MN3007 ADA Flanger Clone Questions

[Paul Marossy]

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.

OK, but what FET are you using?

[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.

OK, but what FET are you using?

I was using a J201 and it cuts any noise when Im not playing. I have some 2n4393 from older flanger builds that I could drop in. The threshold doesn't really seem to have anything to do with the other two mods Bajaman is recommending.

Im about to upload a video of some noise at one part of the sweep too so I can see if other people have experienced the same sound.

[neil411]

Paul,

I replaced R65 with a 150K resistor, added the 22k resistor in series with C37, and replaced the B10k Threshold pot with a B100k. I had to re-tweak all the trimmers again. There is nothing "alleged" about the improvement from my point of view. I definitely have more usable sounds and a much more dramatic range in the flanging effect.

I have the 2N4393 in place, which is what the 3007 BOM called for.

[Nitefly182]

Paul,

I replaced R65 with a 150K resistor, added the 22k resistor in series with C37, and replaced the B10k Threshold pot with a B100k. I had to re-tweak all the trimmers again. There is nothing "alleged" about the improvement from my point of view. I definitely have more usable sounds and a much more dramatic range in the flanging effect.

I have the 2N4393 in place, which is what the 3007 BOM called for.

I missed the change to B100k. lets see if that makes the difference.

[Tantalum7]

How many builders of this board have now been able to compare the stock build with the the build after these changes?  I am still waiting for some parts, and I'm not sure if I should make these changes before I fire it up for the first time or if I should wait to see what happens.  It seems that there are some conflicting reports as to the difference the changes make.  Can anyone else side add some data?

[Nitefly182]

OK

2n4393 in. 100k threshold pot in. Threshold pot now works like people say it should and not just how the manual says it should (ie just noise reduction).

I left the series resistor by C37 out. I didn't like that it reduced the perceived mix of the flange.

Here is a video of some funky noise Im getting if anyone has an idea about what its coming from:

http://www.youtube.com/watch?v=IsbKaK4KhV4

[bajaman]

I left the series resistor by C37 out

Put it back in and adjust the trim pot TR to between 60 -75% rotation clockwise.
Honestly without a scope to see what is going on you are just "pissin' in the wind"
bajaman

[Nitefly182]

I left the series resistor by C37 out

Put it back in and adjust the trim pot TR to between 60 -75% rotation clockwise.
Honestly without a scope to see what is going on you are just "pissin' in the wind"
bajaman

There is no "TR" trim. There are TR1-TR6 pots. Are you referring to TR6 which is right before C37? The Clock Nulling trim?

[bajaman]

nitefly - I listened to your YouTube clip - it sounds like you have not calibrated it properly - if you do not have a frequency counter function on your DMM - BUY ONE THAT DOES!!!!!!!
If you do not have a scope - take it to someone who does - you have way too much delay level compared to straight signal.
A scope with the range set to fully counterclockwise will confirm this - i assume you ave a signal generator (not a guitar ) to see the waveform.
Honestly without meaning to be condesending or crushing your spirit of DIY, this is NOT a project for knob twiddling bootweakers. if you do not have the calibration procedures correct (don't forget to double the ADA recommendations for clock speeds when using the MN3007 ) access to a signal generator, frequency counter and oscilloscope then you will NEVER get this to work properly - take it to someone who has the tools required.
happy flanging
bajaman

[bajaman]

Are you referring to TR6 which is right before C37? The Clock Nulling trim?

not really a clock nulling trim - more a BBD output level trim - but yes the one right next to the MN3007
bajaman

[Nitefly182]

nitefly - I listened to your YouTube clip - it sounds like you have not calibrated it properly - if you do not have a frequency counter function on your DMM - BUY ONE THAT DOES!!!!!!!
If you do not have a scope - take it to someone who does - you have way too much delay level compared to straight signal.
A scope with the range set to fully counterclockwise will confirm this - i assume you ave a signal generator (not a guitar ) to see the waveform.
Honestly without meaning to be condesending or crushing your spirit of DIY, this is NOT a project for knob twiddling bootweakers. if you do not have the calibration procedures correct (don't forget to double the ADA recommendations for clock speeds when using the MN3007 ) access to a signal generator, frequency counter and oscilloscope then you will NEVER get this to work properly - take it to someone who has the tools required.
happy flanging
bajaman

Kinda funny that I have built 30 of these and everyone loves them so I must be doing something right.

The clock is calibrated to 1.3mhz with the manual control at max and all other controls at minimum. Are you suggesting that the clock be set to 2.6mhz? I tried that and the sound was not nearly as nice. The series resistor with C37 reduced the delay level output which made the flanging much more subtle which was also something I did not like.

[moosapotamus]

OMG - "When it rains it pours!"

bajaman!
Where have you been all our lives!!! Oh, yeah... over at the other forum.
Seriously, if you haven't picked it up from oldschoolanalog's posts... your analyses is exactly the kind of feedback that this A/DA project has needed from the beginning.

I've only read up to this point once, But I plan to go back and try out all your findings and suggestions, too. It is really good to hear that the best can be gotten from this initial MN3007 circuit board with only some minor modifications. I feel that some minor revisions to the circuit layout may be in order and more PCBs will be in the future, too!

Awesome!
~ Charlie

[moosapotamus]

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

Just a minor clarification... As OSA mentioned, There is an error in the schematic... Q2 should be 78L09. And there are pads for jumpers in the layout that allow you to reverse the power/ground connections as needed if you want to try using a 3207 instead of the 3007. The details are outlined in the build notes. Post if you have any questions about that.

ITMT - I'm checking out bajaman's recommendations.

~ Charlie

[oldschoolanalog]

The clock is calibrated to 1.3mhz with the manual control at max and all other controls at minimum. Are you suggesting that the clock be set to 2.6mhz? I tried that and the sound was not nearly as nice.

Note bajamans advice to follow the A/DA calibration procedure exactly.
Here: http://moosapotamus.net/IDEAS/ADAflanger/ADAcalibration.jpg

...To adjust just follow the ADA calibration procedure (moosapotamus site has it i think) EXACTLY but set 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)

Take note that A/DA says to take this reading at Pin 13 of IC6 (4047); the clock test point (see A/DA rev 3&4 schematics).
This will give you a 2 phase clock of 34.8KHz to 1300KHz at pins 10 & 11 of IC6.
Exactly double the 2 phase clock of 17.4KHz to 650KHz that is specified by A/DA on the Rev 4 schematic.
My apologies for not making this more clear a long time ago.



 

[Tantalum7]

This recent discussion brings some questions to mind:  can someone who doesn't have a scope or (has yet to build) a signal generator get this flanger working properly without clock noise or other nasty sounding artefacts?  It looks as if at the very least a DMM with frequency counting ability is needed.  Will someone using this board with all of the exact parts listed on the BOM be able to get close by following someone else's settings on the trim pots--close enough to tweak into good working order? 

[Nitefly182]

This recent discussion brings some questions to mind:  can someone who doesn't have a scope or (has yet to build) a signal generator get this flanger working properly without clock noise or other nasty sounding artefacts?  It looks as if at the very least a DMM with frequency counting ability is needed.  Will someone using this board with all of the exact parts listed on the BOM be able to get close by following someone else's settings on the trim pots--close enough to tweak into good working order? 

By all means you can get the pedal to produce awesome flanging without a scope although the frequency counter is a big help. Its the last 5% that the scope is going to make happen as far as I can tell.

[Tantalum7]

Thanks.  To think that for just a few dollars more I could have gotten the DMM -WITH- the frequency counter.  When will I need that, I asked myself.  Hindsight...alas.   Still, when I do get a scope or access to one, I can dial that last little bit in properly.  Who knows, maybe I'll never even notice the difference.

[StephenGiles]

I'm not convinced, let's hear some samples.

[Nitefly182]

I'm not convinced, let's hear some samples.

Youre not convinced of what?

[StephenGiles]

I'm not convinced, let's hear some samples.

Whatever difference the use of a frequency counter makes.

Youre not convinced of what?