December 2009

Burson Audio PRE-160 Preamplifier And PP-160 Power Amplifier
Stellar sonic performers for their relatively low price.
Review By Tom Lyle
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  Burson Audio is based in Melbourne , Australia , and although some (perhaps most) audiophiles in the US might not ever have heard of this company, Burson Audio has been on the audio scene since 1996. The company was named after Mark Burson (the man), now retired, who was part of the Melbourne audiophile community for quite some time, and Burson Audio (the company) insists that their philosophy is the same as Mark's – to "love and enjoy music, and do more than just listen to it, but to feel music and experience it the way it was intended by musicians -- and to recognize the importance of calibrating musical reproduction to live performances." Those are hardly controversial concepts; in fact they are (or at least should be) fundamental concepts for all those attempting to assemble a musically satisfying high-end system. But there are more ways to approach this than I care to think about at the moment, and Burson has decided to focus on affordable (although not budget) solid-state gear -- and that is certainly a route that can be embraced by quite a few audiophiles. Before this review I have never seen any Burson components, but I've read positive reviews on the subject of their op amps, regulators, and clocks for DIY'ers and upgrade enthusiasts.

PRE-160 Preamplifier
In their literature Burson stresses the importance of the power supplies used in their PRE-160 Preamplifier. They designed a new power supply from the ground up for this unit, and in doing so bestowed it with an additional noise filtering stage. Burson claims that this not only improves its noise rejection, but also improves the preamps transient response as well as increases its reproduction of detail and its overall dynamic capabilities. The preamp's Class A circuit uses only discrete Burson op amps, which minimizes distortion, and a "Burson Buffer" input stage is utilized, which they designed to enable the preamp to match any input source and any output impedance. The PRE-160 has no remote control. Burson says that they decided against using a remote because they would instead rather use a complex and pricier custom built stepped attenuator, and as a result this would improve the unit's sound quality. The attenuator uses 1% metal film resistors, and uses gold plated connectors. Only one resistor is used at each step to keep the signal path as short as possible, and Burson maintains that among other sonic benefits this improves soundstage depth.

The PRE-160 is housed in an attractive shiny, silver, rectangular cabinet measuring about 17 wide, 4 high, and 14 inches deep. This is a pretty basic preamplifier, sporting only three unbalanced RCA inputs and a pair of unbalanced RCA outputs. The front panel has only two controls: volume and selector along with its push-button on/off switch. As with its matching PP-160 amplifier the only display on the front panel is the blue power indicator.

PP-160 Amplifier
Just because Burson Audio designs and manufactures affordable gear, they insist that they hardly skimp on quality. Each printed circuit board they produce is optimized trace-by-trace, which often involves manual adjustment to improve performance, and of course each pair of capacitors, resistors or transistors are tested and matched by value and brand. The design and build quality of the power supplies are given special attention to reduce noise, whether that noise's is from extraneous sources or the power supplies themselves. Burson has designed the Discrete Power Filter System which employs a sophisticated noise filter and voltage stabilization network that is intended to match each circuit design. This filters out the noise and at the same time keeps the voltage fluctuations to its goal of less than 1%. Like I said before, Burson especially takes pride in the design and implementation of the op amps used in their equipment. With the introduction of their second generation Burson OpAmp as well as improving upon the performance of their earlier PP-100 amp with premium parts such as Elna capacitors, mil-spec Dale resistors, and their custom built 400VA transformer, the new PP-160 was conceived. A unique feature of the PP-160 is the ability to connect to the speaker outputs of a lower powered 5 to 25 Watt amp, acting as a booster.

The relatively compact PP-160 puts out 95 Watts per channel into 8 Ohms (160 into 4 Ohms) and is housed in the nearly identical to the preamp, rather non-descript, but attractive shiny, silver, with a 17 inch wide, 4 inch high, and 14 inch deep rectangular square-edged cabinet. Its rather hefty 33 pound weight indicated that they aren't kidding about the substantial custom built low-noise torroidal transformers and other power supply goodies that they've packed into its cabinet. On its rear panel are unbalanced RCA inputs and fairly heavy-duty speaker lugs and an IEC socket for the removable AC cord.

Listening
In my listening tests I used two systems; the smaller of the two had the two-way stand-mounted Dynaudio 110 or Coincident Speaker Technology (CST) Triumph Extreme Signature, the CST the larger yet more sensitive of the two. In the larger main system the speakers were the vastly more challenging load of the six-foot tall Sound Lab DynaStat hybrid electrostatics. The amp was sometimes connected to a Panamax power conditioner in the small system, but when in the main system the amp was plugged directly into one of the room's dedicated 15 amp lines. The preamp was also occasionally hooked up to the Panamax in the smaller system, but the power cord was often connected to a PS Audio P600 AC regenerator in the main system, and the PS Audio in turn was connected to a dedicated line. 

At first I was going to critically dissect the sound of either the amp or preamp, then move on to the other, but after a while that seemed pointless -- the preamplifier and amplifier both exhibited almost exactly the same sonic characteristics. I could have copied and pasted the text of the sonic description of one to the other and it wouldn't matter very much. Although the amp or the preamp mated better with some other makes and models of components better than others, they without a doubt performed best when used together. That shouldn't be that surprising, really. But it is worth mentioning that I was shocked how well the 95 wpc PP-160 drove a large pair of electrostatic speakers. I used the amp in the smaller system for quite some time before moving it upstairs to the main system, and was sort of carrying this out as a my duty as a conscientious reviewer more than anything else, thinking that it would be unfair to put the amp in that kind of, well, compromising position. So, despite my initial misgivings, it ended up residing in the main system for quite some time because there wasn't any point when I thought I was reaching the limits of the amp, and heard no clipping or other hints of strain at any time, and most importantly it sounded very, very good. No, the Burson amplifier didn't have the transient snap, or the overall control and power as the resident 250 Wpc amp, but one wouldn't really expect it to. Since the main system was full-range and had a much better front-end, which included but was not limited to a Basis/Tri-Planar/Lyra analog rig connected to either a Pass Labs or Rossner & Sohn phono preamp, and a digital set-up using the impressive Acousticbuoy DAC, my comments regarding the Burson's sound were mostly (but not completely) in regards to how it sounded in this system.

On the timeless Berlioz' Symphonie Fantastique with Charles Munch conducting the BSO on the Classic Records' Living Stereo LP reissue, although the overall sound leaned slightly toward slightly burnished in the highest treble, the Burson gear sounded what can only be summed up as "natural" sounding, that is, instruments emanating from the speakers sounded like the real thing playing in a real space -- and yes, this is the highest praise I can bestow on a piece of audio equipment. Although there was a slight rise in the mid-bass and it was ever so slightly underdamped, the deep bass was extraordinary, and bass drum whacks on side two of this oft played record shook the room. The low frequencies went as deep as my system allowed, and moreover, the lower strings remained pitch stable throughout the climaxes of the piece in the last two hallucinatory movements. The rest of the strings were as lush as I would expect from this slab of wax, and during the "March to the Scaffolds" when they are played with the wood of their bows the sound separates itself from the rest of the orchestra and sounds as menacing as Berlioz doubtlessly intended.

But let's put natural sound aside for a while. Led Zeppelin's The Way The West Was One is one of the best "live" rock albums that have ever been released. "Live" is in quotes because it is pretty obvious, to at least me that this album has logged quite a few hours in post-production, not changing the actual events as they happened, per se, but to the sound of the original tapes. But this hardly matters, especially if one considers that even the best rock recordings can hardly be considered archetypes of reality, especially when it comes to portraying aspects such as what would be considered a natural soundstage, as spectacular as it might end up being portrayed on the final product. The massive wall-of-sound that spewed forth from the speakers as soon as the first notes of "Immigrant Song" slammed into the air sounded like the coming of the apocalypse (albeit in a good way). My listening notes continued to read like an early 1970s issue of Creem Magazine, so I'll just paraphrase and just say that it sounded like pure rock ‘n' roll bombast that was expertly transferred to the speakers by the Burson equipment, mainly because it didn't editorialize the signal, simply passing onto the speakers what the producers and engineers intended. The bass guitar (and even the lead guitar at times) had enough low end heft to shake the room, and combined with John Bonham's thunderous drumming it might not have sounded as if one was at the show (and that's a good thing, since I've never been at an arena show that sounded this good), but it sounded awesome, that's for sure.

I let a few days go by before I played another rock CD, this time a mellower affair, Bryan Ferry's Taxi album, where he covers diverse bunch of tunes including the Gerry Goffin and Carole King chestnut "Will You Still Love Me Tomorrow" in Ferry's singular, rather urbane style. Again, this cut displayed the Burson's bass prowess by digging deep and effortlessly, easily reproducing the lowest notes of the five-string bass. This album was certainly not the best selection to judge a piece of gear's transient response given that every instrument, including Bryan 's voice was bathed in copious amounts of reverb. But what was clear (ahem) was that each instrument's reverb was located in its own space relative to the voice or instrument, and faded into the background when allowed by the musical arrangement. Sometimes the treble on this CD can become a little fatiguing, given that the mastering of the plain vanilla 16-bit/44.1kHz CD isn't the best on the planet, yet the Burson's had somewhat burnished sounding highs that allowed for some very lengthy listening sessions with my wits still intact. But at the same time I never thought for one minute that I was missing any information in the upper frequencies. Accordingly, vocal sibilants weren't overly aggressive, and the overall sound never sounded etched. Some complain that this album treads a fine line between great art and adult-contemporary Musak, yet the Bursons' seemed to be able to sort everything out and present the album as leaning toward the former rather than the latter. Many of his fans think that this is one of his greatest solo albums of the 1990s as it was his best selling of that decade, reaching #2 on the UK charts. As heard through the Burson PRE-160/PP-160 combo, I'd have to agree with them. 

One of the best CDs I heard while the Burson gear was in my system had to be a disc of works by Claude Debussy with Simon Rattle conducting the Berlin Philharmonic. This 2005 release is a wonderful sounding disc, not only because of its excellent recording quality but because of the ravishing performance of the Berlin PO players. It is quite understandable if his interpretation of Le Mer on this disc isn't on the top of your list (I noted 130 versions of this work on Arkivmusic.com), sound quality-wise it should be a top contender for those recorded digitally. But that might be beside the point when one considers the marvelous job the Burson equipment did in transferring its top-notch sound into my listening room. The honeyed sound of the high-pitched percussion that includes cymbals, triangle and glockenspiel, plus the upper-most harmonics of the strings added to the suspension of disbelief that sometimes occurred, sometimes only for a split-second, but enough to at least feel that I was viewing a sonic model of the actual event. The lush strings combined with the Burson's low-end weight and uncolored sound made the piece all that much more enjoyable.

One more thing in case you were wondering: I didn't have too much information regarding the use of the PP-160 amplifier as a "booster". But I'd be remiss in at least trying it out, so I hooked up a 6 Wpc JohnBlue tube amp's speaker outputs to the speaker binding-post inputs of the PP-160 with a run of short Cardas speaker cable. The level of transparency that both these amps are capable wasn't exhibited when them together.  To the PP-160s credit it did indeed boost the meager Wattage of the JohnBlue to useable levels with for use with less than super-efficient speakers, and the character of the tube amp was still mostly intact. But whether the loss in transparency was the fault of the Burson or the JohnBlue, or just some compatibility issue(s) I can't say. I'd rather not draw too many conclusions from this solitary experiment.

Conclusion
Whether this equipment is for you, depends on a few things. First is the Burson PP-160 amp, which might or might not have enough power for one's speakers, and there are times when 95 watts per channel might not be enough. When used in the main system using the super-power-hungry electrostatic/hybrid speakers often I had to turn up the volume a bit more than I was comfortable (even when using it with the matching PRE-160 preamplifier) and I experienced a bit more background noise than I was used to, although I admit I'm a bit sensitive to that. However, it was able to drive the two-way stand-mounted speakers to near deafening levels with nary a hint of amplifier distortion. The Burson PRE-160 preamplifier might match some systems (and their owners) more than others since it has no remote, no balance control, no phase switch, no mono switch, and what I missed most of all since I listen to so many LPs, a mute switch. Intangibles matter more to some than others, for sure. Sonically (and undoubtedly more importantly), both the Burson PRE-160 and PP-160 were stellar sonic performers when one takes into account their relatively low price. When compared to my reference gear I sometimes wished for more resolving power, greater dynamic range, more sparkling highs, and greater soundstage depth – which one should expect when ascending the audiophile ladder.  But considering I was comparing the Burson stuff with components costing as much as five times their price, they held there own. And that is a bit of an understatement.

Kudos to Burson Audio for manufacturing and marketing the PRE-160 preamplifier and PP-160 power amplifier, two components that should be considered by all that are searching for outstanding yet affordable pieces of high-end equipment.

Ratings
These ratings for both the PRE-160 and PP160 are, as usual, very conservative – a perfect five note rating is only awarded for the best that I have ever heard):

Specifications
PRE-160 Preamplifier
Output Voltage (RMS): 25 Volts (20 Hz to 20 kHz) 
Voltage: 80 Volts
Output Impedance: 20 Ohms
Frequency Response: 20 Hz - 30 kHz (+- 0 dB)
Inputs: Threee pairs of line-level RCA
Output: one pair RCA
THD: .002% (20 Hz to 20 kHz)
SNR: 100dB (A weighted @ 1 V RMS)
Input Sensitivity: 285 mV (@ 1 V output)
Input impedance: 250 Ohms
Gain At Maximum Volume: 15 dB
Dimensions: 17 x 4 x 14 (WxHxD in inches)
Weight: 26.5 lbs. 
Price: $2250

PP-160 Power Amplifier
Inputs: One pair unbalanced RCA, Two pair speaker binding posts
Output: 95 wpc @ 8 Ohms (180 @ 4 Ohms)
THD: 0.01% (20 Hz to 20 kHz)
Input Sensitivity/Impedance: 2409V / 20k
Frequency Response 10 Hz to 120 kHz (+-3dB)
SNR: 96 dB (through RCA line input) 
Dimensions: 17 x 4 x 14 (WxHxD in inches)
Weight: 33 lbs.
Price: $2245

Company Information
Burson Audio 
Melbourne 
Australia

E-mail: info@bursonaudio.com 
Website: www.bursonaudio.com