DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: Ansil on September 24, 2003, 10:27:02 PM

Title: using crystals in the feedback loop of an opamp
Post by: Ansil on September 24, 2003, 10:27:02 PM
another thought came to me about two months ago.  if you look at craig adertons book that has the tuner in it. it uses an oscilator to vibrate a one meg hz crystal then uses a top octave divider chip to drop the stable pitch down to usable range.    hmmmm  what couldwe do with this.  well i am not about to draw it in pbrush since it took me two days to do it on paper. but here is an idea that i was playing with .  

radioshack used to carry all sorts of weird freq. crystals. i mean i found some in musical range. so i thought aobut this.  if you can find it.  make a medium gain dist pedal. and put a few in the feedback loop, put a few trim pots there and feed it back to the input. so as you play when you hit the right resonant freqeuncy... lets say 1.5khz it will oscialate the crystal and keep that note ringing.  if you put a few of them in the loop,  maybee put a few  momentary switches you can make a few sustain pseudo feedback switches.  you can also put them in the negative feedback loop and let them notch out what you don't want..  60 cycle hum anyone.   i have only expiramented with this a little but the results i had were extremely pleasant.  maybe some out there can perfect this and make some killer pedals.
Title: using crystals
Post by: donald stringer on September 24, 2003, 10:48:01 PM
I narrowly understand the electronic part of it but if it can be done and tuned to a specific set of parameters[[ by that I mean users set the freq. range, at which part of the neck you want the tone picked up] let say set your gain on dist. down and vol. full up and play above the 12 th fret four some nice singing sustain.... this even sounds like a pseudo pitch shifter or homemade 12 string guitar impersonator :wink: I just had an epiphany well that brain fart is gone. Oh yes once you have the desired  tone then double it for the pitch shift effect. ...IF YOU BUILD IT THEY WILL COME. have a nice evening.
Title: using crystals in the feedback loop of an opamp
Post by: idlefaction on September 24, 2003, 11:29:53 PM
they didn't come  :(
Title: using crystals in the feedback loop of an opamp
Post by: Ansil on January 25, 2004, 04:08:11 AM
Quote from: idlefactionthey didn't come  :(

hey did you ever find that schematic you was talkin about in the above post i emailed you sometime ago just wondered if you found it.
Title: using crystals in the feedback loop of an opamp
Post by: smoguzbenjamin on January 25, 2004, 05:14:50 AM
If you found a 50/60Hz crystal you could make something like a hum eliminator, you know, put it at the end of an FX chain or something. But wouldn't that roll off the 50/60Hz (depends on crystal) frequencies of the guitar aswell?
Title: using crystals in the feedback loop of an opamp
Post by: Ansil on January 25, 2004, 05:25:52 AM
Quote from: smoguzbenjaminIf you found a 50/60Hz crystal you could make something like a hum eliminator, you know, put it at the end of an FX chain or something. But wouldn't that roll off the 50/60Hz (depends on crystal) frequencies of the guitar aswell?

yes.
Title: using crystals in the feedback loop of an opamp
Post by: smoguzbenjamin on January 25, 2004, 05:37:50 AM
damn. :D
Title: using crystals in the feedback loop of an opamp
Post by: Paul Perry (Frostwave) on January 25, 2004, 07:57:46 AM
Audio frequency crystals? I don't think so... they'd be pretty big!! and expensive :!:
Title: using crystals in the feedback loop of an opamp
Post by: Ansil on January 25, 2004, 08:00:25 AM
Quote from: Paul Perry (Frostwave)Audio frequency crystals? I don't think so... they'd be pretty big!! and expensive :!:

rat shack had them at one time
Title: audio
Post by: drew on January 25, 2004, 04:51:49 PM
Hahah. You know, I think I saw someone post something similar before, and I think I posted before that you probably confused mhz for khz, or khz for hz. But people here get pissed when I step in and correct them. So I'll just offer that if you can find any crystal that runs at 1kHz or less, show me, and I'll give you a hundred bucks. How about that? :)


drew
www.toothpastefordinner.com
Title: using crystals in the feedback loop of an opamp
Post by: Alex C on January 25, 2004, 05:28:18 PM
http://www.mfelectronics.com/PDFs/M1380.pdf

http://www.vectron.com/products/military/tcxo/mil_tcxo_index.htm
(bottom of page)

Shall I email you my paypal address?
Title: Re: audio
Post by: Ansil on January 25, 2004, 07:30:01 PM
Quote from: drewHahah. You know, I think I saw someone post something similar before, and I think I posted before that you probably confused mhz for khz, or khz for hz. But people here get pissed when I step in and correct them. So I'll just offer that if you can find any crystal that runs at 1kHz or less, show me, and I'll give you a hundred bucks. How about that? :)


drew
www.toothpastefordinner.com

hmm, well if i could find them now, i would be building this.  but no i asure you i wasn't confused on the mhz khz or hz. quite clearly in fact.  but on top of that.  could always use the top octave divider chip like i said before.  the whole reason i pulled this thread out was because idle faction said he had done somehting along this lines and i was wondering if he found the schematic for it as i towuld be interesing to research further.  no one minds when you correct them there drew,  sometimes we all just jump on the wrong section of the thread that we are trying to prove.  myself included.
Title: using crystals in the feedback loop of an opamp
Post by: drew on January 25, 2004, 08:25:06 PM
'Member, a crystal's different from a "crystal oscillator"... :)

The top octave idea is pretty useful in a lot of applications though, ansil... something you might be interested in is this multi-suboctave generator:

http://www.cgs.synth.net/modules/subosc.html

It takes two inputs, and outputs several suboctaves from each input, as well as the squared-up inputs digitally multiplied with XORs... so you get a ring mod out of it too. I use mine when mixing but it would work well for guitar, even though you might need a preamp tacked onto the front end.

Where do crystals fit into this? Well, if you wanted to play with a divided-down crystal oscillator, you could feed it into one input, as the carrier for the pseudo-ring-mod, and get sub-octaves/other divided-down intervals out of your guitar signal as well. A little off-topic, but interesting nonetheless! :)


drew
www.toothpastefordinner.com
Title: using crystals in the feedback loop of an opamp
Post by: Ansil on January 25, 2004, 08:39:32 PM
Quote from: drew'Member, a crystal's different from a "crystal oscillator"... :)

The top octave idea is pretty useful in a lot of applications though, ansil... something you might be interested in is this multi-suboctave generator:

http://www.cgs.synth.net/modules/subosc.html

It takes two inputs, and outputs several suboctaves from each input, as well as the squared-up inputs digitally multiplied with XORs... so you get a ring mod out of it too. I use mine when mixing but it would work well for guitar, even though you might need a preamp tacked onto the front end.

Where do crystals fit into this? Well, if you wanted to play with a divided-down crystal oscillator, you could feed it into one input, as the carrier for the pseudo-ring-mod, and get sub-octaves/other divided-down intervals out of your guitar signal as well. A little off-topic, but interesting nonetheless! :)


drew
www.toothpastefordinner.com

cool thanx
Title: using crystals in the feedback loop of an opamp
Post by: RDV on January 25, 2004, 09:48:48 PM
yeH uoy syug retteb eb luferac gnissem dnuora htiw taht latsyrc, taht ffuts lliw llik uoy. tsuj ksa ym niarb!!

sdrageR

VDR
Title: using crystals in the feedback loop of an opamp
Post by: Ansil on January 25, 2004, 10:18:52 PM
Quote from: RDVyeH uoy syug retteb eb luferac gnissem dnuora htiw taht latsyrc, taht ffuts lliw llik uoy. tsuj ksa ym niarb!!

sdrageR

VDR

dude i havent' typed like that since i did opium like 15 years ago and that wasnt' on purpose
Title: using crystals in the feedback loop of an opamp
Post by: smoguzbenjamin on January 26, 2004, 10:56:24 AM
Apparantly 'Alice in Wonderland' was written by someone on an opium trip. It explains the hyperactive rabbit :D
Title: using crystals in the feedback loop of an opamp
Post by: Peter Snowberg on January 26, 2004, 12:02:42 PM
Quote from: smoguzbenjaminApparantly 'Alice in Wonderland' was written by someone on an opium trip. It explains the hyperactive rabbit :D
Lewis Carroll may have had experience with a number of compounds, or at least he had knowledge of them. You have a hookah-smoking caterpillar sitting on a big mushroom, and you have mushrooms and drinks creating perceptual distortion when consumed. Above all, he pokes at Victorian society and it's characteristics more than anything else. I think that is where the high-speed rabbit is from.

Sex, drugs, and Rock&Roll...... Whatever happened to wine, women, and song?
Title: using crystals in the feedback loop of an opamp
Post by: smoguzbenjamin on January 26, 2004, 01:32:28 PM
Hmmm. :mrgreen: I think victorian people look kinda cute :mrgreen:
Title: using crystals in the feedback loop of an opamp
Post by: Peter Snowberg on January 26, 2004, 03:18:44 PM
:lol: I agree. If you need another opinion, just ask Alice.......... when she's ten feet tall. ;)