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DIY Stompboxes => Building your own stompbox => Topic started by: Devius on March 26, 2013, 11:26:54 PM

Title: Magnavibe.
Post by: Devius on March 26, 2013, 11:26:54 PM
I have this delightful little marvel penetrating my breadboard. Sounds awesome.
However, when I crank ye ol' depth knob full counterclockwise, the led lights right up, to the point of always on. No pulse, no magic, it's killing my buzz.
would I replace the resistor from v+ with something higher, or is it a bit more complex-icated than that?
Title: Re: Magnavibe.
Post by: deadastronaut on March 27, 2013, 04:53:57 AM
that's probably how i'd attack it...but first try another led in series/para, if it works you've got a nice indicator led too.. 8)


ive been looking at this little circuit to breadboard too...just waiting for space..
Title: Re: Magnavibe.
Post by: haveyouseenhim on March 27, 2013, 06:05:23 AM
Quote from: deadastronaut on March 27, 2013, 04:53:57 AM
that's probably how i'd attack it...but first try another led in series/para, if it works you've got a nice indicator led too.. 8)


ive been looking at this little circuit to breadboard too...just waiting for space..

I have built several and that's how I do it. Just wire it in parallel and have it go to the third pole of the stomp switch for bypass and rate indication.

But I don't think that's his problem. I would just put maybe a 1K resistor in series with the depth pot


What layout are you using?

EDIT   I just re read that it's on your breadboard. I highly recommend nocentelli's vero layout. Has never failed me.
Title: Re: Magnavibe.
Post by: midwayfair on March 27, 2013, 10:24:14 AM
Phase shift oscillators have a habit of conking out when too much voltage/current is allowed to pass. The minimum resistance I can get to reliably work in the Magnavibe even with a superbright indicator LED is 1.8K. I just use 2.2K because any lower and the depth will affect the speed (and also be ironically less deep).

Note that there's also a minimum resistance on the speed? Same idea.
Title: Re: Magnavibe.
Post by: deadastronaut on March 27, 2013, 10:27:34 AM
@jon, interesting, i'll have to try this little circuit out..cheers man.  :icon_cool:
Title: Re: Magnavibe.
Post by: Devius on March 27, 2013, 11:20:17 PM
I already tried the led to no avail however I will probably end up using it as a rate indicator.
I'll muck around with the resistance in that area and see whats what.
Quote from: haveyouseenhim on March 27, 2013, 06:05:23 AM
Quote from: deadastronaut on March 27, 2013, 04:53:57 AM
that's probably how i'd attack it...but first try another led in series/para, if it works you've got a nice indicator led too.. 8)


ive been looking at this little circuit to breadboard too...just waiting for space..

I have built several and that's how I do it. Just wire it in parallel and have it go to the third pole of the stomp switch for bypass and rate indication.

But I don't think that's his problem. I would just put maybe a 1K resistor in series with the depth pot


What layout are you using?

EDIT   I just re read that it's on your breadboard. I highly recommend nocentelli's vero layout. Has never failed me.

I've gotten into the habit of making my own layouts. So far so good.
Title: Re: Magnavibe.
Post by: duck_arse on March 28, 2013, 11:24:28 AM
I'm playing with phase shift oscs again, and I found the 2 transistor circuit used in the vibecaster provides a MUCH sine-ier signal than the single transistor version. although at slightly less output level, which may not be a led driving problem. as you're on the breadboard, you could give it a go.

I can't see a circuit for the magnavibe, so I'm not sure your osc circuit.
Title: Re: Magnavibe.
Post by: nocentelli on March 28, 2013, 06:10:23 PM
I've always used a handrolled optocoupler, and find it's fairly easy to adjust the depth by fiddling with the proximity and orientation of the the LED/LDR pair: However, most people complain that they're not getting ENOUGH depth, not too much.
Title: Re: Magnavibe.
Post by: Devius on March 28, 2013, 08:29:18 PM
I stuck a 1k resistor in series after the led, seems to work fine. All I'm after is getting an even taper from the pots so they don't "jump" to lightspeed.
Quote from: duck_arse on March 28, 2013, 11:24:28 AM
I'm playing with phase shift oscs again, and I found the 2 transistor circuit used in the vibecaster provides a MUCH sine-ier signal than the single transistor version. although at slightly less output level, which may not be a led driving problem. as you're on the breadboard, you could give it a go.

I can't see a circuit for the magnavibe, so I'm not sure your osc circuit.
I googled magnavibe and found the schem. I'll check out the vibecaster.
I'm also working on the vicovibe... which sounds like a trem. I like these low-part sweet effects.
Title: Re: Magnavibe.
Post by: deadastronaut on April 04, 2013, 05:59:08 PM
yeah that vico vibe is a tremolo, going by the videos ive heard..

be nice to get both the vico and magnavibe in 1 pedal... :icon_idea: