Bigfoot FX Magnavibe

madbean · Post by **madbean** » 21 Apr 2011, 14:12

LDR is under the resistor category

MullisMan · Post by **MullisMan** » 21 Apr 2011, 14:29

Thanks madbean, I see it now

I actually went back and added a part from the stock eagle libraries that I like better than gaussmarkov's. I have an updated schem and layout, perhaps a mod would like to delete the original, and I can post the new one along with the layout and transfer. I don't know what's wrong with my flickr links above.

culturejam · Post by **culturejam** » 21 Apr 2011, 14:37

Removed the old schematic/layouts.

As for why the Flickr link wasn't working, there was too much Flickr-centric code in the links. They should be whittled down to just this:

Code: Select all

[img]http://farm6.static.flickr.com/5183/5639232035_de56230ac7.jpg[/img]

[img]http://farm6.static.flickr.com/5223/5639805702_90b93af29e.jpg[/img]

MullisMan · Post by **MullisMan** » 21 Apr 2011, 15:20

Thanks culturejam. I've attached my eagle files along with a BOM, layout, and PCB transfer.

pietro_moog · Post by **pietro_moog** » 24 Apr 2011, 13:11

nice.
guys, could you suggest me an appropriate LDR for this project?
is there any filtering at all on the 9v dc?

KindaFuzzy · Post by **KindaFuzzy** » 24 Apr 2011, 14:21

No filtering on the stock unit, couldn't hurt to add if you're going to use a power supply. I couldn't recommend anywhere to order an LDR, since I get mine locally, but one with a big swing sounds best to me and is closest to the original. One that goes from about 1k-20Meg should be good.

pietro_moog · Post by **pietro_moog** » 24 Apr 2011, 15:19

thanks.
wow, 1k to 20M is a very large range. i'll get a cheap one and see what's happening

BernardBlack · Post by **BernardBlack** » 25 Apr 2011, 23:00

KindaFuzzy wrote:No filtering on the stock unit, couldn't hurt to add if you're going to use a power supply. I couldn't recommend anywhere to order an LDR, since I get mine locally, but one with a big swing sounds best to me and is closest to the original. One that goes from about 1k-20Meg should be good.

So, a 20M at dark is perfect?

KindaFuzzy · Post by **KindaFuzzy** » 26 Apr 2011, 00:16

Should be, as long as it gets nice and low with the led shining on it. I think I tried one that went from 500R to 2M and it was good too.

DimebuGG · Post by **DimebuGG** » 26 Apr 2011, 03:47

I got nothing to do so I made a layout on this little circuit..enjoy!

Notice, I didn't include the 4.7K current limiting resistor of the status LED. That won't be a problem, right?. Instead, I added pads for power supply filtering(marked in parenthesis).

pietro_moog · Post by **pietro_moog** » 26 Apr 2011, 17:24

nice.
i have a VTL5c2 unused, do you guys think it might work correctly?

greenskull · Post by **greenskull** » 26 Apr 2011, 23:37

pietro_moog wrote:nice.
i have a VTL5c2 unused, do you guys think it might work correctly?

Might be a good idea to throw this on the breadboard first in case you need to experiment with component values to make it work with your opto. At least install sockets for it on the pcb to swap it out easily if it doesn't work well with stock values.

pietro_moog · Post by **pietro_moog** » 28 Apr 2011, 23:25

hi guys.
do you think there'll be a difference between a 5mm led and a 10mm one?
i have a 5mm red ultra-bright so i think i'll give it a shot.
objections?

KindaFuzzy · Post by **KindaFuzzy** » 29 Apr 2011, 11:07

You can use it just fine, if you can live with the lower level of mojo.

culturejam · Post by **culturejam** » 06 May 2011, 14:52

I just noticed that Big Tone Music Brewery (the boutique brand operated by the owner of BYOC) has a Magnatone vibrato pedal:

http://bigtonemusic.com/maggie.html

The BTMB Maggie sounds exactly like the real Magnatone 280 because it basically is. We've simply translated the original circuit into a low voltage solid state form. Right down to replacing the 8 varistors that were in the original circuit with JFETs. The most important part of replicating the tone of real Magnatone vibrato is the dual phase LFO (low frequency oscillator). Without it, you cannot have the push-pull effect that gives the Magnatone its lush rich warble....not even when it's in normal(mono) mode. And you certainly can't get the stereo effect that the 280 had where the sound coming out of one speaker was bending the pitch up, while the sound coming out of the other speaker was bending the pitch down.

Sound convincing. Kieth generally knows his shit, so I feel like this would be a pretty damn good clone of the original sound.

pinkjimiphoton · Post by **pinkjimiphoton** » 15 May 2011, 20:11

hi guys, thanks for what looks to be an awesome project...i'm kinda a newbe still tho, and don't understand where the different parts of the schematic connect?
can anybody enlighten my idiot self?
thanks!!

pinkjimiphoton · Post by **pinkjimiphoton** » 15 May 2011, 21:23

ooops...brain death, sorry...too much blood in my caffiene system i guess...

i found the schem/layout, don't know how i missed the first two pages!!

thanks guys, i'm a-gonna get me the parts tomorrow and give it a whirl!!

RnFR · Post by **RnFR** » 16 May 2011, 02:01

culturejam wrote:I just noticed that Big Tone Music Brewery (the boutique brand operated by the owner of BYOC) has a Magnatone vibrato pedal:

http://bigtonemusic.com/maggie.html

The BTMB Maggie sounds exactly like the real Magnatone 280 because it basically is. We've simply translated the original circuit into a low voltage solid state form. Right down to replacing the 8 varistors that were in the original circuit with JFETs. The most important part of replicating the tone of real Magnatone vibrato is the dual phase LFO (low frequency oscillator). Without it, you cannot have the push-pull effect that gives the Magnatone its lush rich warble....not even when it's in normal(mono) mode. And you certainly can't get the stereo effect that the 280 had where the sound coming out of one speaker was bending the pitch up, while the sound coming out of the other speaker was bending the pitch down.
Sound convincing. Kieth generally knows his shit, so I feel like this would be a pretty damn good clone of the original sound.

no that sounds interesting. what do you think KF? you gonna flip for this one, too?

KindaFuzzy · Post by **KindaFuzzy** » 16 May 2011, 02:45

We'll see, once I sell the sweet, this may be the next on the chopping block.

The Rotagilla · Post by **The Rotagilla** » 17 May 2011, 01:33

RnFR wrote:
culturejam wrote:I just noticed that Big Tone Music Brewery (the boutique brand operated by the owner of BYOC) has a Magnatone vibrato pedal:

http://bigtonemusic.com/maggie.html

The BTMB Maggie sounds exactly like the real Magnatone 280 because it basically is. We've simply translated the original circuit into a low voltage solid state form. Right down to replacing the 8 varistors that were in the original circuit with JFETs. The most important part of replicating the tone of real Magnatone vibrato is the dual phase LFO (low frequency oscillator). Without it, you cannot have the push-pull effect that gives the Magnatone its lush rich warble....not even when it's in normal(mono) mode. And you certainly can't get the stereo effect that the 280 had where the sound coming out of one speaker was bending the pitch up, while the sound coming out of the other speaker was bending the pitch down.
Sound convincing. Kieth generally knows his shit, so I feel like this would be a pretty damn good clone of the original sound.
no that sounds interesting. what do you think KF? you gonna flip for this one, too?

Keith's been working on this for awhile. I have a schematic dated 2007 of the Maggie but no idea how much has been changed since then.

Bigfoot FX Magnavibe [traced]