When is it true bypass

[GGBB]

So the best reason to have true bypass switching in a pedal is so that if the battery dies, I can just switch it out, rather than having to unplug it? Really?

Do you play live?

[GGBB]

there is a mechanical bypass built into every pedal.  It's that 1/4" mono cable.

Now that's really stepping backwards. I can see it now - backstage at the Grammy's: 

[slashandburn]

Keep me right with this, I've been under the impression that the only real audible differences between true and a good buffered bypass can pretty much much all be attributed to cable capcitance.  By that I mean, those who say "I don't like what the buffered bypass does to my sound" are actually saying "I like what the signal loss (from not having that buffer) does to my sound" even if they don't know it.

Is this yet another myth I've bought into?  Hope I don't start a fight here!

[GGBB]

If every one of your effects uses true bypass and is bypassed, so there's nothing between the guitar and amp except mechanical connections, then that's an accurate assessment.

[slashandburn]

When you mentioned transparency earlier, are you saying all buffered bypasses "colour" your sound? I always thought that on a basic level, all a buffer should affect in terms of guitar signal is impedance. It doesn't change your tone, it IS your tone, there's just more of it there, and that any issues with a chain of pedals that solely used a buffered bypass would be down to impedance mismatching.  As in, the reason the Woolly Mammoth doesn't play nicely with active basses.  It doesn't like a buffer in front of it, changing the switch wiring wont solve this.  Fixing the impedance mismatch will.

Am I miles away with this?
edit! I'm pretty much trying to say the same thing as Ron said, I missed his comment earlier.  I've got a habit of talking my way round in circles.  Is how Ron explains it here correct?

If you have a low-impedance buffer or amplifier as the first stage after the guitar (and it would not need a stompswitch since it is in circuit all the time), you do not get any tone-sucking if the buffer input impedance it sufficiently high.  After that, if all pedals have a low output impedance, there is not going to be any disadvantage to electronic switching and the low impedance eliminates a lot of noise problems.

[PRR]

> Am I miles away with this?

No.

But fine guitar players pluck the same strings with milli-inch differences, sound "different", and think the electronics are just as susceptible to tiny influence.

[slashandburn]

> Am I miles away with this?

No.

Bless you, Paul. I can sleep now! It's very early hours of the morning, I've had a few of them frothy ales and then started to question if everything I thought I understood about impedance was a lie.

[ElectricDruid]

So the best reason to have true bypass switching in a pedal is so that if the battery dies, I can just switch it out, rather than having to unplug it? Really?

Do you play live?

No, I don't. No-one would turn up if I did!

Let me recapitulate: So the best reason to have true bypass switching in a pedal is so that if the battery dies in the middle of a gig because I decided it'd be a good idea to go to a gig without a reliable power supply for my pedals, I can just switch it out, rather than having to unplug it? Really?

Nar, forget it. I'm only teasing. I know exactly what you're saying. Fair enough if you want to go to the gig with no wall warts, but you're still not going to rescue your solo when your pedal dies in the middle by bypassing it. That's damage limitation at best.

Tom

[J0K3RX]

So the best reason to have true bypass switching in a pedal is so that if the battery dies, I can just switch it out, rather than having to unplug it? Really?

Do you play live?

No, I don't. No-one would turn up if I did!

Let me recapitulate: So the best reason to have true bypass switching in a pedal is so that if the battery dies in the middle of a gig because I decided it'd be a good idea to go to a gig without a reliable power supply for my pedals, I can just switch it out, rather than having to unplug it? Really?

Nar, forget it. I'm only teasing. I know exactly what you're saying. Fair enough if you want to go to the gig with no wall warts, but you're still not going to rescue your solo when your pedal dies in the middle by bypassing it. That's damage limitation at best.

Tom

Ya ever been jammin and some drunk lead singer stumbles over your pedal board and inadvertently pulls the power to it? battery saves the day.. Ya ever been jammin, look down and notice the power jack going to your talent booster has somehow become unplugged? Battery saves the day, again.. It's called back up. Better to have a battery and not need it than to need a battery and not have it...

Let me explain why some people may want "true bypass" even though the words "true bypass" are self explanatory... Apparently, for some this is rocket surgery? 

A dude has 10 pedals on his board and never uses more than 3 at any given time and the other 7 are bypassed. He notices that when he uses his pedal board his guitar sounds dull and sometimes depending on what pedal combination he is using it sounds flat like something is sucking the tone... Dude has 10 pedals that have buffered bypass and when he is not using the other 7 the signal is still running through the 7 input and output buffers on the "bypassed" pedals. True Bypass connects the input directly to the output when the pedal is in bypass mode, that's it, there is nothing else. People who say they want true bypass so they can bypass the pedal when the battery dies or all of the power to the club get's turned off or gamma ray burst, asteroid strike or whatever just don't get it... and probably never will..........

[bool]

Playing live in venues/stadiums is one thing (personally I went up the ladder up to the point of playing smaller euro "football" type sportsfields, festival types etc back in 90's) and there's a certain "don't screw up" feeling that gets up to your head as well as to your ass. Mood enhancers can knock this vibe a bit but it's always there regardless.

But this is nothing compared to the tightness you feel in your pants when doing a live-broadcast radio or a tv show. If you have never done this kind of thing, you haven't got a clue of a warm reasurring feel that the "true bypass" thing brings to the table (if you had pedals not a multi-fx). It's like a next-best thing to knowing you have a fresh battery in your instrument and all-good reliable cabling.

[GGBB]

Ahem.

If you are stringing 10-15 buffers, use op-amp!

One FET buffer is nearly perfect. But not quite. Say it has gain of 0.95. String 15 of those, gain is down to 0.46! (not counting whatever you got between sends and returns)

A low-price TL074 will give gain of 0.999 to the top of the audio band. 15 of those is 0.985, or 1/8dB down, quite inaudible.

One FET at 0.5% THD, 15 stages, rough-computes to 107% THD! The reality is that each stage re-distorts all the distortion products so far, and you have a haze of IM distortion all over the audio band at non-musical frequencies.

This is also a problem with op-amps, of course. It limited early recording consoles. Op-amps got better and 10-15 op-amps in cascade was quite normal in large analog consoles. While the first and last op-amp would be specials, many mix split and EQ op-amps were TL072 even in fine German gear.

My point exactly with regards to FET bypass like in so many commercial pedals.

(Just when you thought it was done!    I'll leave now.)