ADA Flanger Clone!?

[Hairston]

I've never owned an ADA Flanger, just an MXR Flanger. But after looking at the schematics for this beast it looks like a fine candidate for some far-out unconventional mods.

Have any of you BBD gurus tried any of your ideas on this unit? The "Hammer" has some cool ideas, but he has always been a pioneer.

Just curious. I've always wanted one of these to fool around with. I might just build one now if I can get the BBD ICs for a decent price.

CHEERS!
-HB

[StephenGiles]

What do you want to mod it to do?

[Hairston]

Hi Stephen,

Actually nothing specific in mind, I was just wondering if anybody had ideas they would like to share.

How about something like increasing the Regeneration (Enhance) and/or the Sweep range? I dunno, I'll take another look at the schematics.

-HB

[StephenGiles]

Hairston, I think the regen can already be configured beyond the useable by adjusting the trim. Again, the sweep range is wider than usual. Perhaps an envelope follower could be incorporated.

[Hairston]

True, true, I totally agree with that. I was thinking of something more on the unconventional lines of a Flanger that this unit may be capable of, like some wild pitch bending sorta like a whammy.

I've always understood by increasing the delay time, it will increase the amount of pitch bend. Although I am by no means an expert with this, to me it might be cool to fool around with. Any thoughts?

-HB

[StephenGiles]

Not easy with analogue - Mark any thoughts here? I think he'd be better off with a whammy pedal which I understand are controllable up to a point.

[StephenGiles]

What you could do is modulate the LFO with an envelope follower, similar to the EH Polyphase. I think it's posted somewhere.

[Mark Hammer]

I heard my name called.

Sending this in for mods is a bit like sending in Lauren Hutton to get her teeth fixed, Kate Winslett for liposuction, or Kate Moss to get her eyes brought closer together.  Some things are just perfect in their imperfection.

Having said that, and with lip firmly bitten and hands firmly sat on (how DOES he type like that?), I offer the following:

1) The unit lacks any sort of dry/wet blending or dry-lift for vibrato.  R41 and R42 are the resistors that set this balance.   My own preference is to use a smaller-than-stock value for R42 - the resistor that sets wet level - and a variable resistor about 4 times its value (or nearest stock value).  The reason for this is that deepest notching occurs when dry and wet are mixed 50/50 in precise balance.  Since precise balance is hard to nail with 5% resistors, starting off with a resistor that falls on one side of perfect balance, in tandem with avariable resistor that lets you pass through the idealized value to the other side and increase resistance so that intense, high-regen sounds can be moved a little to the background, provides the best of many worlds.  For vibrato, lifting the end of R41 works fine.

2) WHERE the resonance of the regeneration signal lies imparts different tone.  C9 is a DC blocking cap, but it also sets the low end rolloff of the regen signal.  You can chop this down by a factor of 4 or more to raise the low end rolloff a bit.  I don't know where it is set to now, but chopping 2 octaves off the bottom will likely make it sound less tank-ey at high regeneration.

3) The sweep on this thing is a thing of beauty.  I wouldn't change it a bit.  If you are so possessed, however, C24 (C24/25 in a different revision) sets the range of the LFO.  Decrease that capacitance for faster sweeps (e.g., audio-range modulation) and increase it for ultra-slow sweeps.

4) The A/DA and the Boss CE-1 both use a noise gate such that the wet signal is faded out during silent parts and faded in during musical passages.  This reduces filtering needs as well as replaces companding.  You can argue whether it is as effective at keeping noise in check, but that's an academic matter.  IC3a is a gain stage to provide enough envelope signal from the guitar to drive the FET (Q1).  If it is too much or if only a few degrees of rotation are of use to you, reduce R28 for less gain.  Or if you can't seem to make the gate turn on, increase R28 for more envelope gain.  You will note that the resistance formed by Q1 and R35 feeds the non-inverting pin of IC2b.  I gather that whatever comes in on that path cancels out what comes in to pin 6 (note that IC1c is inverting).  So it is really more of a noise canceller than a noise gate.  Clever.  Still, the turn-on and turn-off time is always an issue with gates.  It can be problematic or it can be used creatively.  R33/C17 sets the time constants of the gate.  As C17 increases, both attack and decay time range increases.  As R33 increases, so does attack time.  It may well be possible to have a slower fade in of the wet signal than currently exists, by increasing R33.  That might be interesting, musically.  As is the case on the Dr. Q, increasing that resistance value not only increases rise-time but also decreases the amount of current drive for the transistor, so that you get less sweep with longer attack.  That's another reason why tinkering with R28 may be useful.

5)  Finally, a little more signal is never a bad thing.  R43 can be increased for more output leve;.  That may require some tinkering with values of the input resistors for optimum functioning.

There, I feel dirty.  I'm gonna catch a bus home now and cleanse my soul.

[Hairston]

Sending this in for mods is a bit like sending in Lauren Hutton to get her teeth fixed, Kate Winslett for liposuction, or Kate Moss to get her eyes brought closer together.  Some things are just perfect in their imperfection.

That's fukn funny Mark :lol:

You forgot Jewel and that snaggletooth of hers...

...and I have to agree with you, it is one sweet stock flanger. I just wanted to get some ideas on how all these stages fit together and what would be cool to screw around with.

Those are some outstanding ideas, exactly the starting point I was looking for! I thank you again as always my friend!

-HB

[Hairston]

I managed to dig up some more resources on the ADA Flanger from the guys over at ADA Depot.

These schematics are alot more readable and there is also another redrawn schematic for it I have never seen before. The original manual is included here plus some advertisements.

http://home.lehighone.com/rmetzger/ADA_Flanger_Resources.zip

ENJOY!
-HB

[StephenGiles]

Hairston - that is unbelievable. By the way, we visited Buffalo back in early 1991. My wife won 2 weeks in Florida and we flew up to New York to visit one of her old friends from Buenos Aires and then flew out to Buffalo to see the falls - almost snowed in!

[StephenGiles]

I suppose it would be supremely flash to have two of these buggers wired up for parallel/series, and even a Rat in the same box. I'm off to study the 1024 circuit!

[Hairston]

Yeah, the weather kinda sucks here in Buffalo. I swear I live in the armpit of America when it comes to the quality of the weather. And it's not really the snow, although we do get a good amount of it.

Niagara Falls is pretty cool, especially for the first timers. I kind of take it for granted because I have lived here all my life.

Anyways, thanks for all the advice guys!
-HB

[lightningfingers]

wierd how none of the links posted actually work....... :cry:

[gorohon]

I've had trouble with the one that has the pcb & parts layout.  I managed to print the pcb, but the 2nd page (parts layout) does not load up completely and my printer starts to have problems.  This is just with that link given on the second page (top) of this thread.

[Yuan Han]

thanks hairston !

great stuff

[Mark Hammer]

Thanks for the ADA resources link.  I had never seen the SAD1024 version before.  Illuminating.

Readers/unzippers also note.  The stated specs indicate sweeping from a delay of .33msec to a delay of 14msec.  This is a 42:1 sweep ratio., and is a major part of what it is that is so pleasing about this unit.

If simply having voltage control appeals to you, I have the old Phlanger article that appeared in Radio Electronics posted at my site, courtesy of Peter Snow.

[StephenGiles]

......and perhaps you may like to have a gander at this:
http://www.morleypedals.com/cfles.pdf
.......no prizes for reporting all the similarities!

[StephenGiles]

How about a pitch shifter in the regeneration path? Come on - someone clever!

[Mark Hammer]

Yep, although most people seem to think the BBD does all the magic, the presence of a 4047 or a 4007/4047 combination seems to be the real mark of a good flanger.  Why?  Because it is capable of speeping over a wide range and providing enough current to the BBD clock inputs to overcome their input capacitance.  The MN3101/3102 is a nice convenient chip, but it tends to limit the sweep too much when you get to the really, really short delays, and it is those short delays that permit things like the 42:1 sweep on the A/DA, and the sweeps that come really close to through-zero flanging.

As for things in the regen path, read the review of the old A/DA analog harmonizer floorpedal in DEVICE...as always, posted at hammer.ampage.org.