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Model: | SDS-470C |
Category: | Amplifier (SS) |
Suggested Retail Price: | $695 |
Description: | Stereo Power Amplifier |
Manufacturer URL: | Class D Audio |
Review by rkeman on April 14, 2015 at 19:28:34 IP Address: 67.8.25.5 | Add Your Review for the SDS-470C |
The Class D Audio SDS-470C is a stereo power amplifier offering a potent 300 watts per channel into 8 ohm loads and twice that into 4 ohms. Read that again and be reminded that that precious few power amplifiers can manage this feat and those cost much much more. All this in a trim form factor that operates without producing significant heat, noise or fuss. How can it be?
It's a class D amp! That alone will send many audiophiles running - and it should not. Class D amplifiers have been around for quite some time now and a significant number of good quality examples have appeared. The SDS-470C is made by Class D Audio, a relatively new small manufacturer offering a variety of power amplifiers available fully assembled, as complete kits and as discrete modules and components, all at very attractive price points. The company appears to have had limited exposure in the audio community and their relatively simple website certainly lacks any glossy audiophile trappings or wild claims. Communications with the proprietor are uncomplicated and very informative. The products are produced right here in the USA.
The top-of-the-line SDS series is a half bridge self oscillating design based on International Rectifier output devices and backed by beefy linear power supplies. Facillities on the amplifier are basic - two red pilot lights on the front panel, a small rocker power switch on the side of the chassis, balanced (XLR) and single-ended inputs with selector toggles, volume pots and an IEC power socket in the rear. The build quality and appearance are reminicent of more expensive components. The steel casework has reasonable heft and the silk-screened front panel is attractive in an austere fashion. Not overbuilt, just well engineered. The electronic components are of high quality and the assembly appears to be first-rate.
So how does the SDS-470C perform? The sound is very effortless, a trait often associated with powerful amplifiers. The noise floor is very low and results in a "black" background that preserves musical detail. Part of this certainly results from the inclusion of volume controls. Amplifier gain can be set to match the preamplifier optimizing system noise performance. There is very little tonal coloration. Midrange and high frequency performance is comparable to high quality conventional class A/B amplifiers and bass is taugnt and controlled. Other have described Class D Audio amplifiers as having a "tube-like" sound, and if that means grain-free and transparent then the SDS-470C certainly shares that quality. Imaging and soundstage reproduction are limited only by the source material, loudspeakers and listening room. These characteristics seem independent of the loudspeaker driven, unlike some other class D designs.
In th final analysis, the Class D Audio SDS-470C provides excellent sound and blistering power in a relatively compact, cool running, and cost effective package. Highly recommended.
Product Weakness: | None. |
Product Strengths: | Excellent sound and value. |
Amplifier: | Marantz SR-7009 AVR |
Preamplifier (or None if Integrated): | As above and Oppo BDP-103 |
Sources (CDP/Turntable): | Oppo BDP-103, Technics SL1200 Mk II |
Speakers: | Pi Speakers 6Pi, DIYSG Alpha 8a, Custom Subwoofers |
Cables/Interconnects: | Various Belden and Canare |
Music Used (Genre/Selections): | Classical and Pop |
Room Size (LxWxH): | 24 x 18 x 12 |
Room Comments/Treatments: | Extensive including corner bass bins. |
Time Period/Length of Audition: | One month. |
Other (Power Conditioner etc.): | Brick Wall Surge protector |
Type of Audition/Review: | Product Owner |
I still have my SDS-258 amp of which the 470V is basically a beefed up version.I've owned the following amps in recent years:
= Phase Linear 400 -- OK, lets forget about that one
= NAD C270
= Adcom GFA 555II
= Bel Canto eVo2, (Tripath class D)
= Monarchy SM 70 Pro
= Class D Audio SM-258, (IRS2092-based class D)
= Forte 5
= Pass Labs X150.5Of these the Pass is the best; next best is the SDS-258.
The SDS-258, like the Bel Canto, was maybe a little bright on the very top end -- bright but not grainy or smeared. The SDS-258's midrange was fuller than the Bel but less so than the Monarchy. The SDS-258's resolution was as good as any but the Pass; much better than the NAD or Adcom. The The SDS-258's bass was very precise but less warm that the NAD's and less punchy than the Adcom's. The Forte 5 lacked dynamics, and very rolled-off highs, and was basically just weird sounding.
I love the music of Dmitri Shostakovich
Edits: 04/15/15 04/15/15 04/15/15
Worse than the only good one.It figures.
Edits: 04/17/15
I realize that price is no object for some.
I love the music of Dmitri Shostakovich
But usefulness of this review is extremely limited.
Couple of obvious questions, not covered in the review:
- What was it compared to? If it's the Marantz AVR - I hope you realize that for most people here, that's not anywhere close to being sufficient, to determine whether it sounds good;
- Not even getting to an issue whether you really need 300W into 8 Ohm, and twice that into 4 - I would love to see the measurements of this amplifier, specifically its distortion into high frequencies, at anywhere close to rated power.
Here are a few additions to the review that may be of helpful given the questions raised:
The SDS-470C puts out at least 320 watts into an 8 ohm test load at 1kHz and more then 600 into 4 ohms before visible waveform clipping was seen on an oscilloscope. I don't have enough load resistors to measure both channels simultaneously at those levels, but the power supply should be able to do well enough to meet the manufacturer's specifications. The amplifier was stable driving four 8 ohm subwoofers in parallel for an effective 2 ohm load. The subwoofers are based on the Acoustic Elegance SBP-15s in 6 cubic foot sealed enclosures and reached higher levels than most sane listeners would even attempt. It is a very powerful amplifier.
Operating AM and FM tuners near the amplifier reveals no problems, so RF output seems to be reasonably low.
The Marantz SR-7009 served as the source for most of my listening and sounds great. The Audyssey MultiEQ XT-32 room correction offered by the Marantz allows the bass to be better evaluated in my particular system and is my preference for critical listening. Some auditioning using the Oppo BDP-103 and its volume control as the direct source confirmed my impressions with the Marantz. I don't routinely have a stereo preamplifier around any longer since transitioning to a combined music and home theater system. The internal amplifiers in the receiver are actually quite good with my Pi Speakers 6Pi cornerhorns, particularly when the low frequencies are handled by the four dedicated subwoofers.
Other power amplifiers that have been directly compared to the Class D Audio in my system include a Coda 4/3/2 (bridged and unbridged), Anthem PVA-7 and Emotiva XPA-200 and in a friend's system with an older Mark Levinson (? ML-22) driving Magnepan MG-1.7s. None of these were better than the SDS-470C in any substantial way and all except the Emotiva cost much more. The Mark Levinson may be for sale soon according to my friend! Strictly used as a subwoofer amplifier, the SDS-470C gives up little to even the most powerful professional and plate amplifiers that I've experienced. It is taunter, better defined, electrically quieter and makes no mechanical noise - no cooling fan and no transformer hum.
I've always taken a very hands-on technical approach with audio and video equipment and appreciate a high level of performance. The Class D Audio SDS-470C is an example of what good engineering can do and offers great value.
Thanks!
Well done review of an interesting product. Couldn't ask for more.
By and large I think it pays to be a late adopter of new technology and it sounds like "Class-D" may be getting safe for us Luddites...
Rick
Thanks for the review and wow, weakness ? NONE !!!!!
LOL
I too am curious (thanks Todd) as to what interference it would cause with an FM source, as I listen infrequently to our local NPR for talk and concerts.
I was (and still kinda am) considering this amp (it was near the top of the top five in my list!). Unfortunately, unforeseen repairs on two cars, a relative's wedding, and now a speed control issue on my turntable have forced the cash elsewhere...
Dman
Analog Junkie
I cannot speak for this product, but I'd evaluate any switching amplifier by running a nearby tuner, in both AM and FM. If there is considerable RF interference from the amplifier, I'd reject it.
Switching amplifiers run the gamut with RFI.... Some produce very little RFI, as much as a good DAC. But I've experienced others that put out so much RFI as to transform an FM tuner into a white noise generator. (The NuForce 8 monoblocks were such an offender.)
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