How do you tell if a pedal is true bypass or not ?

[Dr. Tweedbucket]

.... do certain brands build them that way? I was looking at my Boss DD-20 trying to figure that out and without ripping it apart or digging up a schematic, I didn't see anything to indicate one way or another.

 

Supposedly the Voodoo labs pedals are true bypass.

 

Ibanez tube screamer TS9 or TS808 is another in question.

 

 

Anyone know ?

[goldie-gold]

I was under the impression that all Boss pedals have a buffered bypass (i.e. NOT true bypass).

Erm... I don't think Ibanez pedals are True bypass either.

Some stuff that says it is true bypass is not strictly speaking true HARD WIRE bypass.

Best way to test if a pedal is true hard wire bypass is to remove the power supply, and if you still get signal through it (when it is bypassed) it is true bypass.

[goldie-gold]

Hold on.............

You must know this stuff, I just spotted that you're a Hall of Fame member.

Are you taking the piss, or just new to pedals?

[Dr. Tweedbucket]

Originally posted by goldie-gold Hold on............. You must know this stuff, I just spotted that you're a Hall of Fame member. Are you taking the piss, or just new to pedals?

No ...... I was very anti effects over the years, but now playing in a band, I see the advantage of having some different tone options...


..... your comment about disconnecting the power supply is interesting ..... I may have to check that idea out.

[Dr. Tweedbucket]

next question is, what exactly is a buffered bypass ........ probably some logic state that is a through, but requires the circuit to have come bias on it to achieve the through state ? ...... so basically the signal goes through part of the circuit board to get to the output?


My whole idea in this effects thing is to not screw with the true amp tone, or as little as possible both bypass and effected modes.

[andreas]

The only way to know for sure is to open the pedal up and look/measure where the signal ends up as you switch. Also, if you remove the power and the pedal goes stone dead, you can be sure that it is not true bypass (if there are any active circuits in the direct signal path, they will not work without power).

However, goldie-gold's suggestion is not true - however persistent that myth seems to be. Removing the power will not help you determine that a pedal is true bypass. If you still get a signal through, you will know that the bypass system is mechanical (rather than electronic), but you can't tell how the switch is wired.

The Voodoo Lab pedals are a borderline case, as they use a slightly unorthodox method of disconnecting the effect input from the main (bypass) line. But they still qualify, if you ask me. MXR, Marshall, Radial/Tonebone, most Dunlop wahs etc do not meet the criteria for true bypass. Boss and Ibanez-style pedals have electronic bypass systems, and the signal is permanently wired through active circuits, so they aren't TB either. However, if you ask me, their method is actually better than the MXR/Marshall style, as it puts less load on the signal.

But basically, it's a jungle... and many times the only way to know for sure is to open the pedal up and trace the circuit. If you want to read up on this issue, as well as what buffers are and what they do, you can go here.

/Andreas

[p90teleman]

Andreas,

did you check the Crybaby Classic in the meantime - since the last similar dicussion?

TB or not TB? Is it hard to rewire the DPDT switch for TB if it isn't?

however let us know when you do.

thanx

[goldie-gold]

Originally posted by andreas However, goldie-gold's suggestion is not true - however persistent that myth seems to be. Removing the power will not help you determine that a pedal is true bypass. If you still get a signal through, you will know that the bypass system is mechanical (rather than electronic), but you can't tell how the switch is wired. /Andreas

 

 

Ah...... I see.

 

Thanks for the info - I would hate to think that my 'advice' was incorrect.

 

I seem to recall reading the whole remove power supply thing on a fairly major builders website (I forget which). Just goes to show how tricky the issue of true bypass is.

[Dr. Tweedbucket]

Originally posted by andreas The only way to know for sure is to open the pedal up and look/measure where the signal ends up as you switch. Also, if you remove the power and the pedal goes stone dead, you can be sure that it is not true bypass (if there are any active circuits in the direct signal path, they will not work without power). However, goldie-gold's suggestion is not true - however persistent that myth seems to be. Removing the power will not help you determine that a pedal is true bypass. If you still get a signal through, you will know that the bypass system is mechanical (rather than electronic), but you can't tell how the switch is wired. The Voodoo Lab pedals are a borderline case, as they use a slightly unorthodox method of disconnecting the effect input from the main (bypass) line. But they still qualify, if you ask me. MXR, Marshall, Radial/Tonebone, most Dunlop wahs etc do not meet the criteria for true bypass. Boss and Ibanez-style pedals have electronic bypass systems, and the signal is permanently wired through active circuits, so they aren't TB either. However, if you ask me, their method is actually better than the MXR/Marshall style, as it puts less load on the signal. But basically, it's a jungle... and many times the only way to know for sure is to open the pedal up and trace the circuit. If you want to read up on this issue, as well as what buffers are and what they do, you can go here . /Andreas

Thanks for the info and the link

[andreas]

Originally posted by goldie-gold I seem to recall reading the whole remove power supply thing on a fairly major builders website (I forget which). Just goes to show how tricky the issue of true bypass is.

...and how persistent that myth is. I know - I've tried to kill it for years, but it still pops up from time to time.