Hi All,
Has anyone ever heard of checking if a pedal is wired true bypass by plugging the pedal into an amp with nothing plugged into the input of the pedal while powering it with a power supply? If it is true bypass then it will be totally silent when the switch is engaged?
To me this sounds crazy but has anyone else ever heard of this?
I've never heard that one before. It sort of makes sense, I guess they are thinking that a pedal with buffered bypass would have some hiss even when bypassed. So with nothing plugged in and the pedal bypassed if you can hear hiss then it means there's still some circuitry in the signal chain, and if it's silent then it's true bypass. That would sort of work, except that I'm sure plenty of non true bypass pedals are so quiet that you wouldn't hear any hiss.
Another way to check is to hook a guitar and amp up to the pedal with no battery or power supply connected to the pedal. If you get no sound however much you press the stomp switch it's about 99% certain it's not true bypass. If you get sound in one position of the stomp then it's probably true bypass. Some pedals leave the input of the circuit connected all the time though, so it will still pass sound with no power, but they're not true bypass. You might get tonesucking with these, which would give the game away or you might not.
The only real way to check is to open the pedal up and trace the circuit from the jacks to the switching.
Hi Slacker,
Thanks for the info. The reason I am asking is I sold a pedal to a guy on Ebay that is wired true bypass with one of the blue 3pdt switches and I also used one of the little grounded input boards from Steve at Smallbear. He claims I am wrong about the pedal being true bypass. I tried to explain to him but he just wants to argue then he told me his system of checking which i had never heard of before. If any one else can shed some light here i would be thankful.
Pig
WOW. that sounds like a frustrating argument! i feel sorry for you!
if you built it yourself and you didn't go out of your way to make active switching circuity then you can be pretty sure that it is true bypass. maybe point him in the direction of this thread?
i suppose plugging in a power supply to a bypassed (true bypass) pedal CAN still introduce ground loop noise. especially if switch mode?
slacker makes a good point that the pedal usually won't be able to pass the signal at all with no power supply if it is not true bypass. try getting signal through a BOSS pedal with no battery. make that point to him.
tell him the correct way to test is to plug it in with no DC input and see if it passes signal in bypass.
Not 100% reliable, but distinguishes between hard bypass and buffered for sure.
Thanks for the help everyone. Here is what was posted on ebay about the pedal:
As to "my method", I never claim it was THE method to test true bypass. It is merely a good method to test when there is a problem of wiring (no input = circuit open = no noise, this should be especially true with true bypass). This pedal hums when the circuit is opened. No other pedals do.
There is no problem with the wiring. When hooked up normally: guitar-pedal-amp the pedal is quiet with a walwart powering it. I have never heard of testing any pedal by just plugging the pedal into the amp to see if it hums.
Please let me know what you think. You can check out his testing method he used at the top of the thread.
I think he is full of sh*t, that's what I think. Just another Ebay ignoramus who is probably trying to get out of paying for something.
If the pedal functions correctly with the guitar plugged in, you're done. No need for further contact with him.
As others mentioned- to test for "true bypass", don't power up the circuit and switch it to bypass. If the guitar works and sounds reasonably the same as it does when plugged directly into the amp (other than the difference produced by different cable length), it's probably true bypass.
"the correct way of checking is to know the shit you are talking about"
that would be rude, but a realistic answer to that guy.
Thanks for the support guys. I don't really need the money from selling pedals but I love building and sharing something cool with people so when an issue like this arises it hurts(just a little :))!
Pig
I would just tell the guy it IS true bypass, and if he doesn't like the pedal to send it back and refund his money. You don't need to get into stupid arguments with idiots.
Al
Hi,
I told the guy to send the pedal back for a full refund but the problem arose when he wanted me to pay the return shipping. I included free shipping with the sale and stated buyer pays return blah blah...so he said the pedal was defective thus I have to pay the return shipping. I have never heard of this. Anyone else know of this policy? Anyways forget that guy....
But,
I figured out why the pedal does hum when it is plugged into an amp with no input.
I think.
I just started using the Smallbear 3PDT switching boards that ground the (let me see if I can get this right) input to the circuit when it is switched out of the loop to stop the audible 'pop' of engaging the stomp switch. Right? So with no input I think the grounded input of the circuit is caught is some ground loop causing the hum. Help me out here guys.
I guess I don't need the boards as I have been using pull-down resistors or use the grounded input wiring diagram I saw on Gaussmarkov's site. The other pedals I have with standard switch wiring are silent in both on/off modes plugged into an amp with no input.
What a funny situation when I look at it but it brings me to a question now.
Are all of these different ways to the same place or is there a best method? i.e. Grounded input vs pull-down resistors? ???
Pig
grounding the input to the circuit while the circuit is not being used will be of benefit to prevent noise.
please don't stop telling us how you are dealing with ebay, it's actually interesting points that you are making. it's only going off topic from electronics a little bit but we could all use it.
i wouldn't agree that the pedal is at all defective, but then again, the customer is always right, so... hmm... on the grounds that it is not defective you should not be paying return shipping in my opinion. if you can GENTLY persuade him that you are correct (seriously, tell him to get out his multimeter!!!) then that would be nice. ask him to get his meter out and do a scientific test. really, who plugs something in with no input and is surprised to hear hum??!?!?!?
it's even frustrating me....
to answer your final question, here is my personal view on true bypass switching and layout. it doesn't include the resistors but you know where the should go:
http://www.dazatronyx.com/support/what-is-true-bypass/ (http://www.dazatronyx.com/support/what-is-true-bypass/)
just look at the last diagram figure B if you don't want to read the whole thing.
The pedal is not defective and the buyer has no grounds to demand you to pay return shipping.
Welcome to the wonderful world of selling to the general public. You are learning, by the only way which will stay with you, that there are customers that you don't want.
I have this very clear memory of a cartoon from one of the old-line magazines; perhaps the New Yorker in the 1960s, something like that. Imagine:
A somewhat frumpily and formally dressed late-middle-aged woman is standing before a window with a "Complaints" sign above it. There is a man in a suit behind the window, and he's speaking. "Well, ma'am, how about if we refund your money, give you another one free, fire the sales clerk, shoot the manager and burn the store? Will that make you happy?"
Hi Everyone,
Thanks for the switching link Darron. Figure b looks cool to me. I will give it a try. So the grounding of the input is to stop oscillation and it is necessary to still use the pull down resistors to stop popping. I thought the grounded input solved the pop.
To summarize the ebay situation I tried several times to explain to the guy (and actually point him to this thread) but he was having none of it and started accusing and name calling so I stopped writing him and opened an ebay case asking them who is responsible to pay the shipping. (I ran to mom first!) I have yet to hear back but will let you know what happens.
Like R.G. said I think the guy may shoot me if he had a chance :icon_eek:
All those years in prison you'd have thought I'd learned how to work without emotions... :icon_lol:
Pig
Quote from: Pigyboy on June 03, 2010, 10:29:23 AM
Hi Everyone,
Thanks for the switching link Darron. Figure b looks cool to me. I will give it a try. So the grounding of the input is to stop oscillation and it is necessary to still use the pull down resistors to stop popping. I thought the grounded input solved the pop.
To summarize the ebay situation I tried several times to explain to the guy (and actually point him to this thread) but he was having none of it and started accusing and name calling so I stopped writing him and opened an ebay case asking them who is responsible to pay the shipping. (I ran to mom first!) I have yet to hear back but will let you know what happens.
Like R.G. said I think the guy may shoot me if he had a chance :icon_eek:
All those years in prison you'd have thought I'd learned how to work without emotions... :icon_lol:
Pig
The true bypass wiring that grounds the board input IS supposed to eliminate the switch pop. With Gaussmarkov's wiring , which does ground the circuit input, you shouldn't have to use the pulldown resistors, however sometimes people report popping problems even with that wiring (from LED?). Small Bear's board basically uses the same TB wiring with input grounding as the Gaussmarkov version, the board is used just to make the wiring easier, it achieves the same result as doing that wiring scheme without the board.
As far as the Ebay thing, you shouldn't have to repay his return shipping, as the pedal is not defective (the buyer is, though!). I would suggest in your auctions you put in a sentence with the return instructions that states that you will repay all payments except for the return shipping. I've seen this on many auctions, and would make that clear.
Al
Quote from: zombiwoof on June 03, 2010, 03:56:35 PMThe true bypass wiring that grounds the board input IS supposed to eliminate the switch pop. With Gaussmarkov's wiring , which does ground the circuit input, you shouldn't have to use the pulldown resistors, however sometimes people report popping problems even with that wiring (from LED?). Small Bear's board basically uses the same TB wiring with input grounding as the Gaussmarkov version, the board is used just to make the wiring easier, it achieves the same result as doing that wiring scheme without the board.
I used Guassmarkov's wiring in two pedals (twin copies) that I built and no pop at all using the 3PDT switch. I was going to add pulldown resistors before I finished but decided to leave them off in case I didn't need them anyway and that was the case. I'm happy.
Here's a little schematic representation I drew up. I chose to label the 9 lugs of the footswitch like a spreadsheet with lettered columns (ABC) and numbered rows (123):
(http://home.comcast.net/~snmavronis/3pdt_wiring_detail.jpg)
Quote from: Steve Mavronis on June 03, 2010, 04:08:26 PM
Quote from: zombiwoof on June 03, 2010, 03:56:35 PMThe true bypass wiring that grounds the board input IS supposed to eliminate the switch pop. With Gaussmarkov's wiring , which does ground the circuit input, you shouldn't have to use the pulldown resistors, however sometimes people report popping problems even with that wiring (from LED?). Small Bear's board basically uses the same TB wiring with input grounding as the Gaussmarkov version, the board is used just to make the wiring easier, it achieves the same result as doing that wiring scheme without the board.
I used Guassmarkov's wiring in two pedals (twin copies) that I built and no pop at all using the 3PDT switch. I was going to add pulldown resistors before I finished but decided to leave them off in case I didn't need them anyway and that was the case. I'm happy.
I'm really not sure why everyone doesn't use that TB wiring scheme, as it negates the use of the pulldown resistors. It's the way the original Fuzz Faces were wired. Even my old Dunlop Fuzz Face was wired that way. It used to be shown as the "alternate TB wiring with input grounding" in the GEO switch wiring diagrams, but for some reason he removed it, and replaced it with the Millenium wiring diagram.
Al
grounding the input is a big help with the pop. it completely discharges the input cap. however, the output cap is still left floating, so you should put one on the end of the circuit. the input one isn't as important but i've been told by a big name in the biz that the few milliseconds while the switch is latching can make make a difference and i think in some of my builds it has, so i put one on the input too.
Guassmarkov's wiring is exactly the same as the wiring that i do, except the order is switch around a little. there's no difference but i do it my way for convenience of where everything is hooked up in the enclosure. he doesn't however make the short that i do to improve on reliability and continuity, but then again nobody else does that either... nobody has thought of it...
Wow Darron, Nice website! Beautiful pedals!
http://www.dazatronyx.com/
I am going to try your diagram today.
A little Ebay update: I contacted ebay and they said I should not have to pay his return shipping as I had stated in the ad and they told me to request the guys phone number and call him. This does not sound like the best idea to me. I am kind screwed here a bit as after the transaction the guy still is able to leave feedback. If I don't pay him the shipping he is gonna go negative for sure but if I pay his shipping cost there is no guarantee he still won't leave negative feedback. I also tossed in a pack of free strings and a hand full of picks I got at NAMM in January with the pedal. I wonder if he is sending those back too.
Pig
Quote from: Steve Mavronis on June 03, 2010, 04:08:26 PM
(http://home.comcast.net/~snmavronis/3pdt_wiring_detail.jpg)
What I don't like at this topology is fact that bypassed signal goes needlessly thru two switches.
Edit: if there is some advantage over following topology I don't see it:
(http://thmq.mysteria.cz/diystompboxes.com/TBP_3PDT.gif)
Edit2: Sorry, my first drawing was incorrect - you may need to refresh page to see correct one.. :icon_redface:
Quote from: Thomeeque on June 04, 2010, 05:48:10 AM
Quote from: Steve Mavronis on June 03, 2010, 04:08:26 PM
What I don't like at this topology is fact that bypassed signal goes needlessly thru two switches.
well put! it only needs the one! :D