single stage phase shift? who thinks this is worth building?

[lightningfingers]

i found this on the net..............

http://topnet.com.au/~hairbear/orgtrem.4.jpg

its from EA, think its worth a shot? what does 1 stage sound like?
how big a shift will it have?
after all EA gave us their almost sacred tremolo..........

[zachary vex]

one stage phasing sounds like a flipped phase switch.  it does something, but very subtly.  next time you get a chance, flip a phase switch on a mixing console and listen to the effect in the speakers.

that's a very complicated circuit for what it does... a modern version would have 1/3 of the parts count and could actually run off a 9V battery (that light bulb will require an adapter).

[lightningfingers]

thanks dude :mrgreen:

think ill give that one a miss then

[gez]

I re-jigged that circuit many a moon ago using a LED and MOSFETs.  I think I did the audio part using a 4007 (not the best chip for audio but it was something to do), and used one of the MOSFETs from it to drive the LED.

Sounded ok, you can hear vibrato and it had a slight Leslie vibe (no pun intended) to it.  Only breadboarded it though (wasn't worth building).

[puretube]

one stage phasing sounds like a flipped phase switch.  it does something, but very subtly.  next time you get a chance, flip a phase switch on a mixing console and listen to the effect in the speakers.

that's a very complicated circuit for what it does... a modern version would have 1/3 of the parts count and could actually run off a 9V battery (that light bulb will require an adapter).

AHH!! ...finally a topic to disagree with you, Sir! ...

[zachary vex]

AHH!! ...finally a topic to disagree with you, Sir! ...

ok.  umm... so what part do you disagree with?  8^)  the flipped-phase switch console thing?  or the parts count business?

[Tim Escobedo]

I've never tried it. But I've wondered how much could be squeezed from one or two stages. The old Magnatone amps seemed to have two stage "vibrato" circuits, done with tubes and varistors.

[gez]

But I've wondered how much could be squeezed from one or two stages.

You can get a noticeable vibrato effect with just one stage but it's subtle.  Although two all-pass op-amp stages give a more pronounced vibrato, I preferred the one stage phase-splitter.

I'm not a huge fan of electronic vibrato though (which is why I didn't build it), so I like it subtle (op-amp vibrato sounds sickly to my ears).

[puretube]

Fellers: we gotta distinguish beteen "phase-shift" and " vibrato", here!

[gez]

Fellers: we gotta distinguish beteen "phase-shift" and " vibrato", here!

I agree, but the schematic is for a vibrato...

[puretube]

Sir Gez: I`m not argueing with thee, but with Z...

(because the question was more about the shift,
than the pitch)

in fact: the answer is: max 180 degrees

[zachary vex]

oh, well a phase shift button on a recording console is exactly 180 degrees.

[puretube]

...but it (the console-button)
1.) doesn`t "shift", but "flip", or "swap" to either 0 or 180;
2.) does so for all frequencies alike;

while that circuit, lightningfingers asked about,
1.) continuously varies the phase-shift gradually from 0 to 180;
2.) shifts the phase of each frequency by a different amount of degrees
    for a certain value of the LDR;

btw.: if you mix (add) the vibrato output of that circuit with the dry
signal, you indeed get a phaserish sound (very subtle, though)  :wink:

Magnatone never mixed (added)those 2;
They built diff. circuits: 1stage or 2stages;

[zachary vex]

i agree.  but rather than build the thing, push the switch, hear what 180 sounds like at the extreme, make up your mind if it is interesting.  8^)

i know what you mean, though.

[lightningfingers]

what about this one?

its from EA also..........  

looks kinda like a univibe w/ 3 stages

question: why 3 lamps? why not just use one lamp in a lightshield?

[puretube]

..they thought it`d be easier to mount 1 bulb to 1 LDR;
...easier PCB layout;

note: its not univibe-ish, since the 3 caps are identical...

btw.: the ear is not sensitive to the absolute position of a phase,
but to the transition (movement);

phase-modulation in RF is regarded to offer the same effect as
freq.-modulation...

[zachary vex]

exactly... the moment of phase transition as the button is pushed in is when you listen for the phase change.

[petemoore]

So is there any real use for them...what about a couple or three ofem?

[puretube]

exactly... the moment of phase transition as the button is pushed in is when you listen for the phase change.

now do this abrupt scenario about 3 to 10 times per second, and you`ll hear the "overmodulation" type of throb-trem, which you can achieve with the new E-H Pulsar, in squarewave-mode with depth all maxed out...
(the Pulsar can approx. go from 0.15 to 40 Hz)

[puretube]

So is there any real use for them...what about a couple or three ofem?

real use for it was in magnatone-amps (either 1 or 2 stages),
and I happen to know a nice currently produced pedal, which got 3...