Vox 1902 Flanger

[J.Street]

Hello,

I've been looking for a project and think I've found one with this flanger.
Got some questions though.

1) Where is the other end of R32 connected or is it open?

2) Is the switch in J1 used?

3) Is C17 ( IC6,pin7 ) a non-polarized electrolytic?

I'm using , 1902flan.pdf from,  http://www.schematicheaven.com/
for reference.

[Joep]

Hope this helps:

1. Yes, you can leave it open, or you can connect is to the wiper (central
lug)

2. No

3. I think so, although I'm not sure. I would use a non-polarized if I were you.

Bye,

Joep

[Rob Strand]

1) That part of the circuit is definitely wrong on the schematic.

 C11 should connect between pins 1 and 2 of IC 6.
 The wiper connects to R36, and the counter-clockwise pot (R32) terminal.
 The clockwise terminal of the pot (R32) goes to pin 1 of IC6.
 The pot R32 should be a reverse log taper.

2) I could have sworn the original unit use the switch on the input jack and not the output (as shown on that schematic).  It won't make or break the effect  but you might as well make is consistent to other effects.

3)  C17 was a non-polar electrloytic cap.

[Bill Bergman]

Looks like a pretty cool project, any idea how they sound?

[Rob Strand]

They sound as good as any flanger but if you already have an MXR (The vox is a close rip-off of the MXR),  or, a Boss BF-2 it's probably not worth building.  BTW, I owned one of these some time back.   It chews up the two 9V batteries pretty quickly, it's best run from a 18V wall-wart.

[J.Street]

Thanks all for the responses and thanks for the circuit revisions Rob.
OK, last question, IC3,pin5 has R23 connected to it.  It appears to be
2.4K ohms but from the pdf I can't be sure.

[Rob Strand]

It's 2.4k, unfortunately I've spotted yet another error on that schematic: there should be a 3.3nF cap from pin 5 to ground.  Some of those VOX factory schematics are shockers.

Here's another schematic which I have more confidence in,

http://homepages.ihug.com.au/~rstrand/yadda/VX_FLANG.png

If you are comparing the two schematics keep in mind *all* the designator numbers, like IC1, R33, C5 etc don't match- that's because the correct schematic is a trace and numbers weren't marked on the PCB.

[J.Street]

Thanks for the updated schematic Rob.  I'm going through both of them
now and probably start a board layout tomorrow.

Here's another schematic which I have more confidence in,

http://homepages.ihug.com.au/~rstrand/yadda/VX_FLANG.png

If you are comparing the two schematics keep in mind *all* the designator
numbers, like IC1, R33, C5 etc don't match- that's because the correct
schematic is a trace and numbers weren't marked on the PCB.

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