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The BC509 and BC507 digital to analog converters share the same decoding engine. The difference is in what size fuel tank and what kind of fuel they use.

The Digital to Analog Section:

The digital to analog part of the machine will support anywhere from 16 bits to 24 bits - 30KHz to 216Khz and anything in between,  including 16/44, 16/44.1, 16/48, 24/96, 24/196 and more.

Every signal trace on board has been carefully designed and tested. It features a complete DC path to ensure ultra low jitter performance. Another feature that adds to the signal performance is the microprocessor is not used in the control circuit. The less the clock contaminates the signal the better. The unique analog output stage uses a design similar  to those in our best solid-state preamp, the BC109CP2.

The type of fuel and the fuel tank size:

The power supply a.k.a. fuel tank, is of the latest Blue Circle "IAOE" design. The BC509 has a power supply filtering capacitance over 200,000uF. That is more than most 100 watt stereo power amps. This will ensure a very stable power supply, however for the ultimate goal of a silent running power supply, the BC507BA has a 1,000,000uF (1 million micro Farad) additional battery power supply. When running off the ac power line, there is no ground hum or any sort of noise caused by the powerline that can be detected by the audio circuit. The result is a blacker than black background which has a major impact on the micro detail of the musical presentation. This is one of the major factors which contributes toward that elusive sense of effortless and dynamic yet relaxed musicality.

We have designed a circuit that will transfer between battery and ac power with complete silence. When the ac power is taken off, the battery will gently take over without making any noise. It is the same going back onto ac. And what happens if the battery runs low? It will simply turn off the DAC without any complaints or any noise.

We realize not everyone wants batteries in their system so we've come up with something that approaches the performance of the BC507BA without the batteries. It's called the BC507NB. Instead of batteries, we add an additional 1 Farad of capacitance, resulting in a total of 2.2 Farads of capacitance. This gets you close to the performance level of the BC507BA without batteries to periodically recharge and replace. 

Both the BC509 and BC507 are upgradeable in the future. The BC509 can be upgraded to BC507BA or BC507NB.

wpca3924c9.jpg                          Front panel of BC507BA


                           Front panel of BC507NB

What brand of chip set someone may ask (only someone that doesn't know us, of course.) As usual, we would prefer our customers to audition the product instead of reading specs and comparing them to the latest buzz words or trendy parts on the net to make their decision. We don’t make our decision based on how popular the parts are and we believe you shouldn’t make any decision based on the latest fashion trends.



*Standard config: (1) Toslink, (1) SPDIF, (1) AES/EBU - accepts 16 bit to 24bit, from 32 KHz to 192 KHz and anything inbetween

*Optional:  USB 24/96 (will also support 16/44 and 16/48), USB 16/44.


Standard config: (1) pair of XLR balanced, (1) RCA unbalanced

Optional features

*Manual or remote volume control

*BNC jack (replace RCA jack) for SPDIF input at no additional cost

Dimensions and weight:

*BC509 8" wide x 8" deep x 3" high, 5 lb

*BC507BA and BC507NB 8" wide x 16" deep x 3" high, 16 lbs BC507BA, 15 lbs BC507NB

The above dimensions and weights apply to the two illustrated versions of the BC507 standard chassis.

Other chassis configurations are available on request.

Click here to see more pictures of the BC509.

The BC509 and BC507 Digital to Analog Convertors

Rear panel of the BC509 and BC507NB


Click here to see more pictures of the BC507BA and BC507NB

Contact:  bcircle@bluecircle.com  /  519-469-3215