● Output: 225 Watts RMS per Channel
into 8 Ohms
THD: < 0.05 % 20Hz-20KHz
Power Bandwidth: > 130 kHz
Slew Rate: > 30 V/usec
Damping Factor: > 100 1 kHz to 20 kHz
Input Impedance: 100 kOhms
Dimensions: 7.5" H x 17" W x 15.5" D
Weight: 45 Pounds
Red Planet Labs
If I knew nothing about Red Planet's flagship two-channel amplifier before
John Johnson invited me to review it, I am richer for the experience. This
is one impressive amplifier.
Red Planet Labs is the offspring of Daniel Marz. An
Argentinean émigré residing with his wife Graciela in San Diego, Daniel's
product line consists of two 2-channel amps and two 5-channel amps.
The STR102 arrived fully broken-in but without documentation. Unable to find a
downloadable manual on the web, I did what comes naturally. I hooked up
single-ended Nordost Valhalla interconnects from the Theta Gen. VIII to the
amp's input, connected the Talon Khorus X Mk. II speakers via Nordost
Valhalla cabling, and ran a Nordost Valhalla power cable from the PS Audio
P600 Power Plant. (There are two sets of speaker outputs should you wish to
run a second set of speakers, as the amp is stable into 1 ohm.)
There is also a Trigger
On/Off to use when you want to have the preamp turn the power amp on. Flipping the on-off
switch on the front panel set two innocuous red lights aglow. An hour later,
I was ready to listen.
Whenever solid state amplification arrives for review at Casa Bellecci-Serinus, my first concern is that it may sound overly harsh,
bright, or lacking in air. This is why I generally use tube products.
immediately realized that the STR201 is an amp I could listen to for hours
Noting that the amp also has balanced inputs, I disconnected the
single-ended inputs (there is no switch to flip between inputs) and plugged
in Valhalla balanced interconnects. The volume level was different,
requiring immediate adjustment (see discussion below). Once that was
accomplished, I was even more impressed with the sound. There was a
noticeable lowering of the noise floor with balanced connections, resulting
in a greater sense of clarity and musicality. Though I know in part this is
due to the Theta, which excels in balanced mode, it is also due to the
Not far into my listening sessions, Daniel Marz surprised me with a phone
call. He and his wife were 45-minutes away, visiting their son who attends
Stanford University. Could they come by and hear my system? Since I had a
host of questions on my mind, I responded, “By all means.”
When the Marzs sat down to take a listen, Daniel commented that the system
sounded a little dark. Removing two recently arrived Nordost Valhalla
power cables from the high power Parasound Halo JC-1 monoblock on which they
had been breaking in, I used them to replace the Elrod EPS Signature power
cables on the Theta DAC and Power Plant. All my components were now powered
via Nordost Valhalla power cables. Daniel's face immediately relaxed as he
sat down to enjoy listening to some of the same tracks he uses to
demonstrate his products at shows.
Interview with Daniel Marz
After listening for awhile, I invited Daniel upstairs to the office to
discuss the amp's technical aspects. In doing so, I made clear that, besides
mentioning that I thought the amp outstanding for the price, I was not going
to discuss my observations with him as a matter of principle. Daniel fully
understood my position, and never tried to press me for my opinions.
With the Ms. comfortably ensconced in the living room, blissfully listening
to Piotr Andreweski playing Bach and Beethoven, Daniel Marz shared the
“The STR201 amplifier is balanced internally. If the source is correctly
implemented, it should output the same voltage in balanced and single-ended
modes. Normally designers don't do it that way, so the volume will be 6 dB
higher when the amp is driven balanced.”
[While I am in no position to declare whether Theta has correctly
implemented its fully-balanced technology, I did note that a 6 dB volume
adjustment was necessary when switching to balanced interconnects].
“The advantage of balanced topology is rejection of noise that the cables
pick up. In terms of the sound, itself there should not be a great deal of
“I recommend using balanced when you have a long run. It shouldn't make that
much of a difference with 3 or 4 feet; keep cables short. I personally use
balanced interconnects because I make the cables myself and don't have a
problem with cost. In my house the AC is horrendous so balanced
interconnects are better.
[My sense is that even with cables under two feet long, the amp's balanced
mode sounds superior. However, because the Theta Gen. VIII I paired with it
definitely sounds better in balanced mode, I won't swear to it].
“I designed the STR201, and released it close to two years ago. We have a
patent on the amplifier's architecture, issued six months ago. I secured 15
patents while working for other companies, but this is the first I've gotten
in my own name.
“When you register the patent, you describe the invention verses the present
art and then make claims on the Intellectual Property (IP). We made 26
claims for having a unique design. The Patent Office did not challenge a
single one, which is very unusual. This is the first time in my life that I
didn't have a single challenge on one of my claims.”
I asked Daniel what was unique about the design that he wanted to share.
“When schools teach engineering, they teach people how to solve problems.
That's only 20% of the battle. The most important thing is how to define the
problem. In this case, is the problem reproduction of a signal or is it to
produce a memorable experience?
“When people say they are reproducing the experience of a live concert via a
high-end sound system, that is impossible for two main reasons:
1. There is a synergy between a performer and an audience that doesn't exist
2. An instrument or voice is a single source. Stereo offers two sources,
surround even more. So technically it's a completely different experience.
You rely on psychoacoustic phenomenon to recreate what was recorded.
So for me, the important thing is to get the listener involved emotionally.”
asked Daniel why his design was solid state rather than tubes.
“I have studied both psychoacoustics and live acoustics. For ears, in
addition to my own, I rely on my wife who is a guitarist, my kids, and
people who are not necessarily audiophiles. My understanding of
psychoacoustics, combined with a great deal of experimentation – I've been
designing gear for 30 years – led to the development of our proprietary
sets of specifications for amplifier design. We are pretty certain that our
specs have led us to a design that will involve the audience emotionally in
“I don't think tubes are necessary. If I can achieve our goals using
solid state, then there is no need to rely on tubes. I switched to solid
state after using tubes when I was 15 or 16 and never went back.
Solid state's advantage is reliability. If you can define the problem – in
this case arriving at our proprietary specifications – then the solution is
“My approach is considered heretical in the audiophile community because I
use solid state and judicious feedback when necessary, both of which depart
from the norm. The results I think speak for themselves. We did lots of A/B
tests against tube, solid state, and hybrid amps. For the most part, people
prefer our amps. For the money, it's very tough to beat.
“I use my own cables because I have control over what I'm doing. For the
signal I use solid core silver with Teflon coating, and for power cords I
use my own silver-plated copper with Teflon shielding, with the shield
terminated at one end.”
Because the Secrets Forum hosted a short but hot debate about the necessity
of breaking-in solid-state components, I asked Daniel his opinion about the
need for break-in.
“My equipment needs some breaking-in, perhaps 10 –15 hours. Break-in opens
up the sound a little bit and makes it warmer. In the power supply the
electrolytics need to reach a level at which they're stable. Part of our design
is to try to remain as independent as possible of electronic components,
i.e., resistors, capacitors, transistors, etc. within the amp. One of the
reasons we can do this is that the design is quite insensitive to
I note that Daniel also left me one of his personal power cables to try out.
He recommended a minimum of 50 hours of break-in time before listening.
For further information on Red Planet Labs' design philosophy and
Allow me to dispense with the formality of listing each selection auditioned
followed by comments. Whether I played female jazz vocals with simple
accompaniment, Canteloube's Songs of the Auvergne with chamber
accompaniment, Terry Evans singing the blues, the Minnesota Orchestra going
full force in Rachmaninoff, solo guitar, a flute/harp duo, or a New Age
synthesizer disc here for review, my impressions remained uniform. This is
one excellent, highly musical amp.
Everything about the STR201 strikes me as neutral and pleasing. Timbre is
true rather than either metallic, overly bright, or dulled. The bass is
solid and lacking in the bloat that afflicts so much mass market gear.
Detailing is quite good and thankfully not overly etched, and placement of
images is excellent. And in balanced mode, transparency is excellent.
In absolute terms, the STR201 lacks the all-encompassing sense of air,
midrange warmth, and captivating bloom heard from the best tube gear. It
also doesn't produce the widest of soundstages, or supply all the
three-dimensionality I'm used to hearing. Nor does its power supply deliver
the staggering bass slam (and I do mean slam) of the twice-the-cost 400W
current-sucking room-heating Parasound monoblocks. (Nor would one expect it
to). Finally, while the fundamentals of a tone are there in spades, the
ultimate complexity and harmonics - the overtones and undertones – are less
present than from far more expensive gear.
[I have taken a brief listen to the not-for-sale proprietary power cable
Daniel uses on his equipment. I put it on my transport, which along with my
amp registers the most change in sound when I switch power cables. The cable
produces a nice, neutral sound, but the extra detail, shine, presence, and
bass impact - the ultimate extension, detail and depth heard heard with the Nordost Valhalla cords
- are absent. As just one example, the sounds of the
hall heard at the start of Reference Recordings' Symphonic Dances are mostly
lost. I wonder how Daniel's design might have evolved had he had access to
more revealing cabling].
Regardless, the STR201 is tight, fast, and smooth throughout its range.
Highs are well extended, and the bass is thankfully solid and full. But most
of all, its sound is MUSICAL. And for $3000, musicality is something
infrequently heard from a solid state stereo amp, in my opinion.
Musicality is something you cannot derive from specifications. You can put
the finest components in the world together and produce something that looks
and tests great on paper but leaves you cold. (It's no different than
putting a Guarneri del Gesu or Stradivarius violin in the hands of a
mediocre performer.) It takes a musical ear to produce a musical component.
In my most recent period of reviewing, when the combination of revised
speakers and state-of-the-art DAC/preamp and cabling has rendered my system
ultra-revealing, I have auditioned three other solid state two-channel amps:
the Soaring Audio SLC-300, the Edge G-8, and the Parasound monoblocks. The
Parasounds are in a class by themselves, with a host of awards attesting to
their breakthrough-for-the-price design. (The forthcoming Soaring Audio monoblocks, auditioned one afternoon at a Bay Area Audiophile Society beta
test session held at my home, promise another
breakthrough-for-a-considerably-lower-price design.) But for a one-piece
stereo amp, the Red Planet Labs STR201 takes the prize.
The STR201 satisfies in ways relatively few other amps in its price range
do. Its sins, to the extent one can even call them such, are sins of
omission rather than of commission. When you listen to the STR201, you tend
to focus not on specifics but rather on an all-satisfying level of
enjoyment. So much transparent, neutral, and all-enveloping musicality for
$3,000 qualifies the Red Planet Labs STR201 as a breakthrough product.
- Jason Victor Serinus -
Digital Front End
Sony 707ES transport modified by Alexander Peychev of APL Hi-Fi
Theta Gen VIII DAC/Preamp
Jadis Defy 7 Mk III or IV modified with a Siltech silver harness
Talon Khorus X speakers MK. II (with latest modifications and Bybee filters)
Nordost Valhalla single-ended and balanced interconnects and balanced digital
Nordost Valhalla bi-wired speaker cable
Acoustic Zen Silver Reference II balanced interconnects
Either Harmonic Tech Magic One, Nordost Silver Shadow, or Nirvana digital
interconnect for DVD-V
Power cables: Nordost Valhalla and Nordost Vishnu; Elrod EPS Signature 2 and 3
plus EPS 1, 2, and 3; WireWorld Silver Electra 5, PS Audio X-treme Statement,
Harmonic Tech, and AudioPrism SuperNatural S2.
PS Audio P600 Power Plant power synthesizer with MultiWave II
PS Audio Ultimate Outlet; PS Audio Power Ports
Michael Green Deluxe Ultrarack, Basic Racks and room treatment
Ganymede supports in main digital chain and under speakers
Michael Green Audiopoints, and Black Diamond Racing Cones elsewhere
Shakti stones for Amp and Theta
Stillpoints ERS EMI/RFI sheets on some components
Bedini Dual Beam Ultraclarifier
Audioprism CD Stoplight
Marigo as yet unreleased Signature Mat for use atop CDs
Ayre demagnetising CD and the original Sheffield/XLO degmagnetising and break-in
Terms and Conditions of Use