No love for the Maestro PS-1?

[Cliff Schecht]

I had the "pleasure" recently of recapping and revamping an SG Systems 4x10 hybrid amp (SS preamp, tube power amp). The amp is from the early 70's and looked more like an oven than a tube amp. TBH it wasn't a bad sounding amp, better than many current offerings, but wasn't anything too special.

But! There was a redeeming trick that made this amp special. Tucked over in the right bottom corner were knobs for slow, medium and fast. Little did I know when I took this repair on that this was essentially a Maestro PS-1 built into the amp. I've never heard (knowingly) or played one of these before but I was knocked out of my seat when I heard how friggin good this phaser sounded. The slow setting was super lush and full, as was the medium setting, and the fast setting was way into Univibe territory. I had a blast playing on that phaser and really it put my Boss phaser to shame, which isn't a bad sounding little box (maybe IMO ).

Another really cool little trick is that when you go from one speed to the next on this phaser, the unit ramps up and down like a Leslie. Not sure why the designers felt the need to do this but it's a unique touch and sounds cool.

So I've seen a little bit here and there about the Maestro Phaser, but I haven't really seen very much discussion on this forum about it. Why is that? I know they were (and are) expensive but isn't that why we clone in the first place?

If it hasn't been done before I'd like to work up a clone for this. I've seen the schematics Mark has posted and I think I can get started just from those. I'll probably try to redesign the PS-1 schematic (+/-12V one) for single supply 9V operation using modern equivalent parts. Seems reasonable enough, minus finding suitable JFETs that will work in this circuit. Anybody have any suggestions here for a modern equivalent to the FET they used (not labeled in the schematics ).

[Cliff Schecht]

See what I mean?!? C'mon guys, you don't want this sound on your pedalboards?

[geertjacobs]

Some nice links on the PS-1:
http://www.wingspreadrecords.com/maestro_ps1_page.html
http://www.wingspreadrecords.com/maestro_tech.html

The soundclip makes me want a PS-1... and a Fender Rhodes  

[Chugs]

I love that phaser!!!!!!! Got outbid on one on ebay years ago. Sniped at the last second by 0.01 US cent. Back when you could do that on ebay. 

[Mark Hammer]

My first encounter with it was going to see the Mahavishnu Orchestra in 1973, and trotting down to the stage to see what the rig was.

I suspect the "absence of love" is a result of: a) not knowing what the heck the FETs were, or what could sub for them, and b) the preset speeds.  Probably the size had a bit to do with the unpopularity of the original, when you compare it to a Phase 90.

Insomuch as early phasers were often intended to sub for a Leslie, the ramping feature was kind of a natural.  I have that feature on the pearl PH-044 phaser I got recently, and it's really nice.  The recent issue Keeley phaser also has ramping, as did the old Boss AP-7.

[garcho]

subscribe, booya! way to go Cliff, single supply wizard

ramping!

[Morocotopo]

Been looking at the schem. Doesn´t seem too difficult to recreate... I guess that it´s a matter of finding the right modern FET equivalents. Or those had some particularities? It even seems easy to test on the breadboard.
So much effects, so little time...

[garcho]

2N4303?
matched?
Small Bear

[jbgron]

I have one of these beautiful phasers, got it for $25 at a garage sale    I'll take some gutshots if anyone is interested?

[rogerinIowa]

someone gave me one of those sg systems amps, it has the Maestro phase too. I just sold off the footswitch on Evilbay, but the amp is sitting at our rehearsal warehouse unused...I could take photos of the innards if that would help? maybe you already did when you did the cap job?

[Dave W]

Lots of interest in this one!

[Cliff Schecht]

Just finished playing with some sims of this circuit with both a single and dual/split supply. From what I can see it is not a huge stretch to convert this design pretty much as is to a single supply design. I'm going to modernize the non-critical signal path bits with op amp circuits to try to keep the noise floor down because with a reduced supply voltage you also get a reduction in SNR. I'd like to go the other way and get a nice lower noise version of this circuit that (hopefully) others will agree is otherwise functionally similar.