phaser schems with no IC's? and univibe Qs

[sunder]

Are there any phasers which use only discrete components, will say only transistors and no ICs whatsoever?Besides the univibe?

While we're at it, I think about simplifying the Univibe circuit to use only two stages. That's obviously pretty easy... but can I simplify the preamp section, too? Like using a standard booster schematic (LPB) followed by a phase splitter stage?

Would a Univibe phase stage also work with only one tranny?

Could I use a different LFO?

[gez]

I've built discrete vibrato circuits in the past and two stages is pretty subtle so I don't think two stages (phase splitter type circuit that is) would give you a very strong phase effect.

As far as I'm aware you can't get a phase effect with just one stage.

I used MOSFETs for phase splitters - enables you to get high input impedance so you don't need a buffer.  But there's no reason not to add one if the input impedance of your circuit isn't that high.

Most phasers use triangle LFOs, but that's more out of convenience than anything.  Uni used a sine and there's no reason not to in a circuit of your own devising.

[Mark Hammer]

I think Jurgen Haible has an all discrete phase shifter schem posted.  Do a search under his name and it should pop up.

[B Tremblay]

Check out the Phozer at runoffgroove.com

It isn't really a phase shifter, but can sound like one and has no ICs.

[sunder]

I've built discrete vibrato circuits in the past and two stages is pretty subtle so I don't think two stages (phase splitter type circuit that is) would give you a very strong phase effect.

not even when adding feedback?

[gez]

I never developed it into a full-blown phaser, but the fact that the vibrato was subtle suggests that the phase effect wouldn't be that strong.  Who knows?

[sunder]

It doesn't need to have phase90-like intensity...  I like subtle phasing. I think using feedback it will go pretty wild, perhaps even "self oscillate".
:twisted:

har har, a primitive stripped-down univibe with a feedback knob...

[Transmogrifox]

Yeah, you could probably add some kind of a REGEN feedback thing to a Univibe.

I thought I saw something about FET phasers at GEO or something.  I KNOW I have seen a phaser using discrete components as a link from schematics or schematics2 from this forum.

[sunder]

hmm... I didn't find the Jurgen Haible post, nor the schem that transmogrifox talked about...

for adding a feedback knob to the univibe, I would just take the output from the last phase stage and feed it back to the preamp, right?

How about the pot? The wiring I mean? Would a 250k pot between phase stage output and ground, with the wiper going back to the input, do the job?

[sunder]

HA! I found something!

The Carlin Phasor (on the schems page). Looks suspiciously like a Univibe!

[Mark Hammer]

http://www.musicsynthesizer.com/Diode%20Phaser/Diode%20Phaser.html

Not sure if that is "IC-less" enough for you.

[Lurco]

two stages. That's obviously pretty easy

Which stages, I mean the ones with which capacitor values are you going to use, when only using two?

[sunder]

http://www.musicsynthesizer.com/Diode%20Phaser/Diode%20Phaser.html

Not sure if that is "IC-less" enough for you.

:shock:

I guess I have to take some more EE courses! That's a bit over-sophisticated for me. But thanks for the link, it's nice to have something to aspire to.

[sunder]

two stages. That's obviously pretty easy

Which stages, I mean the ones with which capacitor values are you going to use, when only using two?

well, I would probably experiment with the cap values until it sounds right.