Sounds great, but required some fiddling
4 Stars
Posted
Friday, February 6, 2009
by Anonymous
When I first connected this guy and fired it up, HMMMMMMMMM. This is a pretty standard complaint from what I've been reading elsewhere.
First thing to do is to find out if the hum is internal. Unplug everything, get it away from all your other gear, plug in the power supply and a pair of headphones and see if it hums. If not, then you've got other issues but at least it's not internal. By the way, this makes a dandy headphone amp. Really sounds nice
Next, I yanked the Chinese 12AX7 tube and use a lower gain old RCA 5814A (lots of other choices for tubes too). Don't sweat using a lower gain tube, just turn up your amp a little. The preamp has a knob for gain as well. This reduced the hum but not entirely.
Finally, I had to open the case and place a small piece of elec. tape between the PCB and where it mounts (near the LED). Leave that screw out and put it back together with the other three. Hum gone.
Anyway, for the money and fiddling, great preamp. Sounds super.