Product Review (November 2001) - Parasound AVC-2500u Preamplifier/Processor
Parasound is one of those companies that has consistently
delivered audiophile products at reasonable prices. Needless to say, when
we were given the opportunity to take their flagship THX-Ultra certified
A/V surround controller for a test drive, we were quite excited. The AVC-2500u
is the upgraded version of the AVC-2500 and includes the latest bass management
firmware upgrades that gives the user selectable crossover points for
the high and low-pass filters. The optional 5.1 Volume Control card is
available for $200 to control the levels of the 5.1 analog inputs. This
Volume Control card works with the latest multi-channel DVD-Audio and
SACD formats.
Parasound utilized the talents of the Finish company Sample Rate Systems to help them design this new unit. The combined experience of both companies produced a product that sets a new standard for high-end A/V surround controllers. The AVC-2500u sports a stylish front panel with few buttons and controls. While the AVC-2500u looks simple, it packs some powerful features. This simple approach has only one rotary control located on the right side of the front panel and functions not only as a volume control, but also as a selector for various modes set by the user. Several buttons populate the face of the AVC-2500u for controlling source inputs, surround modes, tuner functions, THX and more. Blue indicators and the large vacuum fluorescent display add to the appearance of the unit and can be dimmed for a less obtrusive appearance in the dark.
Signal
Processing
The AVC-2500u utilizes three 24-bit Motorola DSP56009 processors for handling
DTS, Dolby Digital and THX processing. Once data is decoded, three Crystal
Semiconductor 24-bit stereo DACs (CS4390)
handle the conversion back to the analog world. Levels are controlled
by four Crystal stereo volume control chips (CS3310)
and are adjustable in 1dB steps. Similar Micro Analog Systems volume control
chips (MAS9116)
are used on the optional 5.1 volume control module installed in the AVC-2500u
for use with the external 5.1 inputs. Both of these volume control chips
require back-end external opamps, which can be of a higher quality than
the internal opamps built into many of the current volume chips. Two-channel
analog audio is converted to the digital domain using a Crystal 24-bit
stereo A/D converter (CS5360).
The AVC-2500u switches composite and s-video signals as well as a pair of component inputs. The component video inputs have a upper specified bandwidth of 10 MHz ± 1 dB, making it ideal for interlaced DVD sources. However, progressive scan component video will not work with these inputs/outputs. In addition, HDTV signals require at least 35 MHz of bandwidth to prevent video degradation, so these signals must run directly to the display or through a separate high bandwidth video switcher. Personally, I would never run my component video through a controller unless I absolutely needed to.
Rear
Panel
The back of the AVC-2500u has an extensive set of inputs and outputs which
includes six dedicated A/V inputs (s-video included) and six audio inputs.
In addition, there are two 480i compatible component inputs that can be
functionally switched to any of the six video sources. As mentioned, these
component inputs are not capable of passing 480p or HDTV scan rates. There
are four coaxial, two toslink, and one AES/EBU digital inputs which can
be assigned to any of the A/V or audio components. One video output is
provided (both composite and s-video) for a VCR or similar device. Two
video monitor outputs are also available, one with and one without on-screen-display
information. Coaxial and toslink digital outputs are provided for digital
recording devices. Analog 5.1 inputs are available for multi-channel SACD
or DVD-Audio sources. The 5.1 inputs go directly to the internal volume
control card and do not go through any additional digital processing.
The special miniature DIN connector on the back on the unit is designed to mate with Parasound's external RF demodulator for laserdisc players capable of outputting the AC-3 RF (Dolby Digital) signal. The external RFD-1 is powered from this connector and the demodulated data is received through it. Even though AC-3 on laserdisc was relatively short lived, many videophiles have a collection of laserdiscs and expect to have this capability on their A/V processors. The Parasound RFD-1 worked flawlessly with the many AC-3 laserdisc we played on this system.
Main and remote IR repeaters inputs are provided for controlling the AVC-2500u. There are also three 12 volt trigger outputs for controlling the main power amplifier as well as other electrical devices such as lights or motorized projector screens. Finally, an RS-232 port with a full set of commands is available for custom interfaces or touch screen controllers such as AMX, Crestron or Phast.
The
Guts
The inside of the AVC-2500u has one of the cleanest layouts I have
seen in a consumer product and on par with most high-end products. Boards
were stacked neatly without the usual clutter of wires wrapped in bundles.
Each of the boards have specific functions that are kept separate to minimize
interference between one another. The top board is used to switch component
and s-video sources. The middle board is used for composite video as well
as digital interfaces. The bottom board contained all of the analog audio
interfaces. The three Motorola DSPs are contained on a separate board
in the middle of the unit. The power supply has its own section in the
chassis and utilizes a linear type power regulator instead of the more
common, less expensive and noisier switching power supplies. Fairly large
filter capacitors are also used to clean up the power. The modular design
not only improves performance, but also makes the unit easy to service
should it ever require repair.
Setup
The AVC-2500u was mated with the Parasound HCA-2205AT five channel power
amplifier designed by John Curl. We drove each channel into M&K THX-Ultra
certified speakers which included their S-150THX front speakers and SS-250
Tripole® surrounds. Okay, the SS-250 Tripoles® are technically
not THX-Ultra certified, but I can tell you they are slated to be and
I doubt they will have any problem meeting the criteria set by THX. A
pair of M&K MX-350 MkII THX-Ultra subwoofers handled the low-end.
The
remote supplied with the AVC-2500u processor is designed to control up
to seven additional components. There are six buttons labeled Audio 1
through Audio 6 and another six buttons labeled Video 1 through Video
6 for selecting any one of the many audio or audio/video components connected.
Ten additional buttons are included for selecting the preprogrammed radio
stations. In addition, the remote is capable of running macros to sequence
a series of different commands. The remote has the ability to learn any
command from any other remote to completely customize the buttons. Seven
complete pages can be programmed making it truly an all-in-one remote.
Many other universal remotes I've used in the past have a pre-determined
number of functions for a given manufacturer, greatly limiting the needed
functionality. Having the ability to learn any remote command is far more
powerful for the end user. The backlight on this remote is a pleasant
light blue and makes the buttons easy to see in the dark when watching
movies.
What sets the AVC-2500u apart from other processors is the ability to automatically calibrate the levels and time delays of each channel using the supplied self-powered condenser microphone. The cable provided with the microphone was long enough for large rooms. Simply sit in the sweet spot and push a couple of buttons on the remote. Several short bursts of sound are used to detect the distance from each of the speakers to the microphone. Little user intervention is required, yet the term "patience is a virtue" came to mind while I waited for the system to finish. A noiseless room is a must to prevent the software from telling you to keep the room quiet. Status of the calibration is displayed on the screen so you know exactly where you are at all times. The automatic calibration for the subwoofer distance appeared inaccurate, so I set this up manually. The AVC-2500u indicated a distance of 16 feet, but the actual distance from the subwoofers was approximately 11 feet. It should be noted that any of these level or distance numbers can be adjusted manually. The distance can be adjusted in increments of 0.5 feet, while the levels can be set to within 0.5 dB. The cool part about all this is you can sit near anywhere in the room and have the system calibrate the levels and time delays so that the audio is best optimized for your location. Many homes do not have symmetrical listening environments making this auto-calibration feature invaluable.
The
AVC-2500u automatically detects the type of data being received at each
of its digital inputs. The user defines a surround mode for each component
and that mode will be applied to the decoded data. There are five listening
modes offered on the AVC-2500u, which include Cinema, Stereo,
Music, Party and Mono. Each mode has a slightly different
meaning depending on the source of the material. The Cinema mode
is used for watching movies in ProLogic or 5.1 and has the option of applying
THX processing to the decoded audio. The Stereo mode is strictly
for two channel listening plus an optional subwoofer. The Music
mode is for multi-channel (more than two-channels) audio only and Mono
mode is exactly that. The Party mode is basically a dual stereo
mode that works great for general listening anywhere in the room. For
a more complete understanding of how each mode works with different formats,
click on the chart.
Performance
We spent
a great deal of time listening to a wide variety of music as well as watching
movies. The AVC-2500u works extremely well in both categories. Having
had the more mainstream DSP-A1 from Yamaha, I thought I was going to be
giving up many of the conveniences that processor had to offer. This was
certainly not the case. The AVC-2500u was simple to use and had no problem
decoding any of the source material we threw at it. The format detection
was automatic and worked well even with DTS material on CDs. The previous
Yamaha DSP-A1 unit had the annoying problem of outputting a rather objectionable
brief hiss when playing these type of CDs, but the AVC-2500u implements
a quick ramp-up to the volume to prevent this from happening. Quite a
clever implementation. We ran several tests with both Dolby Digital and
DTS 5.1 encoded movies. The level of performance we experienced was simply
amazing.
The external Parasound RFD-1 AC-3 (Dolby Digital) RF demodulator used with the AVC-2500u during our listening tests performed without a hitch. Since this unit is only needed for playing the now obsolete laserdisc format, fewer of these will be seen in the future. We tested the sonic capabilities of the RFD-1 using one of our favorite scenes from the movie Forrest Gump. While deep in the Vietnam jungle, the rain stops and the sun comes out. Just when you think it's calm, all hell breaks loose and you feel like you are right there in the middle of it. Extremely aggressive surround material fills the air with bullets whizzing by along with deep bass extension, which really exercises the audio system. Aside from the inferior video quality from laserdisc, it was a fantastic format before the birth of DVD. It's painful to think about the amount of money spent on these rather bulky discs, but you can't look back with today's rapidly changing technology.
One of our favorite discs of all time is Steely Dan's Gaucho encoded in DTS 5.1 audio. The audio is crystal clear with large dynamics and a wide soundstage. Two channel SACD recordings were played on our DVP-S9000ES with remarkable results. The open and airy sound of the SACD format worked very well in our setup. Chesky's SACD recording of Rebecca Pidgeon's Spanish Harlem, revealed sonic qualities long sought after. We just wish we had the multi-channel SACD capability. DVD-Audio was equally impressive on our Panasonic DVD-RP91N and utilized the 5.1 analog inputs on the AVC-2500u. Nobody really knows which format will last over the next decade, but I can tell you both formats sound wonderful on this preamp.
We
also still live in the dark ages with our old Thorens turntable and Shure
V15 Type V-MR cartridge. Since the AVC-2500u does not have the required
RIAA phono circuitry built-in, Parasound provided us with their P/PH-100
phono preamplifier. The P/PH-100 has an internal jumper for selecting
either moving-magnet or moving-coil cartridges. Having an external phono
preamp was a wise move since few users currently have turntables in their
system. Using one of the audio inputs on the AVC-2500u, we plugged in
the P/PH-100 and it brought us back 20 years to the good old days of analog
LPs. They just have a difference sound to them that can't be fully described.
We can't live without out our old vinyl, so it's part of our reference
system. Sure those occasional clicks and pops are a bother, but so are
our kids and we love them too. The P/PH-100 worked great and our LPs never
sounded better. We were more than happy to keep this as part of our system.
Unlike most high-end processors, the AVC-2500u includes an integrated AM/FM tuner. Up to 20 presets stations can be programmed into the AVC-2500u. The FM performance was impressive with good sensitivity and low noise. We noticed that the FM module inside of the AVC-2500u is completely separate from the rest of the electronics, which may attribute to the quality of the FM we heard.
We tested
the AVC-2500u for an extended period of time and what we found was a preamp
that performed admirably with a very neutral sound that was detailed and
free of colorations. The performance, features and flexibility offered
on the AVC-2500u has made this processor near perfect for our listening
needs. The 5.1 analog inputs allow compatibility with multi-channel SACD
and DVD-Audio as well as any other new formats that may arise. The only
feature I would have liked to have seen in the AVC-2500u is the latest
Dolby ProLogic II processing. Too bad it's not a simple firmware upgrade
on this unit. If you're looking for a 6.1 matrix system for the addition
center rear channel, Parasound offers the new CSE 6.1 Circle Surround
processor unit. We're planning to review this in the near future so stay
tuned. Although the AVC-2500u is showing some age, we couldn't think of
a better sounding processor with all these features for the money.
- Kevin Nakano