MN3007 ADA Flanger - Overall Depth Control?

[Paul Marossy]

I did a search but didn't really come up with anything. What I was wondering is if there is a way to add a depth control that controls the overall depth of the effect. Sometimes I want to have just a touch of   flanging because it's a little to dramatic for my liking, so I would like to be able to dial that back a little without touching any of the other knobs. Is this possible? I have a couple of ideas but I am not sure if they would work or not....

[armdnrdy]

Hey Paul,

Have you tried turning the resonance control down? That's the "feedback" control which should tame the effect considerably.

[Mark Hammer]

It ought to be possible at the mixing node of the dry and wet sgnals.  Where that is would depend on the pedal issue you have made.  I see one SAD1024-based issue has passive mixing via a pair of 8k2 resistors.  If a person made the one coming from the wet side 10k, oe 12k, that would dial back the effect intensity a bit, while not tampering with the sweep, delay range, etc.

This is why I like to say that a REAL flanger has 5 knobs: rate, sweep width, initial delay, feedback amount, and wet/dry balance.

[Paul Marossy]

It ought to be possible at the mixing node of the dry and wet sgnals. 

I was thinking it would be something along those lines, just not sure how to institute it. Looking at this schematic here, http://www.moosapotamus.net/images/FlangerClone_SCH_rev5_MN3007_jan2010.gif I was thinking that maybe I would have to mess with R14 or R41, but I am not real sure about it. I was thinking maybe a 10K pot and 17K resistor in lieu of a fixed resistor in place of R41 might do the trick. I get a little lost with what is happening on this particular schematic. 

This is why I like to say that a REAL flanger has 5 knobs: rate, sweep width, initial delay, feedback amount, and wet/dry balance.

Yeah, I kinda feel that way too. 

[moosapotamus]

Actually, for a wet/dry blend, I think you should probably be looking at R42 (wet signal) and R41 (dry signal). If I was doing this, I might try replacing them with a B50k pot for a wet/dry blend.

Another option would be to make T6 an external control. This is also a mix control and might give you the same kind of sonic result that you might get from replacing R42/R41 with a pot, and might be simpler to implement.

I think armdnrdy's suggestion to decrease the resonance is also a good idea worth trying. You could just tweak T2 to get it as low as you like, to see/hear if that's the kind of depth reduction you like.

These options might sound a little different, so you might have to experiment with each to find what you like best.

~ Charlie

[Paul Marossy]

Yeah, I guess a blend control replacing R41/R42 might work. Although I wrote something else, I meant to say that I would try a 10K pot in series with R41. Guess I need to experiment with it a little bit...

[moosapotamus]

Try putting the pot in series with R42 (not R41) if you want to be able to decrease the depth of the effect.

If that doesn't quite do it for you, you might try just lifting R42 to break the wet signal flow at that point. You'll still get some effect because the delay signal is still being fed back into the clean signal via the Enhance control (P1). Should definitely make the effect less intense, and if you like it, you can just add a toggle to switch R42 in/out. Then you might have a hi intensity setting and a low intensity setting via that toggle.

~ Charlie

[Paul Marossy]

Try putting the pot in series with R42 (not R41) if you want to be able to decrease the depth of the effect.

If that doesn't quite do it for you, you might try just lifting R42 to break the wet signal flow at that point. You'll still get some effect because the delay signal is still being fed back into the clean signal via the Enhance control (P1). Should definitely make the effect less intense, and if you like it, you can just add a toggle to switch R42 in/out. Then you might have a hi intensity setting and a low intensity setting via that toggle.

~ Charlie

OK, thanks! Will try it out when I get a chance.

[armdnrdy]

I was looking at a few flanger designs when I thought of your need for a "depth" control.

I think that you can insert a pot (try a 100KB) between the output of IC4B, and the range trimmer.

Connect lug 3 of the depth pot to IC4B pin 7, the wiper to pin 3 of the Range trim (P4) and lug 1 of the Depth pot to ground.

You might want to put a resistor (try 10K) between lug 1 and ground so that the LFO is not cut out completely when the pot is all the way counter clockwise.

Instead of mixing between wet and dry this should control the LFO amplitude for a genuine Depth control.

[Paul Marossy]

I was looking at a few flanger designs when I thought of your need for a "depth" control.

I think that you can insert a pot (try a 100KB) between the output of IC4B, and the range trimmer.

Connect lug 3 of the depth pot to IC4B pin 7, the wiper to pin 3 of the Range trim (P4) and lug 1 of the Depth pot to ground.

You might want to put a resistor (try 10K) between lug 1 and ground so that the LFO is not cut out completely when the pot is all the way counter clockwise.

Instead of mixing between wet and dry this should control the LFO amplitude for a genuine Depth control.

I'm really liking this idea. Since I haven't tried anything yet, I think I will try this idea first.

[moosapotamus]

That's a cool idea, Larry... a "true" LFO depth control. Seems like you would also have to cut the trace between P4 lug 3 and the C24/IC4 pin 7 junction for that mod to work. Yes/no?

~ Charlie

[Paul Marossy]

Seems like you would also have to cut the trace between P4 lug 3 and the C24/IC4 pin 7 junction for that mod to work.

Now that you mention it, that is a good question.

[armdnrdy]

I'm just working off of the schematic.
Remember....I routed my own board with off board pots.

If you are working from one of Charlie's boards....then yes...cut the trace.

Good catch Charlie!

[Paul Marossy]

If you are working from one of Charlie's boards....then yes...cut the trace.

Thanks for the clarification. I will give it a try soon.