MN3007 ADA Flanger Clone Questions

[Nitefly182]

The 7805 is only to be used if you are using an MN32XX type chip that runs on 5v instead of 15v. The delay line issue is interesting. Ill have to try swapping out R65 to see if the clock works out better.

[Paul Marossy]

The 7805 is only to be used if you are using an MN32XX type chip that runs on 5v instead of 15v. The delay line issue is interesting. Ill have to try swapping out R65 to see if the clock works out better.

I'd like to see what the end result of that is also.

[neil411]

Bajaman,

On mod #2, the 22k resistor goes after C37 on the PCB?

[neil411]

I removed the 15v regulator and put in 48 ohm resistor, and I replaced R65 with a 150k resistor.

OMFG

MUCH better.

I am going to wait for clarification before I do anything else, but I can definitely confirm that changing R65 makes a huge improvement.

I'm going to play now before my wife calls me to dinner....

[Nitefly182]

I removed the 15v regulator and put in 48 ohm resistor, and I replaced R65 with a 150k resistor.

OMFG

MUCH better.

I am going to wait for clarification before I do anything else, but I can definitely confirm that changing R65 makes a huge improvement.

I'm going to play now before my wife calls me to dinner....

It looks like he was taking out the 5v regulator, not the 15v regulator. The 15v IC should stay in place. What difference are you seeing with R65?

[oldschoolanalog]

The board has an additional 78L05 regulator fitted (silkscreen is 180 degrees wrong for this IC!!!!) to power the CMOS and BBD chips - why!!

That's a misprint. That should be a 78L09 9V reg. It is there for those who want to try a 3207. It's not supposed to be installed if using a 3007. That's explained in the building notes:
http://moosapotamus.net/IDEAS/ADAflanger/ADA_MN3007/ADAflangerPCB_MN3007rev01notes.html

I fitted an additional 22k resistor (track break required) in series with the 10n capacitor and the inverting input of the gain stage immediately following the BBD outputs.

Thanks for that tip. That's exactly the type of info I was looking for when this was posted:
http://www.diystompboxes.com/smfforum/index.php?topic=72329.0

This allows a much deeper flanging effect to be heard (it could be a 20k preset with a 10k in series fitted externally if desired ).

I'll give it a try. I just wish somebody suggested this before the fact.

I noticed more than one person on another 38 page  thread on this site, complaining about the wobbly unatural and unusable high speed...

This is usually the result of getting used to the controls and wide sonic pallate of this unit. Try turning the range ccw and/or  back off on the regen. This flanger is capable of many very nice sounds; it's also capable of some very ugly sounds.

Okay - the original ADA flanger used a SAD1024 and then a MN3010 when the SAD became scarce. Both of these chips can give a 1024 stage delay, HOWEVER, they are both used as 512 stage delays in the ADA Flanger - take a closer look at the schematics - that's right, the inputs and outputs are paralleled in BOTH cases.( the MN3010 is two independent 512 stage delay lines)

Understood. Which leads us to...

The oldschoolanalog suggestion to use the MN3007, which is a single 1024 stage delay line has merit - it is still relatively easy to source and cheap (compared to the MN3005 and MN3010 etc.) BUT because we are now using double the delay line of the ADA Flanger we need to double the clocking speed to get the same results.(perhaps two MN3007 chips stacked would get closer to the MN3010 performance??!!).

Which I pointed out here:
http://www.diystompboxes.com/smfforum/index.php?topic=72329.0
Reply #4. The need to double the clock f is mentioned there.

The correct clocking speed should now be 69.6KHz to 2600KHz (not 34.8KHz to 1300KHz as in the ADA calibration specsheet)- don't worry the additional current buffers (CD4049) fitted, easily allow the MN3007 to be clocked at this higher speed.

In the A/DA calibration sheet these readings are taken at the clock test point. I mentioned that I take clock readings at the chip. (If you really want I'll dig up a link to substantiate that...) 34.8KHz to 1300KHz at the chip  is the same as 69.6KHz to 2600KHz at the test point.

I had to increase the 82k in series with the clock range trim pot to 150k to set the higher clocking speeds.(R65)

That will be useful to those who encounter that problem. Thanks! I didn't encounter that issue, nor did Charlie. (He clocked it to 1.4MHz [at the chip] IIRC)

In conclusion - after these modifications the TRUE sound of the ADA Flanger was heard at last.

And order is restored to the known universe  . Thanks Baja! Your expertise is always appreciated!

I am genuinely surprised that no one has seemed to notice that the MN3007 was double the delay line length required for this circuit though.
cheers
bajaman

I'm genuinely surprised that nobody saw mention of this back on Nov. 20, 2008 !

It would seem that there are some misunderstandings that just need to be cleared up. Before picking up a soldering iron, please read the building notes; with a copy of the schematic & component overlay in hand; this can help clarify things.

I'm gonna go build me something exciting now. Maybe a TS...
Peace y'all...
Dave

PS: cathexis built one of these from the schematic on vero and had none of the issues mentioned. He said it was "by far the quietest one I've played". Check out his build report & sound clips:
http://www.diystompboxes.com/smfforum/index.php?topic=73715.0

[bajaman]

Hi again guys
I have been hangin' out on 'the other forum' for the last couple of years so please excuse me if I have missed anything.
one of "the other forum's" members posted a link to moosapotamus and old schoolanalog's retrofit MN3007 boards for sale.
I purchased one of these boards from moosapotamus - very nice board at a good price too - and decided to build it.
When I had finished it I was a little disappointed in the "ugly sounds" it was producing,. This led me to further research the original ADA Flanger and it's versions.
in the process I read a 38 page thread on the ADA and TZF right here on Diystompboxes. Maybe I missed something but i could not see any reference to doubling the clock speed when using double the delay line length. Maybe I missed it BUT, running the clock at half the neccessary speed is the major reason for the "ugly sounds" encountered by many who have built this latest clone version. Honestly, once you double the clock speed ALL the speed and range settings are pleasant and extremely usable.
Another problem encountered during this build was the threshold circuit operation, although this is the first time I have mentioned this. I have tried 2SK117, 2N3819 and the old favourite here - the J201 AND none of them work properly with the ADA threshold circuit. I suspect a lot of builders simply leave the fet out and disregard the threshold control function. The problem is without the fet in position the 1 Meg resistor from drain to source is - well 1 Meg in resitance. Consequently the signal level from the BBD and its following inverting gain stage is very large. With the jfet in the circuit this 1 Meg resistor is paralleled by the drain source resistance of the fet and is typically a lot lower than the 1Meg resistance - it is closer to 120 ohms. This provides a large attenuation of the delayed signal unless the threshold level control voltage acts to turn the fet off.
Even with large line level signals processed by the threshold circuit the fet resistance is still very low - typically in the 3.5K ohms region with a 2N3819 n channel jfet. I went as far as replacing the threshold control pot with a 100k linear pot to get the threshold control to actually work at guitar input levels, but this is something i am still working on, and I will let you all know of my findings.
Naturally, there is a great degree of interaction between the threshold level setting and the gain of the inverting stage following the BBD chip - more later
In the meantime try the mods I suggested in my last post ( it does not matter which side of the 10n capacitor that the 22k resistor is placed ) and double that clock speed for the MN3007 as well as running it from a dropper resistor directly from the 7815 regulator ( toss the 78L05 - it is not needed!)
With regard to using the MN3207 - you will not only need the lower voltage supply but also a completely different layout because it works from a negative NOT a positive ground as the MN3007 runs from
Have fun - more soon!
cheers
bajaman

[bajaman]

follow up regarding the threshold circuit, fets etc.
I just spent the last couple of hours playing with the threshold circuit whilst monitoring the waveforms on the scope.
I retained the 100k linear threshold pot (I just could not get the range from a 10k pot).
With the threshold control fully clockwise it is efectively out of the circuit and consequently the fet is turned hard off.
With this setting and a socket for the fet on the board, I tried a range of n channel jfets that I had stock of. None of the different fets tried had any effect on this setting ( I was comparing to no fet at all in the socket ). However, when I turned the threshold control fully counter clockwise the differences were astounding (well interesting perhaps).
First up the J201 - hardly any difference at all from fully clockwise - not suitable
Next The 2SK117 - slight attenuaton - again not suitable
Then the MPF102 - hardly any attenuation - not suitable
Then the 2SK30 - again not suitable
Then the 2N5457 - very slight attenuation - not suitable
Then the 2N5459 - aha approximately 30% attenuation - looks promising......
BUT when I installed the 2N3819 I got maximum 50% attenuation - ideal - I tried a few more and they all worked fine.
I must get the correct fet LS4393 (or 2N4393) and try it, but for now the 2N3819 works as it should and almost completely attenuates the BBD output leaving just the dry signal.
One interesting discovery along the way - the best flanging effect occurs when the dry and delayed signals are the same intensity. After adding the 22k resistor as I suggested in my earlier post it is neccessary to adjust the trim pot on the output of the BBD (shown as simply TR on moosapotamus schematic) to obtain the same level of delayed signal as the dry signal - this is easy to see on the scope - just set the range control fully counterclockwise and use the manual control to sweep up and down - you will see the delayed signal collapse as you turn the threshold control fully counterclockwise - take a note of the dry signal level. Now turn the threshold control to full clockwise and adjust the trim pot TR until the signal level is now twice the dry level - you may have to sweep the manual control to give a clear picture on the scope.
Try these suggestions and you WILL get a whole range of very usable and satisfying sounds from this Flanger design - On the other hand tweak away in the darkness and you may get some meaningful sounds from within the chaos. Seriously - unless you have a scope and a good digital mulimeter with a frequency counter function on it you are never going to hear the GREAT sound this baby is capable of giving you.
Cheers
bajaman

[StephenGiles]

bajaman  -  I fitted an additional 22k resistor (track break required) in series with the 10n capacitor and the inverting input of the gain stage immediately following the BBD outputs.

Do you mean the 100n capacitor by any chance? I can't see a 10n in that part of the circuit - or has the excellent mexican food at our polo club last night affected my eyes!!!!!

[bajaman]

sorry 100n yes
bajaman

[StephenGiles]

sorry 100n yes
bajaman

That's a relief!! Here's a link to my drawing of the ADA Flanger showing Mike Irwin's modifications for the MN3010 version to use an SAD 1024. His advice was to leave out the FET and threshold circuitry as noise was not really that much of a problem.

http://www.4shared.com/file/90662621/fc1969ce/ada_MI_1024.html

Almost 6 years has passed since I drew this in Excel - and my arm still aches!

[bajaman]

His advice was to leave out the FET and threshold circuitry as noise was not really that much of a problem.

But that is NOT what the fet or threshold circuit is all about - read the ADA Flanger users manual - the threshold control is great IF you set it up with the correct fet etc. - it gives a touch sensitivity to the flanged sound - it was never intended for noise reduction
bajaman

[StephenGiles]

His advice was to leave out the FET and threshold circuitry as noise was not really that much of a problem.

But that is NOT what the fet or threshold circuit is all about - read the ADA Flanger users manual - the threshold control is great IF you set it up with the correct fet etc. - it gives a touch sensitivity to the flanged sound - it was never intended for noise reduction
bajaman

Yes it was, the manual describes it as "A noise eliminating gate". 

[bajaman]

I stand corrected - the manual does descibe it as a noise eliminating gate, BUT it works very much like a touch wah when set wrong as far as the manual is concerned and it is this effect that makes it worthwhile. i agree that the flanger is reasonably quiet without it - just illustrating more than one use for it.
See ya - I'm back to "the other forum" now ( you know where that is Stephen - that place where we only discuss fuzz boxes, as you once said when you were a member there )
bye bye
bajaman

[Paul Marossy]

Maybe I missed it BUT, running the clock at half the neccessary speed is the major reason for the "ugly sounds" encountered by many who have built this latest clone version. Honestly, once you double the clock speed ALL the speed and range settings are pleasant and extremely usable.

So, can you tell those of us who know enough to be dangerous exactly how to double the clock speed on the MN3007 version? IIRC, it's replacing R65 (82K) with 150K, correct?

[StephenGiles]

I stand corrected - the manual does descibe it as a noise eliminating gate, BUT it works very much like a touch wah when set wrong as far as the manual is concerned and it is this effect that makes it worthwhile. i agree that the flanger is reasonably quiet without it - just illustrating more than one use for it.
See ya - I'm back to "the other forum" now ( you know where that is Stephen - that place where we only discuss fuzz boxes, as you once said when you were a member there )
bye bye
bajaman

I love it!! Do have a look at the Space Filter thread if you have a moment.
http://www.diystompboxes.com/smfforum/index.php?topic=37931.40

[bajaman]

So, can you tell those of us who know enough to be dangerous exactly how to double the clock speed on the MN3007 version? IIRC, it's replacing R65 (82K) with 150K, correct?

This is neccessary to increase the high frequency of the clocking speed. To adjust just follow the ADA calibration procedure (moosapotamus site has it i think) EXACTLY but st the speed range to double what they specify. (34.8KHz becomes 69.6KHz at the bootom end and 1300KHz becomes 2600KHz at the top end)
Do the other mods for the delay level setting and threshold  as suggested in my earlier posts and you will hear the ADA Flanger in it's true glory.
If you can get the correct threshold fet (LS4393) all the better. Otherwise use the 2N3819 as a substitute - the J201 is useless in this application
That's all folks - read and do the mods but PLEASE use a scope and a frequency counter - you are pissin' in the wind taking the bootweak by ear route - save that for your next fuzz box build
happy flangin'
bajaman

[neil411]

Baja,

Thanks VERY much for this help. I have the 2N3819s on the way, and a new DMM with frequency counter is also in my future. But the mods (changing R65 and adding the resistor after C37) have made my build come alive, even if I could only tweak it be ear.

[Paul Marossy]

So, can you tell those of us who know enough to be dangerous exactly how to double the clock speed on the MN3007 version? IIRC, it's replacing R65 (82K) with 150K, correct?

This is neccessary to increase the high frequency of the clocking speed. To adjust just follow the ADA calibration procedure (moosapotamus site has it i think) EXACTLY but st the speed range to double what they specify. (34.8KHz becomes 69.6KHz at the bootom end and 1300KHz becomes 2600KHz at the top end)
Do the other mods for the delay level setting and threshold  as suggested in my earlier posts and you will hear the ADA Flanger in it's true glory.
If you can get the correct threshold fet (LS4393) all the better. Otherwise use the 2N3819 as a substitute - the J201 is useless in this application
That's all folks - read and do the mods but PLEASE use a scope and a frequency counter - you are pissin' in the wind taking the bootweak by ear route - save that for your next fuzz box build
happy flangin'
bajaman

OK, but does R65 still have to be replaced? You said something to that effect in an earlier post. From your answer, it sounds like that is a "yes".

I am currently using a 2N4393 FET, which I have been told works in these flanger clones. Seems to work OK, I guess. According to a cross reference sheet I have from the manufacturer of the LS4393, a 2N4393 is supposed to be a substitute for it.

[Nitefly182]

I swapped out R65. The difference was not dramatic. I dont think I could really identify any difference at all.

As I understand the extra resistor ins eries with C37 is supposed to even out the sweep? It really just decreased the fullness of the flange in mine. Reduced the presence of the sweep so it sounds like its in the background a little. I really dont think either mod is making these alleged dramatic differences.