ADA based through zero flanger

[StephenGiles]

http://img.photobucket.com/albums/v517/uncle_boko/ada_TZF.gif

Just doodling really, I've slightly rearranged things so that one SAD 1024 section is clocked by the standard LFO/clock, and the other by a fixed frequency clock - which replaces the dry signal in the scheme of things. I'll say no more for now, but no doubt some folks will
Stephen

[stm]

Nice.

Don't want to rain on youir parade, but the major problem here will lie in the signal, clock and power routing to avoid clock intermodulation.  The bad thing of the SAD1024 is that you can't have separate powers and grounds for each stage, which is quite necessary when using different and non related clocks. 

In this aspect, extra decoupling capacitors on the supply ( 0.1uF/ceramic + 4.7uF/tantalum ) would be wise to help taming clock noise. This should also be applied to each of the clock generating/driving circuitry, as well as the usual star grounding techniques. I think a double-sided PCB would be the wise way to go if a serious implementation is desired.  Think of the layout and decoupling techniques used on the Boss DC-2.

[StephenGiles]

Thanks, it was really just an idea I drew while my wife was cooking dinner. I hope that doesn't sound sexist because I cook sometimes as well! Incidentally we saw a band called Quimantu last week which is run by a Chilean called Mauricio Venegas-Astorga who has lived here since the late 1970s. The percussionist is also from Chile, bass player is from Venezuela and the others are English, so the the music they play is a mix of folk music from Latin America and the UK. Mauricio now has a programme for school children both in England and in Santiago to introduce them to different folk music - which is a million miles from through zero flanging!

I'll rethink this and perhaps consider using 2 separate 1024s - this is the only BBD that I have 2 of right now. Ah no, I have a few TDA 1022 but Ihave always found them to be very noisy.
Stephen

[stm]

Well this is ceratainly a small world!

I didn't want to sound too pessimistic on the use of a single SAD1024 with different clocks, "standard" breadboarding practices won't make it if you want to make a permanent and definitive FX.  However, it is still interesting to try the circuit to see how good or bad the situation really is.

Best regards.

[StephenGiles]

I may well try it and let you know the result. Not for a couple of weeks though.
Stephen

[Jaicen_solo]

I think it's highly likely that I could love you forever if you were to use an MN3007 instead! 
I've got three lying around from an abandoned Ultra Flanger (Actually, I only got as far as buying the chips ). Put in a freeze function and i'm all yours! 

[puretube]

http://www.diystompboxes.com/smfforum/index.php?topic=18760.0

[Jaicen_solo]

OOh, now I feel like i've spilled my heart, only to be rejected 

Haha, no seriously. I read that post a while back, I guess I just forgot about clock frequencies. The MN3007 can use just 512 stages though like in the hollis flanger?? Either way I guess you can't clock it fast enough. Sorry!

[StephenGiles]

Did Bush & Blair listen to the ifs & buts before going into EYERARQ??? No - so I think I'll try my ADA idea anyway, keeping separate power lines to each board (vero of course!) and see what happens.
Stephen

[danfrank]

Hi everyone,
My first post here on this forum and it seems like I'm already breaking the rules with resurrecting this old thread.
Anyway, the reason I'm posting here is that I've always wanted to make a TZ flanger and I really like the A/DA flanger and it's capabilities. So I decided to make an A/DA based TZ flanger. I'm not into making PCBs so I used a couple of Lectric FX Flintlock PCBs. The first board I built as a standard A/DA flanger and I used the second board as the straight delay signal. On this second board, I also assembled the components for the "manual" control and LFO to give this project more options.
Here is a quick and dirty video of the flanger in action:

https://youtu.be/BDZwlXhW4NE

One thing I have not figured out and it would definitely be a huge asset to this project, is how to configure the second LFO to run opposite of the first LFO. Anyone have any ideas because I'm stumped! I do know that the LFO on the A/DA sweeps from 2.5 - 11.5 volts, referenced to ground.
Also, I was looking at other old threads on this forum and saw something about an old WEM Hyperflanger? Anyone have documentation on that? It sounds really interesting.
Again, I apologise for this necro-post but it is the same topic as this thread.
Thanks.

[PRR]

> run opposite of the first

Inverter. Gain of -1. In this case, biased to 7V (midpoint of 2.5 - 11.5 volts).

[danfrank]

Hi there! I've seen you around on other forums and you're always very knowledgeable. Thanks for the reply but please forgive my ignorance...
Would I be taking the output voltage of the first LFO to "feed" signal into the second LFO? What should I use for the 2 resistors for inverting LFO #2? 10K ohms?
Something like the following picture?
Thanks for your help...

[PRR]

[danfrank]

Ok, I'll try that out.
Is there a reason why 100k resistors are used as opposed to 10k? I'm pretty much in the dark about this, I'm trying to learn!
Thanks

[PRR]

Why do they need to be 10k? It's not hi-fi audio. We may want to minimize loading. But if you have a sock full of 39.7k, use those, sure.

We are both struggling with the bias. I put 9V at first, you have 7.5V. The problem as stated really implies 7.0V. But the circuit doesn't read the problem specs. It may be sweet to make it self-bias. This idea works as long as the LFO center point does not change suddenly.

[danfrank]

My values for the sweep may be a little off because of the lag in the multimeter I was using to measure with. The whole flanger uses 15 volts for the power supply and Vbias is at 7.5volts for all the op amps. That's why I used 7.5v. I'll try it tomorrow and report back. I'm excited! Thank you so much.

[Scruffie]

I've mulled this when we've talked, how well matched are the MOSFET's in a CD4007? I'm just wondering if you're going to have to bias 2 sets of clock or if you might be able to get away with 1 with just a fine tuning trimmer for the gain.

[danfrank]

I've mulled this when we've talked, how well matched are the MOSFET's in a CD4007? I'm just wondering if you're going to have to bias 2 sets of clock or if you might be able to get away with 1 with just a fine tuning trimmer for the gain.

This is all above my pay grade. Lol!
I was going to do it like in the attached pic. I'm still working with both boards, so I have a clock for each delay line. Efficient use of ICs isn't my forte...



It's my understanding that the LFO provides a variable DC voltage to the 4007. If I'm using a separate 4007 for each clock, I wouldn't think it matters where that voltage is coming from since the clock is referenced to the same ground. I could see the sweep of one LFO isn't identical to the other LFO but does that matter considering the LFOs aren't tracking the same exact voltage at any given moment? They're at opposite ends of the sweep. In my mind, what really matters is that one LFO is going up while the other goes down and vice versa.

[Scruffie]

The 4007 is a MOSFET which acts as a variable resistor, which yes, is controlled by voltage from the LFO.
But I was saying, I wonder if you could get away with driving the inverted signal from the 'clock adjusting' op amp with only a single extra trimmer to adjust to account for any possible gain variation.

Just trying to cut down the complexity a little, but it would depend on the 4007 being pretty well matched... maybe I shouldn't confuse matters.

[danfrank]

Ok, yes I see your point. I'm just trying to see if this will end up working, kind of a proof of concept type thing. Honestly, I'd be happy just seeing the 2 green LFO LEDs blinking out of phase!