MN3007 ADA Flanger Clone Questions

[12Bass]

Yeah, I couldn't get both points before I changed out those components, one or the other was outside the range. Now both are achievable in a couple of minutes. They are still inter-reactive.
Power is the next issue.
Thanks guys.

What is the voltage at the input of the 7815?

[njkmonty]

17-18vdc?

[Dave W]

If the 1054 output is sagging under load the 7815 might be dropping out.
Once you get a solid 15V out of the reg you will see the clock f's will change and it will need to be re-calibrated.
Also, any strange noises will disappear.

[Pierre]

hi !
i'm just putting toghether my 2nd mn3007 A/DA clone (my 4th counting the SAD1024 versions...). Could it be posible to use Vishay precision multiturn trim pots? like this one ?:

http://www.banzaimusic.com/Vishay-Trimpots/

...in my others A/DA clones i used Piher mini trim pots as the leg spacing is 5 x 5 mm, but i found a little to difficult to adjust (although i got them working ).

Merry Christmas from Brussels !

[Dave W]

Multiturn trimpots are my preferred choice for flangers. Just bend the legs carefully.

Moosapotamus A/DA clone. Rev. 01.

[Pierre]

thanks Dave W !!!
I just ordered a some of those trim pots...

by the way, very nice build !!!, i wonder what all those switches do, and the extra pot?
Would it be possible for you to share those mods ? (i'm very interested !!)

[Dave W]

Thank you. LFO/Comb switches the wiper of the Range pot fully CCW for fast switching between swept & filter f/x. Very useful, especially when using a CV pedal for the Manual settings. S1/S2 switches between the 2 speed pots. S1 is the stock value for slow sweeps. S2 is a 250 or 150kC pot (don't remember  ); optimized for faster sweeps. I still want to install RG's LERA circuit for ramp up/down between speed settings. This is a mod for another day and/or build. Res. Hi/Lo switches the wiper of the Res. (Regen) pot fully CCW for minimum regen. This is useful when switching to faster speed settings or going from extreme flange to a milder more chorus like sound. I did these mods "on the fly" and don't have any documentation. They are very easily figured out though. Worth a try and simple to reverse to stock if they aren't to one's liking. I have found them very useful. Especially in this "desktop" format where I have access to the controls without having to bend down a lot. All the other controls perform as in the build docs.
Happy Holidaze!  

[Pierre]

i'll definitely give some of your mods a try !
I was thinking of put a footswitch (i'll keep mine as stompbox) to do a full regen (à la Paul Gilbert's airplane flanger) "take off"...not sure how to do that, and add this time the pedal switch, as i have a wha enclosure laying around that i've made myself...but again, i'm not sure on how to make the expression pedal...

[WhenBoredomPeaks]

Is it necessary to use a metal enclosure for this circuit? Can i build it into a modular synth form? (MOTM) That basically leaves the circuit naked.

(i am asking this because of thenoise issues)

[StephenGiles]

I once installed a flanger into a cardboard box I cobbled together (rather like the flanger!!) and there was not as much noise as I would have expected.

[intripped]

I have flanger!  
i'm in the process of boxing it up and i'm thinking about the volume drop issue and it's solution
referring to moosapotamus schematic rev. 05 jan 2010, 2 resistors R41 and R42 have been lowered from 68k to 27k and a 10k pot has been added at the output, wired as a typical volume pot.

I'm thinking about a different way:
i want to add a 250K pot, wired as a variable resistor, in parallel with R41 and R42 (back to 68K value)
doing this I would theoretically be able to set the volume, varying the amount of signal at the input of the last op-amp, without changing the output impedence (i don't even know if this is a plus anyway)
what do you think of this solution?

[Fender3D]

R41&42 toghether with R43-R44-C20 form de-emphasis stage, if you change the ratio, you'll end with unbalanced treble (might be usefull though)...
and that pot, connected as per your schematic, will give you issues when fully CW

BTW

I have flanger!  

Bravo!!!
 

[intripped]

ok,
i was trying to preserve the ratio, with the variable resistor in parallel with both R41 and R42; another resistor in series with the pot would do the trick about the fully CW issue...
but probably this kind of solution it's not a good idea afterall. 

thanks for your reply Fender3d!

Bravo!!!
 

grazie! 

[Paul Marossy]

i'm thinking about the volume drop issue and it's solution
referring to moosapotamus schematic rev. 05 jan 2010, 2 resistors R41 and R42 have been lowered from 68k to 27k and a 10k pot has been added at the output, wired as a typical volume pot.

I got out my ver. 2009 MN3007 ADA Flanger clone last night after not playing it for nearly four years (built it right before I lost my job in March 2009 and then on to crisis mode for a couple of years). I'm still digging it. One issue I have though is that I think I have like a 50% drop in volume with the unit enagaged - painfully obvious with headphones on. I'm going to try something tonight to fix that. First thing I will try is changing the 100K voltage divider on the output. Maybe get rid of that 100K to ground altogether and see what that does for me. If that doesn't work, then I'll do a booster circuit at the output or something. Not sure why I'm even having this problem as it's built per the schematic and all...

EDIT: Hmm... I see on the latest schematic R41 & R42 were changed from 68K to 27K. Probably should try that first....

[intripped]

Paul, just modify your unit according to the last scheme from Moosapotamus linked above (change R41 and R42 to 27K and add a 10k pot (or trimmer) before the OUTPUT) - this fixes the volume drop issue.

i'm sorry for the confusion i have made: i knew that moosapotamus's solution was already tested and working, i was just curious about my alternative idea

[Paul Marossy]

Paul, just modify your unit according to the last scheme from Moosapotamus linked above (change R41 and R42 to 27K and add a 10k pot (or trimmer) before the OUTPUT) - this fixes the volume drop issue.

i'm sorry for the confusion i have made: i knew that moosapotamus's solution was already tested and working, i was just curious about my alternative idea

No problem, I built the thing way back in Feb. 2009 on a Rev 1 board so a few things have changed since then. I also discovered that I used 2.2K resistors for R32 & R33 instead of 22K - I had conflicting information at the time and apparently the 2.2K resistors were not the right values to use, although my unit functioned OK with those values. Not sure if that can also affect the volume, might be something of a factor I suppose.

Anyway, I just fixed R32 & R33 and also changed R41 & R42 from the 33Ks I had in it to 27Ks instead. Now the unit appears to be about as loud when switched on as in bypass mode, with a 1kHz test signal. I will try it with my guitar rig in the morning and see how it does. I did read about the 10K volume pot, it's an option I'll take if it's too loud when switched on. While I was at it, the threshold pot I changed to a 50K from the 100K I put in it and I used a 250K linear pot for the speed control, not perfect but it works to my liking.

EDIT: To my dismay, I still have the 50% volume drop. I did notice this morning that I used a 47K for R10 instead of 27K, once again because of conflicting information I had at the time. So I'll fix that tonight and see if that is the culprit.

[Paul Marossy]

Finally got the volume drop issue resolved, I even needed the 10K vol pot on the output. I had to change five more resistors. Apparently when I built it I used the values on the original ADA Flanger parts list instead of what was shown on the MN3007 schematic, which I guess was not the right thing to do. Anyway, I'm a very happy camper now.  

EDIT: Oh, and I also did the blinking LED thing. I think that is pretty cool. 

[moosapotamus]

Glad you worked it out, Paul.
Is that snake skin? Awesome looking enclosure!

~ Charlie

[Paul Marossy]

Glad you worked it out, Paul.
Is that snake skin? Awesome looking enclosure!

~ Charlie

Thanks, I do have agree that it is pretty cool. 

It's a snake skin imitation fabric that I got at a fabric store. I glued it on with white glue like I did with both of my DIY pedalboard cases. It works pretty well actually. Then a little super glue on the seams to keep them from coming apart.

I'm just happy that it's working like it's supposed to now. Shame it's been sitting in a drawer for four years, but it's a nice reunion. 

[jmasciswannabe]

I had one of those enclosures when one of the forum guys were selling, but when I went to indent for drilling I must have hit it too hard and the enclosure came apart. Very upsetting. Yours looks killer, thougH!