Q- component substitution for the Seek Wha??

[solderman]

Hi all
Sometimes someone puts an idée in your head and the only way to get it out is to follow it. This is what happened when I posted a question about the random sequencer for the Seek wha  In this tread.
http://www.diystompboxes.com/smfforum/index.php?topic=77363.0

Jacobyjd kindly gave me the answer I wanted and I replied and joked about that this would
Not fit in a 1590A and he replied that I might get away with 4 steps. That reply sort of got my brains going and I cold not leave the thought of testing and here is the result. I did not manage to fit the random part but I managed to fit in the original Seek wha in a 1590A enclosure.

Here is the project file. Ill get back with PCB layout and pics when I built and verified the layout. Since its so small you might lose it I have named it The Lost Wha

http://solderman.fatabur.se/Future%20project/Lost Wha.pdf

Q- The Q1 tranny TN3226, can I subst that for a 2N3904 or a 2N5088???
Q- Can I use any 4017 or do I have to use a  particular 4017
Q- If I subst the 3,3uF Film Cap with a E-lut is the anod to go to out on op-amp 2?
Q- I'm building my own LDR/LED Combo Any idée' about Dark/Light Resistance?

[jacobyjd]

Niiiiiiice! Nothing like a joke becoming reality...and then becoming awesome!

Any 4017 I've tried has worked fine, so I think you're good to go there. Without more looking, I don't think I could give you a solid answer on your other questions though.

[Mark Hammer]

Seems to me that, like all good sequencer-based devices, you want some means to provide "glide" as well as a stairstep function.  The easiest way to do that is to simply have a cap to ground between the 470R current-limiting resistor and the final common LED.  Choose one of two selected cap values, and you can have stairstep and two different degrees of lag, from a single SPDT centre-off toggle.

[solderman]

Thaks
BTW does any one know who have designed this circut is it Zachary Vex or has he "only" tuned it to hes liking or is ist TTG Andrew or what
I dont want to point to the wrong person or leave out some importent ones in the Design credits in my project file.

[jacobyjd]

AFAIK, the Vanishing Point is all Andrew's thing.

Basically, to do a sequenced effect, you're going to have the same basic building blocks, so the ideas could be completely independent of each other.

[earthtonesaudio]

The wah portion (except the LDR and maybe 1 or two other components) can be found in the Colorsound inductorless wah circuit which predates Zvex by a couple decades at least.  The sequencer portion is probably as old as the chip itself, likely something similar was published in the first appnotes for it.  However, combining the wah with the sequencer is a novel or "original idea," which as far as I know was first offered to the public by Zvex.

[sean k]

When I looked up TN326 there was no such thing but all the numbers corresponded to 2N deisnations so I looked up the 2N326 and it's an N channel germanium so a transistor with an hfe of 100 or so might be what you're looking for. BC109, 2N2222 etc.

[sean k]

So my little brain goes to work and what it does is throw another 4017 into the mix but what it does is step through a bunch of preset resistances that control the speed of the LFO. Kinda like stepper feedback? So the output of the LFO resets it's speed. That would be nuts!

I can't even imagine what would happen then.

Then you throw another 4017 in there on another LFO and it fires a 4066 that changes a range of capacitors, the glide Mark mentions, that hang off the 470 resistor on the LED firing the LDR. Sonic mayhem which may create a black hole or alternate universe...

[solderman]

Thanks all
The need to know questions (about the Q1 trannie and the 4017) has got an answer.  Earthtonesaudio, the info about that the Wha part was from the Colorsound inductorless wah circuit put me on the trace and lead to that I found this splendid article from another distinguished member of this forum, beavisaudio that answered the trannie question. The rest of the questions are nice to know and easier to handle.

http://www.beavisaudio.com/Projects/ColorsoundWah/index.htm

BTW looks like Zvex will have the designer credits.