When is it true bypass

[R.G.]

OK - let's have a show of hands...
one
two ... three...

um, seven;   nine, eleven, um, fifteen...

[thermionix]

This, being a pedal-building forum, might not be the most representative sample.  When I think of players I know locally, one has a big pedal board, because he plays in cover/restaurant bands and is big into The Pink Floyd and whatnot.  Almost all the rest use a few pedals with batteries or just plug straight in.  They all use good tube amps, that's a big part of it.  Reckon I wouldn't go see 'em if they didn't.

[GGBB]

> when I am playing clean, I don't want my signal passing through another 10-15 buffers.

When you record to wax/CD and someone plays it on their system, there may be *hundreds* of bufferish stages between the mike and the listener's ear.

Good lord, I hope they all aren't as poor quality as the ones in guitar pedals!

[ElectricDruid]

it isn't because that i'm obsessd with true bypass, I just wonder what is the opinion on non-mechanocal components that would give same result is.

I've used the 4053 analog switch IC for this job and it does it perfectly, and doesn't have the pops and bangs that a mechanical switch is often prone to. There are lots of other ICs that would do the job too.

I'm with RG on this one. Mechanical switching is a pretty backward "solution", and is mostly marketing-lead. When I was younger, the holy grail was "noiseless switching", and everyone thought the FET switching in the Boss pedals was the bee's knees. But you can't sell new pedals unless you can make out it's somehow better than the previous pedals, so "true bypass" became a way to differentiate a pedal. Now, people clone Boss pedals and strip the FET switching out to replace it with a clunky switch.

Tom

Tom

Tom

[TejfolvonDanone]

Seriously - who uses batteries any more?

LOTS of players still use batteries in pedals.  Especially those of us who use very few pedals.  Wall warts and extra wires are just an annoyance to us.  Obviously a different scenario for those with big pedal boards, wouldn't want to do that with batteries.

I used a power supply even when i had only one pedal. I just was in high school and I didn't want to spend anything on batteries. Especially 9V bat. (On the other hand i had a guitar equipped with active pickups...  But it used 2 AA bats and they only ran out of juice after 2 years if i remember correctly.)


As far as i know a well designed electronic switching system has got no drawback. But putting in 5 more tranies (including 2 FETs) into a 1 BJT booster pedal seems a little overkill for me. 

[R.G.]

Do it with CMOS and skip the trannies.

[Electric Warrior]

it isn't because that i'm obsessd with true bypass, I just wonder what is the opinion on non-mechanocal components that would give same result is.

I've used the 4053 analog switch IC for this job and it does it perfectly, and doesn't have the pops and bangs that a mechanical switch is often prone to. There are lots of other ICs that would do the job too.

I'm with RG on this one. Mechanical switching is a pretty backward "solution", and is mostly marketing-lead. When I was younger, the holy grail was "noiseless switching", and everyone thought the FET switching in the Boss pedals was the bee's knees. But you can't sell new pedals unless you can make out it's somehow better than the previous pedals, so "true bypass" became a way to differentiate a pedal. Now, people clone Boss pedals and strip the FET switching out to replace it with a clunky switch.

Tom

Tom

Tom

From that perspective, it is a backwards solution. It's the way it has been done in the 60's and 70's.
After 50 years, it's become quite clear that switches weren't created equal. Bulgins don't hold up all that well. Arrows on the other hand are mostly fine. I wonder if there was a big price difference between the two.

[Hatredman]

From that perspective, it is a backwards solution. It's the way it has been done in the 60's and 70's.

Did we have 4053s in the 60s?

This is a .sig.

[Electric Warrior]

I was referring to mechanical "true bypass" switching.

[bool]

I think the "true" true-bypass should be workable when there's no power to the pedal, similar to a straight wire - so in essence, as a consequence, in order to qualify for "true" bypass, in this context it should be some sort of a mechanical switching.

Like, "in order to pass the gas, it should be a real true bypass".

[ElectricDruid]

While I agree that the truest "true bypass" is the mechanical metal-on-metal, equivalent-to-a-piece-of-wire switching, I don't see why "must operate with zero power" is a necessary criteria.
I mean, if you're trying to play during a power cut, you're not going to get far with your electric guitar, even if your signal gets through all your lovely TB pedals! So it seems a bit pointless.
Instead, I think we need to be thinking honestly about what the *best* bypass switching scheme is for specific jobs and in general. In this respect, true bypass doesn't look that great, despite claims of "no tone sucking" (well designed pedals don't suck tone anyway, so there's no problem to solve there), since it introduces a big expensive component, adds a point of mechanical failure (the commonest type of failure in pedals) and is often noisy, both physically and electrically - hardly ideal.

Tom

[amptramp]

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.

[GGBB]

I don't see why "must operate with zero power" is a necessary criteria.

I think it's a legitimate concern for battery users.

[bool]

Some older schools of though call for sure-proofing wrt various failure-modes and scenarios, some don't ...

[GGBB]

Love this thread!

This is one of those debate topics where very few if any participants are swayed away even slightly from their positions. But it makes for a lively discussion and educates the uninitiated. So the following will no doubt be an almost entirely fruitless endeavor.

Here's my summary (and y'all need not reply  ). The whole point of true bypass is transparency. RG says TB is a solution to a problem we "mostly" don't have anymore. Mostly as in not entirely, but in reality, the problem hasn't gone away at all, it's just rarely not addressed. In other words "transparent bypass" is still a concern/problem that pedal designers/builders/DIYers must address. And the 3PDT is still a solution for that problem - it doesn't go away just because good alternative bypass solutions also exist. Buffered bypass a la BOSS has come a long way, but not all buffers are created equal - especially for the DIYer. They may be transparent enough in most cases, but they aren't as transparent as direct contact. Electronic TB is for the DIYer quite frankly a lot more work and probably more money than a 3PDT (no longer expensive) - fun and cool (and super effective) but to a certain extent impractical. It's benefits to me (a 3PDT user) are about as valuable as a 3PDT would be to RG (I'd guess). Both buffered and electronic bypasses add complexity and money and take up more precious PCB/pedal space. A 3PDT is all over transparency. Popping is a concern occasionally, but is easy to remedy except in some extreme cases. Reliability? Not really (the others use mechanical switches too), but easy to fix if it happens (unlike a dead or fried bypass component).

So if transparency is the point of all this, the easiest solution by far is a 3PDT - and it is a good one. (I won't use the term "best" because that would just open a can of worms. I am thinking it though.  )

[ElectricDruid]

I don't see why "must operate with zero power" is a necessary criteria.

I think it's a legitimate concern for battery users.

I agree - keeping current consumption as low as possible is a legitimate concern for battery users.

But true bypass switching doesn't "turn the pedal off". It just *switches the pedal out of the circuit*. Unless you pull the input jack out, most true bypass pedals are still powered up and still using up just as much juice. There are probably ways to rewire things to avoid this criticism, but they're not widespread.

If we're serious about designing for battery users, we need to look at a lot more than just the current used by a buffer and some electronic switching. If you're designing (for example) a flanger pedal, the battery life problems aren't going to come from the inclusion or exclusion of electronic switching. Rather than fussing about the bypass method, we'd be better off dumping the little LEDs we put all over things. I've built entire distortion pedals that use a lot less current than a single LED.

Tom

[GGBB]

I don't see why "must operate with zero power" is a necessary criteria.

I think it's a legitimate concern for battery users.

I agree - keeping current consumption as low as possible is a legitimate concern for battery users.

I think you've missed the point. The concern is that electronic bypasses no longer work when power is cut. So no power = no signal. Mechanical bypasses allow you to bypass a pedal with a dead battery, so if the battery fails, you still have signal. Battery users gain this benefit - mains powered supply users don't (assuming if the supply dies so does your amp anyway). Mechanical bypass also has the related benefit to battery or non-battery users of being bypassable when the power supply alone or the pedal itself fails, but everything else is still working.

[R.G.]

By far the most likely thing to fail in a battery powered pedal is - wait for it - yep, the battery. As I tell people trying to repair tube amps, there is a reason they are in easy to remove connectors.

The concern is that electronic bypasses no longer work when power is cut.

Leaving aside that it is entirely possible to design an electronic bypass so that the signal goes through when there is no power, there is a mechanical bypass built into every pedal.  It's that 1/4" mono cable. If a battery powered pedal or its battery fails, unplug the cable from its input and plug it into the next pedal's input or the amp's input.

The immediate thing that will come to some minds is "but what if the cable won't reach?" Get out one of your spare cables.

The next thing is "but what if you don't have a spare cable?". If that's true, you haven't done enough gigs to know what to take. If it's not a gig, the problem is a non-issue.

Next is "but if you have to stop playing and swap pedals!" Sure. But if you're in the middle of a high distortion solo and the battery fails suddenly (??) and the pedal goes quiet and you flip back to bypassed that no one will notice the change in tone.

Well, OK, maybe no one will notice, but then the pedal isn't needed.   

I think that we're back at true bypass being a solution to problems we mostly don't have any more. It is possible to concoct situations where it might be what's needed, but those situations need a lot of things to fall the right (or wrong!) way to happen.

And I believe you're correct. This is an issue that substantially no one will change their opinion on.

[ElectricDruid]

I agree - keeping current consumption as low as possible is a legitimate concern for battery users.

I think you've missed the point. The concern is that electronic bypasses no longer work when power is cut. So no power = no signal. Mechanical bypasses allow you to bypass a pedal with a dead battery, so if the battery fails, you still have signal. Battery users gain this benefit - mains powered supply users don't (assuming if the supply dies so does your amp anyway). Mechanical bypass also has the related benefit to battery or non-battery users of being bypassable when the power supply alone or the pedal itself fails, but everything else is still working.

Ok, I understand the point you're making, but it doesn't seem like much of an issue, tbh.
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?

Just to be clear, I'm not particularly religious about this either way. My recent Flangelicious pedal design was set up as a true bypass pedal since I was trying to keep it as simple as possible and didn't want to add another chip (it's only 4 x 8-pin DIP, so another 14(16?)-pin DIP for switching would be a big deal). On the other hand the digital delay I'm working on currently is buffered bypass, since that offers me a few more possibilities (delay tails, for example, as well as noiseless switching) and doesn't require any extra hardware. You can choose which makes sense for a given circuit or situation.

Tom

[J0K3RX]

I now know the definition of "True Bypass"...

True - accurate or exact.
Bypass - to go past or around. <Which is what I should have done before clicking on this topic and finding myself caught in a vortex that threw me into another dimension. 

A fifth dimension beyond that which is known to man. It is a dimension as vast as space and as timeless as infinity. It is the middle ground between light and shadow, between science and superstition, and it lies between the pit of man's fears and the summit of his knowledge. This is the dimension of imagination. It is an area which we call The TrueBypass Zone.