Blue Circle BC21 preamplifier & BC22 power amplifier Kalman Rubinson September 2003
More than two years have passed since I reviewed the Blue Circle BC21 preamplifier and its stablemate, the BC22 power amplifier, for the February 2001 Stereophile. Having jogged my memory by re-reading those reviews and my original notes, I now recall enjoying the Blue Circles' performance, singly and mated, despite finding the BC21 to have rather more forceful a personality than was ideal. I was less impressed by their construction and cosmetics. When Blue Circle's Gilbert Yeung offered me the new BC21.1 for a Follow-Up, I hoped that this successor, while addressing what I saw as the BC21's idiosyncrasies, would retain the original's clarity and dynamics.
Well, the BC21.1 retains the original's rather dowdy appearance, but the resemblance is only skin-deep. Inside the substantial steel case are two 6922 rather than 6SN7 tubes, in a circuit similar to what's found in more expensive (and highly rated) Blue Circle preamps such as the BC3 (reviewed by Chip Stern, August 2000). In fact, my overall impression was of a more substantial, more orderly internal arrangement that, while retaining Blue Circle's point-to-point wiring, now seems immune to the physical stresses of packing and transport.
The BC21.1 costs $1650 with the standard Alps pot. (The BC21 cost $1500.) For $1900, the BC21.1 is also available with either a Shallco stepped-ladder attenuator or with a motorized version of the Alps pot and a wireless remote control. For an additional $75, any version can also be ordered with the Processor Loop Option, for use as a unity-gain pass-through (as might be useful in integrating a BC21.1 into a multichannel system). My sample had the Shallco attenuator option.
Because the BC21.1 came with no documentation (a special consideration for reviewers, I assume), I connected it up in place of my resident Sonic Frontiers Line-3 preamplifier, using single-ended connections.
The BC21.1 exhibited none of the operational problems I'd had with the BC21. There were no power-off transients at all (although the turn-on delay seemed a bit longer), and no signal-line noise. I can be emphatic about the BC21.1's lack of noise because it seemed to have much less gain than any other preamp I've used; I had to twist the Shallco attenuator up to 2 or 3 o'clock to get any reasonable output. Even so, with my ear any more than 6-8" from the tweeter, I heard no noise.
Only some time later did Gilbert Yeung tell me that a different range of gain settings can be selected via a little toggle on the back of the Shallco attenuator (footnote 1). With that switch flipped, comfortable listening levels were possible with settings below 12 o'clock, but the BC21.1 performed equally well at both settings.
I mated the BC21.1 to the McCormack DNA-1 with Cardas Golden Cross, as I had the BC21 for my original review, and, using the same reference recordings, reconsidered my observations.
Everything seemed more as they'd been with the Sonic Frontiers Line-3 (which, though a far more complex design, also uses 6922 tubes), but not necessarily as with the BC21. There was no lack of transparency and detail in the high frequencies or midrange, and the size of the soundstage equaled that of the Line-3 in the lateral dimension, and approached it in depth.
The biggest improvement was in the bass. While the original had great extension and good definition at the low end, it was cursed or blessed, depending on your preference, with more copious midbass and deep bass than I consider correct, judging from auditioning a wide range of recordings as well as the very familiar WQXR announcers. Well, the BC21.1 had none of that excess, and offered, overall, a very honest rendition of bass instruments and voices. While this made the BC21.1 a good match for most power amps and speakers, it's probably (remember, I was working from notes) not as well-matched to its stablemate, the BC22, which benefited from the kick in the bottom provided by the BC21.
Of course, I would have liked to assess how much of this improvement was due to the changes in tubes and circuits (the latter not unrelated to the former) and the fancy Shallco attenuator, but I could only guess that the first two were likely responsible for most of it. The Shallco option offers repeatable settings with low noise as well as parts quality cachet, but was probably not as great a contributor to the improvement in sound. But it was a pleasure to use, and that should count for something.
Although its similar appearance and barely altered model number imply only incremental differences from the BC21, the Blue Circle BC21.1 is a new and improved preamplifier. For those who want gut-wrenching bass, the original BC21 is, according to Blue Circle's website, still available. The BC21.1, however, deserves a model designation more indicative of its advances on its predecessor: It has everything nice—clarity, wide soundstage, tight bass—that I heard two and a half years ago from the BC21, while improving on them and adding a subjectively honest tonal balance. It is a formidable line stage.—Kalman Rubinson
Footnote 1: The actual gain of the BC21.1's active circuitry is fixed at 23.5dB. The switch changes the amount of attenuation at various settings of the Shallco; eg, the minimum position (one click up from the first or mute position) changes from -84dB to -66dB. Clearly, there will be finer steps with the latter setting. Perhaps that was a factor in my greater comfort with it.—Kalman Rubinson