I've had an Almarro 318B (to Zu Driud speakers) for about 5 months and tried a wide assortment of tubes. All are very pleasant. Highly recommend it. I asked a tube dealer to put together a samling of 6SN7 and 6SL7 tubes and I got 9 different tubes for $210. It has been really fun switching out and making notes on the boxes of what I hear.
I listen 6-8 hours a day and so I was concerned about "burning through" tubes but that has not been the case. Just bought a back-up pair of the 6C33C tubes for $48 a pair shipping included from Russia. I was skeptical but they sound better than the old tubes (which may be getting near their end) and look identical. I can do $50 every 6 months.
Biasising has not been an issue at all - I have not had to adjust the new pair during their breaking in - about 50 hours so far. I run them a bit "hot" at 24 as that improved the sound even though they say it wears the tubes out faster -- but at these prices they are the least expensive cost of this hobby for sure.
I listen 6-8 hours a day and so I was concerned about "burning through" tubes but that has not been the case. Just bought a back-up pair of the 6C33C tubes for $48 a pair shipping included from Russia. I was skeptical but they sound better than the old tubes (which may be getting near their end) and look identical. I can do $50 every 6 months.
Biasising has not been an issue at all - I have not had to adjust the new pair during their breaking in - about 50 hours so far. I run them a bit "hot" at 24 as that improved the sound even though they say it wears the tubes out faster -- but at these prices they are the least expensive cost of this hobby for sure.