Eastern Electric MiniMax BBA Preamplifier Review

Quick, name a component which:

– Was originally developed as an adjunct to the Sony Playstation One acting as cdp.
-Is not a pre, nor an amp, but can function as a preamp.
-Is an ancillary to your cdp, DAC, preamp, power amp(s) or subwoofer.
-Can be used in pairs for greater effect.
-Costs a paltry $850.00

The component reviewed here, the Eastern Electric BBA, is that very component. It is a most unusual device, both in its development and its function. As we shall see, it’s also an unusually adaptive piece which can influence a wide range of audio systems through the use of an adjustable gain. Intrigued? So was I – that’s why I had to give it a listen.

It’s officially known as the Minimax “Booster Buffer Amp” or BBA, made by Eastern Electric. I’ll come right out with it: This is one of the most fun and eyebrow-raising devices I’ve encountered in two-channel audio, with the power to make a sea change in whatever system it’s dropped into. Further, I’ll state that the BBA has the capability to upscale the sound of rigs, from a modest set up to the audiophile’s hard core system.

That’s a fairly large build up for a component that I haven’t yet described and which is hardly on the average audiophile’s radar. But I suspect you will know this component in the near future, for it breaks barriers and touches a sector of audiophilia that is woefully lacking – it addresses the impedance mismatches which exist between components.

“Impedance mismatches have been well known and almost universally neglected for decades.”

Impedance matching seems to be the latest frontier, if not the last (I hesitate to say the last frontier since technology seems to always be peeling off another layer of possibility) in audio. Impedance mismatches have been well known and almost universally neglected for decades. Manufacturers of fine audio equipment by and large have deemed it of lesser importance to other design concerns. Recently, I reviewed the MIT Cables Avt MA line, which includes in its IC a selectable impedance switch. It is an indication that manufacturers are waking up to the impedance mismatch issue. Eastern Electric has addressed it directly and extensively in the BBA.

So, what exactly is a BBA? It’s a tiny silver crate of fun, created to support the Playstation One (Dear Audiophile, please do not stop reading at this point! Yes, your tender high-end sensitivities have been offended by the suggestion that anything related to the Playstation One belongs solidly in Low Fi. But do not be deceived, for this is one component which can be considered a hi-fi wolf in low-end sheep’s clothing!) Alex Yeung of Eastern Electric, the designer of the BBA, has friends who are collectors of vintage German studio power amps. Designed for professional use only, these amps have extremely low input impedances and can’t be driven satisfactorily by typical audiophile preamps.

Alex explained, “One member of the group suggested the idea of an output pentode in a feedback circuit, which allows for a wide range of voltage settings to match the input impedance and voltage sensitivity of the associated device.” The idea was not novel; it’s been used successfully by German DIY’ers to ameliorate the low voltage output of the Playstation One. Not so unexpectedly, the device produced excellent results with both the German amps and the PS1.

The “value added” brainwave was to place the device into the chain of traditional audiophile components, where it proved exceptional. In fact, it was discovered to be outstanding between almost any components (Note: the BBA operates on the analogue signal; one location it will not operate is between DIGITAL OUT of the CD and a DAC)! Members of the group clamored for more than one of them, Eastern Electric was brought in with Alex formally supervising the project, and the name “Booster/Buffer Amp” was coined. The rest is histrionics – wildly fun, outrageously unexpected performance!

The BBA is a little box of major potential. My dumbed down description of the BBA is that it’s a tube preamp with variable gain. Alex was more discreet, “We recommend the potential buyer see it as a device to improve the performance of any existing hifi system, similar to use of NOS tubes or after market power cords…except the improvement should generally be much greater.” He’s being modest. There have been very few cdps, pre’s or amps which have brought as much change to my system as the BBA. How’s that for a superlative statement? This gain regulator is capable of making me stop in my tracks and listen well.

It’s disarmingly simple looking, with the characteristic Eastern Electric brushed aluminum face and stainless steel body. Two polished knobs, GAIN on the left and VOLUME on the right, flank the power button with it’s trendy blue LED. The top is vented to cool the three Eastern Electric tubes inside, an EZ90/6X4 rectifier and a pair of ECL82/6BM8’s. The unit does get warm after a few hours of operation, but never enough to harm. Still, it should be kept from smaller hands, partly because in using both a gain and volume knob it can very quickly ramp up output. A small twist of the knob can produce a prodigious increase in the listening level.

The rear of the unit is as clean as the front, with only one set of input/output jacks for single-ended use. A gain selector switch (230v/115v) makes this a great unit for those relocating internationally. A fuse socket and detachable IEC complete the features.

The ever-affable Bill O’Connell from Morningstar Audio, the U.S. distributor for Eastern Electric, first mentioned the BBA as I was working on a review for the M520 tube hybrid integrated amp. He was quite excited about the BBA, so much so that I twisted his arm to hear his pre-production model. After spending several weeks with it I realized it wasn’t enough, for I now have two BBA’s in my possession. Once the production run had begun, Bill (not so accidentally) let slip that BBA’s can be used in multiples to further enhance a system. I couldn’t let that go by without investigation! Bill obliged my curiosity, which allowed me to experiment with twin BBA’s.

Single-Stage

I’ll start with the performance of a single BBA and work my way up to the twin setup. I did mention the purpose of the BBA to a high-end store owner who makes his own branded equipment and his initial comment was, “So, it adds distortion.” Though I thought it was a seemingly harsh initial assessment, I kept it in mind as I listened to the unit. There is some truth to his comment: The BBA alters the character of the sound of any component with which it’s associated. Soundstage is typically exploded to a surprising degree.

I could not get over how large the rather moderate sized review pair of Wilson Benesch Curve speakers sounded when used with the BBA. (Doug’s Wilson Benesch Curve review was published in July 2007. –Ed) Larger floor standing speakers sounded massive. It may be debated whether this is a positive or negative result. For some individuals an ever enlarging soundstage is good, while others may want to keep a sense of common spatial relationships intact. The BBA enlarges the soundstage while illuminating the entire presentation.

Just as a bulb on a dimmer can be set to a lower or higher setting, so also the BBA enlightens the music. The Morningstar Audio website describes it, “The BBA will not alter the overall tonal characteristics of your existing system but it will eliminate dull or dark sounding music reproduction that is missing dynamic contrast and detail.”

Frankly, I don’t see how one can eliminate dull or dark sounding music reproduction without altering the overall tonal characteristics of the system. The conundrum is that the BBA is capable of such different sonics when connected to associated equipment that it becomes tricky placing a definitive description on its sound. In general, the BBA has a tendency to shift the system toward more reverberant, expansive and brighter sound while making the soundstage larger overall.

Possibly, I can get the point across by comparing the BBA with hair-styling products which add “volume”. These mystery chemicals which add volume to hair styles are called humectants – substances that retain or attract water. The purpose of a volumizer is to make hair follicles plumper from moisture.