mutron phaser II question

[pinkjimiphoton]

hi guys, i've been eyeing these things for years since i sold my last one probably 20 years ago.
doesn't look impossible... i'd like to try and vero the sucker.
but i had a question...

i see it has 6 separate dip ic's in it. could i use a quad oa for the actual phase shifter stages, if i keep the  lfo separate?
i know it's probably a retard question to ask, but sadly, i'm just the guy to ask it.

seems like it would be a lot easier and save quite a bit of board space, especially on a vero!!

here's the schems i'm lookin' at...






also, i don't understand where you connect the lfo to... is there something i'm missing?

i'm thinking charge pump for power supply, too...

any caveats? i really loved the sound of these things..

[digi2t]

Probably best to keep everything seperate. This is similar to the Infinitphase, and on vero, I still had to add a cap to squelch the ticking. That, and lots of shielded wire. Everywhere.

Look at the Infinitphase schematic (available at Prophesysound's website), and you'll see lots of similarities. I say if you're looking at this, and your mouth is watering, then just go all out and build an Infinitphase. I know it's a monster build, but you'll never want for another phaser, for as long as you live.

Promise.

[Processaurus]

I like the Phasor II!  I don't see why combining the phase shift stages and input stages in quad opamps would hurt anything.  Also don't think using dual opamps would be much different though, price wise or time wise, and they might make the layout easier.  You already have the right idea, the important thing is separating the LFO opamps from the signal opamps.  It would be a good idea to locate the LFO as far away, physically, from the input, and to star ground it back to the power supply.  Could even build a little grounded tin hood for it if there were problems.  As far as going crazy using shielded wire everywhere, I would wait to have problems, maybe initially just use it on the input, because it is high impedance.  The phase shift stages are fairly low impedance.

One thing that would probably make a clone sound better, is 1% resistors in the phase shift stages, and vactrols or LDR's that are matched or nearly matched in response, so each stage is shifting the phase equal to the others.  A similar idea to matching the FET's, in FET based phasers.

For the power supply, a charge pump would probably be just fine.  Those, like the LFO, should get star grounded back to where the power supply comes in, and it is good to locate the charge pump circuit there too.  They can put noise into the signal above the audio spectrum, but the 830pF cap in the output stage would probably filter that out.

[armdnrdy]

I built one a few years back. Sounds great! This is the schematic that I used:



Sorry It's a bit messy (I cleaned it up a little today) I just started using Eagle...and was far from proficient!  

Edit:
C22 sets the charge pumps frequency. (to get it out of the audio range) Use a 5-25pf ceramic cap. Use the smallest cap to achieve quiet operation and best efficiency.

[pinkjimiphoton]

thanks brothers...
dino... it's more phaser than i would know what to do with!! and WAY too big to fit on my pedalboard (which is important!!)

ben...thanks for the headsup(s) i think this looks do-able, and this was my FAV phaser of all the ones i ever owned.

larry... thanks bro, if you built this, i know i can trust it!!!

gonna start trying to suss it out soon i hope...thanks for the advice!!

[alanp]

Jimi, Bangarang101 and Madbean did a layout for this that uses a 9VDC power supply (uses a TC1044SCPA charge pump), and normal LDR's (not the VTL stuff, which costs.) Haberdasher can etch the boards for this.

If you want to do vero, though, that's cool

[armdnrdy]

But....

Does that layout fit in a 125B? 

[pinkjimiphoton]

i'm hoping to get it to fit in one of my beloved rat-shack boxes!!!



larry.... that looks sweet!!

i still wanna try and see if i can work up a vero tho, with a quad (maybe 2 for double the stages?) opamp for the stages, and i'm thinking a separate board for the LFO, and isolating it inside it's own little faraday cage made from some grounded lightweight steel i found at lowe's.

[armdnrdy]

and isolating it inside it's own little faraday cage made from some grounded lightweight steel i found at lowe's.

I don't think that will help for charge pump noise. That's more for transformer noise.

What you have to watch out for is proper routing, grounding, and filtering.

[pinkjimiphoton]

i was thinking maybe to help nuke some of the lfo ticking. remember, this is ME we're dealing with here bro!! lol

[newperson]

larry l,
do you have a link to that layout?