So awhile back I picked up a DBX 900 frame because I thought it would be a cool platform to work with. Friday I finally did my first project with it.
2 312 style pres on a single 900 card.
The 900 PS gives me +-15V regulated and +- 24V unregulated.
I don't have a front panel for it yet so everything is just hangin' off the board which isn't too bad as I'm still hunting down some issues.
So the pres fired up first go. I just plugged a 57 in and did some speech tests and life was good. I had the gain pots wired backwards but that was an easy fix. I thought I could get away with using the +-24V as 48V potential for phantom power but that doesn't seem to work so well. All the power rails share the same common reference point.
So no worries...I'll just cheat and use the +24V rail as my phantom. I test it out with a AT 4033 and life is good. Clean, no noise, nice clean sound. However when I go to test it with a Shure Beta 98 I get all sorts of hum and buzz when the phantom is on. I don't get it with the 4033 or a KM184...Just the Beta 98.
Any ideas?
I've considered just doing a "house" phantom supply that way I wouldn't have to keep reinventing the wheel with every time I needed phantom.
I've also thought about rebuilding the supply in the 900 and customizing it for preamps since that's what I'm building right now. But I'm not too sure I like the idea of bastardizing the 900 frame as I would like to get a 903 comp or two. (also thinking of getting a couple of Pico comps. :grin
Or is there a way that I can turn 24V into 48V without a ton of parts?
Thanks,
James
2 312 style pres on a single 900 card.
The 900 PS gives me +-15V regulated and +- 24V unregulated.
I don't have a front panel for it yet so everything is just hangin' off the board which isn't too bad as I'm still hunting down some issues.
So the pres fired up first go. I just plugged a 57 in and did some speech tests and life was good. I had the gain pots wired backwards but that was an easy fix. I thought I could get away with using the +-24V as 48V potential for phantom power but that doesn't seem to work so well. All the power rails share the same common reference point.
So no worries...I'll just cheat and use the +24V rail as my phantom. I test it out with a AT 4033 and life is good. Clean, no noise, nice clean sound. However when I go to test it with a Shure Beta 98 I get all sorts of hum and buzz when the phantom is on. I don't get it with the 4033 or a KM184...Just the Beta 98.
Any ideas?
I've considered just doing a "house" phantom supply that way I wouldn't have to keep reinventing the wheel with every time I needed phantom.
I've also thought about rebuilding the supply in the 900 and customizing it for preamps since that's what I'm building right now. But I'm not too sure I like the idea of bastardizing the 900 frame as I would like to get a 903 comp or two. (also thinking of getting a couple of Pico comps. :grin
Or is there a way that I can turn 24V into 48V without a ton of parts?
Thanks,
James