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REVIEW: Blue Circle Audio BC 204 Amplifier (SS)

Model:	BC 204
Category:	Amplifier (SS)
Suggested Retail Price:	$7795.00
Description:	Hybrid Amplifier
Manufacturer URL:	Blue Circle Audio
Model Picture:	View

Review by redneckaudio (A) on November 28, 2005 at 19:01:47 IP Address: 69.155.124.187

Add Your Review for the BC 204

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Blue Circle Amplifiers: The Story of Pinky and her brother

Disclosure: I am not in audio retail, nor do I write or review at anyone’s request. However, I do know the maker of this amplifier, Gilbert Yeung, whom I first met at AK Fest 2005 courtesy of Venus HiFi owner Brian B. After hearing Blue Circle products, I have since purchased a CS Integrated amplifier; a BC 21.1 Preamplifier; a BC 28 (Pinky) Hybrid Power Amplifier; and a BC 27pi Phono Stage. Not all these components are in one system, but needless to say, I have given Blue Circle a great deal of business. As a result, I was given the opportunity to audition at great length Gilbert Yeung’s BC 204. Yes, I am biased, I like BC products, and this review will be positive.

Intro:
At first glance the box is big, bigger than any amplifier box I’ve ever seen. The UPS guy had to get the dolly out. It’s not quite as heavy as it looks, but its so big its difficult to carry. The box opens and reveals extra dense gray foam custom fit and holding a stainless steel case with a huge PINK faceplace. I laugh, I have the only pink Blue Circle BC 28 in existence. I wrangle Pinky out and immediately set her up (I’ve been waiting several months and its better than Christmas). I place Blue Tofu (get this CD) into the Lector, turn on the Juicy Music Blueberry, and fire up Pinky… I thought my Shahinian Arcs sounded good before, but now I wear a shit eating grin. I reach for the phone and make three calls: one to Venus HiFi, then Blue Circle, and lastly to an audiophile amigo. I must tell them all how amazing this amp is! No burn in, no waiting, this amp brought my system together, all the pieces were there. Contrary to Mick, I Got Satisfaction. After years of pursuing the Audio Grail, it was now in my 12 x 12 x 10 man cave. I called into work and cancelled my afternoon schedule and played LPs and CDs for 10 hours straight. My system at that point:

VPI Scoutmaster w/ SDS and Shelter 90x
Lector CDP0.6T
Sansui TU-9900 (hot rod modded by Mike Williams of Radio-X)
Juicy Music Audio BlueBerry Extreme Tube Preamplifier
BC 28 Hybrid Amp
Shahinian Arc Speakers
Assorted other stuff: BC MR1200 power5 filter; PS Audio XStream Statement Cables; and Silver Circle Audio Dreamcatcher Speaker cables.

I had been previously using custom NOS Valves Monoblock PP tube amps that put out plenty of power and sounded great (still do just in another system now), but I didn’t know what I was missing until I received the BC 28. The Shahinians have a strong solid state following and the NOS Valves did a fine job. However, the hybrid BC 28 did an exceptional job. The improvements were obvious and immediate: 1. Detail/resolution listening to LPs Shades of Dring, and Soular Energy I was hearing cymbal taps and fingers on double bass strings not heard before; 2. Overall bass bloom and slam was enormously improved; 3. Pace and “boogie factor” were present like never before; 4. depth, imaging, spacing, absence of noise – OUTSTANDING; and most importantly, MUSICALITY – that thing that occurs when it just sounds right, did indeed sound just right.

Over the course of the next several weeks Pinky “broke in” limbered up a bit and just kept getting better. After much appreciation directed towards my retailer and his suggestion that this may be the amp for me, and my kind words to Gilbert Yeung of Blue Circle, I was offered the opportunity to audition a BC 204 Hybrid amplifier. Not one to turn down an amplifier that costs more than most used cars, I gladly accepted the offer.

Blue Circle & Pinky’s Big Brother:
As I ramble on, let me say a few words about my opinions of good business and audio equipment. First, I find large retailers rarely know much about their products, are unable to give personalized service, and cannot (or will not) take responsibility for poorly made goods. What I have noticed is that places/businesses that have the owner on site, whether chef, cobbler, tailor, or audio manufacturer, give better service and build better products. Generally, when a person’s name and reputation are at stake, they make sure you are and their products excellent. Every piece of audio in my system, with the possible exception of PS Audio, I can contact the owner/designer/builder. Trust me, it makes a huge difference. Earlier I mentioned that it took a couple months to get my BC 28, why? Because Gilbert Yeung does the final assembly.

I met Gilbert at AK Fest, the least pretentious gathering of fine audio I’ve ever been to. Gilbert was there showing his products. He made no sales pitches, was a bit unhappy with the room acoustics, but totally accessible, friendly, and disarming. Considering he makes some extremely expensive equipment and took time to come to a small audio show, tells that he loves audio, loves music, and doesn’t need to be in the spotlight. Certainly, compared with other manufacturers, his equipment is not often reviewed, though he has a faithful following on various audio websites. One of my reasons for wanting to write this review, was to let others know about a small audio manufacturer that puts his name up front, builds great products, and loves what he does.

Pinky, as I call my BC 28 is perfect for my needs. All the headroom I want, able to provide all the dynamics I need, and it just makes me happy. Pinky’s big brother is the BC 204 amplifier and is a significant price step up into Blue Circle’s 200 series amplifiers. The 204 is hybrid in that it has a pair of 6922s in the input stage along with power op-amps in the place of more traditional solid-state output devices. Blue Circle’s op-amps are designed for industrial and aerospace applications, and thus built to drive difficult loads. The BC204 uses three output modules, which consist of two op-amps and a circuit board mounted on their own heatsink, and has a 850VA power supply. In short, it’s a robust amp. The clearest evidence that this amp was built by hand is the point to point wiring and the size of the chassis (if one is to solder, one must have room). The amp weighs 70lbs, and has dimensions roughly 18 x 10 x 22 in – this wont fit on your rack, trust me. Then again, with its shiny stainless steel cover and customer choice of faceplate color and material, this amp was not meant to be hidden.

Sound:
Although Pinky and the 204 are from the same manufacturer, and are both hybrids, they have very different sonic signatures. My first impression was that the 204 provided fuller sound with more pronounced bass. The highs were not significantly different from the BC 28, but the mids, mid low, and lows were markedly deeper, more powerful, and more articulate. The resolution and detail I so enjoyed with my BC 28 was there but less obvious. This is not a drawback, but instead a compliment – the amp disappeared more, I wasn’t noticing changes in the music but the music itself.

Over the course of 3 mos with the 204 I began to appreciate its versatility. This is not a picky amp. Its not better with classical, rock, chamber music, or jazz, its just a hell of an amp. Overall impressions: the best recorded piano I’ve ever heard; the cymbals on Bill Evans’ Waltz for Debbie are softer and last longer than I thought; Beck Hansen’s Guero has at least 5 layers of sounds/instruments/dubs etc; absolutely no strain, sibilance, or listening fatigue – none, zero, nada. Can I find a significant fault? No. Obviously, this is an expensive piece of equipment and clocks in at nearly 8000 dollars, is it worth 8000.00? That’s not for me to say. What I can say is that the difference in sound between the BC 28 and the BC 204 is significant. The 204 excels in mids, mid lows, and low lows. Is the improvement so profound I now enjoy my BC 28 any less, not a chance. I would characterize the 204 as a more refined, deeper, and a slightly more “complete” amplifier. The BC 28 is more lively, has a different pace and “boogie” that I really like, and still has plenty deep bass. Thus, there’s no chance I’ll be changing amps for a long while.

I can wholeheartedly recommend the BC 28 and the BC 204 to any serious audiophile. They are stellar pieces of equipment, however, they must be paired with source components carefully as they will reveal upstream deficiencies, and are likely not for every speaker, especially speakers known as being on the “bright side.”

Inadequacies of this review:
1. no other comparable amp to review against – not fair to put up against PP monos
2. no blind testing was done – all of this is my opinion
3. other than Klipsch La Scalas, no other speakers were paired with this amp. I gave little mention to the La Scalas as they are not my favorite speaker and in my best opinion, only sound good with an all tube system that has a fair degree of forgiveness.
4. Listener bias, my Shahinians are a little picky and these two amps sounded so damn good, it’s hard to find fault.

Minutiae:
• output: 150watts into 8 ohms and 250 watts into 4 ohms per channel.
• True balanced from input to output with both positive and negative being "hot" with signal.
• DC coupled output stage.
•Blue Circle "Blue Puck Cap" used in power supply filtering, both in output stage and B+ supply.
• ªlocal "on board" filtering capacitors located less than an inch away from the actual output devices for better transient response.
• all control circuits are done in the analog domain. Therefore, no digital clock to contaminate the analog signal integrity. It’s an analog amp after all.
• heavy gauge power supply ground return path for both tube and output stages with the exact same reference for both tube and output stages, to yield the best matching performance.
• 20Amp Neutrik "Power Con" power connector for optimum connectivity of ac power.
BC61 (14 AWG ) power cord with Wattgate plug. The standard length is 4 ft. Longer lengths are available to suit specific customer requirements.
• All internal ac power is controlled by 30A ac power relays for shortest ac power run inside the chassis.
• 850VA power transformer supply for output stage only.
•three separate power transformers for output stage, tube input stage and controls
• over 240,000uF in power supply filtering.
• power HexFred rectifier in both output stage and B+ supply.
• 12Ga steel chassis for mechanical integrity.
• 1" thick MDF base tightly coupled to the bottom of the chassis for ultra rigid damping control.
• Various colours of faceplate, base and cover as options.
• Two pairs of binding post per channel for shot gun biwire.
• RCA and XLR inputs.
• Ground lift switch to eliminate ground loops. This switch will only lift the signal ground, the chassis is connected to earth ground at all times for safety.

Measurements, including tube input stage (measured with matched tubes):
• Residue noise reference to full power output: >-100dB or <300 uV non weighted
• Residue noise reference to full power output: >-110dB or < 150uV within audio band
• Tracking error: < +/- 0.09dB
• Frequency response (10W into 8 ohms): 10Hz to 35K +0.00db, -0.05dB; -0.9db point at >100kHz
• Distortion at 10W into 8 ohms: <0.09%
• voltage gain: 21.5dB
• input sensitivity: 3.19V
• input impedance: 100K (SE); 200K (BAL)

Output stage measurements
• Residue noise reference to full power output: >-100dB or < 250uV non weighted
• Residue noise reference to full power output: >-112dB or < 100uV within audio band
• Tracking error: < +/- 0.025dB
• Frequency response (10W into 8 ohms): 10Hz to 50K +0.00db, - 0.025dB; -0.5db point at >100kHz
• Distortion at 10W into 8 ohms: <0.03%

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Product Weakness:	price, availability
Product Strengths:	overall musicality, no faults, a complete amplifier.

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Associated Equipment for this Review:
Amplifier:	BC 28
Preamplifier (or None if Integrated):	Juicy Music Audio Blueberry Extreme
Sources (CDP/Turntable):	VPI Scoutmaster w/ Shelter 90x; Lector CDP0.6T
Speakers:	Shahinian Arcs
Cables/Interconnects:	PS Audio and Silver Circle Audio
Music Used (Genre/Selections):	mostly jazz and rock
Room Size (LxWxH):	12 x 12 x 10
Room Comments/Treatments:	none, room a tad bright
Time Period/Length of Audition:	3 months
Other (Power Conditioner etc.):	MR 1200 power line filter
Type of Audition/Review:	Home Audition

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