe octave multiplexer, mostly about the weirdness of the octave down, but also a mention about the Howard Davis fundamental extractor.
http://www.diystompboxes.com/smfforum/index.php?topic=52725.0

[StephenGiles]

Thanks. Of course a 311 is used in the synth and the multiplexer to square up the sinewave.

[loss1234]

do those create distorted square tones or clean?

stephen-any luck get the square out working?

[StephenGiles]

do those create distorted square tones or clean?

stephen-any luck get the square out working?

No not yet. I may get half an hour later.