Equipment Review No. 1 January 2002
Five-Channel High Current Power Amplifier
Parasound Products Inc.
950 Battery St.
San Francisco, CA 94111
- Continuous Power Output - Each Channel: 220 watts RMS x 5, 20 Hz - 20 kHz, 8 ohms, all channels driven; 300 watts RMS x 5, 20 Hz - 20 kHz, 4 ohms, all channels driven
- Current Capacity: 60 amperes peak per channel
- Slew Rate: 130 V/µsecond
- Power Bandwith: 5 Hz - 100 kHz, +0/-3 dB @ 1watt
- Total Harmonic Distortion: < 0.03 % at full power
- IM Distortion: < 0.03 %
- TIM: unmeasurable
- Dynamic Headroom: > 1.5 dB
- Interchannel Crosstalk: > 80 dB at 1 kHz; > 60 dB at 20 kHz
- Input Sensitivity: 1 V for 28.28 V, THX Reference Level; 1.5 V for full output
- Input Impedance: 33 k ohms
- S/N Ratio: > 118 dB, full power; > 96 dB, THX Reference
- Level Damping Factor: > 1000 at 20 Hz
- Power Consumption: 1500 watts
- Dimensions: w 19" x h 7" x d 21", h 7 5/8" with feet
- Net Weight: 85 lb.
- SRP: $1995
We're not exactly first on the block to be reviewing this five-channel, THX Ultra-certified basic amp - it has been around since l998 and has established itself as one of the best buys available in a multichannel amp. One important thing has changed, however, and that is its price - it sold for $2500 until recently, and the $500 drop has solidified the 2205A's unique position providing lots of clean power per channel in a home theater basic amp without a fan.
First and foremost, as a back-challenged individual, the sheer heft of this monster amp struck me strongly. Namely, how was I going to get it out of the box and into my cabinet by myself? It does have good handles - a pair on the front and a pair on the rear, but that helps little if you can't lift 85 lbs. There are some rather sharp corners involved too - the four corners of the front face plate which are designed for rack mounting, plus all the corners on the many heatsink fins extending on three sides of the amp. The fins strike very musical tones - actually all are the same tone, but they still demonstrate a serious resonance that tweakers might want to damp with a bit of silicon at the edge of each one. So watch out for getting scratched when moving the amp. I found the 19 1/2-inch depth of the amp too great to be accommodated in the bottom shelf of one of my CWD cabinets, and since this is the highest-power multichannel amp designed without a fan, it needs all the vertical and horizontal space you can give it for the fins to do their heat dissipation properly. I put the amp on a trio of Black Diamond Racing cones sitting on an MSB Iso-plate resting on a trio of Valid Points brass cones - the points going thru my carpet and felt pad to the flooring. At time of writing the amp has been on continually for several days and the top is comfortably warm enough that our new kittens will probably make it a favorite lounging place as soon as they discover it. (Might have to add some Valid Points on top pointing the other way.)
The 2205A doesn't have the look of a rectangular piece of modern sculpture a la Boulder or Chord but its big anodized black appearance is thoroughly professional/industrial and doesn't put one in mind of entry-level gear in the least. The height of the front panel is the equal of four vertical spaces in a pro rack. The back panel has all RCA inputs grouped vertically on one side of the big heatsink fins, and all the speaker outputs on the opposite sides along with their respective small level-adjustment knobs. Things are neat but extremely crammed together, so I doubt if anyone will want to use any other speaker connection option than good old banana plugs. Otherwise some serious shorts are going to be in your future. This is especially true when the amp faces toward your listening position and you have to reach around the back of it for speaker connections. A 12-v. trigger connection is provided on the rear for use with certain preamps and processors that are able to automatically turn on the power to an amp when the preamp is turned on. On the front face plate the 2205A has its power switch on the left with an indicator window about the center. The window shows if the amp is in standby or powered-on status, and warns of overloads or high temperature conditions on any of the five channels. It remains lit when the amp is turned off, which can be confusing at first.
The 2205A is another John Curl design using high-bias Class A/AB operation. It is direct-coupled with no caps or inductors in the signal path. There are independent power supplies for each of the five channels. The 1kVA Toroid power transformer has independent secondary windings for each of the five channels, and a filter capacity of 150,000uF. The complementary JFET and MOSFET driver stages are hand-matched. The amp contains a total of 40 beta-matched 15 amp/60 MHz bipolar output transistors - eight to a channel. Overall inside layout and construction appear to be up to the same high standards as the exterior. A hefty "audiophile grade" detachable AC cord is supplied with the amp, as well as a package of color-coded banana plugs (suggesting that Parasound also feels that's the best way to handle the speaker connections).
I had been living for some years with a previous John Curl-designed three channel Parasound basic amp, the HCA-2003. It is (only!) 200 watts per channel vs. the 220w of the 2205A and powered the L, C & R frontal speakers of my system, while a Mondial 200-watt stereo amp powered a pair of Celestion System 6000 subwoofers. Now the 2003 has been moved to the rear of my new listening room to power the two rear surrounds, with the third amp pushing the Clark transducer mounted in my sofa. The level controls also found on that earlier amp come in handy to set a lower level on the "butt-shaker" when listening to music vs. action-film soundtracks. The 2205A's five channels have been assigned as follows: Channels 1 thru 3 to frontal speakers L, C & R; channels 4 & 5 to my front Celestion subs. The biggest challenge now comes about due to slightly short speaker-cable lengths and the need to occasionally roll my Pioneer RPTV in and out between the two CWD equipment racks on either side of it. The 2205A amp must sit on nearly the same area of real estate as the left-channel Celestion speaker/subwoofer. Still working on that one.
The first indication of the astonishing bass response of this amp occurred during auditioning the Wanamaker pipe organ Dorian CD reviewed elsewhere this issue. Some of the 32 foot pipes' frequencies were inaudible but they nearly blew out my subwoofers. There was no hint of that sort of thing with my previous Mondial amp powering the subs. Of course there was also a 20-watt increase in power output here over the older Parasound amp, but that was probably not the major factor. The sonic quality of the 2205A was almost exactly the same as the 2003. That should make for extremely well-balanced surround playback since all five Celestion main speakers are also identical. The overall characteristic, if I had to be specific, would be neutral and natural with plenty of detail, and not a hint of tizziness or harshness in the extreme high frequencies.
My favorite test tracks on the Opus 3 Test CD sounded better than ever using just the L & R front speakers and subs. There seemed to be more impact and control than with the previous three-channel Parasound amp. And those basement frequencies really came to the fore when required by the music or soundtrack. Speaking of soundtracks, big explosions such as those in the DVDs of Godfather and Ghosts of Mars (reviewed in DVD section this month) really shook things up seriously, even without benefit of the butt shaker transducer or my rear-surround powered subwoofer. I found for the very first time that on certain music sources - especially multichannel hi-res discs that made use of the LFE channel - I actually had to reduce the level control on the Celestion subwoofer crossover control box. And I will definitely have to put my 25 Hz high-pass filter back in the circuit to the subwoofers to avoid damaging them. Perhaps this is not 100% due to just extension of the lowest frequencies when using the 2205A, but as much to its dynamic muscle. Whether that is strictly from the additional 20 watts or enhanced circuit design in the newer amp I couldn't say.
The sometimes startling dynamic range with a good 5.1 movie soundtrack such as the Apocalypse Now Redux is a testament to the sonic impact of this amp, yet it is equally proficient in effortlessly transmitting the silky sounds of a string quartet from a multichannel DVD-A (such as the Debussy/Ravel/Faure reviewed this issue). Whether you have a powered sub and power-hungry speakers and need a good five channel amp that's reasonably-priced, or whether you envision a more complex division of labor among your amps, I don't think you will find any serious disadvantages with the 2205A (except perhaps for a couple visits to your chiropractor...).
- John Sunier
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