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.

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.

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

Review System

Display - Pioneer Elite PRO-610HD 58-inch HD-Ready TV (ISF calibrated)
Amplifier - Parasound HCA-2205AT THX-Ultra Certified Five-Channel Power Amplifier
Set-top Box - RCA DTC100 HDTV/DSS Satellite Receiver
Dish - RCA DSA8900E DirecTV Plus Elliptical dish.
DVD/CD/SACD Player - Sony DVP-S9000ES DVD/CD/SACD Player
Laserdisc Player - Pioneer Elite CLD-99 Laserdisc Player
Turntable - Thorens TD-146 with a Shure V15 Type V-MR cartridge
Front Speakers - Miller & Kreisel S-150THX (L+R) and S-150AC (Center) THX-Ultra Speakers
Rear Speakers - Miller & Kreisel SS-250 Tripole® Surround Speakers
Subwoofer - Two Miller & Kreisel MX-350THX MkII THX-Ultra Push-pull Subwoofers
Room Treatments - Echo Buster panels and Bass Buster towers
Audio Analyzer - Sencore SP295 Audio Analyzer

Review at a glance

Parasound AVC-2500u Audio/Video Preamplifier/Processor


  • Dolby Digital, DTS, Dolby Surround processing using three Motorola 56009 processors.
  • Home THX-Ultra certification.
  • Proprietary bass management eliminates smear and distortion.
  • Independent dual zone control of audio and video systems.
  • 100% automatic calibration of channel levels and delay times, including sub channel.
  • Calibration mic included.
  • Composite-video, S-video, and Component-video switching.
  • Automatic digital audio and video input selection.
  • Digital inputs and surround modes are assignable to sources.
  • Discrete analog line drive stages, four layer military-spec circuit boards.
  • Intelligent on-screen display and backlit learning remote control.
  • Reference quality FM/AM stereo tuner with 20 presets.
  • External analog 5.1 inputs assure forward compatibility with DVD-Audio, SACD and others.
  • 3 rack space height front panel.


  • Frequency Response: Front/Center/Rear 10 Hz - 24 kHz; Center (small or THX) 80 Hz - 24 kHz; Subwoofer 10 Hz - 80 Hz.
  • Harmonic Distortion: front < 0.006%; center < 0.006%; rear < 0.005%; subwoofer < 0.006%
  • Input Impedance: all inputs 10 k ohms IM Distortion: < 0.06 % all channels
  • S/N Ratio: flat/A-weighted: front 94 dB / 97 dB; center 94 dB / 97 dB; surround 78 dB/85 dB; subwoofer 88 dB/96 dB
  • Video Section: sensitivity 1 V ± 0.5 dB; frequency response .3 MHz - 10 MHz ± 1 dB; overload 2.5 V P-P
  • Tuning Range: FM: 87.5 -108 MHz; AM: 520-1610 kHz
  • Sensitivity: FM: mono: IHF 11 dBf; stereo: IHF 37 µV for 50 dB of quieting; AM: IHF 10 µV/m
  • S/N Ratio: > 74 dB Stereo; 65 dB IHF-weighted
  • FM Stereo Separation: 50 dB @ 1 kHz; 40 db @ 10 kHz
  • Selectivity: FM: 80 dB; AM: 30 dB
  • FM Frequency Response: 30 Hz - 15 kHz, ± 1 dB
  • AM Frequency Response: 20 Hz - 4.5 kHz, ± 1 dB
  • Total Harmonic Distortion: FM mono ¯ 0.08%; FM stereo ¯ 0.2%; AM < 0.5%
  • Capture Ratio: 1 dB
  • AM Suppression: 60 dB

    Source: Manufacture loan
    MSRP: $3495
    Size: 17-1/4" x 51/4" (5-7/8" with feet) x 13" (WxHxD)
    Weight: 16 pounds
    Warranty: 5 year parts, 10 years labor

    Parasound P/PH-100 Phono Premaplifier


  • Works with all line drive preamplifiers
  • RIAA curve accurate to 0.25 dB
  • Ultra low distortion
  • Internally selectable adjustment for moving coil or moving magnet
  • Analog Devices operational amps
  • Audiophile grade resistors and capacitors
  • Computer grade glass epoxy circuit boards
  • Gold-plated RCA jacks
  • 9 1/2" width front panel
  • Removable IEC AC cord
  • 1 rack space height front panel
  • Two unit fastening hardware available for side-by-side rack mounting


  • input Sensitivity: moving magnet: 2 mV; moving coil: .5 mV
  • Input Impedance: 47k ohms
  • Input Overload: 220 mV, I kHz mm
  • RIAA Accuracy: 0.25 dB, 20 Hz - 20 kHz
  • S/N Ratio: 72 dB, ref 5 mV input

    Source: Manufacture loan
    MSRP: $120
    Size: 9-1/2" x 1 3/4" (2 3/8" with feet) x 7" (WxHxD)
    Weight: 3 pounds
    Warranty: 5 year parts, 10 years labor

    Company Information
    Parasound Products, Inc.
    950 Battery Street
    San Francisco, CA 94111
    Ph: 415-397-7100
    Fax: 415-397-0144

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