Adding TZF module to MXR Flanger

[jdub]

Hi Folks-
For fun, I'm thinking about playing with adding Tomas' TZF3007 module (http://www.diystompboxes.com/smfforum/index.php?topic=85977.0) to my MXR flanger.  As this would entail a send and return from the board, I examined how thw TZF board was added to the Electric Mistress, and it seems to me that the correct places to tap out/in to the circuit would be as in the link below (couldn't get pic to post):
http://www.aronnelson.com/gallery/main.php/v/jdub/flangerm117_12.jpg.html

Would any modulation maniacs be so kind as to chime in and let me know if I'm on the right track?  It would be most appreciated.  Also, for further fun points, I might try messin' with "theta processing" by inserting allpass stages, and as far as I can tell the best place to put these would be between the output of U1 (pin 7) and R41 (82k).  Does this sound reasonable?  Thanks for any help!

[Fender3D]

To achieve TZF you need to "delay" the wet signal before mixing it with the flanged signal.
You'd better take off R37 and place your board instead (U4's pin7 will be the send and pin2 will be return, you'll need a mixing resistor to choose from 82K and 150K)

[Mark Hammer]

I think Fender 3D means delay the dry signa, before mixing it with the wet/delayed signal.

Remember that the TZF effect is produced by having the delay get soooooo short that it runs ahead of the dry signal, before pulling back again.  A single BBD cannot do that itself, but if the dry signal is "slow enough", it can.  It's a bit like asking your jogging partner to slow down a bit so you can run a little ahead of them and look better.

[Fender3D]

I think Fender 3D means delay the dry signa, before mixing it with the wet/delayed signal.

Yep thanks Mark 

[jdub]

Thanks, guys.  I was clear on the way it works, but for me it was a toss-up between U4 pin 7 and U2 pin 7- looks like I guessed wrong     Actually, couldn't you tap a dry signal from either point, since it's before the BBD?  As for the return, I wasn't sure if it should be before or after U4a...does it matter?  Federico: do you mean I should choose either 82k or 150k as mixing resistor?

Any ideas for the allpass stages?

Thanks again for the help!

[Thomeeque]

 Hi!

R37 is "dry" path.

1. Pull R37 out and use it's pads for following connections
2. Connect PAD1 (IN) of TZF3x007 with U4 pin 7
3. Connect PAD2 (OUT) of TZF3x007 with U4 pin 2 but not just by wire - put serial RC into this path, where:

As R use trimmer 220-250k (it will allow you to adjust dry/wet ratio - TZF3x007 module will boost the signal slightly).

As C use film capacitor with value approx. from 220n to 1uF (C is here because TZF3x007's output should be decoupled).

I'm short of time (and little sick) but ask, I'll answer soon or later (os somebody else), good luck, T.

[Fender3D]

 ^ Yes R37 is "dry" path.
it mixes with R41 which is "wet" path.
This schematic takes into account the loss occurring in the "wet" path (BBD, filters, level trim..) so you won't have a 1/1 mixing ratio but 100k(R39)/150k(R37) for the dry side and 100k/82k(R41) for the wet.
I suggested above to choose the TZF-module's mixing resistor (which will substitute R39) between those values, 'cause they would probably be right. A trimmer, as suggested by Tomas, might be a better solution.

[jdub]

Wow, thanks fellas- makes sense to me now.  Greatly appreciate the clarification.

Tomas, hope you feel better soon    I'll let you know how it works out.