Toasted R33! I'm An Idiot...

[ghetto3jon]

i'm an idiot, and on my seventh SCA kit (first six work fine), i put Q1 and Q2 backwards...then i powered it up, and R33 started smoking.

so now i've properly oriented Q1 and Q2, and R33 still meters correctly...is it safe to power it up again? could i have damaged something else?

(let this be a lessen...don't build a SCA kit after you've accidentally taken a double dose of your migraine medication)

[ghetto3jon]

i'm not very good at reading schematics, but it seems like R33 is in the phantom power circuitry...so i checked the phantom power at the XLR connector with my multi-meter, and it reads about 47 volts...which is still good, right?

i'll be away for a few days, so i can't perform any more tests...including passing sound through it. but i'm anxiously awaiting some feedback from someone who may know more than i about this...could i have damaged anything else by installing Q1 and Q2 backwards, and now that they're properly oriented, is it safe to plug in a mic and give it a go?

[mikeiver]

Bit late on the reply but I thought you would like to know that you are correct. There should be no problem with powering up the unit and trying phantom power on a mic. It might be a good idea to replace it when you get a chance, it's cheap insurance against a failure during tracking.

FYI, the resistor is part of a simple RC input filter to the ramp circuit on the phantom power switching. It is there to try and catch any residual hum or ripple on the line from the switcher.

Mike

[ghetto3jon]

thanks for the reply, mike.

i ended up replacing R33, and Q1 and Q2. now everything is fine.

i've been using the module a lot lately, and it sounds great...no problems to speak of. lessoned learned: double check your medication dosage.