Blue Circle BC21 preamplifier & BC22 power amplifier
Blue Circle products are a throwback to the days when each product in a company's stable had a recognizable personality, and Gilbert Yeung's wide product line has examples of almost every tube and solid-state design topology. Blue Circle products share a clean, stainless-steel front-panel design, small size relative to function, and, of course, that soothing illuminated blue circle indicator—but some are tall, some are wide, and the size of the heatsinks varies widely.
When I step into a Blue Circle demo room, I never know where to start; Gilbert Yeung tells me that I don't have to know the details—that I should just sit down, listen, and enjoy. I usually do. Yeung and I had played a cat-and-mouse game for a few years, but now it was time to stop being coy, and for me to take home one of the setups. We agreed on Blue Circle's least expensive combination: the inexpensive BC21 tubed line stage—Chip Stern reviewed the more expensive BC3 last August—and the BC22 solid-state, class-AB, 125Wpc power amp. Each design, despite its modest price, is entirely hand-wired.
My wife expressed surprise and disenchantment with the BC21 line-stage preamplifier's three big, wooden knobs. "How could they do that?" I guess someone must like it. Although it holds its own with other Blue Circle gear at the shows, in my rack the BC21 looks a bit dowdy.
But when I looked past the BC21's wooden knobs and feet I saw that it is actually a very clean and intuitive design. The front panel has an input selector, tape-monitor toggle, balance control, volume control, and power switch. In the center is the eponymous Blue Circle combination logo and indicator light. When I leaned over to take a look at the rear panel, I noticed that the labeling of inputs and outputs is inverted for easy reading.
The instruction manual is cursory but not really needed. I connected the line inputs and single-ended outputs, plugged in the IEC power cord, and flipped the power switch. After waiting a few seconds to heat up the two 6SN7 tubes, the relay clicked and music came out. Because I left the solid-state BC22 power amp on continuously but tried to conserve tube life by switching off the BC21 between sessions, I found that the preamp's turnoff was not quite fast enough to mute an annoying little transient. Of course, if you follow correct protocol and first turn off your power amp, you won't have this problem.
Intermittently, the BC21 developed high levels of hashy noise, but usually the unit was silent; in fact, even during its epileptic fits, its sound was otherwise okay. Nevertheless, Blue Circle dispatched a replacement pair of 6SN7s, which gave me an excuse to pop the unit's top. It's quite lovely inside, with high-quality Cardas point-to-point wiring that eliminates the need for any printed-circuit boards. Components are stacked and fixed with what appears to be hot-melt glue. I checked the internal solder joints and found a signal lead on the balance control that came loose with a little jiggling. I resoldered this, replaced the tubes, and the noise problems never recurred.
The BC22 power amp was a surprise in many ways. First, it seemed much heavier than its dimensions or stated weight suggest. Blue Circle's literature attributes this to the "serious overkill" power supply with its large toroidal transformer and "massive filtering." Second, the stainless-steel faceplate—with only the subtly illuminated Blue Circle logo and the power switch—gives this midpriced amp a clean, lab-style appearance. Third, even though the BC21 preamp has only single-ended outputs, the BC22 sports balanced (XLR) inputs along with the RCA jacks. Of course, because it's a fully balanced design, it would have taken a perverse personality to deprive the user of this facility. In addition to these jacks, the rear panel bears two pairs of sturdy combination binding-posts and toggle switches for selecting inputs. All connectors and signal-path wiring are by Cardas.