I have just posted a review of Glenn's amplifier here: http://www.tweak-fi.com/apps/blog/show/42754587-building-a-reference-system-part-2-glenn-s-headphone-amplifier
The version of the amplifier I have is the one that allows the use of six-6BL7s as output tubes.
Below is a picture of the amplifier in my system:
The amplifier sounds fantastic. Thanks again Glenn for making such a terrific headphone amplifier!
Is that a special version of Glenn's OTL ?