New Phaser Design - “Causality 4” – Built with you in mind!

[frequencycentral]

Hey Rick,

I've been watching this thread. I'm curious how this one compares sound-wise with your Phase Revolution? I've been playing the heck out of that guy pretty much every day, and I love it, especially in the box with a Magnus Modulus. Does this phaser bring something new to the table in your opinion?

Thanks!

Hi Chris, 

The concept with this project was for a phaser that anyone could build with no matching of components. Do a search for builders who have issues around FET matching in Phase 45, Phase 90 and Phase 180 builds and you'll see what I mean.

This is my third phaser build. My first was the Phase 45 with Maillet mods a.k.a. Phase Evolution, I was so disappointed in the (lack of) phasing that I added two extra phase stages, which makes it a nice phaser, somewhat akin to the Phase 90. My second was the Phase 180 Plus a.k.a Phase Revolution, it's taken some tinkering to get it near to what I want, and I'm still not entirely satisfied with it. Causality 4 has some great sounds, more flexible IMO than my Phase Evolution, easier to use than my Phase Revolution - as you'll know there are a number of settings on the Phase 180 which just do nothing.

So, all in all, Causality 4 is not trying to compete with a Phase 180. It has a sound of it's own, there are no settings that 'do nothing', and the Depth control works particularly well and gives a broad palette of tones. I'd say it's probably 'more' than a Phase 45 or Phase 90, and an easier build than either of them. For it's sound, simplicity and utility, Causality is my favourite of my three phasers right now - but I do have the PCB's to build an 8 stage Ross Ropez, to which I'll add 8 extra fixed stages making 16 in all, I'll have each set of four stages switchable, and it's going to have every concievable mod................

[doc_drop]

My brain waves are getting a little "phasey" trying to keep the names all straight!

But, it sounds like this one might be a fun build to do, one way or the other. I'll let you sort out the details, and put this on the to do list. (I'll have to wait see what your 16 stage phaser winds up looking like...)

It is true that there are settings that don't phase on my Phase Revolution. But what I love about it is that you can get everything in between nothing and wide crazy resonant phasing. By the way, I have found that running something that buffers the signal in front of it helps with the sound. I especially like a valvecaster in front. It can easily overload with a hot signal, so keeping the signal tamed really helps pushing it to the edge of madness and not having hiss n' stuff.

Thanks as always for the in depth response!

[frequencycentral]

Finally, the regen on my build is a little further from self oscillation than on my breadboarded version, so I'm going to experiment with maybe dropping the value of R24 to 8k2.

Whoa! 8k2 makes it into a SIREN! I think I'll stick with 10k. 

[invalidcd]

Hey Rick , what are the dimensions for the PCB layout?

Thanks,Carlos

[frequencycentral]

Hey Rick , what are the dimensions for the PCB layout?

Thanks,Carlos

My perfboard is 50mm x 56mm approx. The PCB layout should be the same size.

[sean k]

Well I doubt it would be as small as whats already done but I just gotta do things my way.

[frequencycentral]

Your layout has it's own unique beauty Sean, as always. Did you catch these couple of important updates?

I did experience some strange behaviour though when I first turned it on (with the Depth control at minimum), which could have passed for the 'envelopephaser' effect that Helge mentioned. It turns out that the Iabc inputs of LM13700 don't like to be so close to ground (actually two diode drops above) , and phasing didn't start for me straight away. I played around on the breadboard and replaced R8, 10k on my PCB layout, with a 47k. Now that problem is solved.

I also used a 47k Log for the Regen control instead of 47k Lin, which makes sense as it's actually audio that the pot is dealing with.

[frequencycentral]

[sean k]

Nope, I didn't Rick but it easy enough to change those things as I haven't bought parts or even started the etching so its all good. I'm looking forward to this one actually. In the future, theres going to be a museum devoted to your stuff...well a section anyways in the great little DIY analog FX museum... thy will catch on! 

[jacobyjd]

Nope, I didn't Rick but it easy enough to change those things as I haven't bought parts or even started the etching so its all good. I'm looking forward to this one actually. In the future, theres going to be a museum devoted to your stuff...well a section anyways in the great little DIY analog FX museum... thy will catch on! 

Definitely--I can see it now: "The 21st century guitar effect designer: A picture of complete and hopeless insanity"

[danielzink]

Rick - any idea where to tap an LED for a "speed" indicator ?

Thanks !

Dan

[sundgist]

Hi all,
Quick intro to get out the way first. Been a lurker for ages, learnt loads while i've been here. I'm sure i'll post an official hello at some point but for now........

Anyone working on a vero layout for this?
I'm about half way through one and hope to post it for all at some point over the weekend, (if my wife and daughter allow me!)
Probably won't get to build it till next week so a few eyes glancing over it would be great.

[frequencycentral]

Rick - any idea where to tap an LED for a "speed" indicator ?

Thanks !

Dan

If you look at the LFO on the schematic, it's made up of two opamps. It's basically a Phase 90 LFO with a unity gain buffer tacked on. I would think tapping off the output (via a suitable resistor) of either of the opamps would do the job. I'd try the second opamp, so tap off from lug 3 of the Depth pot. Personally I avoid speed indicator LED's as the current drawn by the LED as it switches on can cause ticking.

Hi all,
Quick intro to get out the way first. Been a lurker for ages, learnt loads while i've been here. I'm sure i'll post an official hello at some point but for now........

Anyone working on a vero layout for this?
I'm about half way through one and hope to post it for all at some point over the weekend, (if my wife and daughter allow me!)
Probably won't get to build it till next week so a few eyes glancing over it would be great.

Uh, I have a real problem deciphering vero layouts.  But I'll give it a shot if you want to post yours. cathexis is the vero expert around these parts though.

[sundgist]

Have checked this out as much as I was able to last night, should hopefully be ok, but had to keep breaking off to do home and family stuff so possibly some mistakes have crept in.

My parts references are a bit random to say the least and with the many similar resistor values makes following this layout a bit of a PITA. Should have followed the numbering of the existing layouts.
For some reason DIYLayout didn't show the complete parts list so i've left this off and typed them out below.
If anyone feels courageous enough to have a look over it and notices any mistakes let me know and I'll update. But I don't envy the task. I'll do another check before I start building tomorrow.



Watch for jumpers and trace cuts under the IC's and trace cuts under R25, R16, C4.
No track cut between pins 1 and 16 of IC1.

R1: 220K   
R2: 220K
R3: 1K     
R4: 470K
R5: 27K     
R6: 27K
R7: 6.8K   
R8: 100K
R9: 100K   
R10: 10K
R11: 10K   
R12: 10K
R13: 10K   
R14: 10K
R15: 10K   
R16: 10K
R17: 1.8K   
R18: 27K
R19: 10K   
R20: 27K
R21: 1.8K   
R22: 27K
R23: 27K   
R24: 10K
R25: 4.7K   
R26: 220K
R27: 220K   
R28: 220K
R29: 47K   
R30: 220K
R31: 10K

C1: 10uF   
C2: 10uF
C3: .1uF   
C4: .1uF
C5: .0047uF   
C6: .047uF
C7: .033uF   
C8: .033uF
C9: .01uF   
C10: 10uF

IC1: lm13700
IC2: tl084
IC3: ne5532

[sundgist]

Quick edit on the above to add wet only switch.
Refresh browser.

[svstee]

Awesome! This looks great, thanks for the layout. 

[deathfaces]

This is definitely going into my BUILD NOW FOR THE LOVE OF GOD pile. Question, is it possible to somehow make a wet only output in tandem with the regular output?

[sundgist]

Re-checked my vero layout. Have updated so refresh browser if you don't see v1.1
Found a resistor in the wrong position (10k at bottom right of board).
Have re-labelled all parts with their values (makes it easier to follow), all caps are in uF.
Should be fine to build, I was hoping to start today but don't think I'll get a chance. Unless anyone else has a go I should be able to verify the layout next weekend.

[frequencycentral]

Question, is it possible to somehow make a wet only output in tandem with the regular output?

I would imagine you would need to tap off from the output of the final fixed phase stage opamp (top right of the schematic) and feed it into a duplicate of the output buffer stage. Not 100% sure that this would work but worth a try.

@ sundgist: I'll try to look your layout over by next weekend.

[frequencycentral]

A guy on another forum asked about adding extra swept stages. "Causality 6", unverified.