Robert Cray's Magnatone Stereo Vibrato sound...

[jrod]

Is this kind of what you are looking for? http://bigtonemusic.com/maggie.html

Edit: Just noticed Kipper4 had posted a link of a youtube video of the Maggie.

[midwayfair]

Sure.  180⁰ is anti-phase.  So that when one side is at some maximum of whatever is being modulated, whether it be pitch or level, the other is at minimum.  With 90⁰ difference, what you get is one side essentially following suit with the other.  So, left is falling as right is falling and left is rising as right is rising, except lagging behind.  Although there is clearly a directional element to both, the over-here, NO! over-here, NO! over-here aspect to it is reduced with a phase lag, as opposed to phase-inverted relationship between the two modulation sources.

Make sense?

If you want proof of the shortcomings of 180⁰ difference, just see how long you can stand to listen to an Ibanez Flying Pan.  If you can put up with more than3-5min, you're a better man than I.

But what's causing this? It looks like two stages with two signals that are 180^o out of phase. What am I missing?

[Mark Hammer]

I think we're missing each other here.  What I was implying earlier was not what the Magnatone does, but what might sound good, or even better, than what's out there.  Smaller phase differences between left and right tend to produce more listenable effects; i.e., less listener fatigue

[Dave W]

Boscorelli's "Stompbox Cookbook". Project 30. "Vibrato-Matic". Have a look.... 

[tca]

Here is the patent: https://www.google.com/patents/US3146292

[R.G.]

Yep. The Magnatone vibrato is just phase shift introduced by the vacuum tube variant of the Univibe phase shift stage. The LDRs are replaced by "varistors", those being voltage variable resistors in the form they were first used, not the modern sharp-edged protection varistors.

I've built a tube variation of the univibe using LDRs instead of Magnatone's varistors. No reason that could not be reduced to pedal size.

Magnatone amps and their effects are not mysterious, only under-understood.

[duck_arse]

here it is.....45⁰

Not on your keyboard, but on the 2nd row of icons for posting, just above the "undecided" face, and below the centre-justified icon.

what, so I need to post just to see it ....... ah. ok. as for all the left of second row above squre, it's not.

I think when mark said

My gut sense is that one moves closer to an "animated", rather than "seasick" sound

he hit the, well I won't say nail, but anyway. I've played with the seasick before. since asking the question, I did think of a 4 stage divider, with switch-selectable gating so that you can have 90* or 180* outputs. it's the bit coming after that makes it sticky.

carry on, back to 180*.

[Mark Hammer]

Maybe the most "animated" stereo sounds come from using two unsynchronized-and-smoothed S&H units (which can still be fed from the same noise/random-voltage source), or two of these: http://www.cgs.synth.net/modules/psycho_lfo.html