Originally Posted by gitrob
I got my 1073LB two weeks ago and I use it with an A-Design 500HR Rack.
First the slot was too narrow so I had to file a littlebit to make the 1073 fit into the 500HR rack. So please don't use this two components together, although the A-Design rack really looks good and is built very very well.
The 1073LB sounds great with my tube mics and the ribbons but when I turn on the 48Volts phantom power first a loud hum starts and becomes lower but stays there.
Does anyone of you have this problem too with the 1073LB???
Most tube mics have their own power supply and don't require 48V phantom. Most Ribbon mics do not take phantom either, unless they are something like one of the Royer designs with an active preamp. It sounds like yo uare using your equipment incorrectly. Be careful with your ribbon, under certain patching conditions, you can destroy your mic with 48V active.
**EDIT** I may be misreading your post, saying that it sounds great on ribbons and tubes, but when using 48VDC on other condensers, the problem exists? Sorry if I'm jumping the gun on my previous assumption that your using 48V on tubes and ribbons. Do you have other 500 series pres? It could be a power supply issue which would evidence itself on other preamps too. If you have a multimeter, check that the voltage is symmetric on pin 1 to 2 and 1 to 3.