Care to make a video?First Impressions of LA90
Application: Near field listening for media production with a Windows PC,
iMac, MOTU AVB audio network and interfaces, Rode Podcaster Pro, and
BlackMagic Mini Extreme ISO video switcher.
Speakers are Martin-Logan LX16s: Sensitivity: 92db @2.83 Volts / meter, spec'd
at 5 ohms, and a Klipsch SPL-100 Class D powered subwoofer, single ended
stereo line in.
Inputs are balanced out from a Rodecaster Pro, a MOTU Ultralite AVB, and an
A90 connected to a D90SE. All the digital audio is 48KHz/24 bit.
The LA-90 arrived via DHL in Lexington, Massachusetts coming from Shenzhen,
China. Ordered Tuesday, shipped Wednesday, received the following Monday.
Your kilometrage will vary.
During shipment the packaging received an attempted perforation, which pierced
the outer plastic wrap and entered the first layer of cardboard but didn't
pass through into the outer box. The amplifier itself lies in a bed of
form-fitted CNC'd foam inside a heavy duty dress box which in turn is
supported by styrofoam blocks at the corners. Those blocks fit neatly in the
outer box's corners, leaving an air gap of a couple of inches around the
inner box. The whole thing is sealed in a heavy waterproof plastic wrap that
is difficult(but not impossible, evidently) to penetrate. The outer box has a
small double-paned plastic window over the serial number label on the inner
box, but the plastic wrap covers it.
First LA90 impressions: very quiet, a little deaf, a little warm, very very
cute, and utterly transparent.
Very quiet: Nothing there between passages. You can tell when a microphone is
shut off in a recording mix by the drop in background noise. There's
absolutely nothing coming from the amplifier to compete with it, no matter
how high the level.
A little deaf: This amplifier expects high input levels, and deals beautifully
with hot (5 Volt!) signals. As the power amplifier for an A90 or direct from
a D90SE it delivers sufficient volume that I really must find my SPL meter.
Fed from the balanced outputs of a Rodecaster, however, it's not possible to
get loud enough to be uncomfortable. If you want loud, you have to give it
A little warm: The LA90 top surface temperature when doing normal listening
for comprehension rather than immersion runs around 93F (34C). Playing
"Another One Bites the Dust" at maximum tolerable level over and over makes
the amp hot, but you can still hold your hand on it. YMMV.
Very very cute: The front panel design and compact half rack width of this
amplifier's CNC'd aluminum chassis have a minimalist Jobsian design affect.
The front panel seems the kind of quick sketch an industrial designer would
do before figuring out the details - it has a button, a knob, and 3 LEDs. And
ironically, in the configuration I am using, the knob has been disabled, so
all that's left is that one button and 3 LEDs.
The overwhelming impression of the LA90 is transparency. I can now recognize
the slight coloration of each input device, with the A90/D90SE easily the
The LA90 replaced a Class D Parasound Zamp v.3 rated at 60 watts into 4 ohms.
The LA90 has less gain but is definitely capable of being much louder. The
LA90 has no discernible distortion at very high sound levels.
Biggest hassle was extracting a stereo line out for the subwoofer from the
speaker outputs. This is really only necessary if you are using the LA90's
input switch and want the subwoofer to follow that, otherwise there's a
single ended line out available on both the A90 and the D90SE. I had a couple
of single ended resistor divider networks, so I tried using them into an
isolation transformer before the subwoofer, but the sub had considerable hum.
I removed the isolation transformer and made a DC connection instead, and the
hum vanished.(I was concerned about connecting Left and Right minus out
directly to each other, hence the transformer, but it turns out they are
connected inside the LA90 anyway.)
The rear panel is crowded, as the heatsinks take out a couple of centimeters
either side, leaving around 6" by 2U for 6 x XLRs, 4 x binding posts, 1 x 64
VDC @ 4 A, 1 x USB C (firmware upgrade only), and 4 x switches.(Apologies for
the reckless use of measurement units.)
And speaking of 64V, you won't replace the custom Topping power supply at your
local surplus store. It runs slightly warmer than ambient, even when the
amplifier itself is piping hot from too much Freddy Mercury.
I am a retired television systems engineer, with 40 years experience designing
and managing the design of professional television production equipment. I
can recognize a labor of love when I see it, even if I can't hear all the
sound it makes any more (and my hearing never was great at 50 KHz). The
LA90 is not for everyone - the compact form factor drives a few inconveniences
and you won't melt buss bars with it - but someone cared very much about the
design and construction and packaging of this amplifier, it's a lovely device.