Blue Circle BC202 - October 2024 Service / Modification
Lid off and front faceplate removed. Unfortunately in shipping the front wood panel was damaged from having been dropped. Luckily the damage wasn't enough to necessitate creating a new one and I was able to repair the original, while also refinishing it in the color of the customer's choosing.
Interior side shot showcasing two of the 3 output stage capacitor banks, one in the foreground, the other under the input stage.
Some of the internal damping to the top of the chassis lid where no other support is present. In current designs Angela-Gilbert Yeung uses large silicone tabletops or "helicopter landing pads" that brace the top panel with the rest of the chassis.
This is one of my favorite shots inside of the amplifier. You see here the output capacitors, the artful installation of the B+ rail and a glimpse of the dual regulated DC filaments.
On the PCBs utilized for the output stages, note that even here the large capacitors in the circuit are mounted with silicone to dampen vibrations, reduce strain on the solder joints, and allow for natural thermal expansion and contraction.
While here in the shop, now is the best time to add some future upgradeability, so I have installed an FCF and TP jack. FCF allows for the increase in capacitance of the solid state output stage while the Tube Pack jack allows for the same in the tube based input stage. The input stage is removed in this photo as I am completing some remounting of components and adding silicone, and the output stage on this channel is removed for better access while drilling, soldering, and cleaning.
Fresh white silicone applied to all of the components and input stage reassembled. While my silicone works, its amazing how easy Angela-Gilbert makes it look working with the stuff. Practice makes perfect as they say.
Now I don't have much experience in the 3D form of building and direct point to point in the way that AG is, but I am a firm believer at this point and honestly am starting to prefer looking at circuits built in this way. I didn't want my repair to stick out from the overall build of the amplifier and I want to learn from the best, so this is my first attempt at building in this style. The rest of the amplifier is built on acrylic platforms, so I allowed myself more space in adding one to keep the tube power supply together as I dropped the B+ voltage to increase tube life. These are all heat dissipating devices, and I used different positioning for each to channel that heat up and away from the capacitors.
Time for testing. I had also recently finished up a service on this tube amplifier, so it joined the mix in the reference listening and testing area. Both the BC202 and tube amp have much lower damping factors than the NAD 218 that I use for woofer duty, so I tamed them down to blend better with the damping factor controllers. I started with a DF1, but realized I only needed the DF16.
Finally here we have the finished product ready to ship back to a happy home. The front face has been refinished in a semi gloss black, painted the same way that the originals were with roller and high quality paint.
The Sound
Very rarely I have the opportunity to come across something that makes me question if I can afford something in the future, and the BC202 I can say is definitely one of those products. I am already a fan of hybrid power amplifiers, but honestly there are not many especially in the older market that are truly worthwhile or stable. This amplifier has been going strong for over 20 years without a hiccup and the only reason it came in was due to a power anomaly that fried a power conditioner in front of it.
This takes up a very large footprint, I cant even think about putting it in my current rack, but despite the size it absolutely disappears into the music like nothing else that I have put on the QLS to this day. I honestly wish that I had more time and tubes to test with this amp to see the affect that tube rolling has with it, and in the same breath I could be happy placing this amp as is in the system and being happy for years myself. It gets the music oh so right to the point that even though in the past I have written reviews breaking down the sonics of various components, on this one I won't. It seems almost disrespectful to do so because that would mean opening myself to be conscious of listening to the amp itself instead of the music. At some point in audio you reach the point of diminishing returns and a lot of things are just different instead of actually better than another. At that point it just comes down to personal taste and synergy. The BC202 is an amp who loves live music, vocals, and long listening sessions. You wont experience any fatigue with time, only a sore finger from selecting yet another song and a few tears of joy as day turns to night and you yourself get lost in the music.