Cutting off power in bypass.

[swever]

Is there a way to do that? Guess I can do it with 4pdt switch?

Does it sound like a good idea? Why is not it a common thing?

[chuckd666]

Ah some circuits need time to start up (?) so it would be a bit unnecessary. It's a bit overkill for the negligible power draw of a little guitar pedal.

[swever]

The pt2399 delays Ive built seem to eat batteries like mad. Haven't tested if there is any significant start up time to them though, thats a thing to consider indeed.

[roseblood11]

Why is not it a common thing?

Crack!

[swever]

Crack!

Not sure I understand you completely. Are you implying that crack is the reason for it not being a common thing? Or that there is going to be a loud crack if that feature is implemented? Not a native speaker, sorry 

[bluebunny]

Yes, you'll probably hear some kind of thump as your dormant circuit powers up.  Or you might experience a period of silence (or perhaps garbage) before the effect kicks in properly - as chuckd666 mentioned.  This might be a bit disconcerting mid-song!  As for PT2399-based effects, these really were never intended to be run by batteries: the PT2399 consumes too much juice.

[swever]

Yes, you'll probably hear some kind of thump as your dormant circuit powers up.  Or you might experience a period of silence (or perhaps garbage) before the effect kicks in properly - as chuckd666 mentioned.  This might be a bit disconcerting mid-song!  As for PT2399-based effects, these really were never intended to be run by batteries: the PT2399 consumes too much juice.

That's bad news for me! Although I do beleive there must be some workarounds, if only I was smart enough and knew more about electronic engineering! 
I do run everything on batteries. And I have a feeling a 2399 delay could run off a single battery for plenty of time if it was only powered when engaged.
There must be a solution 

[antonis]

There must be a solution 

And it's name is: Wallwart Power Supply...!!!!

[R.G.]

There is a meta-solution to your question. That is to learn the numbers involved, instead of having a feeling that something might be possible. Trying things out is an important part of learning, but getting the answers down in numbers, not feelings is how you make real progress.

In the case of turning off power in bypass, this idea comes up pretty frequently as people decide to start learning electronics. Not using power on an "agile" basis is one way that modern logic circuits get to very low powers, so it's a good idea. But it's only usable when the process of turning on and off doesn't cause worse problems than using the power.

As the previous posters have said, turning power on and off to audio electronics during bypass is usually a bad idea because it results in ugly pops and thumps as the circuits power up and down. Yes, there are ways around this, but they are very complicated and expensive to do, and take power themselves.

But back to learning the numbers. Batteries are a fixed bucket of power. They can only hold so much. For typical PP3/9V batteries, that number depends on the internal chemistry, but for typical alkaline batteries, it's about 300-500ma-hr as an approximation. So you can pull out maybe 30ma to 50ma for 10 hours, or 3-5ma for 100 hrs. As an approximation, add up your milliamperes times hours, divide into the ma-Hr for your battery chemistry and you get a good approximation to the hours.

Digital chips like the PT2399 use a lot of lower-voltage power, much more than a couple of transistors in a distortion circuit. In fact, the datasheet for the PT2399 lists a maximum power supply current of 100ma. That's a maximum, so any given unit will be less. Still, if they're in the range of 50ma to 100ma, then a "typical" battery would only last 5 to 10 hours, matching your experience.

If replacing batteries is not making you happy - and at $2 - $3 each, it shouldn't! - you have only a few choices. One is rechargeable batteries. You can run a battery charger and always keep a freshly charged battery ready. Another choice is an AC-powered power adapter. If you are using only batteries in several pedals, you already know that it gets expensive very quickly. It is possible to get a plug-in power supply designed especially for pedals for under $30 that is guaranteed to be quiet, and has adapters for various different plugs and such on pedals. At least one of these units that I have some experience with can power up to 100 or more typical pedals at the same time. So for the price of one or two mass battery replacements, you can run from AC power essentially forever. Finally, you could come up with a much bigger rechargeable battery. You can get 12V lead-acid sealed gel cell batteries with very large capacities, perhaps several ampere-hours.  You still have the problem of charging them, but they will last for long periods of time.

And you will have noticed by now that what tells you what can be done is in the numbers. You have to know the numbers to make intelligent choices. As  William Thomson, Lord Kelvin (you know, the guy whose name is on the temperature scale... ) said in 1883:

"When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts advanced to the stage of science."

[swever]

Thank you for the insight, R.G. I really appreciate your experience and understand what you mean here. However, I have to say that I never intended to "make real progress" in electrical engeneering. Building pedals in not my source of income and not even my primary hobby.

I agree with you on that numbers are the way to go in engineering. However, there is no need to apply scientific method to tell that a battery dies fast with 2399 or that it would live longer if 2399 was not powered when bypassed.

All I wanted to know is why (in layman's terms, without numbers ) is it not a good idea.

[R.G.]

It's OK to know that you don't need to know.

You're right - no science is needed to know that a 2399 eats batteries and that turning it off as much as possible would preserve battery life.

It's a bad idea because powering it up will make thumps and/or funny wait periods before sound comes through when you un-bypass it.

[amptramp]

This assumes you want to control power switching with the stompswitch that selects bypassing or using the effect.  You could add a separate switch for power on/off.  Just never use it unless you are in bypass mode.

[PRR]

A possible practical answer is to put a power switch in the lead to the regulator to the PT chip. If 90% of your act is no-reverb, you leave it powered-down for the dry(*) stuff, power-up in the gap between songs, then stomp the effect in and out as needed in the wet songs. Power-off when you get back to dry material.

Of course this BEGS for you to get to the Heavy Reverb bridge, stomp, "Oh no! I forgot to power-up, this will suck!" A PT-power LED is a clue, but can't look-ahead and yell "Hey! Turn me on!" (Or "turn me off" when done with reverb.)

(*)
> Not a native speaker

Few people are "native" at Musician's Lingo. And it varies. I might say "POP" where roseblood was yelling 'crack'.

"Dry" no reverb, "wet" with reverb (sounds jumbled like under water).

[swever]

Well, its seems like anything other that actual swithcing power off simultiously with bypassing (witch is not possible as have settled upon) appears to be too fussy indeed!

As for CRACK! the first thing that came to my mind when I saw it was that doing it the "tranditional" way does provide the builders engough of it not to bother about the silly things if you know what I mean.