I am a satisfied owner of a BC-21 specifically for its use of 6SN-7 tubes; great customer service by Gilbert Yeung (Blue Circle); simple (point-to-point), yet well-thought design; and because it just sounds great. I use Tung-Sol "Black Glass" 6SN-7's, Ken-Rad "Black Glass" 6SN-7s, or Raytheon 6SN-7's with great results.
Also, I had mine modified by Gilbert - adding a Shallco volume attenuator, Blue Circle's best caps., a separate power supply, and additional inputs...the process to upgrade (communication, service, etc.) was just customer service at its best...I am a firm believer in Blue Circle because of Gilbert's design experience, service, and attention to detail...My modded BC-21 will not be leaving my system...Just my opinion and experience...
If you prefer the sound of octal tubes (6SN-7's), I suggest you'll be more than satisfied with a Blue Circle BC-21...
Also, I had mine modified by Gilbert - adding a Shallco volume attenuator, Blue Circle's best caps., a separate power supply, and additional inputs...the process to upgrade (communication, service, etc.) was just customer service at its best...I am a firm believer in Blue Circle because of Gilbert's design experience, service, and attention to detail...My modded BC-21 will not be leaving my system...Just my opinion and experience...
If you prefer the sound of octal tubes (6SN-7's), I suggest you'll be more than satisfied with a Blue Circle BC-21...