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These days, other audio companies are trying to over engineer their products and give them a fresh coat of paint to impress their customers. Concepts like more power, bigger is better, and technology that reinvents the wheel are commonplace. Then there’s the cosmetics. I guess if you can’t make it sound better you can always make it look fancier.

We at Blue Circle do not forget the important issues and we choose to stick to what we know best, namely simple, elegant designs, resulting in superior sound. A case in point is the the power supply. The new BC109 is a simple yet elegant line stage preamp design that incorporates several principals that allow for an amazing variety of ways to supply it with power. Bringing this idea from Gilbert’s kitchen table to production has taken us 4 years and we named it the Pinkie project. Well it is pink.



The Sound

No, it doesn’t have tubes. No, it doesn’t sound like it has tubes. No, it doesn’t sound like typical solid-state either. Quite frankly, it doesn’t sound like anything. As usual we set out to make a component that plays music and that’s what the BC109 does. It simply reproduces music. As usual, we’ll leave it to the reviewers and users to do the talking about how it sounds. We’ll just get on with telling you how we managed to come up with Pinkie.


Front view of the BC109

The basic version of the BC109 is called the BC109*. It has over 110 Farads (110 million microfarads) of capacitance. It will play up to 3 hours without a/c power in one charge. With the CP1 capacitor pack, it totals 550 Farads and will play up to 15 hours. With the CP2, at a total of 1200 Farads, it can play well into the 20+ hours. The CP2 also has built-in automatic charging circuit. It monitors the power supply in real time and when it drops to a certain level, it will automatically engage the charge circuit so it will seamlessly maintain its power.

With the CP2 capacitor pack installed, it will be a delight for the user who wants to tune the sound. You’re probably familiar with tube rolling but how about IC rolling! Yes. We said IC rolling. The BC109 incorporates user changeable ICs.This feature makes the BC109 well-suited to any system. Tune it to your hearts content with the large variety of ICs available on the market.**

So why do we need all that capacitance? First, it was designed to run on it own capacitors and not from the power grid. As a result, there is no hum, no buzz and by definition zero powerline noise! There’s no need for a powerline conditioner. Second, by using capacitors instead of conventional batteries, there is no complicated charging circuit to deal with. Unlike batteries, capacitors have no recharge memory. Capacitors charge to 100% every time. Batteries die a little every time they are charged. Have you ever seen battery companies claim their rechargeable battery can take up to 1000 charges? Capacitors can easily take 100 times more charge cycles than a battery and still remain 100% charged every time. Charge and discharge the unit whenever you like, you can’t harm the capacitors. As long as the maximum charge voltage does not exceed the rating, it will not over charge. Capacitors also have a much longer life span than batteries. With 10 years of normal use, a BC109 will use the equivalent of 21,900 AA alkaline batteries.

As an additional feature, the BC109 can also be charged directly by other energy sources which makes it the very first unit of its kind that can operate totally independent from the power grid. It can be charged directly by a solar panel, a car battery, a windmill or any device that can output DC voltage. It can even be connected to the 12V socket in your car. Any kind of DC source from 10Vdc to 16Vdc can be used to charge the BC109.***


Rear view of the BC109

*Several cosmetic options available at additional cost.

** Several ICs have been tested to make sure they are BC109-compatible without the CP2 option.

***Specific adaptors may required for different sources of power to charge the BC109.

Features and Options

Standard features......

*Dual differential balanced audio signal paths.

*Dual decks - balanced 31 position Shallco attenuators with 2 level gain switches for a total of 62 settings.

*Direct path selector switch, this also allows the BC109 to be used as a final mixer in a multiple mixer set up.

Optional features...

*Dual decks balanced 47 postion Shallco attenuators with 2 level gain switches for a total of 94 settings.

*Single four deck 31 or 47 position Shallco attenuator with 2 level gain switches with balance control.

*Processor bypass loop.

*Remote volume control.

*Wide range of faceplate and cover options.

*IC rolling with CP2 option.

*USB input + digital output

*Headphone jack output


*12V socket and battery charger adaptor.

*Solar Panel charger adaptor.



-Residue noise reference to full rated output: >- 100 dB or < 60 uV non weighted

-Residue noise reference to full rated output: >- 110 dB or < 20 uV within audio band

-Tracking error: < +/- 0.05 dB

-Hum below 400Hz: <1.0 uV

-Frequency response at 5V output: 10Hz to 55K Hz +0.00db, - 0.00 dB; -1db, -1db at >100 kHz

-Distortion at 5V output: < 0.0028 %

-Voltage gain: 20 dB

-Maximum output: 8.5 V

-volume control range: -95dB to 0db in 62 steps standard in Shallco attenuators

-input impedance: 100K ohms

-output impedance: 2.5 ohms

BC109 and BC109-CP1

Dimensions: 17.5" wide x 3.5" height x 15.5" deep

Weight: 35 Lbs

Contact:  bcircle@bluecircle.com  /  519-469-3215
BC109 Preamplifier and CP1 and CP2 Capacitor Packs