Is this "true bypass"?

[Mark Hammer]

Suppose you had a pedal that, for a variety of reasons, you couldn't manage to bring the effect level up to match the bypass level.  Now I *know* some of you, many of you, are going to say "Well that's just crazy, just stick a....in there and boost the level".  But again, I stress, you CAN'T do anything to increase the effect level in this instance.

Okay, without the option to boost the effect up to the level of the bypass signal, what could you do to match effect/bypass levels?  One option is to LOWER the "bypass" level.

Yeah, you heard me right, LOWER the bypass level.  How?  By sticking in a simple 2 resistor attenuator that would drop the bypass level down a bit without providing too much loading on the "straight" signal.  So, for instance, imagine a 680k resistor to ground, and a 39k resistor in series, functioning like a 719k pot turned down just a hair.  That's ALL the bypass signal sees: 39k in its way, and a 680k path to ground.

In principal, this should contribute little noise, and should have negligible loading effects that might suck tone.

My question:  Is it still true bypass?  If you bought something that had this in the bypass path would you feel ripped off if it claimed to be "true bypass"?

[Ge_Whiz]

If it didn't affect the tone at all, under any circumstances, I wouldn't feel ripped off, no. But it ain't "True Bypass".

[davebungo]

Your box would not be true bypass.  How could it be if it has a measurable effect on the original signal path?  Don't forget, you are adding 39K of resistance to the signal path.  This would make it more prone to loading effects downstream (in cable or into another effect/amp/whatever)  :wink:

[niftydog]

absolutely ripped off! My signal goes in loud and comes out soft!

But then again, IMO true bypass isn't all it's cracked up to be. Ok for a couple of pedals, but when you're like me and you have 12 pedals on your board, it causes headaches.

[cd]

I would feel ripped off.

"True bypass" to me means than in the BYPASS mode, my signal is only going through a little piece of wire, isolated from the switch elements by air, not being touched by anything else.  This includes FETs, large value resistors, etc.  I don't care if it doesn't sound any different, sounds the same, I won't be able to tell the difference, etc. - it ain't true bypass.

[Ge_Whiz]

After all, the use of the word "True" ought to have some element of truth about it...

[davebungo]

In any case, what's the big deal?  I mean just call your effect what it is and don't call it what it ain't.  I don't think I would be particularly bothered if an effect wasn't "true" bypass provided it didn't seem to alter the signal in a significant way.  Most modern effects are not true bypass in any case (in the sense that they rarely use a straight DPDT mechanical switch).  You could, of course, fit a DPDT around the whole thing and then it has two bypass modes ("sort of bypassed but level a bit reduced" and "definitely bypassed - honest")

[Paul Marossy]

you CAN'T do anything to increase the effect level in this instance

I had that problem with one circuit I built, Laurier's Vibrato. Never did figure it out. Someone suggested to change the feedback resistor on the opamp to increase gain. But, somehow I don't feel that it would work, because if an LPB-1 at the output didn't have any noticeable increase in volume, something inside the circuit is apparently whacked. At least that's how I see it...

I think Mark's suggestion could work, except the one flaw that I see with it is that when you take the pedal (or whatever) out of the loop, things will get considerably louder. Maybe that's not a problem, though. The other thing I am thinking is that it would probably have some kind of tune sucking affect, probably not enough to bother me, but some people might find it objectionable.

[R.G.]

Nota bene: It is possible to make a two-resistor, two-capacitor divider that is demonstrably flat in frequency response up into the many MHz. The commonest application is oscilloscope probes and attenuators. The frequency response on the divider can be **flat** so it could be volume sucking but not tone sucking.

This has nothing to do with whether the term "true" applies, of course.

[Paul Marossy]

Now that could work...

[toneman]

just *hafta* say....
What part of "true" don't U understand?

say it ain't so...
so it ain't

[puretube]

"UN" true bypass...

[Paul Marossy]

"UN" true bypass...

Is that like the "un-cola"?!   :lol:

You people that were kids in the 70s like me ought to remember that advertising slogan that 7UP used to use...

[StephenGiles]

Well Mark, you heard it all from the True Bypass Police!
Stephen

[Paul Marossy]

The TDP. Kinda sounds like KGB, CIA, FBI, etc.  :lol:

[Rodgre]

My question is why would you want to bypass your pedal anyway?



Roger

[Ben N]

I'm not sure if this fits in the rules of the exercise, but I'd rather just have a well-buffered non-TBP.