Hibernate Audio
Member
Hi folks - I have a Samson S-Phantom 48V mic supply on my bench right now, could use some help troubleshooting.
The phantom power section seems to be working fine, I'm able to measure 48V on pin 2 and 3 of each Mic In XLR. However, the audio output is extremely low. When I use the same mic and cables with my interface's phantom power, it works just fine.
Some details:
- measured 48V phantom on the Mic In XLR connectors
- I can hear and see phantom power turn on
- tried different mic and cables
- contact cleaner on audio jacks and the phantom switch
- I don't see any obviously blown electrolytic caps
- audio just barely registers on my interface's VU meter when I tap the mic loudly. If I turn up the gain on absolutely everything, I can hear audio (and of course a huge noise floor)
Traced the audio part of the circuit a bit, attached a little hand drawn snippet.
Additionally, I think I may have applied 48V from my audio interface to the output of the S-Phantom at some point... I assumed it would have enough protection and bipolar caps, but I may have been mistaken. This could cause the zener diodes to fail, correct? And then maybe the 47uF coupling caps?
Any ideas of what could be going wrong here?
My next step was going to be reflowing solder in the audio path. After that, maybe replacing the protection diodes and the electrolytics. Thoughts?
The phantom power section seems to be working fine, I'm able to measure 48V on pin 2 and 3 of each Mic In XLR. However, the audio output is extremely low. When I use the same mic and cables with my interface's phantom power, it works just fine.
Some details:
- measured 48V phantom on the Mic In XLR connectors
- I can hear and see phantom power turn on
- tried different mic and cables
- contact cleaner on audio jacks and the phantom switch
- I don't see any obviously blown electrolytic caps
- audio just barely registers on my interface's VU meter when I tap the mic loudly. If I turn up the gain on absolutely everything, I can hear audio (and of course a huge noise floor)
Traced the audio part of the circuit a bit, attached a little hand drawn snippet.
Additionally, I think I may have applied 48V from my audio interface to the output of the S-Phantom at some point... I assumed it would have enough protection and bipolar caps, but I may have been mistaken. This could cause the zener diodes to fail, correct? And then maybe the 47uF coupling caps?
Any ideas of what could be going wrong here?
My next step was going to be reflowing solder in the audio path. After that, maybe replacing the protection diodes and the electrolytics. Thoughts?