SOLVED I'm VERY close on a duo phase

[Jonnytexas]

I have built 70 pedals or so, but mostly 808's and various other simple overdrives, phase 90's, PT2399 delays and such. I decided to man up and build this beast. Given the complexity, I have not boxed it. I ran short on TL072s, but had enough to get one side working. I am getting the most lush, badass phase sound I have ever heard (seriously, unbelievably good), but have a high pitched whine (not super loud, but nonetheless annoying). I can't seem to dial out with the trimpots. It got much better when I turned off the lights in my garage, but even using sharpied tape over the LED and LDRs, I can't get rid of the whine. A couple of thoughts:
1) I didn't have any 1044s and used 7660s. I have always used these interchangably without thought in Klones and such, but could this be the issue?
2) I didn't have any 820pfs, but used a 680 and 220 in parallel that measured close (say 900ish, but I was drinking beer, can't remember exactly).

I can post pics tomorrow, but it is working except for the little whine, and I don't believe it is a soldering or component misplacement issue; it sounds righteous except for the whine. Thanks in advance for any suggestions you might have.

 

[fig]

It do take it's share of TL072s. I'm sure the talent will be along shortly to help you get this sorted. Meanwhile, would you care to hear my Harmonica solo performed completely in Portuguese?

EDIT: someone knowledgable (more better)

 

[Jonnytexas]

It do take it's share of TL072s. I'm sure the talent will be along shortly to help you get this sorted. Meanwhile, would you care to hear my Harmonica solo performed completely in Portuguese?

Yeah dude, rock it.

 

[Robert]

Are they 7660SCPA? The S is important.

I'd suspect the charge pump ICs before the opamps.

Does the noise occur when either side is active, or just one side?

 

[Jonnytexas]

Just checked, They are7660cpa. Will order the correct part and report back. I have heard funky charge pump noise before, and I suspect this is the issue. Thanks for the quick reply.

 

[Chuck D. Bones]

Still waiting for that Harmonica solo, Fig.

In the meantime, here's the Harmonica Lewinski Blues for your listening enjoyment.

https://drive.google.com/file/d/1-df9BgMmoxRAphmykJi9zFlGheGU7E8t/view?usp=sharing

 

[fig]

Still waiting for that Harmonica solo, Fig.

In the meantime, here's the Harmonica Lewinski Blues for your listening enjoyment.

https://drive.google.com/file/d/1-df9BgMmoxRAphmykJi9zFlGheGU7E8t/view?usp=sharing

I couldn't find my Fb harp ....
...I mean, I have the B# right here but you can't possible play that piece with this harp.
***sigh***

 

[Coda]

I couldn't find my Fb harp ....
...I mean, I have the B# right here but you can't possible play that piece with this harp.
***sigh***

Not with that attitude...

 

[Jonnytexas]

Hello harmonica enthusiasts. So I got the 7660scpas and that took care of my noise issue. Now I have another one. Phaser B is tits mcgrits. I got it all biased up and it kills. Phaser A is being an ass. I get a very loud cop siren or car alarm sound. Biasing changed the frequency response. No dry comes through. As I increase the feedback, it finally goes away and I get a dry that has effect, but is not phasing. My wife thought someone was breaking into our house or that the cops wwere there to arrest me. Pics coming soon. Should I get the 9,000,000,000 IC voltages as well?

 

[fig]

Hello harmonica enthusiasts. So I got the 7660scpas and that took care of my noise issue. Now I have another one. Phaser B is tits mcgrits. I got it all biased up and it kills. Phaser A is being an ass. I get a very loud cop siren or car alarm sound. Biasing changed the frequency response. No dry comes through. As I increase the feedback, it finally goes away and I get a dry that has effect, but is not phasing. My wife thought someone was breaking into our house or that the cops wwere there to arrest me. Pics coming soon. Should I get the 9,000,000,000 IC voltages as well?

Wrap it in a wet towel and bury in the backyard (~2m) for 3 days during a crescent moon. It will work perfectly!

Oh....a Duophase?....nevermind

I'll have to take a backseat on this, BUT...I will anticipate the possible need of pictures and voltages.

 

[Jonnytexas]

False alarm. It works perfect. Time to drill. I started to take voltages, and noticed a funky looking chip. I had broken the legs on one of the 072s during install. Popped a new one in and all is well with the world. I love this thing. I used tape to cover the LEDs and LDRs. Some light still bleeds through my super shitty cheap tape. Should I sharpie it?

 

[zgrav]

do you have any electrical tape to use instead? or an old dark sock to stuff in the enclosure?

 

[giovanni]

I always assumed that once it’s in the box it doesn’t matter much.

 

[zgrav]

of course the sock doesn't have to be old, but it has more mojo if it is.

most boxes with one LED/LDR combo are OK when boxed, but it helps for the Duophase to isolate the light leakage between the two LED/LDR units inside the box.

 

[fig]

of course the sock doesn't have to be old, but it has more mojo if it is.

most boxes with one LED/LDR combo are OK when boxed, but it helps for the Duophase to isolate the light leakage between the two LED/LDR units inside the box.

Now see...I wouldn't have thought of that until AFTER scratching my head for an hour wondering what the deal was. Thanks!

Great news @Jonnytexas ! Now you can post those pics in the build reports instead!

 

[Chuck D. Bones]

In my optical phasers, I cut a strip of cardboard from a 6-pack holder (craft beer is preferred) and make a cylinder that wraps around the LED & LDRs. The cylinder should be tall enough to contact both the board and the enclosure cover. Check out my Stereo Vibe for an example of this. Looks ghetto, but it works.

 

[Coda]

In my optical phasers, I cut a strip of cardboard from a 6-pack holder (craft beer is preferred) and make a cylinder that wraps around the LED & LDRs. The cylinder should be tall enough to contact both the board and the enclosure cover. Check out my Stereo Vibe for an example of this. Looks ghetto, but it works.

I imagine some black vinyl tubing would work the same. It could be cut to size, though you lose the street cred...

 

[Jonnytexas]

I was using electrical tape, but it is green and leaks light. I tried a beer bottle cap (have PLENTY of those floating around in the garage) and it was too big. I am honestly digging the sock idea beacuse, well, it's a sock.

In my optical phasers, I cut a strip of cardboard from a 6-pack holder (craft beer is preferred) and make a cylinder that wraps around the LED & LDRs. The cylinder should be tall enough to contact both the board and the enclosure cover. Check out my Stereo Vibe for an example of this. Looks ghetto, but it works.

I guess I might have to grab a sixer tonight in that case.

 

[giovanni]

In my optical phasers, I cut a strip of cardboard from a 6-pack holder (craft beer is preferred) and make a cylinder that wraps around the LED & LDRs. The cylinder should be tall enough to contact both the board and the enclosure cover. Check out my Stereo Vibe for an example of this. Looks ghetto, but it works.

It sounds too modern with non craft beer. You want that vintage craft beer vibe.

 

[Jonnytexas]

I'm back, damn. Drinking some craft beer. I boxed it and of course the problem reared its ugly head again. I de-boxed and went through everything. I noticed something odd, which is the only place on the entire circuit where the layout is not exactly symmetrical:
R38B is 68K, and R46B is 3k9. The corresponding resistors on Phase a are reversed. Is this right? The traces on both sides from 46B and 38A both connect to the 47K resistor directly below, but as it is currently laid out one side is connecting the 3K9 and the other is connecting the 68k. Is this right? Thanks in advance.
EDIT: A more detailed explanation of the sound..Phase B is killer. Phase A is ok when the feedback knob is in the lower ranges, but goes all cop when it is increased.