Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier Review Highlights
Burson Audio, based in Melbourne, Australia, markets power amplifiers and headphone amplifiers, mostly the latter. Their newest headphone amplifier model is the Conductor Virtuoso.
It runs in Pure Class A bias, has an asynchronous USB input to connect to your computer, and outputs enough power to work with any headphones.
I found it to be very musical, which is the result of its harmonic spectrum.
I used it with two planar magnetic headphones, one of which requires more power than the other, but the Virtuoso easily handled it without having to turn the volume control up more than 2/3 of its range.
Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier Review Highlights Summary
- Sounds great
- Plenty of power
- Gain stages biased into pure class A
- First rate build quality
- Choice of two DACs
Introduction to the Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier Review
Burson Audio, which is an Australian company, makes a wide range of headphone amplifiers. They also make a power amplifier, but headphone amps seem to be their focus.
Their newst model is the Conductor Virtuoso.
BURSON CONDUCTOR VIRTUOSO USB DAC, PREAMPLIFIER, AND HEADPHONE AMPLIFIER SPECIFICATIONS
- Design: USB DAC, Preamplifier, and Headphone Amplifier
- DAC Choices: SABRE ESS9018 DAC or Burr Brown PCM1793 DAC
- CODECS: PCM – up to 24/192
- Power: Headphone Amplifier Section – 4 Watts
- MFR: 1 Hz – 50 kHz ± 1 dB
- THD+N: 0.03% at 30 Ohms and 1 Watt
- Input Impedance: 36.5 kOhms
- Output Impedance: Preamplifier – 30 Ohms; Headphone Amplifier – 3 Ohms
- Inputs: 1 x USB, 1 x Coax, 1 x Toslink, 2 x Analog Coax
- Outputs: Preamplifier – 2 x Analog Coax, 1 x Coax DAC; Headphone Amplifier – 1 x 1/4″ Phone Jack
- Dimensions: 3.4″ H x 10″ W x 10.6″ D
- Weight: 12 pounds
- MSRP: $1,995 USD with Sabre ESS9018 DAC; $1,495 with Burr Brown PCM1793 DAC
- Burson Audio
- Tags: Burson Audio, Headphone Amplifiers, USB DACs, Preamplifiers, Conductor Virtuoso
The review unit had the SABRE ESS9018 DAC, which is the more expensive of the two DACs available.
The Design of the Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier
The Virtuoso is a combination of a DAC, preamplifier, and headphone amplifier. The preamplifier serves as the input stage for the single gain stage in the headphone amplifier.
The aluminum chassis serves as the heat sink.
The power supply has 32,800 µF of capacitance, and there are are two pairs of Mosfets which serve as the output devices for each channel. Some mass market receivers use only three or four pairs per channel and rate the output at 100 watts per channel. Using two pairs in the Virtuoso, and rating it at 4 watts output means the amplifier is easily working in its linear range.
The photo below shows the interior of the chassis.
It also weighs 12 pounds, and heavy is good (12 pounds to produce 4 watts output is my kind of ratio).
The front panel has a volume control with an LED readout, volume control, and input selector button (see photo on Page 1). The volume control is a TI PGA2310 that has 100 discrete steps.
The rear panel has, from left to right, the USB jack for connection to your computer, a coaxial RCA digital input jack (C), two pairs of RCA coax analog input jacks (II and I), a Toslink digital input jack, a pair of DAC ouputs, and a pair of coax RCA analog preamplifier outputs. To the far right is the on/off toggle. The AC socket is three-prong grounded.
The remote control is small, with only a few buttons. It allows you to change tracks, adjust the volume, and mute. It’s made of brushed aluminum and is quite attractive.
The Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier In Use
I tested the Virtuoso with my computer using the supplied driver and USB connection, an OPPO BDP-105 universal player using the coax digital output, and Pass Labs Xs monoblock power amplifiers (connected to the Virtuoso Pre-Out). Speakers were Carver Amazing Mark IV Ribbons. Cables were Mogami and Wireworld. The headphones were OPPO PM-1 and HifiMAN HE-560.
The first thing I noticed was how much power the Virtuoso has. The HE-560’s are less sensitive than the PM-1’s, but I didn’t have to crank the volume control more than about half way up to get the volume I wanted.
I used JRiver Media Center 20 to play music from the computer, through the USB connection on the Virtuoso, so my complete library of music was available with just a few clicks of the mouse, instead of having to change the discs. This makes it simple to listen to my favorite tracks on numerous discs.
One such track is from Francois Couperin’s Pieces de Clavecin, called “Ordre #5. Les Baricades Misterieuses”. Although the music was written for the harpischord, Angela Hewitt interprets them on piano, and they are delightful (Hyperion Recordings CDA67440 – François Couperin – Keyboard Music – Angela Hewitt – Volume I).
Headphones, especially planar magnetic ones, such as the PM-1 and HE-560, allow the listener to hear details that are lost with speakers because you are sitting several feet away. However, the details can be lost as well, if the headphones and/or headphone amplifier are not up to the task. That was not the case here. I could detect the click of the keys as she played, and the ruffle of her dress on the bench. The music itself was extremely pleasing, and had a tube-like quality to it, yet there were no rolled-off highs as there are with many tube amplifiers.
Brahms’ “Intermezzo” is one of his most famous short piano solo studies. It is very romantic, and a bit sombre, but incredibly beautiful. I’m sure you would recognize it even if you are not a classical music aficionado. Through the Virtuoso, it can bring one to tears, and I had to fight them back. I listened to it over and over again, and finally had to get up and rest because it made me feel so sad, remembering a recent death in the family. Yet, it brought me peace as well. There are numerous recordings of this composition, and I have listened to many of them on various albums sold at Amazon (they often have short excerpts from albums that they sell), but the best one is Romantic Piano, with Nina Postolovskaya on the piano.
Beethoven wrote nine symphonies, and when his name comes up, we always are reminded of Symphony No. 5. But, he also wrote many, many other types of compositions than just symphonies. His Piano Concerto No. 5, also called the “Emperor” is gorgeous, and again, you would recognize the famous melody line even if you are not interested in classical music. Through the headphones and the Virtuoso, it was even more beautiful, in this case because I could hear the strings more easily than through speakers. Nevertheless, through the Pass Labs setup and my Carver Amazing Mark IV ribbon speakers, it mesmerized me. Since I started testing and listening to headphones again after a hiatus of about 40 years, and now that the technology of both the headphones and headphone amplifiers is so good, I find myself sitting closer to the speakers so I can hear the detail that I used to lose, sitting so far back in the room.
Of course, Saint-Saëns Symphony No. 3, also known as the Organ Symphony, was a good way to test the bass. The wonderful thing about a headphone setup is that, even with deep bass notes, the membrane in the headphones only has to move a millimeter or two, which is easy. But if the membrane is not mounted properly, or the headphone amplifier cannot drive the headphone at such a frequency, you will be disappointed. But, I was not disappointed. Those pedal tones rattled my brains, and at my age, I can’t afford to lose neurons, so I rattled them at sane SPL’s.
The Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier On the Bench
For distortion measurements, I used the coax and USB inputs on the Virtuoso, within a bandwidth of 80 kHz.
First, the tests using the Virtuoso as a preamplifier, connecting the two RCA coax analog pre-outs on the headphone amplifier. For testing the output at the 1/4″ headphone jack, I used an adapter that let me load both channels with a 39 ohm ceramic resistor.
The maximum output voltage at the 1/4″ headphone jack, with a 39 ohm load, was 8.5 volts, so I present the power amplifier bench tests at 5 volts output (these results are located in the 24/192 bench tests below), except where noted. This represents slightly less than 1 watt RMS.
We start with the RCA coax input tests, using 16/44.1 or 24/96 sampling, as noted. Output is from the pre-outs on the Burson. Maximum output from the pre-outs was 11 volts.
At 1 kHz, distortion was less than 0.01%.
With 1 kHz at 24/96 sampling, distortion was slightly less, but this is an insignificant difference. However, notice that the noise floor is lower than at 16/44.1, and in this case, the predominant harmonic is second ordered, while at 16/44.1, the third harmonic is the largest. These are differences that are not reflected in the numerical representation of the distortion. This is why it’s important to show a spectrum rather than just list the numerical distortion readout when presenting bench test data.
Using 19 kHz and 20 kHz test signals, although there are not very many side peaks around the fundamental frequencies, there is a significant B-A peak at 1 kHz, which is at -63 dB.
At 24/96, the B-A peak is at – 69 dB.
IMD at 16/44.1 was 0.023%.
Going to 24/96 sampling, IMD was higher, but insignificantly so.
Here is the measured frequency response at 16/44.1 sampling. It is 20 Hz – 20 kHz, – 0.5 dB at both 2 volts and 5 volts output.
For 24/96, the frequency response is extended to 42 kHz.
For 24/192 testing, I used the USB connection between my computer and the Virtuoso. This requires installation of a driver that is downloadable from the Burson website. For these tests, I measured the output from the 1/4″ headphone jack, loaded with 39 ohm ceramic resistors, so in these cases, I was measuring the output of the power amplifier instead of the preamplifier (preamplifier graphs are shown above at 16/44.1 and 24/96). As with the preamplifier, I measured the power amplifier at 5 volts output.
At 1 kHz, distortion was essentially the same as at 24/96, including the predominant second ordered harmonic.
With 19 kHz and 20 kHz, the B-A peak was at – 63 dB.
IMD at 24/192 was 0.019%.
Frequency response at 24/192 sampling extended to 85 kHz before it rolled off.
Between the two inputs – digital coax and USB – I could not hear any difference in the sound quality. However, with the high resolution formats – 24/96 and 24/192 – I could hear more detail than with 16/44.1, but that is nothing new. Audiophiles are moving swiftly into high resolution music, mostly downloaded from the various sites that offer music in a variety of formats, including DSD.
Conclusions about the Burson Audio Conductor Virtuoso USB DAC, Preamplifier, and Headphone Amplifier
The Burson Audio Conductor Virtuoso is a fine headphone amplifier. It produces a musical sound quality similar to tube products, and therefore, the warm sound will be appreciated by many. At $1,995 it has plenty of competitors, but its unique sound quality will encourage many consumers to get out their credit card upon listening to it.