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Kompromat only works in bypass

Started by notanelectricalengineer, February 04, 2022, 01:14:32 PM

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jimilee

Quote from: Zerro on February 08, 2022, 07:51:03 AM
Let's give him time to make some trials and measurements and then we all will be smarter.
Im thinking it's got to be that diode.


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Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

matmosphere

That jack is kind of unusual. I'm wondering if it could be the problem. Since our pedals all use center negative I wonder if the metal casing, which is probably connected to the positive barrel of the power supply is causing a short.

Any link to that part?

Zerro

No problem to swap that power jack polarity. Center + and body -. Seems to me, it was always better concept.
"Nudíte se? Kupte si našeho cvičeného ježka! Pobaví vás svými veselýmí kousky!"

matmosphere

Quote from: Zerro on February 08, 2022, 12:15:36 PM
No problem to swap that power jack polarity. Center + and body -. Seems to me, it was always better concept.

Yeah, but then standard power supplies won't work

jimilee

Quote from: matmosphere on February 08, 2022, 11:13:17 AM
That jack is kind of unusual. I'm wondering if it could be the problem. Since our pedals all use center negative I wonder if the metal casing, which is probably connected to the positive barrel of the power supply is causing a short.

Any link to that part?
It doesn't look as if the jack is mounted. It won't be a problem until it's connected to an enclosure.


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Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

matmosphere

Quote from: jimilee on February 08, 2022, 12:37:10 PM
Quote from: matmosphere on February 08, 2022, 11:13:17 AM
That jack is kind of unusual. I'm wondering if it could be the problem. Since our pedals all use center negative I wonder if the metal casing, which is probably connected to the positive barrel of the power supply is causing a short.

Any link to that part?
It doesn't look as if the jack is mounted. It won't be a problem until it's connected to an enclosure.


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I was thinking the same thing, but it looked a little like there were three wires connected to it, so I wasn't sure.

madbean

Couple things jump out:

#1 Get rid of that DC jack. Use a proper insulated (plastic) jack. Even outside of an enclosure it's possible to cause a short between the barrel of the DC plug (which is +) and the metal casing of the jack.

#2 Ideally, you'd want to have the ICs socketed especially for a case like this. That allows you to remove the ICs and rule out any issue of a current sink on one of them. IOW, it would let you more clearly determine where the issue with the 9v supply in the circuit resides. Since it appears they are soldered directly to the PCB it may make debugging more challenging. At the very least, do step #1 then see what voltage readings you get on pin8 of the TL072. That might help us narrow down the issue :)

notanelectricalengineer


madbean

Absolutely. I may have a spare or two I can mail you. I can check.

notanelectricalengineer

That'd be great because it would probably get here sooner than any website would ship.

madbean

Quote from: notanelectricalengineer on February 09, 2022, 10:43:15 AM
That'd be great because it would probably get here sooner than any website would ship.

Okay, looks like I can spare one or two. Pretty low but I have enough. I should have your address from your order. I'll get back with you.

notanelectricalengineer

Little update: With the new jack, the whole pedal works! I'm never buying a metal jack again haha. I appreciate everyone's help in the matter.

matmosphere

Quote from: notanelectricalengineer on February 20, 2022, 07:03:50 AM
Little update: With the new jack, the whole pedal works! I'm never buying a metal jack again haha. I appreciate everyone's help in the matter.

Pretty sure we've all mad that mistake once.

jimilee

Quote from: notanelectricalengineer on February 20, 2022, 07:03:50 AM
Little update: With the new jack, the whole pedal works! I'm never buying a metal jack again haha. I appreciate everyone's help in the matter.
Nice, congratulations!


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Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.