RC time constant TZF

[armdnrdy]

I thought I would run this by you all so that I would learn why something so obvious and simple in theory will not work in practice.

I was looking at the Mono/Stereo Chorus Flanger by MH Becker when I had a thought. 



This circuit runs two delay lines from one clock.
I was wondering if it would be possible to add a RC constant circuit to shift/retard the clock lines going to one of the delay lines to be able to achieve through zero flanging.

The "shifted" clock lines would most likely have to be buffered again to clean up any issues related to the RC circuit.

Would this work? or would we be back to the same old problem, unwanted products produced by two separate clocks.

[Fender3D]

If you're afraid about heterodyne issues (they may be bypassed though) you can always use 2 different lenght BBDs

[armdnrdy]

Filtered without noticeable loss in bandwidth?

[Mark Hammer]

I had not seen this particular design/project previously.  As near as I can tell, it is two synced parallel units intended to provide true "stereo" processing (2 in / 2 out).

What sort of TZF were you aiming for?  Remember, one feed will have to be some sort of staggered "clean", while the other will have to be a modulated delay.  Plus, they will need to be combined.

Strikes me that too much in this circuit needs to be undone in order to make it function as a TZF.  If you have a pair of TDA1097 chips, then you just need to set one for a fixed delay of a few ms, and stick it in the clean path, prior to the mixing stage, and you're done.

[armdnrdy]

Thanks for the reply Mark,

As you were writing I thought about the TC thing...all it will do is put one delay line slightly behind the other...The two lines will be out of sync. This won't change the clock rate at all. I wonder what effect that would have?

It took more than a few glances to see that this switching circuit (IC7) allows for mixing the two delay lines for mono operation.

I have a couple of 1097s coming from Italy. Maybe I'll bread board a simplified version of this circuit when they arrive.

[Mark Hammer]

You want the Infinite Flanger, found here: http://www.milton.arachsys.com/nj71/index.php?menu=2&submenu=6

Then you want the schematic I retouched, found here:   http://hammer.ampage.org/files/INFLSCHM.gif

It uses a pair of 1097s, one fixed, one swept.

[armdnrdy]

I built the 3007 version about 3 years ago.

I am with flangers as Jimi Photon is with fuzz circuits......always looking for the better version!  

I'm kind of gravitating toward the stereo capability of the Becker flanger, but would like to see if I can add TZF to it's features.

Maybe I could switch in/out a fixed clock for one of the lines for mono operation.

[Fender3D]

Another option could be the wet side of phaser instead of flanger's "dry"...
It may be fixed or modulated, interesting for sure...

[Mark Hammer]

If you're dead set on building this thing, then do the converted DC-2 thing.  That is, use a single lfo to countersweep two clock generators, such that one 1097 is speeding up while the other slows down, and mix those two modulated delay outputs together.

I have a pair of Boss BF-1 flangers.  I made a 1->2->1 splitter/mixer to feed the two flangers and recombine their outputs.  I lifted the dry signal from each, such that I can either fix one of the short delays, or have the two modulated delays sweeping independently.  That lets you make the amount of time on the other side of zero, variable, as well as introduce through zero points in more random manner.

[armdnrdy]

Another option could be the wet side of phaser instead of flanger's "dry"...
It may be fixed or modulated, interesting for sure...

Didn't they do something like that for the Flanger Hoax?

[armdnrdy]

Mark,

I'm not really dead set about anything. 

I'm just testing the waters and weighing my options.

I purchased the 1097s because they are not very common, they were cheap, and I didn't have any in my BBD collection.

Actually, I don't see anything that the 1097 can do that the 3007 can't.

Thanks for the info on the DIM-C. I've breezed through that thread many times while searching for other things....I think I have to spend more time to get a better understanding of how that was implemented.

[Mark Hammer]

In case this hadn't drifted by you I past, I direct you to Scott Stites conversion of a Dim C to a TZF, courtesy of nudging from Mike Irwin and myself.

http://www.birthofasynth.com/Scott_Stites/SLS_main.html

[armdnrdy]

The Dim C TZF is the "page" I was referring to in my last post. I inadvertently referred to it a thread. 

I'll give it a good read through.

Thanks

[Fender3D]

Didn't they do something like that for the Flanger Hoax?

It has 2 BBDs plus some phaser stages before delay stages...
FH can do true TZF, my "tip" doesn't, but it's easier to try...

[StephenGiles]

Didn't they do something like that for the Flanger Hoax?

It has 2 BBDs plus some phaser stages before delay stages...
FH can do true TZF, my "tip" doesn't, but it's easier to try...

to say nothing of a quadrature LFO I'd wager