General View required on Switching Systems

[simon111]

I want to try out different switching styles (instead of the usual 3PDT switch)

So just really want to know what people on here think is the best or their preffered method for doing a true bypass with an LED electronic switch that is as quiet as possible.

CMOS?
JFET?
Relay?

other....?

Be intersting to see what people use.

Simon111

[donald stringer]

You may get a lot of suggestions on whats best or preferred, this will not qaulify as best but its different and a door open to a little more understanding into cmos. Go to http://www.geofex.com/  and scroll down to electronicswitching with cd4053. This chip contains 3 spdt electronic switches, its very versatile as its quite capable of an effects loop type switch.  I have built no less than 4 of these already, Ive got the circuit whisper quiet [ but you have to bias the input and outputs to VR.] just read the article. Someone on this list has an pcb for that project but you can also perf it. Which is my preferred method. Go to layout gallery and seach for troublerats switching diagram and you can see a block diagram of a pedal board I have made based around two of these chips.I have half of the project up but I"m having trouble uploading the other half. I hope this helps.

[Chuck]

Personally I'm a believer in relays.

Its probably from not trusting tone through electronic black boxes.

Chuck

[Gilles C]

I've always been a fan of Boss Fet Switching. So I'm influenced by that taste in my choice of circuits...

So I use DOD and Boss Fet Switching, and transistors to switch the Leds.

I don't mind having the signal going through Fets. As soon as we use an effect, even if only a clean preamp, we are adding something in the signal path anyway, so why not a Fet or two that are used only used as resistors anyway.

I tried some 4066 and 4053 circuits, and realised that even these were popping if not used correctly.

It's not to say that I don't use true Bypass, that's what I use in my AB/Loop boxes. I suppose it depends on where it will be used.

I must add that I also like to use transistor circuits instead of opamps sometimes, so it must be in my genes...

Btw, your thread reminded me that I wanted to build a circuit based on this layout but never found the time.

http://www.diystompboxes.com/smfforum/index.php?topic=44115.0

Gilles

[g.e.o]

check this from geofex. very interesting. needs advanced knowledge though! http://www.geofex.com/Article_Folders/fxswitchr/fxswitchr.htm

[RedHouse]

Life always seems a trade-off, shutter speed -vs- apeture, performance -vs- economy, high yield risc -vs- safe low yield return ...etc, etc, etc.

With relays you get zero added hiss to your signal ...but... some contact noise same as you do with a toggle switch.
(and a risk of poping noise it you power the relays with the same regulated branch of the power supply)

With JFET and CMOS analog switches you get noise free switching ...but... the devices can add noticable hiss to the signal and can partially blead signal when they are supposed to be off which is a common ailment in BOSS pedals.

[R.G.]

Its probably from not trusting tone through electronic black boxes.

It is indeed an article of faith, not science. There are good and bad examples both ways. I guess I've always trusted electronic black boxes to switch the signals from other electronic black boxes (the effects).

Life always seems a trade-off, shutter speed -vs- apeture, performance -vs- economy, high yield risc -vs- safe low yield return ...etc, etc, etc.

It really is all about tradeoffs.

However, there is at least one other dimension to the issue - the quality of the design and the amount of money spent on the product.

Relays can be pop-free with the addition of the separated supply, slowed-down operation, or at the high end, shielded relays.

JFET and CMOS can be hiss, bleed, and pop-free, but it may take more than a 9V battery supply to do it.

[Doug_H]

I've always been a fan of Boss Fet Switching. So I'm influenced by that taste in my choice of circuits...

So I use DOD and Boss Fet Switching, and transistors to switch the Leds.

I don't mind having the signal going through Fets. As soon as we use an effect, even if only a clean preamp, we are adding something in the signal path anyway, so why not a Fet or two that are used only used as resistors anyway.

I tried some 4066 and 4053 circuits, and realised that even these were popping if not used correctly.

It's not to say that I don't use true Bypass, that's what I use in my AB/Loop boxes. I suppose it depends on where it will be used.

I have no qualms with the Boss switching and buffers either. I have a number of Boss boxes on my board, interspersed with other stuff that use electronic switching and buffering schemes as well. The bypass sounds "true enough" for my ears. If there is a tonal difference, I've probably unconsciously compensated for it with my amp tone controls or something. And I use a diy loop/bypass box too, which is 100% gen-you-wine completely without a doubt true honest-to-goodness bypass as well. I didn't see much point in buffering that as my loops are small and I have enough buffering in my chain as is. I use a couple overdrives that interact nicely with my guitar pups so I put them in the chain first. That makes sense since the buffered stuff would normally come after a drive anyway, in my setup.

I understand trying to avoid "tone suckage" when an effect is in bypass. I used to fight that with my wah. But as for the myriad ways of correcting that and which one's the "best"- ehhh... I think too much is made of it IMO.

[Gilles C]

Speaking of leakage in some Boss effects switching, here is an article that shows how and why to fix it in a SD-1 effect.

http://www.musicianshotline.com/issue/2006/0806/62.pdf

As mentioned, the quality of the switching also depends on the quality of the design and the quality of the parts. I remember that I once had problems with a DPDT true bypass scheme. The switch I used wasn't good enough, and it was popping and all. Changing the switch fixed the problem. The same can happen with relays if someone uses relays to swith heavy AC loads for example instead of audio relays. The gap between contacts can be wider and make the true switching pop because of that.

Gilles