Primaluna tube gear

Rest easy my friend. This brand is excellent. I don't own it but I have a close friend who does and I have spent many hours listening to his system. He owns a preamp with built in MM phono and a stereo amp, both Signature models purchased at RMAF in 2010. You cannot pass judgement on any performance criteria for a component because they hit the for sale rack on A-Gon. Wait long enough and you will see everything from the cheapest to the most expensive listed here.

In this video it's claimed that Primaluna's adaptive bias circuit is the only one that adjusts the tube bias as the gain increases. Is it really the only one that can do this? There are other auto bias tube amplifiers out there.

http://www.youtube.com/watch?v=H5pklu3pNo8

I owned a PrimaLuna ProLogue One for a time. The unit was heavy and sturdy, but sounded, well, heavy and sturdy. Granted, the ProLogue One was the cheapest in the lineup, but I had a Sophia Electric Baby amplifier that was a far better sounding amplifier and cost about a 3rd of the price. My 2 cents anyways.

Bought a Primaluna PL2 5 years ago. Upgraded the rest of my system several times sill have the Primaluna.

I am running a Primaluna Prologue Three preamp feeding a Prologue Five amp.
I found the stock Chinese tubes to be lacking.
In the Prologue Three I replaced the rectifier tubes with early 60's Mullard 5AR4's, the driver tubes with NOS 60's German RFT/Philips 12AU7's, the input tubes with 60's Telefunken ribbed plate 12AX7's.
In the Prologue Five I replaced the Output tubes with a new quad of reissue GL KT-88's, the driver tubes with late 50's Sylvania long black plate 12BH7A's and the input tubes with new Black Sable Cryo treated Sovtek 12AX7LPS's.
My tube rolling has really made these Primalunas sound wonderful. They are not leaving anytime soon.

Al.