Results 1 to 4 of 4

Thread: US-1800 phantom power no longer works

  1. #1
    Join Date
    Jul 2012
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0

    Unhappy US-1800 phantom power no longer works

    Sign in to disable this ad
    About a month after the warranty's up, my phantom power stopped working on both banks (1-4, 5-8). Ugh.

    I understand connecting bad cables or mics can damage the unit, but I run pretty much a static setup with the same (balanced, tested) cables and mics (all condensers) I've been using for a few years, so I'm stumped as to how I would have fried it, but at this point I guess it doesn't much matter.

    Anyway, is there anything I should do to further diagnose the problem, and is this something that's repairable for someone with electronics experience? (Since standalone 8 channel phantom power sources are a significant chunk of the cost of a new US-1800...) The US-1800 works fine otherwise.

  2. #2
    Join Date
    Jun 2011
    Location
    N.W. Indiana
    Posts
    1,037
    Thanks
    20
    Thanked 19 Times in 18 Posts
    Rep Power
    6963833
    I'd just open it up and see if there's any thing obvious. Burnt resistors, loose or disconnected wires. Maybe the buttons are bad? test the continuity. Call me Mr. Obvious....but unplug the unit 1st. and be careful around the caps.
    Wow, now I feel really stupid. Thanks.

  3. #3
    Join Date
    Dec 2010
    Location
    Denver, CO
    Age
    50
    Posts
    19,500
    Thanks
    956
    Thanked 703 Times in 633 Posts
    Rep Power
    21474864
    I am going to guess it is a simple fix, though how easy that is, would depend on your electronics skills. I'm pretty sure it would cost more to have a shop repair the unit, than it would be to buy another. Hopefully you know a guy who can help you out.
    PC Win7-64-24G i7-4790k/Cubase 9 Pro 64-bit/2-Steinberg UR824's/ADAM A7x/Event TR8/SS Trigger Plat Deluxe/Melodyne 4 Studio/Other things that don't mean anything if a client shows up not knowing what it wants.

  4. #4
    Join Date
    Jul 2012
    Posts
    2
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0
    Thanks for the replies (and the 1.5 votes of confidence). To make a long story short (or at least a little less long), the phantom power's fine. I visually inspected over 700(!) resistors and caps until my eyes started bleeding, and then tested several around the +48V path with a multimeter. This prompted some other testing (after the denial and shame of completely missing the point of this problem wrong wore off, that is).

    It seems my phantom power confusion largely came from the fact that the inputs seem to need a lot of gain before I hear anything: at or near the US-1800's max. of +60dB, which gets me some significant clipping and distortion. If there is a sweet spot on the dial, it must be real thin. The same mics (and same cables) plugged into an older Behringer UB802 mixer are loud and clear (except for the UB802's own annoying hum) with around +15-20dB gain and everything else at +0.

    Do you think there's actually a hardware problem somewhere here, or is this just the way it goes with these on-board pre-amps? Suffice to say, I'm working through retrograde amnesia, and have apparently forgotten some important bits of how I made this work before, or whether I worked around the same issues. My testing mics include an SP C-1 (condenser) and SM58 (dynamic, ignores +48V), straight in via XLR, no external pre.

    Apologies for hijacking my own fun electronics diagnostic thread for want of some real newbie questions.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 5
    Last Post: 11-17-2011, 10:15
  2. Cubase SX3 my metronome no longer works, can someone help?
    By nashunbooking in forum Steinberg / Cubase User Forum
    Replies: 4
    Last Post: 06-30-2008, 10:02
  3. phantom power on non phantom power mics?
    By seismetr0n in forum Microphones
    Replies: 15
    Last Post: 10-20-2005, 08:05
  4. Phantom Power works, Desk doesnt!!!! Help!!
    By crowbar0 in forum Newbies
    Replies: 3
    Last Post: 01-24-2005, 05:57
  5. Homemade pop-filter no longer works
    By kdgospel in forum Fostex Forum
    Replies: 11
    Last Post: 07-28-2003, 10:26

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •