I've owned these headphones since I was a teenager.  After all these years the headphone still sounds great.  Made originally in Austria in the mid to late 70's these headphones have had several variations:  early, mid and late.  My sextet is the LP version.    Do not judge the quality of these  headphone by the sound out of a normal headphone jack, unless it is a well powered vintage receiver headphone jack.  At 600 ohms they need power.  In comparison they are more difficult to drive than my Beyerdynamic Tesla T1.  The T1 is more efficient with...

BACKGROUND:   After having the experience of using a less expensive tube amp, the Bellari HA540, I was interested in upgrading my desk amp. without going through multiple expensive tube trials.  Tube upgrades add significant cost and time to the process of headphone listening. I also had the positive experience of using the portable ALO Audio MKll amp. on all my current headphones.  I found the solid state amping up to the task of amping my efficient 600 ohm Tesla T1's and my less efficient 600 ohm vintage AKG K240 sextet's.   I spent time...

After several weeks of auditioning I feel comfortable sharing my impression of this portable amp.  In comparison to the FiiO 11 it provides more battery life and improved amplification.  I like the expansive sound that it provides out of my Rockbox iPod 5.5G and my MacBook Air.  The signature feels transparent and I did not hear any coloring.  I feel the amp is more than adequate to drive both my HD595 and HE400. It paired well with the DF out of my Mac and the audio out of my iPod Wolfson DAC felt warm and authentic.  At $349 I feel it is a bargain...