FOXX Phaser

[Michael_Telecaster]

Hey guys!
i recently got a request from a mate about putting together a phaser pedal that he really wants, he had done some hunting and found this schematic to go along with it. i've tried turning this schematic into something workable but im definitely getting nowhere. just wanted to post here and see if anybody can help please!

[PMowdes]

You're gonna need to post a bigger picture than that if you want anyone to respond.

[Michael_Telecaster]

[Travis]

Looks phase 90 esque but 6 stages? Very cool

[Michael_Telecaster]

Yeah i've heard one before in person and they sound bloody amazing, but I just have no idea how to convert this schematic into a stripboard design

[nocentelli]

Six matched (semi obsolete) FETs!?

[GrooveChampion]

Kill me now.

Thing is I've seen a FOXX Phaser built on OTAs

[Michael_Telecaster]

Built on OTA's?

[GrooveChampion]

It used chips like the CA3080 or LM136/700 instead of Jfets.

[AuditoryDriving]

I ve had and built many phasers but this is the definitive sound for any Queen / Brian May fan - judt listen to White Queen from Live at the Rainbow, absolutely majestic and haunting.

The task can  be simplified if the auto / manual switch is left out. I really hope someone will give this a chance - thanks in advance!

[Alex]

This would be quite large but not too difficult to draw compared to some other circuits.
Now on the schematic..
Never seen this pedal before (not many infos) but I've found this:
http://www.effectsdatabase.com/model/sears/phasingpedal
I assume "Q" is the Depth pot?
Are the original ICs LM324?
Do you know the original FETs?
Are diodes 2 - 6 1n4148?
I assume points marked 1.8V get connected all together (same thing for +6)
The Toe Switch numbering is not very clear.
I guess it's a DPDT like this:

[AuditoryDriving]

Hi Alex and thanks so much fores your reaponse!

I m currently not able to move much (injured leg)  so i ll come back asap with move info. For now, i had found the transistor types in another forum but they were unobtainium. D4 to D6 must be 1n4148 since the voltage denoted on the junction is 1.8v (3x0.6v)

Thanks again!

[AuditoryDriving]

oh, and you re right, q is the depth / feedback.it comprises of  trim pot that sets the maximum feedback possible (max when set to zero) and an external pot that allows manual control externally between the aforementioned max value and a min value that also depends on the trimpot value.

[AuditoryDriving]

i think that in lieu of a wah-style case you can hardwire the switch to the lfo side, it s useless otherwise!

[AuditoryDriving]

and you were right lm324n's

https://dubaldomusic.com/wp-content/uploads/2017/04/Foxx-Foot-Phaser-Studio-Model-7-17-940x626.jpg

[AuditoryDriving]

Transistors photo

https://images.reverb.com/image/upload/s--6EiOTXad--/a_exif,c_limit,e_unsharp_mask:80,f_auto,fl_progressive,g_south,h_620,q_90,w_620/v1496115350/e7jpswhebqzskgzcfjnt.jpg

Also note that the fet bias trimmer value is missing but if the colour of the trimmers in the photo above is indicative of the value it can t be 1m since the q trimmer is 1m and the two trimmer colours are different.

[AuditoryDriving]

And an excellent all-star thread

http://www.diystompboxes.com/smfforum/index.php?topic=110315.0

[Alex]

This was a nightmare.
Took me a while cause I don't have much time for layouts anymore.
I think it matches the schematic but....
I'll post it on the main page once it's ok (not sure how many people would be interested anyway)
I've left the mode switch for "originality" reasons but it shouldn't be too difficult to remove.