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

[Brymus]

I listened to the first set of clips you posted .
I liked the first riff the 3rd time you played it as having the sound I liked best.
SO what sub minis does this pedal use again?

[frequencycentral]

Those little black low profile ones that you can get nowadays......

[Ben N]

Rick, those sound great!

[Mark Hammer]

Finally listened to the clips.  Very impressive.  One of the things that I was sure I had heard on my 4-swept/2-fixed Ropez was that the effect got more intense as it swept upwards, and the same seems to be even more true with 2-swept/2-fixed in this instance.  Very musical sounding.  Thanks.

[Ripthorn]

Dang you, Rick.  Just when I think I am caught up with builds, you go and do something like this and make me put another project on the to-build list.  The wife doesn't like you much, I don't think.  That's okay, she doesn't know it's your fault.

[frequencycentral]

Finally listened to the clips.  Very impressive. Very musical sounding.  Thanks.

Wow, praise indeed from from high priest of DIY phasers, thanks Mark!

Dang you, Rick. The wife doesn't like you much, I don't think.

 

I'm working though the perf/PCB layouts at the moment. Not sure yet if it will end up using a quad opamp or if I'll go for all duals. I was aiming to get it on a 20 x 20 pice of perf, but the more I think about it the more I think I should spread it out a bit, as the concept is for an intermediate, easy build phaser, so I might try 20 x 25 which is the same size as the Tonepad Ropez. What do you guys think?

Oh, and cathexis - do you fancy doing a vero layout for this?

[Ripthorn]

20x25 is still a reasonably small piece of board, so I would be fine with that.  This is going to be fun.

[Skruffyhound]

Could we have one layout for your normal users, and one for us perfboard masochists . For some inexplicable reason I get a kick out of building the tiniest layouts I can find, it takes longer, it's incredibly fiddly, you can't just use any old parts and there is normally no real advantages.... but I like it
Can we get it in an Eddystone 111x60x27 ?

[frequencycentral]

Well it looks like it's going to be 20x22, which will easily fit in an Eddystone 111x60x27, that's the size enclosure I plan on using anyway. I'm a perfboard masochist myself, but I'll only be doing the one size layout (sorry Aston), it could be smaller but I want to make it an accessible and easy build for less experienced DIY'ers. If this project becomes popular I'm sure we could persuade John Lyons to do a run of PCBs.

[Skruffyhound]

Fair enough , a bit cheeky to hope for a separate layout just for me! Its just that I'm getting glasses for the first time in my life next week, so I'm looking forward to being able to see what I'm soldering and consequently build even smaller thingamajigs.
Thanks for this build Rick, it's on the list and I've got free time coming up *rubs hands together*

[Ben N]

I'm a perfboard masochist myself...

Pain is good. Embrace the pain.

[frequencycentral]

Here's the perf layout, as yet unverified, I'll go over it with a fine toothcomb and build it this weekend. Anyone wanna check for errors with me? The only variance from the schematic is that I've used the two OTA's of the LM13700 in the opposite order, which just made the layout easier. I've also included a LED resistor (R33) with a nominal value of 1k.



..............and here's a reveal view of the same layout:

[Skruffyhound]

I'd be happy to look through the schematic/perf, but the safest way for me to check it is to build it, unfortunately even after 3 mammoth orders  recently I'm still missing two of the IC's.   
I'll run through it, perhaps fresh eyes will catch something.

[puretube]

Too much dry signal for me in them clipz...

I`d replace that 10k going to the 1st stage (drawn above that input-1k) with a link...
(or should I say: Carbon-comp 39 Ohm in parallel with a bifilar wire-wound non-inductive 5.6 Ohm    )

and, err: for fun disconnect that 1st 27k going from the input-opamp to the output-opamp
for a while on your next clip ( ) , while turning up the "Regen"...

[frequencycentral]

I'll run through it, perhaps fresh eyes will catch something.

Thanks, I've already spotted a missing jumper between u16 and u17. I'm going to update the layout when I'm sure I've thouroughly debugged it.

Too much dry signal for me in them clipz...

I`d replace that 10k going to the 1st stage (drawn above that input-1k) with a link...

Thanks Ton, I'll try that.

and, err: for fun disconnect that 1st 27k going from the input-opamp to the output-opamp
for a while on your next clip ( ) , while turning up the "Regen"...

Police siren?? 

[puretube]

and, err: for fun disconnect that 1st 27k going from the input-opamp to the output-opamp
for a while on your next clip ( ) , while turning up the "Regen"...

Police siren?? 

Cutting out the dry from the out won`t hurt your feedback ("Regen"),
but it will take the smearing dry from your vowelling...



On another try, I`d feedback from the last stage...
or even try to feedback to an earlier stage (tweak, tweak...)

[puretube]

I've also added a 10K resistor between lug 1 of the Depth pot and ground, as I found weird things were happening with the pot fully grounded. It doesn't do much to limit the range, but sorts out the issue.

Kinda reminds me of a similar issue (last year ?) in an other OTA-project,
where the CV needed to get over the "diode-drop-hump" to become effectively turned into a proper I_ABC 

[frequencycentral]

Cutting out the dry from the out won`t hurt your feedback ("Regen"),
but it will take the smearing dry from your vowelling...

Ah, a vibe switch. I misunderstood, I read as replace with a link. 

On another try, I`d feedback from the last stage...

I'll try that - but should it make any difference? Please explain....

or even try to feedback to an earlier stage (tweak, tweak...)

But it has to be an odd number of stages right?

[puretube]

But it has to be an odd number of stages right?

Who says: "ODD" anymore, when such a circuit is shifting its phase-relations from at least zero° to almost or even over 360°
for almost any frequency  

[puretube]

Cutting out the dry from the out won`t hurt your feedback ("Regen"),
but it will take the smearing dry from your vowelling...

Ah, a vibe switch. I misunderstood, I read as replace with a link. 

No: it`s not a so-called: "Vibe-switch", but rather a: "Wet-Only-switch"...