Craig Anderton Envelope controlled Phase Shifter

[MAO]

03/30/2018 added an updated/improved layout below (but larger)

03/12/2018 Updated cuts view (Thanks velouriafx!) And removed the mirrored image layout

Probably my favorite from Craig Anderton's book Electronic Projects for Musicians.

I've combined both the Envelope Follower and Phase Shifter into a single vero, and updated to use TL074s and a LT1054.

With the Envelope Follower engaged, the amount of phase sweep is controlled by your picking dynamics. Adds a whole new dimension. This in itself makes this pedal a winner (IMO).  Also, with the resonance up high, you can get talk-box like sounds.  

The book suggested using a SPDT switch to engage the EF, I use a 3PDT stomp switch. I have it setup so when not using the Envelope Follower, it's removed from the signal path and the input of the LM356 is grounded. It's not necessary, a SPDT is all that is required if you don't want a 2nd LED and leave it connected to the phase shifter's input at all times.        

The original Phase Shifter's optos were CLM6000s, I've used NSL-32s in the past. Going to try Tayda LDRS and GL5516s when I get a chance.  

The socketed components allow for tweaks as described in the book. I also socketed the four 10nf caps so Univibe values (15n 220n 470p 4n7) or Voodoo Vibe values (15n 100n 47n 4n7) can be subbed.

The Vibe, Filter, Speed and Envelope switches are all optional:
If you don't want the vibrato option, connect the 2 vibe wires together. Omit the Vibe Switch.  
If you only want standard phasing and not the filtered option, connect the wires for Filter SW 2 & 3 together. Omit Filter SW-1 wire from the board and the Filter Switch.
If you want just the filtered sound and not the regular phasing sound, connect wires 1& 2 together, and omit wire 3 from the board and the Filter Switch.
The original 10u LFO "speed" cap is shown with an *. If you add the DPDT speed switch, you should lower the value of the 10u cap, and switch in higher value(s) in parallel as shown on the Speed Switch diagram.  If you don't want the speed switch, omit the 2 wires, switch and the two extra caps (C2 &C3).
And last, if you want the have the envelope follower engaged at all times, connect Envelope SW wires 7&8 together, connect sensitivity lug 2 to the Envelope SW 6 board connection and Sensitivity lug 3 to the 2nd input board connection. Omit Envelope SW-9 wire from the board and the Envelope Switch.    

The layout was designed to be rotated CCW and fit into a 1590BB.

Verified by me


03/12/2018 - Updated cut's view



Sample layout - tribute to Crag Anderton for getting my started and Brain Wampler for re-igniting the fire.

[H.A.M]

Wow! GREAT LAYOUT! thank you man. Hope to build it soon.
I'm already busy with finishing a Naughty Fish  (madbean pcb / Mutron III) and going to start on a Liquid Mercury Tap Phaser (Alex80 layout / David Rolo)

One thing, ... since it's verified by you, shouldn't it be in the verified section?

[Neil mcNasty]

Cool layout!
But...
The main layout picture is too small (low size & resolution) to be readable/usable.
See if you can make the file bigger...

Looking forward to building this.
Any chance for some kind of demo?

[MAO]

Thanks,

FWIW, I'm reworkings Alex's Liquid Mercury layout to accommodate LDRs. Like Mark had done with JohnK's Mutron II layout.

Should have the layout finished tonight, hoping to knock it out next week.

I'll record some sound samples of the Phase Shifter next week too, or maybe tomorrow :0)



 

[Kinski]

Whoa! Amazing!

[MAO]

I got back to this today and tried some LEDs and LDRs. None of them sounded all that good. The LEDs all seemed too dim, couldn't get the superbrights to go bright, they were also very dim.

The NSL-32s sound better at the moment.

The envelope control is sort of working with the Phase Shifter in the "subtract" mode, but isn't doing much in the "Add" mode...something is off because this was the best sound when I originally built the pedal, and really the whole point in building it again!

More later...  

[MAO]

Well, turns out I was losing the -9Vs. No shorts, but when I had both TL074s connected, the -9v would drop to -0.7v. If I removed either one, the -9v would re-appear. (-7.7v to be exact)

I remembered just reading about decoupling caps in a followup letter (by Charles Hansen) to the JamMix article. Page 14 Electronics Now - 04/1997

I added a 1u monolithic cap from pin 11 to ground on the upper TL074 and the voltage came back to -7.7v. I then tried a 10u electrolytic and the voltage is now -8.3.

MAybe this is a known issue with charge pumps, but 1st time I've run in to this sort of thing. Going to do some further research but it seems Charles Hansen's suggestion is on to something. Funny how things work out, I literally just read that article a couple weeks ago.

I'll post an updated layout with the additional cap(s) once I have it sorted out.

 

[velouriafx]

Hey, MAO. Any news?

[velouriafx]

I mounted this one and it did not work, but the layot ​​with the components is different from the cuts. The cuts below TL074 are different. Which one is right?

[MAO]

CONTENTS DELETED

The author has deleted this message.

[velouriafx]

Hi, MAO. Thanks for your attention. The layout with cuts has a few cuts misplaced. The cuts below the 10uf and 10pf caps are wrong. I fixed my board using the left layout and it worked perfectly. Thank you so much for the layout. The effect is fantastic, I will change some values ​​to see how it sounds according to your notes.

[Addy Bart]

Is there a larger image of the layout?
Edit: I see it now. Thanks MAO.

[MAO]

Ouch, so sorry for that velouriafx, looks like that whole block of cuts was shifted down 1 row. Really glad you were able to still work with the layout though!

I updated the cuts view and removed the reverse image view.

What LEDs/LDRs did you go with?

[MAO]

Also, I borrowed the original pedal I had built in the mid 90s using PAIA etched layouts. I will post the voltages and if possible the LDR readings later this week.

Haven't opened it up yet, everything still works, but it's a noisy bugger.

I was surprised to see that it's powered with 16v AC!  

Can't wait to see how I converted the AC to +/- voltage.  Don't remember doing that, but that was way before I discovered charge pumps.  

I'll have to post some pictures of this beast just for kicks...    

[velouriafx]

I used the 5mm LDRS from Tayda and diffuse red LEDs. I'm thinking of some way to change the offset to decrease the time the LEDs are off. At the beginning of the course of the pot, the time the LED is off is much greater than on and the wave is well squared. I wanted to leave it a bit lush to sound like a more traditional phaser. The Envelope is cool, I got good vibe and tremolo settings, but the phaser still did not please me. Maybe changing by high brightness led, the transition will be better.

[MAO]

I was having the same issues trying to use LEDs and LDRs. Never did find a combination that worked all that well with the circuit as is.

Didn't think about modifying the offset though, let me know if that works out.

One thing I had noticed is the original opto isolator used in this project (CLM6000) had a light resistance of 500 ohms (and dark 500k).  The Tayda LDRs have a 10k light resistance. Seems like a big difference. And if the LEDs are dim, the Tayda LDRs may never drop the resistance enough.  

The NSL32 also has a 500 ohm light resistance and a 500k dark resistance. These are what I used as the closely match the original CLM6000.  

Also, the measured forward voltage on my NSL-32s is 1.5v. (using the diode check on the meter). My LEDs read closer closer to 1.8v.

With both the Offset and Frequency controls maxed out, check the voltage you are getting at the Envelope SW9 (N) connection. If it is less than 1.8v, there may not be enough voltage/current from the LFO to light the LEDs bright enough.  

If that's the case, maybe lowering the 15k tied to lug 3 of the offset pot just a bit will do the trick. Or maybe lowering the 47k tied to lug 2. I'm not 100% sure, but would probably give those both a try anyway.  

Also, one thing I was thinking about before but didn't try: Other phasers have 220k resistors in parallel with the LDRs. This project uses 470k resistors. Might be worth lowering those to 220k to see if that evens things out.



 

[velouriafx]

Hey, Mao. Thanks for the reply again. Here it is very difficult to find NTLs, but I can try to get some VTL5C. Tomorrow I will measure the voltages. I will try to change the resistors you suggested. That's what I thought, too. Perhaps decreasing the value of CLR is effective as well. I believe that in Phaser's case it would be the 2k2 connected to the envelope switch with the speed switch. Raising a little bit of sensitivity could also be cool. I got good Envelope results basically with him as pot at max.

[MAO]

03/30/2018 updated/improved layout (but larger)

I drew up this new layout for easier offboard wiring, combined the vibrato and filter/phase switches to a single DPDT on/on/on, eliminated the speed switch (which can easily be added back in) and replaced the envelope switch with a SPDT by permanently connecting the envelope follower's input, which also eliminated the need for adding a pulldown resistor.  

Latest observations:
With the stock 10n caps you get a typical phasing sound. And in the Filter mode at faster speeds, you get a nice chimey, almost chorus like effect. You can also get a talk-box like effect in the Envelope mode with the Resonance turned up high. The vibrato is ok too with the Intensity, Speed and Offset up higher.  

I found the Voodoo Vibe cap set sounded pretty good in the Phasor mode at moderate speeds, but not as good sounding in the Filter mode. I do think it's worth socketing those 10n's and trying the Voodoo values, from bottom to top of the layout replace the four 10n* caps with 15n, 100n, 47n, 4n7. With the Envelope engaged, the Voodoo caps get a nice warbly vibe like sound, but not as much talk box as the original 10n's.

Actually, If you are going to build this, I would suggest socketing all the * components so you can customize it to your gear and liking. For instance, I found the 470k* gave to much gain with my humbuckers, and the effect would distort with the Resonance turned up high. Sounded fine though with the humbuckers in dual-sound mode. 240k worked better for me. Also, fine tuning the attack resistor and decay capacitor is key to getting the Envelope feel/response just right.

All in all, may not be the best sounding "stand alone" phaser on the site, but the versatility with all the controls, switches and envelope control is nice.  


 

[velouriafx]

Hey, Mao. I only had time to touch this board today. I kept the board from the first layout, but I made some changes that you suggested in the second, like the 10n caps that replaced two, the 47r resistor by 22r, input resistor. I also changed the 2k2 resistor from the Speed ​​Sw to the Envelope Sw and the resistors connected to the Offset. Now it's sounding pretty good to me. This week I have to record a video and post here. Many thanks for the layout and the attention.

[MAO]

Thanks for the update!

I'm still not crazy about the Offset control, may I ask what values you settled on?