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Bryston BP-25 Preamplifier

Original price was: R58,000.00.Current price is: R14,800.00.

The Bryston BP-25MC preamplifier is a full-function control center with one balanced and four single-ended inputs, including one input for a moving-coil cartridge. The BP-25 is shielded in a black steel cabinet said to reduce electromagnetic interference effects. The power transformer is housed in a small external chassis, the BP-PS. The BP-25’s remote control allows volume up/down, along with buttons for mute and absolute polarity. Signal switching and audio connections, including balanced and unbalanced input and output connectors, are heavily gold-plated to provide good long-term connections. A 12V AC/DC screw terminal connector on the rear of the power supply provides convenient use when used in conjunction with the remote start feature optionally available on Bryston power amplifiers.

From left to right, front-panel controls include a Tape/Source toggle switch, the infrared sensor for the remote, and an MM Phono/MC Phono toggle switch. Next is a rotary control to select input sources, which includes settings for Bal 1, Bal 2, Phono, CD, Tuner, Video (for laserdisc), and Disc. At panel center is a rotary balance control. To the right of this is the motor-driven volume control, followed by toggle switches for Polarity/Invert and Mute/Normal. (These switches change settings each time they’re switched up or down-rather than muting, for example, only when Mute is pushed down.) The tricolor LED glows red when the preamplifier is not muted or inverting, yellow when non-muted and inverting, and red when muted.

The BP-25MC’s build quality and circuit layout are superb. Almost all components are directly mounted on the main system circuit board extending the full width and depth of the chassis. Signals from the unbalanced jacks travel from an input board to this main board via two large ribbon cables. The main board features solder mask and extensive component designators. A written table at pcb center bears the signatures of those installing the capacitors and semiconductors, and the date the system board was completed. Many individual components are used, including very-high-quality film capacitors in a number of places. Looking at the system board from above, I saw no point-to-point wiring.

The BP-25MC’s internal power supply—situated at the right when viewing the chassis from the front—seems to be rugged and well-designed. It employs a discrete bridge rectifier (four 1N4004 diodes) feeding two 4700µF electrolytics. Three 3-pin IC regulators are mounted on individual heatsinks, two of them (a 7824 and a 7924) supplying ±24V to the electrolytics, while the third (a 7808) supplies voltage for the logic to control muting on turn-on. Final filtration is accomplished on the low-voltage regulated side by 2200µF electrolytics. A separate source for the power-on muting system shorts all inputs until the preamplifier has settled. Additional 2200µF electrolytic capacitors provide further filtration at key points in the preamplifier, including the phono stage.

The BP-25MC’s built-in phono section occupies the left side of the chassis: two matching circuit areas, one per channel, run the depth of the chassis side by side. Two metal-shielded cans, transformers for the moving-coil input, sit just behind the front panel. (These transformers are identical to the company’s TF-1 outboard transformer.) The BP-25MC can be ordered with two different gain configurations: the higher configuration of 22.5dB gain, with the transformer wired in series; or 16.5dB gain, with the transformers wired in parallel for a lower source impedance. Behind the transformers sit two identical circuit boards for the moving-magnet cartridges, these including the RIAA equalization circuitry. Total gain for moving-coil cartridges at mid-frequency through the entire phono section of the BP-25MC is 56.5dB.

The line amplification for the BP-25MC is provided by operational amplifier chips, three per channel. Two of these op-amps are to buffer the signal to the tape output and level control, the remaining four for the two balanced outputs. These integrated circuits are specified as delivering high output with low noise. The high 24V rails supplying the op-amps mean that the preamp is relatively resistant to overload.

Listening to the BP-25MC
My interest in the Bryston BP-25MC preamplifier first centered on its remote control—it allowed me to adjust volume during casual listening sessions. This proved to be addictive, as my listening position was 12′ from the preamplifier. I soon discovered that the infrared sensor has a narrow angle of reception at that distance, and will not respond if signaled from more than 45 degrees off-axis. To make certain the preamp responded, I turned it so that one corner overhung the edge of the shelf. I also found that when the preamplifier was left on for long periods of time without use, it sometimes went into mute; the remote’s Mute and Phase pushbuttons then had to be cycled repeatedly to wake the BP-25MC from Mute.

Even with these minor frustrations, the Bryston BP-25MC proved to be a superb preamplifier for reviewing. The volume-control settings provided stable and reliable output, essential for product comparisons. When reviewing the D/A processors mentioned in the Sidebar, I made a light pencil-mark on the front panel next to the rotary volume control to record the approximate setting needed to produce the same voltage out (read by a multimeter) at the speaker terminals when playing a tone from a test CD. These settings produced the same voltage, within 100mV, each time the appropriate D/A processor was put into the system.

Initial impressions of the BP-25 MC, obtained by listening through its phono section, was that it leaned toward a warm, somewhat distant presentation with an open-sounding top end. As time went on, this sonic signature became clearer and more distinct, particularly in comparison with other preamplifiers at my disposal. With the Quad ESL-63s and Totem Model 1s, which emphasize midrange character, the BP-25 had a warm, smooth midrange. The Snell Type A Reference system revealed the preamp’s open, unrestrained top end.

The line section had good bass extension, with a powerful, focused bottom end. Synthesizer-generated deep bass chords in “The Hit,” from James Horner’s Patriot Games soundtrack (RCA 66051-2) sounded clear and solid. The pace and energy of the choir’s foot-stomping on Lyle Lovett’s “Church” (from Joshua Judges Ruth, MCA MCAD-10475) were easily experienced. The Bryston BP-25MC rendered the full weight and power of the bass drum in La Fiesta Mexicana, from Fiesta (Reference Recordings RR-38CD). Bass slam came from the bass guitar and drum kit on “Behind the Veil,” from Jeff Beck’s Guitar Shop (Epic EK 44313). Gain-matched comparisons between my Levinson ML-7A and the BP-25MC showed equal abilities to render the impact and clarity of deep bass from synthesizer and bass drum heard on the “Main Title” track of Horner’s Clear and Present Danger soundtrack (Milan 35679-2).

The BP-25MC’s phono section was equally competent in the bass, reproducing 32Hz pipe-organ notes as well as the rhythmic drive and pace of the double-bass sections of orchestral music. This was evident in its accurate portrayal of the wide dynamic range and powerful orchestral rhythms found in Shostakovich’s Symphony 6 (Stokowski/CSO, RCA LSC-3133). Similarly, the BP-25MC equaled the ML-7A in reproducing the rhythmic drive of Bartók’s Concerto for Orchestra, as heard on Classic Records’ remastered LP of the original RCA recording (Fritz Reiner/CSO, LSC-1924). This firm, solid bass was also heard on “After Anthem,” from the LP of James Horner’s Glory soundtrack (Virgin ST-VR-897678, 1-91329). The full orchestra and the Boys Choir of Harlem presents a dense, colorful sonic fabric; the BP-25 MC conveyed a lovely, warm string tone and the full strength of the soprano voices without strain or distortion.

The BP-25MC’s midrange reproduction convincingly captured instrumental and vocal timbres. On “I Don’t Get Around Much Anymore,” from the When Harry Met Sally… soundtrack (Columbia CK 45319), Harry Connick, Jr.’s voice had just the right timbre without sounding tubby or nasal. On “Grandmother Song” (from The Raven, Chesky JD115), I heard Rebecca Pidgeon’s delicate soprano center-stage in a palpably three-dimensional sonic image. The piano placement on that recording—slightly behind and to the right of the singer—is eerily precise, and was depicted with equal precision by the BP-25MC and the ML-7A, as were the dynamics of Pidgeon’s voice. However, the ML-7A was slightly more transparent and more immediate, and did a better job of rendering the sweetness of that voice.

The Bryston BP-25MC captured the timbre of string instruments while playing two of my favorite excerpts from the chamber music literature. One is from the third movement of Haydn’s Quartet in d (“The Quinten”), recorded live by the Lindsay String Quartet (CD, ASV CD DCA 622). This movement features a canon with two violins playing together in octaves, followed three beats later by viola and cello; its driving tempo has earned it the nickname of “The Witches’ Minuet.” The music was greatly enhanced by the timbre of the instruments, the warmth of the viola and cello resonances, the tonalities of wood and bow, the sweetness of the violin strings.

This recording contains the usual ambient audience noise found in a live recording, including coughs and chair movements, which added to the hall ambience. The BP-25 MC gave a wider soundstage than the ML-7A, with the cello far to the left. The ML-7A, however, was more neutral, with clear delineation of instruments and space. The ‘7a also captured more timbre from the cello and viola, more sense of wood and bow. Violin string tone was equally sweet through either preamplifier.

The second piece—the Assai agitato of Schumann’s Quartet in A, Op.43 No.3 (Joachim Koeckert Quartet, Calig-Verlag CAL 50849)—showed that the Bryston BP-25MC was the ML-7A’s equal in capturing the rhythmic pace inherent in brilliant chamber music. The BP-25MC captured the dark, swirling torment of the L’istesso tempo section, and its preservation of natural string resonance was quite involving. Dynamics and good transient response were also evident with the BP-25 MC, as heard during the opening movement of Prokofiev’s Romeo and Juliet on the original direct-to-disc vinyl (Leinsdorf/LAPO, Sheffield Lab 8). Both the ML-7 and the BP-25 MC were able to capture the dynamics of “Romeo Resolves to Avenge Mercutio’s Death,” totally involving me. While the BP-25MC did a better job of creating the orchestra’s rhythmic drive, the ML-7A was somewhat better at conveying the width and depth of the orchestral sonic image, as well as its timbre.

The BP-25MC’s treble register was extended and neutral. Space was well depicted, almost equal to the ML-7A’s transparency and ability to reveal the sense of air around instruments. Generous soundstage depth and width were heard playing Holst’s Chaconne (Howard Dunn/Dallas Wind Symphony, Reference Recordings RR-39CD). Driven by Bryston 7B-STs or the ML-7A, the Snell Type A Reference System created a seamless choral fabric behind José Carreras, spread across the soundstage in the opening Kyrie of Misa Criolla (Philips 420 955-2, DDD). The spoken “Well done!” was perceived correctly over both preamplifiers at the extreme left stage, where it appears at the end of Anna Maria Stanczyk’s performance of Chopin’s Scherzo in b-flat, Op.31 (on Stereophile‘s first Test CD).

Overall, the BP-25MC proved to be fast and powerful, and excellent in bass response and soundstage presentation. In direct comparisons to the (discontinued) ML-7A, the $2995 BP-25MC lagged behind only in terms of transparency. However, it does have a remote control for the volume and an internal phono module that accepts low-output moving-coil cartridges, which the Levinson does not.

Summing up
The moving-coil features and its purist, low-profile chassis and outboard power source make the Bryston BP-25MC preamplifier perfect for the audiophile market. It is optimized for quiet operation to handle low-output moving-coil phono cartridges. I grew totally addicted to the remote-control options, so I warn you right now: If you take this preamp home as a loaner from your local audio dealer, you’ll buy it.

If you do, you won’t be disappointed—the BP-25MC has world-class bass response and a midrange that can capture much of the natural instrumental timbres of chamber and orchestral music. Bryston has done very well with the BP-25MC; I recommend it as a solid Class B product for any system.

It’s an interesting question to ponder. In this world that seems to constantly gravitate to the newest and greatest item of the moment or pushes the latest emerging trend, what do we have, from an audio standpoint, that is of true value and actually lasts?

It doesn’t help either that, as hobbyists, we are constantly susceptible to catching the “upgrade bug” and the industry we follow is all too happy to oblige that sickness with all kinds of shiny new remedies. Is periodically moving on to the latest and greatest really a good value in the long run? This whole notion occurred to me as I was swapping out a piece of review gear from my two channel rig and reconnecting things back as they normally are. All my 2 channel audio gear has seen some sort of turnover in the past 10 years. The only piece of equipment that has consistently stayed with me through numerous other changes (of gear and life) has been my preamp. It will turn 20 years old in a few months. It’s a Bryston, the BP-25 to be exact.

It’s a very simple looking and streamlined unit, very much in the typical Bryston style. The face of the unit has only 3 knobs, 4 mini toggle switches and a headphone jack. The rear is tidily organized with both RCA and balanced XLR inputs and outputs. It also comes with a small external power supply and a basic remote that is heavy enough to give someone a concussion if you got angry and pitched it at them. I purchased it in the early part of 1997, brand new, from a little stereo shop in Pasadena, which was not run by a little old lady by the way. I was in the market for a preamp and the reason I purchased the Bryston was that every review I’d read on it said essentially the same thing. That it was practically bulletproof and that it was the closest thing to a straight wire with a gain that I could find (and afford, barely) at the time. I wanted something that would not molest, in any way, any source that I routed through it. Just input switching, tape monitor, volume and that’s it. Sounds simple, right? Well it definitely takes some skill to design a quiet analog component, and have it remain consistently so after all these years. It has since travelled across the country with me and been unfailing in its operation, never once giving me even a hint of an issue. It’s very clear to me now why Bryston warrants their gear for 20 years. It’s still essentially noiseless. Turn the volume wide open with no input signal and you will hear not a peep of noise coming through my speakers. I began to wonder though, how does the BP-25 stack up against more modern components?

I mean it’s 20 years old, surely things have come along that have surpassed its performance since then. I decided to go ahead and subject my trusty old preamp to a few of our standard bench tests and hoped it would make a half-decent showing for itself. The benchmark tests were conducted through the analog XLR inputs and outputs. The source device was a LYNX Two professional PC sound card using test signals created by SpectraPLUS audio measurement software. Measurements were done at 2 VRMS and 5 VRMS respectively.

At 1 kHz into the XLR input, THD+N was 0.000386%. We see almost no harmonics throughout the spectrum with barely a visible second harmonic at 2 kHz being about 118 dB below 2 VRMS. This is outstanding performance.

At 1 kHz into the XLR input, THD+N was 0.000339%. A few harmonics begin to creep into the spectrum with the second harmonic at 2 kHz being about 109 dB below 5 VRMS.

The IMD measurement using the XLR input was 0.002466%. We see very minimal noise spurs on either side of the fundamentals and no visible second harmonic.

The IMD measurement using the XLR input was 0.002467%. An almost identical measurement and spectra to the 2V graph.

Here are the results for the 19 kHz, 20 kHz combined test frequencies using the XLR input. There is no visible B-A peak at 1 kHz. We see minimal distortion spurs throughout the spectrum. The second harmonics at 38 kHz and 40 kHz are about 112 dB below 2 VRMS.

At 4.5 VRMS for the 19 kHz, 20 kHz combined test, we see a visible B-A peak at 1 kHz about 98 dB below 4.5 VRMS. We see a few more distortion spurs throughout the spectrum. The second harmonics at 38 kHz and 40 kHz are about 92 dB below 4.5 VRMS.

I measured the frequency response of the BP-25 out to 96 kHz. Through the XLR inputs, the response is flat out to about 70 kHz and then we see a gradual roll-off of the high frequencies at 80 kHz. Note that the minor “tick” at 2.5 kHz and shallow dip past 20 kHz are artifacts from my measuring setup.

As you can see from the above graphs, not only does this old piece of kit sound good, but it measures pretty darn well at 20 years on. Sure you could find something that measures even better today but I think you’d be spending a good deal of money to get a modest improvement that may not even be subjectively detectable. Then there is always the temptation to upgrade to Bryston’s newest preamp model, but I admit to have grown quite attached to my BP-25 over the years. And I know if something were to happen to it, Bryston would service it, without a hitch. So for the time being, she’s still going to be a keeper. You know the old saying of; when you make a mistake, you learn from it and move on? Well it’s nice to know that the good choices we sometimes make, can occasionally follow us around for a while too. The Bryston BP-25 has been one of my better audio purchases in life and I consider it a true and lasting value as a component. Just thought I would share.

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Description

Specifications:

  • Frequency response: 20Hz to 20kHz
  • Total harmonic distortion: 0.0025%
  • Input sensitivity: 500mV (line)
  • Signal to noise ratio: 100dB (line)
  • Output: 3V (Pre out), 15V (Pre out Max)
  • Dimensions: 431.8 x 44.4 x 280mm
  • Weight: 7.5kg

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