Edcor 2020

I was looking at that quite a while back (before I found Head-fi) for use at work. Never pursued it though.

"Excellent for headphones from 4 ohms to 50k ohms." Can that be true ?

What cans did you use with it ?

LOL ! Yeah, flamebait for sure... You preferred it to the Creek ? While the Creek has it's detractors, I find it to be a capable amp especially when purchased used for a good price. (I have only used it with the Grado 60's, perhaps it's underwelming with other cans) But the Edcor is less than half of a used Creek. And the specs look awesome but you can't judge it on specs alone. I'd be very interested in hearing you A/B it against the MGHead with the 600's. Can't help but wonder why they went with an 1/8" output jack inlieu of 1/4" if it's a serious headphone amp...

Doesn't your Edcor 2020 have significant baseline hiss? Even at zero volume I get a light low-level hiss with the ER4S...those IEMs need some juice, though. With anything more sensitive and low impedence like the 7509 it would be unuseable. I have two 2020s. They both do this, though, they both shorted out the wall warts when I first got them. I was their first 2020 customer and the power supply's pins on the bottom contact the metal plate on the amp. They sent me a second and it did the same thing. Then the engineer figured out what it was and sent me two wallwarts for my troubles. The solution was just some electrical tape or some other insulation between the supply and the plate.

It is VERY high gain. I mean, even with an old Panasonic 10mW portable I still have like 60% gain left. An insensitive Beyerdynamic might be a good match. Right now I have it connected to a modded Denon DCM-370 listening to some HDCD Nirvana. The pot is at the lowest point I can get with the L/R balance being the same, which is still slightly louder than I'd like but less pain than moving it down slightly and wobbling it to get proper balance. Any way to bring the gain down but keep the current/impedence up would be nice. Zero sibilance. Organic, tan-toned...highly revealing of recording or source equipment grit. Physical. Length of cable makes a big deal going into it. Another good DAC for it are the Cirrus Logic Twin Core DACs in a number of receivers out there. In fact, the Cirrus Logic's may match better than the Denon's Burr Browns. I know they're smoother and more refined than the CL's in my Emu 1212m.

Back to the hiss. So did the short out possibly screw something up in there that caused the hiss or is it just from so much gain? Possibly damage some resistors or the opamp that might be causing the hiss? Anyone?

Also, do amps' nominal input levels mean you shouldn't go over them? Is it o.k. to send the Denon's full 2V signal into it or should I look up what the Edcor's nominal level is supposed to be and turn the Denon down to that?

Found the manual on Edcor USA. It says it will accept up to 4 Volts on the inputs. I'm listening to Radiohead in HDCD on the Denon right now. Amazing body and physical sense to the music with the Etymotics. Again, zero sibilance. Doesn't seem quite as open or separated as it could be. It's an improvement over the Redsound Micro Amp and the one in the HK AVR7200 receiver overall. HK's in particular has a sort of glassy, almost out-of-phase, hollow midrange. Snaps into focus on the Edcor. Not sure about the one in the Denon, since it has to be disconnected to get rid of the distortion-causing thing in there. I have no doubt there are better amps out there. I got two-for-one, though. What was wrong with the power transformer? EDCOR is pretty well regarded amongst the pro audio community for their transformers...sort of a specialty. Maybe that's now, not then?

Also, if it had hissed, I would think you'd have noticed it with the 7509. Any idea what opamps worked in it?

Ironically, the Edcor turned out to be wired 180 degrees out-of-phase, not the HK.  The latter tested very well, even better than an Allen & Heath's board jack.