SAC amp = yum.
Vintage Marantz amps = yum.
Vintage Marantz amps = yum.
Hi, I have to add some thoughts about using any Tripath amp with the K1000: All Tripath applications show an output filter usually designed for 4 Ohms loudspeakers. If you use this application with an 8 Ohms loudspeaker the ripple in the frequency response will be around 0.5 dB which is rather unproblematic. If the amplifier is measured with _open_ outputs the peak at 20kHz reaches a value of around 30dB(!) which would be more than unacceptable. Nevertheless I assume that with the 120 Ohms of the K1000 (factor 30 compared to the filter's calculated load) you will have a treble peak of several dB which is more than just a nice coloration. To use an AKG K1000 with such a Tripath based amp one should shunt the amp's outputs with 8 Ohm resistors to avoid the high frequency peak. The same resistor will also reduce the energy in the 100kHz  1MHz band where the switching frequency is wandering dependent on the power drawn from the amp but this is another effect. 
Originally Posted by Tyll Hertsens
We've got the VolksAmp version of the Pass designed Aleph 1. I like it just fine with the K1000. I think the K1000 NEEDS a VERY good amp to really bring out what they can do. Underdriven they sound pretty poor.

Originally Posted by Hirsch
It's not a question of impedance, so much as power. Typical headphone impedances range from 32 ohms to 300 ohms, so the K1000's 120 ohm impendance is right in the ballpark. However, the K1000 is very inefficient compared to most headphones, and normally requires a speaker amp rated at 710 watts to drive them. However, that rating is normally into 8 ohms or so, so the real output needed would be the wattage of the same amp into 120 ohms, which is a bit less. Some headphone amps have enough power to drive the K1000 (but fewer will drive it well). There are some good suggestions in this thread.

Originally Posted by Uncle Erik
I've gotten halfway decent sound from a Denon receiver and the PreSonus Central Station.
I know, I know, you're not supposed to use those with the K1000. 