Pedal doesn’t work if placed in a True bypass loop (phase issue?)

[Reauxbeaux]

Hi,

I'm new to the board because I'd like to start building diy stompboxes. Right now though, I have a question involving my vintage guyatone rolly box phase shifter, I hope that's not against any rules..

I just received the Pedal, and when I plug it straight between my guitar and amp, it works and sounds great. However, when I place it in a true bypass looper, it doesn't give any signal when the unit is on. Same behavior if I place it in any of the other loops. I checked cables, powersupply, different pedals etcera, and I'm 100 positive that the problem comes from within the unit. My guess is that the Pedal is out of phase in Some way, causing it to short out the audio signal when connected within an "in phase" audio cirquit, like a loop switcher. If I'm right, I would however have No Idea How to get it to work within the loop switcher. Maybe make a phase converter cable? Would I need one or two?

Any advise would be greatly appreciated!

Robbert

[Fender3D]

First things first..
WELLCOME

...it doesn't give any signal when the unit is on....

..and when it's off?

It's a strange behaviour, because if your looper is "true bypass" you shouldn't have any impedance issue,
phase inversion really does not matter here, unless you have some loop in parallel with another and you're actually using that...

[Reauxbeaux]

Thanx!

When the unit is off it will let the clean audio trough.

No parallel looping involved just analog switching(one control iguana). George L solderless cables, so no chance of out of phase cables.

The whole pedalboard is in my amps effect loop. I also noticed that if I disconnnect the send return cables, the phaser's led turns of, it seemed to need that connection for power. I'm dazzled:)

[GGBB]

George L solderless cables, so no chance of out of phase cables.

Have you tried other cables just in case? I can't think of any other way to explain that problem except possibly a phase inverting cable (even then I'm not sure).

[Reauxbeaux]

Haven't tried other brands in this case, but I'm absolutely positive the cabling is perfect. I'm going to try phase inverters this week. Still hoping someone can come up with the winning answer:)

[Fender3D]

the rolly box has a vintage bypass, effectively connecting the output and input sockets when in bypass.
Then since it

will let the clean audio trough.

we may assume its bypassing system works.

You should make 2 checks:

• Connect your bypass looper in front of the amp and check it actually works
• swap input and output cables on the phaser pedal

[DIY Bass]

Phase only matters if you are mixing the signal back in with itself in some way.  If you are using the looper to mix the wet signal in with a dry signal then phase could matter - but you would still hear something, just weak and bad tone.  The pedal sounds like it is working as it should - you say that without the looper the bypass and effected signals from the pedal both work. The pedal works.  It sounds as if you have checked other pedals in the same loop and they work? if that is the case then it is almost impossible to explain.  Some weird interaction between the 2 is all I can think of, but I an not sure what to start looking for.

[GibsonGM]

^  DIY Bass nails it.  The only way to get 'silence' from phase issue would be to have complete and opposite phase reversal - a pretty much impossibility with the types of circuits and parts we use.  You'd hear SOMETHING, even a tinny and tiny garbage signal.   Weird = phase problem.  silence = something we did wrong 

[Reauxbeaux]

thanks everybody for all the input. It's the weirdest thing ever, that much is clear:) I checked again, it doesn't work in any loop, but works when its between my guitar and amp.

Couldn't the ground and hot signal be switched within the circuit? Maybe it wouldn't really matter if its placed between guitar and amp, but when its in a looper, the hot signal (normally ground) would be tied to the ground of the looper, causing it to short the signal?

I wish I could upload a video to prove it to you guys:)

[Reauxbeaux]

http://www.diystompboxes.com/smfforum/index.php?topic=87933.0

read the second to last reply:)

Found it:)

(vox 1900 is the exact same cirquit)

[vigilante397]

Huh, well now I'm curious. If it's 9V negative ground with a standard 2.1mm barrel center negative jack, what in the circuit would make it not work with a daisy chain? The link to the schematic posted on that thread is a dead link.

[reddesert]

http://www.effectsdatabase.com/model/guyatone/box/ps101

Look at the picture showing the DC jack (I can't link directly to it). It is a center negative barrel jack but the jack is mounted deep inside the enclosure, not to it. It is possible that the outer, positive side of the plug is shorting to the enclosure, or that the effect is built in such a way that the enclosure isn't negative ground.

[vigilante397]

http://www.effectsdatabase.com/model/guyatone/box/ps101

Look at the picture showing the DC jack (I can't link directly to it). It is a center negative barrel jack but the jack is mounted deep inside the enclosure, not to it. It is possible that the outer, positive side of the plug is shorting to the enclosure, or that the effect is built in such a way that the enclosure isn't negative ground.

Ah, okay, I could see that being the case. Thanks

[Reauxbeaux]

Thanx everybody!