A/DA Flanger does TZF?

[oldschoolanalog]

or what about a step up regulator like http://cache.national.com/ds/LM/LM1577.pdf with a choice of wall wart or battery for a portable

Would the 52 kHz oscillator on this chip create heterodyning issues? I believe this is the reason the MAX1044 was decided against. Interesting chip, though. Probably very useful in other apps.

[Horace]

I don't know if any heterodyning between the LFO and the 52kHz oscillator would be an issue or even within human hearing range. The MAX1044 has a 20kHz internal oscillator that would be more likely to cause problems if any. 

[puretube]

the LFO will hurt nobody (except for "clicking", caused by wrong layout...),

but as can be read from the calibration page,
the clock goes from 34.8kHz to beyond 1MHz,
which means: it goes "through 52kHz",
and that`s where the regulator can hurt the clock or vice versa...

this can be cured/prevented by proper layout, though,
and special filtering measures,
especially easy in rack mount units.

(where OTOH, with a built-in PS, switched regulators are not needed... )

[Horace]

i am sorry, you are completely correct, I utterly forgot about the clock  and was stupidly trying to think how 52kHz heterodyning within a clockless flanger could be a problem . I have just finished building a badstone clone and must have LFO's on the brain (a bad lm324 was the problem). I just want to try to build the ADA clone in a stompbox version for gigging (although, having the option of the extra's to eventually build a rack mountable would be brilliant) , the rest of the band would never forgive me if we had to try to find more room to drag along an extra rack for effects.

[StephenGiles]

To me, reaching up to plug my guitar into a Marshall amp on top of 2 4 x12 cabinets is the ultimate, but to fiddle around with a rack mounted ADA Flanger on top of that is in another dimension!.........but then so is seeing my tulip bulbs grow early next year!!!

[Horace]

  ...now you put it that way....bring on a rack mountable. please picture our gig mobile, http://www.lansingpd.org/images/overloaded-car.jpg

[moosapotamus]

Speaking of power supplies...
My PC is not well, dead in the water, couldn't do a thing all weekend (I'm writing this from my PC at work  ). But, I'm hoping to be back in business sometime tomorrow. I'm waiting for dell to replace my motherboard & power supply.

But, I think an 18VDC wall wart + bog standard LM7815 regulator circuit (two big caps and a diode) should do it for the ADA, right?

~ Charlie

[oldschoolanalog]

Rev 4 has (after the FWR); 470uf to gnd on the input side of the reg, and 1uf tantalum to gnd on the output side. IMHO, nice and simple like this is the way to go. If it works for A/DA; it works for me! Thanks!

[StephenGiles]

Sounds good to me - even at 6am in Gatwick Airport!!!!

[markusw]

But, I think an 18VDC wall wart + bog standard LM7815 regulator circuit (two big caps and a diode) should do it for the ADA, right?

Sounds good to me too 

One Q for Stephen, and of course all of you 

There is so much variation of flanging sweeps available on this beast. I am going to have the max clock trim as a panel control because it provides continuous control of which part of the sweep area can be used. So, for instance, if a narrow sweep is set up, the max clock trim can fix whether that sweep is in the high or low end.

Actually via the manual pot it should also be possible to set the sweep to the high or low end. What do I miss? 

[StephenGiles]

How's it going?

[RaceDriver205]

Aye, could someone summarise where were at with this thing, so as to keep focus?
Flan-ger Dut-dut-dut, Flan-ger dut-dut-dut! (I love flangers the most )

[StephenGiles]

Search me, I've been to Spain and back since the last post.

[moosapotamus]

Well... I am about 3/4 done with the layout. Would like to be done by now, but I've just been pretty busy with the stuff of life, mostly good, some not so good, you know? Wish I could go to Spain, again. Anyway, making steady progress.

~ Charlie

[RedHouse]

Keep up the good work Moose!

[StephenGiles]

Our visit to Spain was for visiting a relative in hospital, but it was nice to take the ambience for a couple of days - decent espresso coffee and wonderful food. I noticed the complete lack of electronics mags as in England!

[RaceDriver205]

Good on ya moose. I look forward to the sounds of jet engines flying by.

[markusw]

Well... I am about 3/4 done with the layout. Would like to be done by now, but I've just been pretty busy with the stuff of life, mostly good, some not so good, you know? Wish I could go to Spain, again. Anyway, making steady progress.

~ Charlie

Cool! Thanks for doing all the work!

Markus

[oldschoolanalog]

 Thank You for doing all this work. Just out of curiousity; did you end up making this a 2 sided board?

[Mark Hammer]

Here's a silly thing to suggest

One can pick up a Danelectro Fab flanger for a pittance these days.  Buying two of them is cheaper than buying almost any other individual flanger. Strikes me that figuring out where the dry-side mixing resistor is and removing it, and feeding a pair of them with a splitter, then taking their outputs to a 2-input mixer, would provide a pretty darn quick introduction to through zero flanging.

Note that this would provide limited access to both symmetrical and asymmetrical TZF.  For latecomers, asymmetrical TZF involves having one very short fixed delay and a second swept one.  The through-zero poin occurs as the swept delay gets shorter than what the fixed delay is set to.  How "long" the sweep spends on the other side of zero depends on the sweep speed and depth, but also on what the fixed delay is set to.  A symmetrical TZF involves having two counterswept delays driven by the same LFO, with the through-zero point being where they each achieve the identical time delay (one on the way up, the other on the way down).

Using a pair of Fab flangers provides speed, width and regen controls for each delay.  The individual LFOs are not readily sync-able, although I suppose some invasive surgery could cure that, but I'm aiming for quick-and-dirty not lengthy-and-involved.  By keeping the sweep rate VERY slow, and the sweep width minimal, that would permit one of the delays to be relatively constrained (although obviously it would change a bit).  Increasing the sweep width equally on each pedal would provide something closer to symmetrical TZF, though clearly not as predictable as something like diyfreque's modded Dimension C.

Note that the switching scheme on such pedals almost always involves use of a single FET to connect or lift the delay signal from the mixing stage.  So, if you remove the dry signal from the mixing stage, stepping on the pedal's bypass switch will get you stoney silence.  The bottomline is that should one wish to use a pair of pedals in this manner for gigging or other performance contexts, I suspect your only choice would be to use the whole mess with a loop selector pedal.  Still, you have to admit that a pair of $15 flangers, and $10 worth of mixer-splitter stuff and patch cables is pretty inexpensive.