Authorized RePrint of Stereo Magazine

Bear Killer

Let's concentrate a bit about the concept "Canada": Endless expanses, gigantic forests, hard winters, wild animals, oil in the ground, Neil Young, and High End.
Bryston BP-25S Preamp and Bryston 4B SST Amplifier - This combination did not step up to the plate in order to propagate a revolution, no, its charm lies in its maturity

Bryston - These are amplifiers with which one will have no problem to drive the proverbial nail into a wall

by Holger Barske

What do you think? You wouldn't have readily thought about the last item (High End)? Yet in the land of the maple there is an active "scene" to which well-known names like Oracle, Energy, Mirage, and of course Bryston, belong. And the latter recently presented a small sensation: an update for their successful BP-25/4B ST preamp/amplifier combination. The new components are known as BP-25S (preamp) and 4B SST (amplifier), and change owners, i.e. are sold for 2,500 and respectively 3800 Euros.

Only STEREO "Hardcore" readers will still have the test report of the predecessor versions in the 10/96 edition, and precisely these six years of product time until the brand new updates, document belatedly that one is not fond of fast decisions in Peterborough, Ontario. Trust in one's own art of accomplishments is also documented by an undoubtedly unique approach to the matter of acceptance of responsibility: Bryston provides a 20 year full warranty for all of its components. Incidentally the associates around the brothers Brian and Chris Russell - the sons of NASA engineer and founder of the firm, John W. Russell - build no other equipment besides amplifiers.

In the meantime however there are multi-channel examples besides matching processor-preamp combinations, although these also maintain the unmistakable, conservative, and original rugged Bryston handwriting.

Our test units are anniversary models for the fortieth birthday of the company, and especially the amplifier can look back to an impressive history: The concept is already in the marketplace since 1975, and up until now about 30,000 4B amplifiers have been sold, which represents a very hard to beat record.

Although the BP-25 preamp does not have quite such a long tradition, it also follows specific construction principles, which during the years were further developed and led to a seldom seen product maturity. The circuitry is based upon text book correct complementary symmetrical amplification stages, which obtain their excellence through consistent parts selection, protracted optimized circuit board layout, and high quality passive components. Especially the last point should not have been completely irrelevant for the decision to bring to life the "S" version of the BP-25 preamp, since quite a bit has happened in the quality of available components since 1996.

And since we are already here we can immediately take a look at the updates of the power supply: With the BP-25S this was done radically by "planting" aproper toroidal transformer into the outboard enclosure. Added to this are double the filter capacity and an electronic input conditioner.

The amplification circuit board provides evidence of the high level of evolutionary maturity of the preamp. The placement of all of the components appears to have been carefully thought out, and should hardly leave room for further improvements.

The build-up of the amplification stages consists of discrete bipolar transistors, and the layout is largely unbalanced. However two of the seven inputs of the BP-25S preamp are XLR balanced, but the signal immediately thereafter becomes unbalanced and does not become balanced again until the very end of the circuit chain: four output stages supply the XLR outputs.

This approach makes sense, because only with an extremely expensive quadruple volume control arrangement does one reach the benefit of the advantages of all balanced circuitry, potentiometers like the Alps model that is used here is only available in a twin version in order to meet the targeted price. So the reliable safe solution is better than precarious experimentation. Correct thinking!

A very special frill - which is also a tradition at Bryston - is the optional phono section which is available for the BP-25S preamp for an upcharge of 700 Euros. Electronically it is conceived as an uncompromising MM amplifier, but two very expensive, triple MU metal encapsulated transformers, from the legendary British transformer specialist Hammond, are added to the printed circuit board and make it into a formidable MC prepreamp. Both operating modes are of course switchable.

The 4B SST amplifier first of all calls attention to itself by its hefty 25 Kilograms - a weight which one would not have suspected in the "Canadian" because of its moderate measurements. The main reason for this is the considerably increased output of the power supply: Two stacked toroidal transformers with 600 VA power handling capacity - their actual power output is probably significantly above that - contribute to the considerable weight.

The result of such an energy reservoir - 550 Watt continuous output per channel, and over 700 Watt peak output. Even bridged operation with 8 ohm loads and two amplifiers is possible, which undoubtedly could cause any conceivable speaker voice coil to melt.

Bryston reaches these power outputs with a "shrewd" amplifier output stage configuration - the only area where textbook circuitry has been exited. Under normal circumstances there would be respectively four of the same type of the total 16 output transistors, but the Canadians thought of a stratagem to "even out" the natural unevenness of the "positive" and "negative" transistor types: as a matter-of-fact two pairs of unequal polarity transmissions function in parallel in each of the output stage sections. This can only be accomplished through an expensive approach, but it assures that both halves of the output stage behave exactly identical. It is only odd that no one else has thought of this good idea.

However without exact "matching" nothing would work in the output stage: Bryston even selects the 250 Watt power transistors for uniformity at "cut off."

The appearance of both "Canadians" in our listening room turned out to be a special event, and clearly documented which different interpretations of the concept "musicality" are possible then and now. That is to say that the Bryston components definitely do not follow the modern ideal of fast as an arrow, hard as nails, and above all straight line playback sound.

First of all the amplifier makes no secret of its power: The "thing" pushes so relentlessly "down below", that even the smallest sturdy audiophile speakers are imparted with a genuine foundation. However this is by no means simply power output: The "foaming pressure in the cellar" is joined by a very colorful middle high tonal response which, although it waives the very last grain of "through listenability", does provide wonderful tonal splendor and uniformity. But lastly you have perhaps chosen your speakers a bit too bloodless or anemic? Please, here is the optimal problem solution for such eventualities.

The preamp already behaves in a "mainstream-conforming" mode: Although concepts like "warmth" and "impact" are not strangers to it, in sum it does sound tonally linear, and for that reason perfectly matches the 4B SST amplifier. In matters of room reproduction both components follow a similar ideal: Monumental size with perfect resolution of the speaker is the designated objective.

Within the admittedly widely placed boundaries the localization succeeds perfectly: Especially here the care that Bryston has bestowed on these components should pay dividends. As expected genuine elitism: the welcome noise free phono section. Dynamically top class - trying to achieve more here with an external solution appears to be practically impossible.

And with that the portrait of the Bryston components turns out to be well rounded: The indestructible construction is joined by the tonal characteristics: Wild, rugged, charming, and for every circumstance master of the situation. It fits perfectly with the Canadian stereotype: Kill bears? Not a problem at all!

BRYSTON BP-25S

BRYSTON 4B SST

from ca. 2500 Euro Measurements: 43 x 6 x 32 cm.(WxHxD) Warranty: 20 years Distributor: Sun Audio, Tel: 089/479433 www.sunaudio.de Traditional concepts driven to the highest zenith. The most recent incarnation of the Bryston preamp again qualifies itself for a liaison of many years. Truthful, powerful, linear: These are qualities which should impart welcome notice of themselves in many high end (audio) systems. The optional phono section, whose qualities are not available at a comparable price as an external solution, is an additional incentive for vinyl listeners. LABORATORY Distortion? At the limits of measurement: .0001/.0001/.003 % distortion, .001/.001./.005 % intermodulation distortion with an output voltage of respectively .3 Volts/30 Millivolts. The noise behavior is also very good: 85/60 dB (A rated) signal to noise ratio with .3 Volt/30 Millivolts. Exactly as in the phono section: 81/73 dB (A rated) with MM/MC operation. The BP-25S preamp shows itself to be extremely resistant to overload and accepts over 10 Volts at its inputs. 71 ohms output impedance are operationally correct. The frequency deviations of the phono section are under 1 dB, and the volume control shows merely .5 dB channel to channel difference. CONFIGURATION Plentiful: Five unbalanced and two balanced inputs, two unbalanced and one balanced output, plus a complete tape loop. Balance adjustment, a switch for muting and for absolute phase: the last two are also available, besides the volume control, on the all metal remote control. STEREO-TEST SOUND-STANDARD - 70% PRICE/PERFORMANCE - * * * VERY GOOD

ca. 3800 Euro Measurements: 43 x 16 x 38 cm.(WxHxD) Warranty: 20 years Distributor: Sun Audio, Tel: 089/479433 www.sunaudio.de Although it is at heart a "battle ship" with 27 years of existence, the new version of this Bryston legend shows many a young tenderfoot how it should be done. It offers power and dynamics to excess, paints with glowing colors and capitulates to no imaginable speaker load. Moreover its dependability is legendary. LABORATORY Performance is available in spades: Twice 351/551 Watts at eight/four ohms, in the latter case even 709 Watts momentary output. 13 Milliohms output impedance indicate a high damping factor, and distortion is not a issue: .019/.018/.035 % distortion, .017/.019/.04 % intermodulation distortion at total modulation/5 Watts/50 Millivolts. Signal to noise ratio: Superb 95/75 (A rated) at 5 Watts/50 Milliwatts. The stereo channel separation is in order: 52 dB at 10 Kilohertz and five Watts. CONFIGURATION For a power amplifier there is an amazing amount available: Inputs for XLR, RCA, and 1/4" phone plugs. A switch permits the input sensitivity (gain) to be adjusted by six dB, bridged operation is available, and a built-in local or remote voltage controlled, power-up is selectable, although normally the amplifier is powered up with the front panel membrane switch (incorporating the Bryston logo). Speakers are connected via excellent self-built terminals which accepts all standard connection hardware. And last there is a robust circuit breaker/power switch (on the back panel). STEREO-TEST SOUND-STANDARD - 70% PRICE/PERFORMANCE - * * * VERY GOOD

Translated from the German by Peter Ullman

We invite you to experience the Bryston SST² Series amplifiers

20 Year Warranty - A Generation of Music