Bigfoot FX Magnavibe

Nocentelli · Post by **Nocentelli** » 12 Apr 2011, 16:14

Haha - To clarify - The second (verified) layout is correct in terms of pin-out.

When you swap the transistors, the LED should start flashing immediately. If it doesn't, I'd then swap the LED around. Also, you'll probably get more depth if you have the LDR facing the LED straight on.

Nocentelli · Post by **Nocentelli** » 12 Apr 2011, 16:17

...also I've just tried it out through a bigger amp at higher volume, and there is some quiet, but noticeable ticcking/brrrr-ing: I'd definitely try out some power filtering...

kinski · Post by **kinski** » 17 Apr 2011, 16:14

Hmmm....okay....turned the transistors around and it all works now. The only thing is, there is not much "vibrato" going on. Its sounds much more like an okay sounding tremolo...even with the depth all the way up. What could the cause of this be? I'm using a bright white LED.

Thanks!

kinski · Post by **kinski** » 17 Apr 2011, 16:18

Does the 27k resistor on the Speed pot connect to all 3 lugs? Thats how i have it wired.

kinski · Post by **kinski** » 17 Apr 2011, 16:37

Okay, noticed another strange thing....the LED flashes even when clicked off to bypass. WTF?

Nocentelli · Post by **Nocentelli** » 17 Apr 2011, 18:16

kinski wrote:Okay, noticed another strange thing....the LED flashes even when clicked off to bypass. WTF?

That's totally normal: The flasher circuit runs all the time.

As far as a lack of depth, the LDR type and LED brightness will affect the maximum depth of the effect. You need to have the LED facing the LDR directly, preferably taped together or surrounded in shrink-wrap. My LDR is labelled 24k-72kOhm (1M), and at maximum depth the effect is a fairly seasick vibrato.

kinski · Post by **kinski** » 17 Apr 2011, 18:27

Hmmm...im using a Photocell Silonex NSL-7532....would that not work? Are they not often used in Univibes, etc?

kinski · Post by **kinski** » 17 Apr 2011, 18:29

From the pictures from the degoop, it looks like that is what is used.

Also, with the depth all the way up, it gets pretty choppy, but its more of a tremolo...not much ,if any, pitch bending.

kinski · Post by **kinski** » 17 Apr 2011, 20:49

alright, tried another photocell, and no improvement. It just made the choppyness of the "tremolo" a little bit less extreme. But still no vibrato!

kinski · Post by **kinski** » 19 Apr 2011, 16:07

Okay, so it does work just fine. Its just much more subtle than I thought. I moved the led and photocell around a bit and got sounding pretty good. Anyone find a good color led to use? Whats the original use? The white one im using does not sound so good when the depth is up all the way.

KindaFuzzy · Post by **KindaFuzzy** » 19 Apr 2011, 23:07

kinski wrote: Anyone find a good color led to use? Whats the original use?

Original had a superbright red waterclear 10mm. I think I used a superbright yellow 3mm in the one on my breadboard since the LDR I had was pretty small.

kinski · Post by **kinski** » 19 Apr 2011, 23:12

nice! thanks! I've got a 5mm Clear Red, that i'll try. I did not like this circuit at first, but its REALLY starting to grow on me...

culturejam · Post by **culturejam** » 20 Apr 2011, 00:01

Has anyone drawn up a unified, electronic format schematic for this one?

RnFR · Post by **RnFR** » 20 Apr 2011, 00:22

not yet. I volunteered earlier, but have been busy on other projects. sorry about that! feel free to take the reigns, if you're willing.

MullisMan · Post by **MullisMan** » 21 Apr 2011, 03:26

Will this do?

*mod edit: old version deleted

bigorangefan79 · Post by **bigorangefan79** » 21 Apr 2011, 04:10

MullisMan wrote:Will this do?

Looks good to me... but the LDR is a light dependant resistor, not a capacitor.

MullisMan · Post by **MullisMan** » 21 Apr 2011, 04:18

I know

....I didn't have a parts library for an LDR so I just went with what was handy.

MullisMan · Post by **MullisMan** » 21 Apr 2011, 04:25

Here's a layout and transfer as well if anybody's interested. Should be able to fit it into a 1590A. This layout isn't verified however.

*mod edit: old layouts removed

culturejam · Post by **culturejam** » 21 Apr 2011, 13:55

MullisMan wrote:I know ....I didn't have a parts library for an LDR so I just went with what was handy.

The libraries that are available in the link below have LDR included (as well as all sorts of other awesome stuff):
http://gaussmarkov.net/wordpress/tools/ ... libraries/

MullisMan · Post by **MullisMan** » 21 Apr 2011, 13:58

culturejam wrote:
MullisMan wrote:I know ....I didn't have a parts library for an LDR so I just went with what was handy.
The libraries that are available in the link below have LDR included (as well as all sorts of other awesome stuff):
http://gaussmarkov.net/wordpress/tools/ ... libraries/

Hmm....I actually use gaussmarkov's library and I couldn't find any LDR parts in there. I don't see any description for it on that page either. I've looked in the categories but couldn't locate one. It's probably hiding right in front of my eyes

Bigfoot FX Magnavibe [traced]