Blue Circle Audio SB90T Hybrid Stereo Amplifier

At this stage of the audio game I figure most of you have seen some products having a round blue circle with a dot in the middle and recognize it as the Blue Circle logo. The founder and designer of Blue Circle Audio is Gilbert Yeung. If you want to get a little insight into his truly creative mind, please look at his company’s website. Once there you can see the many wonderful products he has created such as power amplifiers, preamplifiers, music amplifier, phono stages, DACs, powerline conditioners, cables (interconnect & speaker), power cords, cones, isolation pucks, speakers and even something called the "USB Thingee" (I will let you check that out on the website yourself). What he does not offer though are SET (single ended triode) amplifiers. Quoting from his website, "I don’t do SET". He does however make hybrid power and integrated amplifiers as well as tube preamplifiers. When it comes to SET amplifiers his feelings are that he just does not like the complete sound it produces. As he told me in an email, different people like different things, and SET does not have the sound he is looking to create. So just what is the sound that Gilbert Yeung is seeking with his new amplifier the SB90T? Well read on and lets explore this together as I tell you what I heard.

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SYMMETRICAL HIFI POWER AMPLIFIER

DESCRIPTION

Characteristic Summary : power amplifier mosfet complementary symmetrical hifi complete with very height output
power and good dynamic, because real delay of the way in level of end exploited for
compensation of frequency to be obtained absolute stability

Output Power : 140 watt at 8 ohm each chanel / 180 watt maximum at 8 ohm
180 watt at 4 ohm each chanel / 250 watt maximum at 4 ohm

Distortion : less than 0,01 % at 140 watt and 8 ohm / at 180 watt and 4 ohm

Input Sensitivity : 1 volt-ef for 130 watt at 8 ohm

Input Impedance : 25 Kilo-ohm

Frequency Characteristic : 4 - 50000 Hz (with source resistance 600 ohm)


BLOCK DIAGRAM



POWER SUPLAY


SCHEMATIC DIAGRAM



COMPONENT LIST




LAYOUT PCB (BACK SIDE)



LAYOUT PCB (FRONT SIDE)