Goone: I did a bit of tube-rolling in the AL before I did the transformer upgrade. The stock Mullard 12AU7s supplied in my unit were very lively sounding but too hot for me in one frequency band in the upper mids, where they had a glare, so I switched them for first Teslas, which sound a bit mellower but didn't last long, then Telefunkens, which are more to my liking and last much better. I'd imagine Siemens would sound very good as well. The Teles have a very nice bloom but lack the high frequency "sparkle" of the Mullards and are slightly richer than neutral in the lower mids/upper bass, something which obscured the need in my system for a phase control in the active crossover at 220 hz for my speaker system until I did the transformer upgrade. For the stock Sovtek 6922s I've used both Siemens and Telefunken Ccas and ECC88s with good results--again, they are far more rugged and longer lasting than the Sovteks, a number of which went bad on me in the unit. Hope this helps.
Inna: Having just heard some of the Burmester digital gear at my dealer's, I'd expect that it too would work well with the Audio Logic.
