MN3007 ADA Flanger Clone Questions

[Paul Marossy]

A few questions:

1. Referring to the MN3007 ADA Flanger clone PCB I recently recieved from moosapotamus, is it OK to use a CD4049UBE chip for IC9? I ask because I remember that there is a buffered and unbuffered version of that chip, but I don't know if it matters for this circuit or not. The parts list does not specify anything other than "CD4049".

2. On the 18V wall wart, what mA rating is required?

3. Has anyone had any problems with popping noises occurring when adding an LED to the bypass switch?

4. Is the heat sink on the LM7815 really necessary? All of the real ADA Flangers that I have been inside of never had a heat sink on the power regulator.

5. Is there any advantage to using an LM324 for IC1, IC2 & IC3 over using a TL074?

6. Where do you get a 500K reverse log pot from? Small Bear?

7. On the 2N4393 FET, has anyone used something else that works besides that FET? I only ask out of curiosity because I recently repaired a broken ADA Flanger for someone, and the original LS4393 turned out to be the culprit (or appeared to be), and when I tried to use any other FET with similar specs to the LS4393, it wouldn't work - including the 2N4393. The only FET that would work was a J201. I just want to be prepared for a Plan B in case I have the same experience with my clone that I am building right now...

[oldschoolanalog]

1: 4049UBE is fine.
2: I'd say 18V@100ma is more than adequate.
3: No pops. Use a high brightness LED w/a large current limiting R.
4: No.
5: LM324 uses a bit less current. Not really much of an advantage in this case.
6: Yes, Steve has them.
7: In J201 we trust.
Enjoy!
Dave

[Paul Marossy]

Thanks! I can't wait to get it up and running. 

[oldrocker]

Hey Paul, it's good to see you excited about building again.  Let us know how it goes.  I wouldn't mind trying to build one using a 4049 also.  I'm not sure how to do it myself.

[Paul Marossy]

Hey Paul, it's good to see you excited about building again.  Let us know how it goes.  I wouldn't mind trying to build one using a 4049 also.  I'm not sure how to do it myself.

Well, don't expect me to building a bunch of stuff. I already am helping someone wire up their one the guitar pedals in their product line for money since my hours were cut at work last year, so I'm only building stuff that is really worthwhile. This is one of those types of projects. 

Not to mention that I have a "full-time" job of 36 hours a week, playing on the church music team & doing a little studio work here and there, in addition to being a dad and a husband. I'm busy enough! 

[neil411]

Charlie, I have another question.

In reading the calibration and setup instructions on your website, it says to use a frequency counter. I don't have one of those. Is there any other way to calibrate, and if not, can anyone recommend a good, relatively cheap one?

Thanks

[StephenGiles]

Your ears

[neil411]

That's good, my ears are cheap, and I have two of them.

Is there a specific order to adjust the trimpots, or should I just use the order that's laid out in the Calibration and Setup sheet?

[oldschoolanalog]

Your ears

+1 on that. Just realize the trimpots are very interactive. You'll have to go back and forth between them to get it "just right".
I would start with T4 & T5 centered and take it from there. Be patient and trust your ears.

[neil411]

Thanks,

Do the trimpot numbers on the PCB match up with trimpot numbering in the A/DA calibration sheet? They don't seem to.

[oldschoolanalog]

T4 & T5 of this schematic:
http://moosapotamus.net/IDEAS/ADAflanger/ADA_MN3007/ADAflangerSCHmn3007.GIF

[Nitefly182]

Is there a test point for the cancel trim? I dont have my board in front of me but Im guessing its going to be on an IC rather than a dedicated point on the board.

[neil411]

I guess my question really is what does each trimmer do, and how do I know if it is the correct range? With six trimpots and five external knobs, it's a little difficult to set it "by ear" if I don't at least have some idea what each trimmer is supposed to adjust and what I can expect each knob to do. I don't have an original A/DA flanger to compare it to, so I'm a little lost here.

[Paul Marossy]

Your ears

+1 on that. Just realize the trimpots are very interactive. You'll have to go back and forth between them to get it "just right".
I would start with T4 & T5 centered and take it from there. Be patient and trust your ears.

Yeah, that's basically what I did on the last two ADA Flangers that I have repaired. It just takes a little bit of patience.

I guess my question really is what does each trimmer do, and how do I know if it is the correct range? With six trimpots and five external knobs, it's a little difficult to set it "by ear" if I don't at least have some idea what each trimmer is supposed to adjust and what I can expect each knob to do. I don't have an original A/DA flanger to compare it to, so I'm a little lost here.

The schematics specify what the trimpots do. You can get some idea about what they do by their descriptions.

[oldschoolanalog]

I'll go through my notes/files and post some answers/suggestions as soon as I can. In the mean time search "A/DA+flanger" (type it in with the quotes and the +); there is enough there to answer many questions.
Happy reading!
Dave

PS: Brew a large pot of strong coffee.

[Jason M.]

A few questions:

5. Is there any advantage to using an LM324 for IC1, IC2 & IC3 over using a TL074?

Isn't the LM324 part of achieving that signature wide sweep LFO?

The TL0xx series are JFET input op amps.

[neil411]

thanks oldschool,

I have been tweaking it. I read the original A/DA owners manual and that helped me understand what each knob was supposed to do, although the sample settings they show don't work with my build at all.

It also seems that the range and manual knobs have a really narrow useful range, way less than the full sweep, more like 1/10th of the full sweep, and a very small movement makes a huOrge change in the sound. It seems that one of the trim pots might make the range wider. Or is that the way it's supposed to work?

[Nitefly182]

thanks oldschool,

I have been tweaking it. I read the original A/DA owners manual and that helped me understand what each knob was supposed to do, although the sample settings they show don't work with my build at all.

It also seems that the range and manual knobs have a really narrow useful range, way less than the full sweep, more like 1/10th of the full sweep, and a very small movement makes a huOrge change in the sound. It seems that one of the trim pots might make the range wider. Or is that the way it's supposed to work?

Sounds like something is wrong. Did you use the right pot tapers and values?

[Paul Marossy]

A few questions:

5. Is there any advantage to using an LM324 for IC1, IC2 & IC3 over using a TL074?

Isn't the LM324 part of achieving that signature wide sweep LFO?

The TL0xx series are JFET input op amps.

I don't know the answer with absolute certainty, but comparing data sheets, the TL074 has a much higher slew rate and twice the bandwidth of the LM324. It would seem to actually be a better IC chip to use than the LM324...

[neil411]

Nitefly,

Yes, I have the right parts. I have been playing with it some more, and I didn't have the threshold up high enough. Now the range and manual make more of a difference. I think I can get even more with a little trim pot adjustment. I'm starting to figure out how the thing works.