A/DA Flanger does TZF?

[StephenGiles]

http://www.bandboston.com/flash17.html

Click on the spaceships to the right of the screen for some very nice doppler!

[puretube]

 

[StephenGiles]

Could we perhaps use one of the unused sections of the 4007, voltage controlled by the LFO, to vary the wet signal's series mixing resistor? What about including a small signal detector so that it only kicks in
a) when the sweep approaches the near TZF point and therefore the level is considerably reduced or
b) some other point which could be preset

Pmos or Nmos?

[puretube]

I`d implement something more predictable, like an OTA...

[joelap]

<noob mode>Uhhh... yeah I feel like a bit of an outsider here... I know the flanger is great and has a very wide sweep and thats my reason for building it... but what is exactly TZF?  </noob mode>

[oldschoolanalog]

OK, you're about to build this thing, so... Make a big pot of coffee, and go to pg. 1 of this thread. Go through the whole thing.  It's all in there, and then some.

[joelap]

OK, you're about to build this thing, so... Make a big pot of coffee, and go to pg. 1 of this thread. Go through the whole thing.  It's all in there, and then some.

That's what I was afraid of 

[StephenGiles]

I`d implement something more predictable, like an OTA...

That makes sense, but the CV would need to be held at a point that provides 1:1 gain in the OTA until the audio signal drops to the level below which gain is to be applied to the VCA - then that level would be detected and allow a portion of the LFO voltage (converted into a current I think for the OTA) to make the required gain.

I don't have the circuit of the noise reduction section of the ADA with me, but part of the circuitry required may already be there because that is effectively a small signal detector is it not?

[StephenGiles]

On the other hand, it would probably make the flanger sound quite unnatural - but still a good excercise in electronics!

[StephenGiles]

Sorry, double post!

[StephenGiles]

What about a VCA on the output driven by a pluck follower in the control circuitry, as designed by Craig Anderton in the AMS 100, on which the voltage increased with the speed of plucking the strings. Again this might be configured to only increase the VCA output once it approaches or drops below a certain level?

[oldschoolanalog]

Upward compression? Somewhere?

Any thoughts?

[oldschoolanalog]

OK folks.  Rev 01  was for 20+ boards. I only count ~5 build reports. What is everybody waiting for? Anybody else have anything to report?

[BMF Effects]

OK folks.  Rev 01  was for 20+ boards. I only count ~5 build reports. What is everybody waiting for? Anybody else have anything to report?

I'm ordering the last of the parts I need while trying not to ask stupid questions. There are a few things that have me stumped but I'm trying to work through the answers myself. The other thing is I'm a little afraid to fire this thing up because if it fails (and I was very careful with the build so I don't think it will), trouble shooting will be a nightmare.

[StephenGiles]

But I have suggested time and time again that one section is built at a time and tested to make sure that it works before moving on to the next section. Just stuffing the board like there's no tomorrow (ring any bells?) is likely to result in disaster, unless you are working in an electronics sweatshop, and the nice gentleman in the next room tests the beast on a nice scope!

[oldschoolanalog]

Please feel free to ask any questions about this circuit/build. Thats what this forum is all about (That was my impression, at least...). Some of us who have successfully completed this build would be happy to answer to the best of our abilities. OK?

[BMF Effects]

But I have suggested time and time again that one section is built at a time and tested to make sure that it works before moving on to the next section. Just stuffing the board like there's no tomorrow (ring any bells?) is likely to result in disaster, unless you are working in an electronics sweatshop, and the nice gentleman in the next room tests the beast on a nice scope!

You're right, you did. So if it doesn't work I have myself to blame. I did take my time though and I'm fairly confident. If all should go wrong, I promise not to whine and complain about it.

[BMF Effects]

Please feel free to ask any questions about this circuit/build. Thats what this forum is all about (That was my impression, at least...). Some of us who have successfully completed this build would be happy to answer to the best of our abilities. OK?

Okay...

C17 is listed as a 2.2uF. The legend on the board denotes a normal film cap. Is that correct? A 2.2uF film cap would be rather large, so am I correct in assuming it's a 2.2uF tantalum?

C29 is a 51pF and is screened twice on the PCB. Is this installed twice, one or the other...?

From Charlie's notes - "Pads at E - Timing capacitor(s) for LFO. For the ADA Rev4 configuration, install only C24 and install a jumper to tie the positive terminal of C24 to the junction of the Speed pot lugs 2 & 3. Experiment with the cap's value, orientation and/or using a non-polarized capacitor in this configuration."

I do not have the board in front of me right now but I think I remember reading through this thoroughly, comparing the board to the notes and seeing that there was no junction between the cap and lugs 2 and 3. I'll have to go back and check it when I get home.

Also, if anyone would be willing to post pics of their completed boards I'm sure people would be most appreciative.

[bluesdevil]

I've got a helluva toothache/jaw infection right now, but I'll try to make sense and help:
For C17 I made a non-polar cap by using 2 tantalum caps wired in series with their negative leads connected... see the FAQ for more info. I used two 4.7uf's in series and it worked.

Just use the lower "C29" spot for one 51pf. The extra "C29" and the two pads are for  another cap to be switched in parallel, if you want to experiment with a selection of timing speeds.

The LFO caps choice can be confusing!!! I went with using two 4.7uf tants in the two spots with their negative leads connected by placing a jumper from pad "E" to the pad between 'em.
    I basically went with revision 4 parts and used Charlie's additional parts add ons.

Hope that helps and good luck.... now I'm going to have to find the courage to try DIY dentistry, haha!!!!

[bluesdevil]

Oh yeah, make sure to print out the layout and schematic to study together....... blowing up the layout to full page size really helps you to see what's going on with the board and will make more sense along with the help of the schematic.