optical bypass??? whaazzisss???

[pinkjimiphoton]

so i was surfing thru the rullywow website the other day, as a friend sent me a pcb for their jfet tester.

and i noticed something called a dual optical bypass board.. i THImK it's using an led and opto isolator chip to control bypassing effects, or perhaps triggering a jfet bypass?

i dunno, seemed kinda neat, and actually seems like it could be a really useful way of doing it in cases where pops can be unruly.

is this worthy of pursuing? seems like it would be a great way to get away with just using a simple cheap momentary switch.

educate my ignorant arse, by all means, if you will. i think it sounds kinda neat!

actually, i went to find a link to post, and found this: www.rullywow.com/product/detour-optical-bypass-pcb/

it looks easy and pretty cool!! what do you guys think?
anyone tried this?

[electrosonic]

I think that type of bypass first showed up in the Voodoo Labs Sparkledrive. Two guitarists I know had issues with the pedal picking up radio stations - the fix was to add a small cap to shunt the radio signals to ground. Not sure if anyone else has had this issue here.

Andrew.

[R.G.]

Optical bypass seems like a little grandiose term for it. The actual switching of the audio path is done by some MOSFETs, not optics.

What's optical is that the MOSFETs are turned on and off by leds turning on and off. This style of bypassing was done long ago with LDRs as "switches", suffering all the issues that LDRs have. The modern photo-activated back to back MOSFETs make it handier, and give a bigger off-to-on resistance ratio than MOSFETs.

Something similar has  been around for quite a while in the H11F1/2/3 series of LED-to-photoFET modules, although the single photoFETs were quirky.

Otherwise, the actual bypassing circuitry, using the MOSFETs as a switch, are variants of the bypassing in the technology of bypassing at geofex.

[PRR]

Read the Build Document.

"...a genius solution especially back in the earlier days of pedal building where 3PDT switches were not as reliable/common/inexpensive as they are today."

It avoids need of a 3P2T switch by using a 2P2T switch and a opto-relay.

Seems to me a 3P2T is a better solution, if you can get a 3P2T.

[pinkjimiphoton]

thanks guys.
i agree... sounds WICKED cool... but in operation, seems a 3pdt  (or 4pdt these days even) is cheaper and easier to implement.

i mean, i can get 3pdts in bulk for lilke, 1$ and change already....