Check yer switches with a meter next time.

Started by frankclarke, October 22, 2007, 10:40:24 PM

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frankclarke

Low volume motorboating tonebender, the Carling DPDT had the middle 2 terminals internally connected, so the bypass was always on. Took me 4 hours to work that out. Identical Carlings were fine.

I just spent four hours burying the cat. *Four hours* to bury a cat? Yes - it wouldn't keep still.

John Lyons

Argh! That stinks... I guess we all take pots and switches for granted...

John

Basic Audio Pedals
www.basicaudio.net/

DougH

I've experienced some funkiness with the Carling DPDT's. No problems with the blue 3PDT's so far...
"I can explain it to you, but I can't understand it for you."

R.G.

My latest column in "Tech Views" for Premier Guitar is on the rising failure rate in stomp switches. It'll hit the stands in a couple of months, as I just sent it in a week ago. The reliability of stomp switches in general is getting worse for effects use.

In a perverse way, the reliability of these switches for their intended purpose may not be changing at all, or may actually be getting better. They were originally designed for switching amperes of 120/240V AC. The kind of slight changes in contacts and operation that make them do that well may not map into better switching for low-level analog operation. It's the classical problem you get with an unintended use of a component for something that's not on the data sheet. The maker can change the part to make it better for its intended use and ... sink your boat...
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Gus

#4
R.G.

  Is the failure rate higher or does it just look that way because there might be more switches that ever before are being used at low voltage and current (higher volume of effects being built with dpdt etc switches)?

  Are you implying the contacts inside might be changed for better 120VAC switching?  So the contacts oxidize over faster at low current and voltage causing them not to work well in effects?

  Things like this make me wonder why some clones of TS are made with "true bypass" and not solid state switching like in the real TS,with that circuit the stock switching might be better.  The failures I have seen in TS switching have been due to stuff like beer etc getting in the old termial/PC keyboard switches used(switches made for low voltage and current and long life).  I have taken them apart and cleaned the contacts or used switches from older broken keyboards, newer keyboards(last 10 or 15 years?) are not made the same.

  I think SOME circuits might be better built with solid state switching

Pushtone


Cliff has showed a 3PDT switch they claim is designed and intended for low level audio signals.

QUOTE "Suitable for low level audio switching applications."


http://www.cliffusa.com/info.asp?ID=346
It's time to buy a gun. That's what I've been thinking.
Maybe I can afford one, if I do a little less drinking. - Fred Eaglesmith

Dragonfly

Quote from: R.G. on October 23, 2007, 09:54:30 AM
My latest column in "Tech Views" for Premier Guitar is on the rising failure rate in stomp switches. It'll hit the stands in a couple of months, as I just sent it in a week ago. The reliability of stomp switches in general is getting worse for effects use.

So you've noticed this too ?

I've had a few switches fail lately...they're just fine for a week or two, then "BAM", they don't switch on or off like they should...

I'm actually thinking about spending the extra money and going to the fulltones, even though theyre 3x the price.

analogmike

Quote from: Pushtone on October 23, 2007, 12:02:18 PM

Cliff has showed a 3PDT switch they claim is designed and intended for low level audio signals.

QUOTE "Suitable for low level audio switching applications."


http://www.cliffusa.com/info.asp?ID=346

i think cliff just stamps their name on the standard taiwan 3pdt.
DIY has unpleasant realities, such as that an operating soldering iron has two ends differing markedly in the degree of comfort with which they can be grasped. - J. Smith

mike  ~^v^~ aNaLoG.MaN ~^v^~   vintage guitar effects

http://www.analogman.com

skiraly017

Quote from: analogmike on October 23, 2007, 02:03:53 PM
Quote from: Pushtone on October 23, 2007, 12:02:18 PM

Cliff has showed a 3PDT switch they claim is designed and intended for low level audio signals.

QUOTE "Suitable for low level audio switching applications."


http://www.cliffusa.com/info.asp?ID=346


i think cliff just stamps their name on the standard taiwan 3pdt.

The Cliff rep I spoke to awhile back swears they're not. I got some Cliff's in a trade awhile back that looked a bit different. Lighter blue and duller finish than the Taiwan stuff. Nice switches...felt good and solid. It was all probably in my head though.  :icon_wink:
"Why do things that happen to stupid people keep happening to me?" - Homer Simpson

Pushtone

Quote from: analogmike on October 23, 2007, 02:03:53 PM
Quote from: Pushtone on October 23, 2007, 12:02:18 PM

Cliff has showed a 3PDT switch they claim is designed and intended for low level audio signals.

QUOTE "Suitable for low level audio switching applications."


http://www.cliffusa.com/info.asp?ID=346

i think cliff just stamps their name on the standard taiwan 3pdt.


If you read the datasheet on that switch page you would probably agree with AnalogMike.
There is no specs in the datasheet that would lead you to believe they are any different from what we have been using.
It's time to buy a gun. That's what I've been thinking.
Maybe I can afford one, if I do a little less drinking. - Fred Eaglesmith

snap

Quote from: Pushtone on October 23, 2007, 12:02:18 PM

Cliff has showed a 3PDT switch they claim is designed and intended for low level audio signals.

QUOTE "Suitable for low level audio switching applications."


http://www.cliffusa.com/info.asp?ID=346

"suitable for" doesn`t neccessarily mean "made for" or?

aron

Well, I have tested a good number of switches for sure....

BDuguay

I've messed around with Carling switches in the past, trying to repair/rebuild them using scrap ones. I built a DPDT from SPDT parts, or so I thought. I ended up with the same problem Frank described. There is a part in those switches that looks like a miniature dumbell and it turns out that part in the SPDT is made of a solid piece of conductive material and in the DPDT, it's made from a non conductive material and only the 'dumbell' ends get 'capped' with a conductive material. i wonder if maybe that one switch of Frank's was built using the wrong part.
B.

frankclarke

Yes, I took it apart, and there it was, the conductive dumb-bell. I'll measure next time. So a part got in to the wrong bin, makes sense.