Tycobrahe Parapedal Vero

daverdave · February 16, 2009, 08:36:12 AM

The problem with using either dual vactrol or the circuit I posted is that you'd need +9v to power the led and the parapedal is a positive ground circuit. You'd need a dual power supply to use an optical control or make the parapedal negative ground, but I don't know how to go about doing that and whether it would change the sound of the circuit.

alteredsounds · February 16, 2009, 09:38:55 AM

The original is certainly positive ground but it is only a matter of reversing maybe 3 components (2 polarised caps and the diode) to change that to negative ground.

daverdave · February 16, 2009, 09:43:54 AM

I thought tht but looking at the schematic it doesn't look right, the diode looks like it would be that way round anyhow, not sure about the caps though. I read a previous post where someone had trid that method and said it didn't work.

alteredsounds · February 16, 2009, 09:53:38 AM

Cant see why it shouldnt? maybe i'm missing something, i'll have another look

daverdave · February 16, 2009, 01:37:21 PM

So would you reverse the diode and the caps, then switch the battery terminals so 9+ is going to the diode. because the opamps would then have +9v going to ground (pin 4).

Solidhex · February 25, 2009, 05:14:33 AM

Yo

R.G. has the schematic up on his site with both positive and negative ground versions of the parapedal.
I was stoked to see that anderton retrofit since it had never occurred to me an LDR could work as a voltage divider in conjunction with another resistor. Seems simple now. To use it with the Parapedal circuit I think it would be good to grab one of those dual vactrols like these? Http://www.smallbearelec.com/Detail.bok?no=349
Since the dual pot in the Parapedal is dealing with two different signals you'd need to have two circuits like the anderton wah retrofit. Its late so I might not be thinking clearly but if we are looking at the R.G. schem. You would have a single 100k wah pot paralleled with the 100uf cap wired with the .22 cap/ 2k2 led current limiter hooked up to the dual opto. The middle lead of the opto would run through the 220 ohm resistor to ground. the other two would connect to points "G" and "D" on R.G.'s schem. Then you'd need ( I'm assuming ) a 10k resistor from points "A" to "G" and "H" to "D"? If this makes sense to anyone let me know...

-Brad

daverdave · February 25, 2009, 04:26:45 PM

The schematic at geofex doesn't show a negative ground as far as I can see. One of them is the original and one has millennium bypass, but they're both positive ground.

The vactrol would be a good idea (just ordered some stuff from small bear as well), you wouldn't actually need to make the parapedal negative ground though. just reverse the led going to the ldrs and have -9v going to the pot. Did anyone have a look at the circuit I made for it on the last page?

I'll try it out soon and let you guys know.

Solidhex · February 25, 2009, 09:57:22 PM

Yo

The schem is positive ground but the layout right next to it has both positive and negative ground versions. The clone I built I used a positive ground version. I'd love to get the led/ldr thing working. The dual 10k I used is extremely stiff. A regular wah pot would be way better.
Can't remember if I mentioned this before but the Chicago Iron version doesn't use a custom made pot. I actually ordered one of their pots hoping I could use it in my clone. I paid $15 or something like that. They just sent a regular $3 panel mount alpha dual 10k pot. No hardware, no gear.

--Brad

visualdistortion · April 14, 2011, 01:49:03 PM

Hi
http://cgi.ebay.fr/5pcs-B10K-Dual-Stereo-Potentiometer-Pots-20mm-Shaft-S-/160573140652?pt=Guitar_Accessories&hash=item2562e7aeac

Do you think that pot will be good or shorter?
I saw on banzai effect one pot for the Ibanez WH-10, it looks great but no the good value, is it possible to get 10K with resistors on parralel?

http://www.banzaimusic.com/Wah-Pot-IZ-10.html

Thanks a lot

knopflergx · April 12, 2012, 04:17:50 PM

Hello!

Sorry, just one quetion:

what kind of opamps was used in the project?

There were no information about this.

Thanks a lot!

knopflergx · April 16, 2012, 09:07:27 AM

Quote from: knopflergx on April 12, 2012, 04:17:50 PM
Hello!

Sorry, just one quetion:

what kind of opamps was used in the project?

There were no information about this.

Thanks a lot!

Nobody knows?

Thanks!

Derringer · April 16, 2012, 04:41:26 PM

I don't think the circuit relies on specific types of dual opamps
the usual suspects will more than likely work just fine (4558, TL072 ... etc)

knopflergx · April 18, 2012, 03:31:23 AM

Quote from: Derringer on April 16, 2012, 04:41:26 PM
I don't think the circuit relies on specific types of dual opamps
the usual suspects will more than likely work just fine (4558, TL072 ... etc)

Thanks a lot Derringer, as i supposed...TL072 is the way!

knopflergx · May 18, 2012, 07:00:10 AM

Sorry guys, i'd like to build this but with positive ground.
Can you describe me step by step what I've to change in this layout?

I' want to use a positive ground to delete the problems with my powerpack...that are all in boos compatible style.

Thanks a lot.

fleeps · May 18, 2012, 08:51:49 PM

Quote from: daverdave on February 09, 2009, 04:08:35 PM
So this one works (finally)

missing image?

JimSalabim · June 23, 2015, 09:02:10 AM

Has anyone saved daverdave's vero layout (tycobraheparapedalveroue4.gif) and can post it again here?
This would be really amazing ...

JimSalabim · June 25, 2015, 10:41:02 AM

I have reconstructed the vero layout based on RG Keen's schematics from geofx and the small preview image of the vero layout which was still on Google.

StriKeR · October 11, 2015, 06:35:47 AM

I don't seem to find any 1N270 diodes here. Could you suggest an alternative? Also, the ground from battery and both audio jacks should be connected to the same spot on the veroboard?

italianguy63 · October 11, 2015, 06:41:00 AM

I believe I got my 1N270's from Tayda.

I would expect a 1N34 germanium would be a good substitute.

MC

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Tycobrahe Parapedal Vero