Mine is around two years old however I only used it for several months .

The current version is the HE – 1 tube MK3 . However, the MK3 version is technically exactly the same as the MK11 and sounds exactly exactly the same. They just put a nicer casing on it.

It cost me roughly $3300 including shipping and extra tubes. I’m selling for $1500 and the person can take it home and test it for a week before committing.

Here are two reviews:
https://hometheaterhifi.com/reviews/amplifier/preamplif ... er-review/

https://www.stereophile.com/content/audio-gd-vacuum-he1 ... eamplifier

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