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by Bubber
This issue cropped up and I said, man, I wish the Tech Room still existed right now. Lo and behold. I guess this is the new Little Tech Questions From Your Day thread?
Anyway, this past year I picked up a couple of Rane ML-1 preamps. IMO these are a real sleeper--clean, good two-channel rackmount preamps with Burr-Brown chips, with an option to send them S/PDIF out, and one of the few Rane items that uses a standard power cable (instead of their weird phone cable power situations) --as long as you don't mind getting behind it to adjust the gain with a tiny screwdriver. Since there are plenty of opportunities for usually set-and-forget, I think they're an incredible deal. They very occasionally pop up for about $100 (for two nice channels) lately.
I've been using this one with a condenser (4033) on one and a dynamic (635a) on the other. A few days ago when I fired it up, the 635a made a crackling speaker noise out the mic (going the wrong way). That's not great, but I noticed the mic (and pre) was still passing sound, so I winced and shrugged it off. (I'm going to need to check that mic out more closely.) Then yesterday I noticed when I swapped out the condenser for another condenser that the phantom seems to not be working. Both condensers themselves are still fine, glad to say.
So it seems that the phantom has crapped out. Gain is still working on the dynamic, and it's still sending to the S/PDIF.
When I've glanced ignorantly at other simple preamp build schematics and info, it has seemed that getting phantom going is one of the easier things to do.
Sure, I didn't pay much for this, and I have another, but I hate the idea of letting something go to crap just because a fix is too expensive. Any basic advice on how I can trace out fixing this phantom with limited skills? My dad is a retired EE but he doesn't really enjoy messing with this stuff on my behalf.