Todd Warnke

Authorized Blue Circle Dealer Oklahoma Area

October 1997

Blue Circle BC6 Amplifier

Blue Circle Audio, located in Ontario, Canada, is a relative newcomer to the High-End. Founded in 1990, they had remained relatively unknown outside of their native Canada until recently. It wasn't until the DAS review of the BC-3 pre-amp that I first heard of them. After reading his VERY positive review, I called Doug to ask if the pre-amp really was that good. He confirmed that it was that good, perhaps even better - the proof of that is that he bought one himself. From Doug I found out that it was Stu McCreary at Positive Feedback who turned him onto Blue Circle. Stu had found the performance of the class A, single ended BC-2 amplifiers absolutely first rate.

It wasn't until CES '97 that I had my first chance to hear the line for myself. While show conditions are never a good place to form a concrete opinion, the Blue Circle room sounded very good indeed. "Hmm, keep an eye on them," I thought. Then, at Hi-Fi '97, the Blue Circle/Merlin room was my best of show. I knew at this point that I had to hear this stuff in my own place. The amplifier showing at Hi-Fi ’97 was a new model, the BC6. Based on circuit topology of the BC-2 monoblock amp, it's a stereo model with less power output. The way it controlled the Merlin VSM-SE, it sounded like at least 100 watts, not the 25 watts it's rated at. Since Gilbert Yeung, President, Designer and Chief of Office Supplies at Blue Circle Audio was standing next to me as I listened to the setup, I asked (okay, begged) if I could get an amp to review. He reply was, "How about I ship this one to you after the show?" So, if you were in San Francisco, you heard the exact amp I'm writing about.


Gilbert Yeung is a person who follows his own ideas. When designing his amplifier line, he decided that single ended, pure class A was the way to go. However, instead of designing another "me too" single ended tube amp, he built his single ended amplifier using a bi-polar transistor output stage. Then, unlike the Pass Labs’ amplifiers, which are also single ended solid state designs, Gilbert put a 6922 tube in the input stage of each channel. This unusual hybrid circuit topography was chosen because Gilbert felt it would offer the best sound, rather than the best bench measurements - although it measures admirably.

[BC6 Amplifier]The BC6 also looks different than most amplifiers. The central 17 by 5 by x 15 inch body of the amplifier is made of #304 grade stainless steel. The black, Levinson-like heat sinks that stick out another 4.5 inches from each side are mounted flush with the top of the amp and extend an inch or so below the bottom of the central box. To keep these sinks from touching any surface, the amp is supported by three wood and rubber feet, which, at about 2.5 inches tall, give the amp a cantilevered, light look in spite of its total 26 inch width and 55 pound weight. As for other distinguishing marks, when powered up, a 1.375 inch diameter blue circle lights up in the center of the faceplate. With the exception of an on/off toggle switch and an engraved Blue Circle Audio emblem and model number, nothing else clutters the front of the amp. As for the top of the amp, with the exception of vent holes drilled directly over the input tubes, it is without markings. The rear of the amplifier is also very clean. A pair of Cardas 5-way binding posts per channel, a pair of Cardas RCA input jacks and an IEC power cord connector sum it up. The BC6 is one of the most unusual looking amps I've seen, and also one of the best looking. Modern but artful, powerful looking but graceful, it makes a strong visual statement.

The guts of the BC6 are as beautiful as the skin. A peek under the lid reveals why the BC6 costs as much as it does. Sharing only a power cord, the dual-mono layout is neat and impressive. Each channel has it's own transformer larger than those I'm accustomed to seeing in 200 watt amps. Separate PCBs for each channel are neatly laid out and tightly packed with high quality parts. By themselves, parts and design quality can justify the price of the BC6.

Philosophy 101 (Mine, not Gilbert's)

Before jumping into the performance of the amplifier I want to give you some context for my comments. In High-end audio, as in many applications - warfare, software, cooking, lovemaking - greatness is in the details. Anybody can follow a Joy of Cooking recipe (or Joy of Sex illustration for that matter), and turn out a serviceable meal. But making a great Thanksgiving Turkey is more than following a series of steps, I’ve tried following the book and had competent, although unexciting results, just ask my wife (about the Turkey that is). To make a great meal takes intense attention to the subtleties. In a like manner, any competent amplifier design gets you at least 75% of what the best amplifier can. That is, the amplifier section in an average Kenwood receiver gets you 3/4ths of the way to Krell, Levinson, AR, C-J or anyone else. But to be great, to reach the ultimate in audio orgasmic delight requires fanatical attention to detail.

As a corollary to the above proposition, since the difference between competence and greatness is only 25% of what's possible, small gains become disproportionately important as you get close to the limit of what's possible. The first gain of 10% in absolute terms represents about 40% of the total possible difference between any two components. Moving from a Kenwood receiver to gear like Adcom, Rotel, Carver and McCormack moves us, on the absolute scale, from 75% to the upper 80's, perhaps to even 90% of what is possible. This leaves precious little room for absolute performance increases from entry and mid level High-End gear to the ultra-fi stuff. It also magnifies the importance of each additional step forward.

For an amp to make real increases in performance beyond the 90% point there is great pressure on the little things -- on the details that make for greatness. Entry into the top echelon requires painstaking attention to the miniscule, that may only bring a fraction of a percent increase in absolute terms. On the other hand, since the difference between competent High-End designs is small in absolute terms, it is easy to misconstrue my (or other reviewers) comments regarding their relevance. In the absolute, differences between two quality amps may only be a percent or two in a couple of different areas. You may not find that to be a revelatory change. Still, since that 1 or 2% is also 10 to 20% of the total change possible, to someone closely monitoring the margins, it is a big difference indeed. In a nutshell, what separates the good from the great is near maniacal attention to detail. The results of which can be very small, while at the same time very significant. In that context, I offer the following comments on the performance qualities of the BC6.


One advantage of getting the amplifier that was used in San Francisco is that after a brief warm up it was ready to go. Since the BC6 arrived on a Friday afternoon, I popped it into the main system, turned the CD player on infinite repeat, went camping for the weekend and returned with an amplifier ready to listen to.

From the git-go it was obvious that what I had heard at Hi-Fi ’97 was real. I was surprised at how nimble, powerful and revealing the Blue Circle/Dunlavy combo was – much more than promising, it hinted at greatness. Much of the credit for this quick and easy alliance goes to the Dunlavy speakers as well as to the BC6. With a narrow impedance window (a low of 4, but a max of 5.4 or so) and 92 dB sensitivity the SC-III's give an amp room to show what it is capable of without requiring it to be a Gold’s Gym graduate.

Speaking of Gold's Gym, let's start with that traditional stronghold of the muscle amp, the bass. The BC6's lower end was deep, powerful, quick and detailed. It also was extremely organic. That is, it flowed with a natural grace, and was very moving and emotional. In spite of having only 25 watts to the play with, the bass of the BC6 boogied with the best I've ever heard. When Andrew Rigby (of DAL) and his wife were over for dinner and cigars (my first cigar and of course we went for the High End of the cigar world…thanks Andrew!) his first comment regarding the SC-III's was about the incredible quality of the bass. Still, the Dunlavy's only go down to 45 hertz or so, which gives a nice but incomplete window to pass judgement on. So, when the Kharma Ceramique 2.0 was put in, which reaches to 35 cycles, I listened closely for bass weakness, and found none. What I had heard with the SC-III's was there in like manner with the Kharmas. No, not a true full range test, but indicative of many if not most home environments. When driving the Platinum Studio 1's, a stand mounted mini-monitor that reaches to about 50 Hz or so, but are less efficient than either of the other two speakers, the bass went as deep as the speaker allowed. As for the quality of the bass, it was the best I've heard from the Platinum speakers.

The midrange of the BC6 was as delightful as the bass was. Vocals, male or female, had expressive magic. k d lang's Drag was, at once, seductive and malignant. John Hiatt has spent a lot of time in the transport lately, and while the newest, Little Head, isn’t up to the standard of Bring the Family or Slow Turning, it's still better than 98% of what ever else you're listening to. With the BC6, his voice was masculine, emotional and powerful and most importantly, startlingly real.

Guitar, such as the intriguing combinations on Pat Martino's All Sides Now (the Tuck Andress duet is very cool, but then so is the Joe Satriani), was another area that showed the midrange excellence of the BC6. Martino's guitar/vocal duet with Cassandra Wilson on Joni's Both Sides Now is emotionally overwhelming. The BC6 let every last drop of the emotional juice flow through. This level of midrange control, beauty and accuracy allows the Blue Circle amp to re-produce music very convincingly. When listening to the BC6 I found that music had a tonal and emotional center that intrigued, captured and held me. No, bad recordings didn't become good, nor did poor performances become acceptable. Rather, the BC6 uncovers the heart and soul of what it's fed, and it does so with virtually no imprint of its own.

Treble was sweet and extended and definitely not lacking for detail. Triangles pierced with laser edges, not sloppy and dulled serrated ones. Cymbals shimmered without losing a jot of micro detail. Staging, whether due to the dual-mono design, class-A operation, or something else, was beyond reproach. Right to left was broad and focused. Front to back was deep and solid. In short, the best I've had the privilege to enjoy.

As for dynamics, I've saved this for last, because with only 25 watts, it is, on paper at least, the area of biggest concern. Not to put too fine a point on it, but in my system and with my speakers and with my musical tastes I found the BC6 had superb micro dynamics and very good macro dynamics. The micro level is where music lives and breathes. And with the BC6 that flow was natural, easy and refined. Large macro swings were nicely portrayed, although only with close to full impact with the Kharma speakers. This is not to say that such swings were poor with the Dunlavy or Platinum speakers, simply that both of those speakers need more than 25 watts, even of the superb Blue Circle type, to be fully energized.

To its credit, regardless of the speaker used, the BC6 never ran out of headroom...with one exception. That occured when I had a friend over to help fix a busted water spigot. He saw the 6 foot tall Dunlavys and the 26 inch wide BC6 and wanted to hear Power Bass. We put on Seal and cranked it. Everything was great until we tried to go louder than about 96-98 dB. When pushed beyond that, the amp ran out of steam, and did so quite abruptly. After moving faster than either Dameon Bailey or Michael Johnson to shut the volume down I vowed to never push the limits again. Still, as memory of that event faded I found that my average volume level quickly returned to normal levels, and then ventured beyond. After many more hours listening, including sessions with Seal once again, I've yet to hit that wall another time. Overall, the 25 watt BC6, subjectively, sounds as strong as any 50 watt amp I've had in my room, and as powerful as many 100 watters.

If you haven’t guessed by now, I am extremely impressed by the performance of the BC6. However, I wanted to make sure I was not limiting myself. As good as I felt the BC6 was, I knew that I had to put it against another contender that has received considerable praise to really puts its performance in perspective (I also knew that if I didn't, the e-mail be remorseless). In the limited habitat of the High-End, the natural enemy of the BC6 is the Pass Labs Aleph 3. For $2300, it offers 30 watts of single ended, pure class A, all transistorized power, and looks to be a leaner predator poised to take over the ecosystem. To find out I arranged to borrow one for a weekend brawl with the BC6.

My brief experience with the Pass amplifier confirms that it is indeed superb and a bargain at its price. Like the BC6, because of its relatively low power, proper system matching is a must. Up against the BC6, the results were intriguing. Roughly, the Pass had highs that were very slightly more extended than those of the BC6. Bass extension with either amplifier was equally deep, but the Pass did not sound quite as fleshed out. The Pass midrange was excellent, but not as dimensional as the BC6. Macro dynamics as offered by the Pass were slightly better, although I preferred the micro level detail of the BC6. Soundstaging was close enough to call equal. Grain is non-existent with either amp, although the BC6, by the smallest of margins, sounds smoother. Harmonically I found the Pass to be a tiny bit lean, where the BC6 was an even tinier bit warm. This slight leanness gave the Pass a greater sense of bass and midrange impact, although the BC6 rang truer to the music in the same areas. The differences, in almost all cases, were small but significant. Keep in mind that when dealing with amps so close to the limit of what’s possible these small differences take on magnified value. I can easily envision a system where the Aleph 3 would be a better fit than the BC6, but, overall, I feel the BC6 to be the better amp. Strong words considering the acclaim the Pass amp has received, but, for me, that puts the performance of the BC6 into sharper perspective. For $2300 the Pass is a killer deal. But for $3700 the BC6 is as well. And in my system well worth the price differential.

Final Details

After those comments you may think that the BC6 is perfect. Well, it's not. I have four small reservations. First, the BC6 is ever so slightly warm in its harmonic presentation. The reason I reiterate this is that even though the deviation is very slight, when you are playing the game at this high level each little deviation counts. Second, 25 watts will not impress your friends and that may bother some people. Third, as powerful as it seems, a 25 watt amplifier can only do so much. More than with more powerful amps, you must take care when using this amp with inefficient speakers or when trying to fill a large room with sound. And finally, because of its peculiar size, it may not fit into your audio rack.

Other than those quibbles, and unless you have an aversion to black heat sinks, stainless steel, or blue lights, I recommend that you check this baby out. Blue Circle has paid very close attention to the details that make an amp great. And I feel very, very comfortable calling the BC6 great. The best? Well, it’s the best I have heard. It's my new reference.

...Todd Warnke

Authorized Blue Circle Dealer - New York State Area

Blue Circle BC6 Amplifier
Price: $3,700 USD

Blue Circle Audio, Inc.
RR #1, Box A-0
Innerkip, Ontario
Canada NOJ 1M0
Phone: 519-469-3215
Fax: 519-469-3782