A/DA Flanger does TZF?

[StephenGiles]

Funnily enough, I downloaded a 30 minute set of the Jeff Beck Group from 1968 in good quality stereo last night - listening to it in my car this morning I thought why crucify a good guitar sound with effects???Just one future Stone, one future Rod Stewart, a drummer and the man himself - guitar - lead - Marshall stack! But we carry on don't we!

[Gripp]

all for a non-obtainable chip... 

Yes, all is not well in flangerland.

I am well aware of the problem here but I for one don't have the knowledge to design a high sweeping good sounding flanger from the ground up using obtainable BBD's...yet.
I could of course buy say the hoax, which is really spectacular sounding too judging from the soundclips, but then I wouldn't learn more about BBD's and flangers. It wouldn't be DIY.
One thing I love about this hobby is that it fuses two of my main interests, music and technology.
Just some Friday thinking.

Best!
Pelle G

[analog kid]

So Steven , You don't recall at all what configuration that was you used was , the  "simple diode limiter configuration from an early version" that I refered to in reply #234, which you stated that Irwin recommended you to change too?    I'd like to find out if there was even yet another configuration of this section of the crkt maybe used in Rev 1/2 that's different from the two used in rev 3 and 4.  And if so also what the benefit of employing it instead?   though i';m sure it's not affecting the very UNeven sweep
    No ideas yet on areas I may look for errors/tweak values that could have an effect on smoothing that out alot?       also Is it still AT ALL possible that this could be a trimpot adjusting issue? I remember having some real problems my 9v electric mistress until I got just the precise combo of ajustment between the Bias and Clock trim and BAM came into all of a sudden, I don't know if they could help adjust this kind of problem with the sweep on the ADA since although the bias trim is setup much the same here as on the Mistress, I don't believe the "clock range" trims here work the same as the "Clock trim" on the Mistress because the trims on the ADA adjust Range of the clock I think where there's still flanging thougout the rotation of it. In the EM there's an area of the trim where it comes into flanging and can ajdust for flavors in that small area.  sorry if this doesn't apply at , trying to compare differances between two different flanger circuits on means of adjusting to get nice smooth and even sweep.  I realize this is an entirely different beast. 
I'm just so close it seems

[StephenGiles]

The 2 other diode limiters:


I used the bottom one. Now this can surely have absolutely no effect on the LFO

[analog kid]

Ok  good, for some reason that's the diode config I was thinking it may have been at first thought when you said simpler . and it was.  Even though when you said from an older version I thought it may be different than the setup in either 3 or 4. BUT this IS exactly how they're set up in the layout I'm working with here , as they are in Rev 3.      And no they would have no effect on lfo for sure BUT they COULD be involved with the trouble I'm having with the Enhance conrtol ( or Trim more likely) in where I can't trim the feedback down. It's always capable of sqealing ,etc.. at 1/2 rotation or more.  I don't seem to recognize the diode configuration on top though. It definitely isn't the same as the "other" setup , the 6diode config in Rev 4.  hmmmm what's the chance that schem snippet is from Rev1,2 I wonder?
  I'm still trying to locate where the cause of the sweep being so all over the place (noticeable at faster speeds) might be.  So do we agree that the sweep acting THIS uneven definitely could NOT be just a matter of the trims not being alll properly adjusted with one another?

[oldschoolanalog]

OK, the kids in bed. The wife's out. I can partake of this madness again analog kid: First congrats; You're almost there it seems. 2 thoughts. 1: The enhance issue. Is it possible that there is too much gain somewhere due to an incorrect component value somewhere. How does the vol compare to when bypassed. You could always try a larger value for the enhance trimmer, but this approach might be just a way of masking the real problem. Or not... Worth a a shot I guess. 2: The LFO issue. I would personally (though I take no responsability for anyone doing as I do ) build the LFO from a known, verified version (Stephens) on my trusty protoboard; disconnect the existing LFO, and hook up the protob'd LFO. Pain in the cojones? Of course! But the results might be very revealing. Or not...(again ) Anyhoo, wife just got back, and divorce is not an option, so, good luck! Till nextime...

[Herec]

Sorry for "cutting in in the middle" but...

Just a couple of questions.

Is the main reason this effect is being so troublesome in its "stock" form is the conversion for IC8 from the MN3010 to the SAD1240? Are all of the other part alterations because of the one change? Were there also some errors to previous layouts/part values?

[StephenGiles]

Ooops.......you mean SAD 1024 - BBD police will be out in force!!! No I don't think that is a problem, because I successfully built this a couple of years ago. It seems to be PCB layout problems in the main - which is why I always build on veroboard and test while I build. That way, I can eliminate problems as I go and not be faced with a mass of soldered components with possible (and from tired eyes probable) errors.

[analog kid]

" Are all of the other part alterations because of the one change? Were there also some errors to previous layouts/part values"   
   we know what you mean, gotta be careful referencing those somewhat mystical devices : )  Anyway , my answer is I don't know if there were possibly any errors in previous or just the one I'm working from most directly . THAT'S what I'm trying to find out everyday.  I would have to say NO though, as I would think out of the few very talented folk who have built from an original Rev. , that most any discrepancies would've been caught and posted SOMEWHERE like the redraw or in our fabulous forum.
Oldschool,  no the  flanged output volume is strong indeed, manual seems to be working very well. Again just the auto sweep is "sick" and the enhance problem which PT also suggested a larger value Pot or trim, I thought I'd explained it wrong and larger value would make it more FB faster.  I may try a series resistor before the Trim . BUT as I responded before, my thoughts are like yours. I would hate to make that change...fix the problem, and just be masking the thing that caused it in the first place!!
Thanks guys I'm confident knowing you're all thinking about it.
Still I haven't gotten any thoughts on improper trmpot settings possibly causing a sweep so uneven and detun(ey)? I know I should be able to answer that myself but I don't own a scope and also sometimes don't trust thelittle metal trims I use either. 

[moosapotamus]

Oldschool, no the  flanged output volume is strong indeed...

I think oldschool was asking if there is any difference in volume between bypass and flange. If so, that might point to his idea that there might be too much gain from somewhere causing your enhance control issue.

BTW, Gripp sent me his layout docs to post...

http://moosapotamus.net/IDEAS/ADAflanger/ADAflanger.html

... at the bottom of the list. Nice work!

analog kid - That's the layout you are using, right?

~ Charlie

[oldschoolanalog]

Yes, I was referring to a vol difference. I noticed something  curious. The pre emphasis (A/DA schem) has 2K7 & .01u. Stephens scheme uses 4K7 & .01u. This is less pre-emph gain than the A/DA. Maybe this is having some effect w/the enhance issue? Maybe try 4K7 there?

[StephenGiles]

Yes but don't forget the limiter would compensate for any increased gain - or would it? Surely that little circuit hanging from the - input of that opamp is to tell it what range of frequencies to boost and by how much? Mark?

[Gripp]

I'm not Mark , but I'm really curious about this too, so Mark?
The way I see it, the two approaches used in the limiting section (diodes in op amp feedback loop, rev4, like the one on top in the schem Stephen just posted, or diodes to Vbias, rev3, the one in the bottom of that schem) are very different in that the rev4 setup includes the global feedback (enhance) and so limits global feedback while the rev3 is more of an interstage limiter but has no effect on global feedback. Is this line of thinking right?
Best!
Pelle G

[StephenGiles]

I was throwing this to Mark Hammer! I have to cook dinner now - my wife has left her sing (sacred harp) to miss the football crowds in London.

[oldschoolanalog]

+1 for a Hammer intervention. Maybe R.G. could help shed some light on this too.(pretty please w/sugar on top... ) Thats what I call "asking for it w/both barrels" !  Thanx guys!

[analog kid]

PLEASE don't let me stop the coming together of minds here but since parts values came into discussion I had to put these in the discussion!   btw I plan to post my vtgs or partial at least but there are so many that are effected by Range and Manual setttings it'll take time.
  because I've found quite a few difference between values I'm using and those found in an ADA operational schem of Rev 3. that I've just looked at.  my ref vltgs do match those in the schem at least
as follows if someone can help me figure it any of this could play into problems:

two major cap differences
C 28 (IC3c) and C7 (IC1b) are both listed  a whopping .47uf rather than .0047 respectively 
   I know it's not unheard of for couple wrong values to be planted in a fact.schem though

Resistor values that are different are as follows:
R3 shown as 2.7k rather than 4.7k in my parts list
R10(between diode limiter in series with c7)
          is 27k instead of 47k

May be ironic but it seems to me values for c7,r3,r10 could all affect the area around IC1 which I'm having issue with.

R43 (at pin 6/7  output amp)   27k instead of 4.7k  ?

   these all around max clock range trim
R63/64 are both 10k rather than 20k 
these are just in series with each outer max clock trim
C26 as 22uf opposed to 33uf
to ground from LM324 pin 4
  Sorry oldschool , that's what I meant when I said  " flanged output is strong indeed", Compared WITH BYPASS! Duh, I'm sorry
I notice my flanging is fairly darn nice and useable when set to slower speeds, maybe it's that the eneveness is not as noticeable when "stretched out" but as soon as higher speeds are reached it becomes extremely wide, abrupt and detuned in character. sorry I wish I could sample it.

[analog kid]

Ok guys sorry for the back to back posts but while investigating some of these values I came across I believe a big part of my problem due to (what I see) as a layout error of sorts, more specifically error in the layout instructions.  I've been scrutinous of the note stating all polarized pt +'s to Left or Down, but until now thought it to be correct. But while trying a lower value from LM324pin 4 to ground I dicsovered that C26 , if placed in the board (+)Left is indeed reversed! So on that cap it's (-)left (+)right.       Unless of course I've lost my mind ?
Upon putting in a 22uf(in place of 33uf) correctly I seem to be able to get much better sweeps at fast speeds but still yet only with the right combo fo Range(very low) and Manual controls. otherwise I still got something like those really annoying type abulance sirens..we-ah-we-ah-we-ah-we-ah.          can someone else please look at this cap polarity? I'm very anxious to hear outlook on those prt values as well.   I hope I'm getting close to the end result, Hopefully any of my discoveries from troubles will help some of you build this thing easier 

[oldschoolanalog]

Part values HAVE to be discussed at some point, so consider yourself a pioneer of sorts on this aspect! Here is what I will do if you're interested. I have a 3010 reissue A/DA flanger in my arsenal. Post some control settings (you know, this pot 12:00, that pot 10:00 etc.) so I can get a better idea where the detuning occurs. I will compare them w/the same settings on my A/DA, and maybe we can come up with something. In the mean time try turning down the range(less LFO) and/or enhance pots at faster settings; and see if that helps. Also try turning up the manual pot at faster settings(less delay),and check out what gives. This unit is capable of a vast array of sounds. Some beautiful, some weird, and some downright nasty/ugly. The controls are very interactive, and there is a definite "learning curve" when first experiencing one. This aint no BS2 man! Keep us posted!

[analog kid]

Thanks for being willing to break our your 'piece' to help me out! check your PM.
Yes as I said but didn't elabortate on the ugly uneven sweep with "faster" speed settings DOES disappears with the Range pot turned down low.  And when I say faster speeds(I'm using a 500kB btw rather than Revlog/ I'll put one in tonight ) I DO mean speed, but the taper is not what I expect from a linear pot. The rotation where all my mid-fastest speeds are is the last 1/4 turn and also where all of the following begins to become at all aucible. And now to be more descriptive of it w/o samples... With Range pot at FULL CW goes from a staggered 4 note sweep where you can actually hear it's travel across a four 'tone
                                                                           ' wuh
                                                                                  uh
                                                                                      uh'   (representing slight pitch drop
(this pattern controllable of course by the speed setting, again, in the last quarter turn where all the speed is)  Then as the Range pot is rotated CCW as it reaches probably 12:00 this 3 tone pattern begins to sound more like just a Two note wobble back and forth with less "pitch" defintion between the 3 individual tones as turned ccw. Until at min. Range becomes not much more than a mild Vibrato.  Which unfortunately is the only place I can get very useable flanging.
I know it sounds a bit funny desribed that way but I think it's a pretty accurate description of the sweep , I'm sure you guys can relate to it and recognize what I'm describing. (fingers crossed)
But that repeatable stagger is maybe something that will point out a problem to a more experienced lfo mind than mine.

[RedHouse]

Hey Moose, I've lost the plot after 13 pages of posting.

Are we making an ADA flanger with (modern available parts) or are we re-designing the ADA into a SBF-DIY mod project?
(just asking)

Seems at first we were going to do a double sided board, made in a board fab shop, gettin rid of the in-between-the-IC traces and make it work with modern available delay chips, then a bunch of we-should-do-this-n-that came along with LFO mods etc ect ect ...where are we now?

When I threw my hat in the ring buy boards waaaayyyyy back in this thead ...I was wanting an ADA flanger, are we still going there?.

-Brad