I don't know if anyone here has played with this stuff too extensively, but I'm interested in alternative switching methods to true bypass. I just read The Tone God's article on switching using the CD4066 and 4049. Can anyone speak to the level of signal crosstalk in a switch like this? My primary interest in alternative switching setups is eliminating input/output crosstalk in high gain circuits, as recent experiences with the SansAmp and memories of Joe Davisson's BlackFire before it got the inverting transistor as a fifth stage lead me to think that a switching setup with the effect in and out coming within millimeters of each other might not be such a good thing.

Furthermore it seems like it would be possible to use the SPST/RC network arrangement in TG's article to drive a second pair of inverters, and thus a seperate 4066, allowing one to simultaneously have a DPDT on both in and out, operated by a single stomp switch.

OK I'm just thinking into my keyboard now. Any thoughts?

(Apologies for a second thread about electronic switching - but I think this one is divergent enough from the SPST thread....)

I haven't had much experience here and am looking for a similar way to switch between effects. I have heard that relays are a good way to do this as are a series of ICs like the Harris DG213DJ. I was led to believe that either of these are better a better choice than the CMOS type of switches.

I hope someone more knowledgeable will clear this up.

(BTW, checkout the series of Millenium Bypass articles at Geofex if you haven't already.)

J

Quote from: SamuelI don't know if anyone here has played with this stuff too extensively, but I'm interested in alternative switching methods to true bypass. I

So finally... I'm not alone.      

Well, they say that a FET can be used to aproximate an analog switch, because it is never completely OFF or ON, only very highly resistive, or at a low (50-150 ohms) resistance.

http://www.engin.umd.umich.edu/~fmeral/ELECTRONICS%20II/09%25c3-FET%20Project/JFET_Project.pdf

But it's been used in Boss and some other brands for years. So, even if they are not perfect, they can do a good job. With a good design, of course.

Check this FET for example.

http://www.ligo.caltech.edu/~vsanni/ph5/Datasheets/FET/2N3819.pdf

It is supposed to have a very high ac/dc resistance when OFF. The on resistance is 150 ohms.

That's one I just found that could replace the 2SK30. It has the same pinout (DGS) and is said to be good for analog switches. I'll try to get some for my tests.

To make sure to eliminate crosstalk, I suppose it would be best to use a lower resistive path in the circuit. Like 100K before and after the FET in place of 1M as I once used. It also makes it easier to get rid of popups.

I'm learning all the time since I began to experiment with electronic switching, and it seems I still have a lot to learn, so any info you could get will be welcome...

Gilles

Sam:

FWIW, I breadboarded a WS back in the winter, and it was fine.  Clean and silent (as I recall).  My hangup was I couldn't figure out how to wire it on perf.

how did i missed this topic???!!!

i used two 4066...

and had a chain sorted like this

one 4066 had the inputs and the other had outputs of the two chanells..
that way the two hi gain gt2's didn't interfere!!!

otherwise...

i tried putting it all into one chip and it oscilated like nuts...

and the rest of the unused 4066 i used for powering indication led's

Branimir - thanks for letting me know that'll work! That's fantastic. Also good to know that the crosstalk problems for a single chip I was fearing were indeed worth fearing...

I'll have to go out and grab a CD4049 and give this a shot...

no problem!

glad i could help, i find helpful info on this forum everyday...

i'm really happy that i contributed something finally!!

cheers everyone!

ps: anyone have 4049 datasheet? i tried googling but i found nothing...

http://www1.jaycar.com.au/images_uploaded/CD4050BC.PDF

thanks!