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Tried out an experiment today and am I ever glad I did. I've been gradually assembling a little lunchbox amp in a cute little wooden box I bought at Dollarama for $3. It has a pair of big-magnet 3" speakers purloined from some computer speakers, powered by a pair of 2W amps. Since I wanted to run it in stereo, I wondered what I could do to enhance the stereo feel. I settled on running a pair of unsynced Magnavibes, one per channel. Spent much of the afternoon and evening perfing them up, and just fired them up, plugged into two different amps. Lordy, lordy it's gorgeous. Rich, in a way that compels you to play clean, because you don't want a single moment of it to be obscured by anything else. A bit of reverb, maybe, but that's it.

The Magnavibe is a subtle vibrato, using an optical phase-shift stage, adapted from the old Magnatone amp. On its own, in mono, it gives a pleasant jiggle to the sound. In stereo, though, instead of jiggling in one place, it moves around. It's like if your guitar was a snowglobe. Of course, once I move it from the free-standing board feeding two amps a few feet apart, to the eventual enclosure where the speakers are about 4" apart, finding the sweet spot will be a little trickier.

All of that said, it's not a Jazz Chorus, but it's nice and swirly.

 

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One of the advantages of being able to build: when yuh age a sound in your head you just put it together. Nicely done. Make sure to post pictures
 

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Discussion Starter #3
I will. I'm having some difficulties biasing one of the FETs in the preamp feeding the stereo arrangement. If I get it fixed tomorrow, I post some stuff ASAP.
 

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Cool. Magnatones are so amazing. I didn’t know about that pedal. I also love running two amps set far apart with any kind of warbley stereo vibes and choruses etc.
 

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Hey!
Been a while lol.
Mark a few years ago I built a magnavibe, but was never able to get the kind of depth you hear in that video.
I saw on another forum you used a red led and 500k dark ldr, if I recall correctly.
I used a white super bright and 1 meg dark ldr, but tried a bunch of different leds.

My next step would’ve been adding more Ldrs and leds, but I got sidetracked by kids n stuff.

Are you getting the kind of wobble with your work as I’m hearing in that video?
Mine at full depth sounds like the video one at half, and from what I saw at the time online,
That’s common for diyers with this circuit.
 

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Discussion Starter #6
I'm getting about 2/3 - 3/4 of the depth heard in that demo. Part of that is the compatibility between the wavelength of the LED and the maximum sensitivity of the LDR, unless one uses an actual sealed vactrol. Many LDRs will like something in the orange-ey green range, with white providing only a bit of the needed spectral content.

I may well get greater depth once fully installed inside the chassis. All I have to make the LED/LDR "lightight" is a simple piece of black heat shrink around the LED, with the round end of the LED ground off flat to lie the LDR flush against it. Perhaps in the darkness of the amp chassis, the contrast between more and less LED illumination will result in greater depth. As the orange guy says "We'll see what happens."

We're going to be in Stoney Creek on the 27th -29th. If I can get the thing running properly this week, I'll bring it along. Maybe we can touch base while I'm in town. I'm sure the in-laws will tire of me at some point.
 

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Certainly not the same thing, but this has got me thinking of cooking up 2 vibes w/ different modulation frequencies in series in my Zoom pedal & seeing what happens.
If it were possible to pan one left & one right, that would get closer, but that is not to be...
 

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All I have to make the LED/LDR "lightight" is a simple piece of black heat shrink around the LED, with the round end of the LED ground off flat to lie the LDR flush against it.
I've had LEDs go dimmer after being ground down... no idea why, as I didn't get near the diode itself - but have switched to using Flat-top LED's to be safe.
 
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