Found good & affordable amp for Magnepans

This isn't a formal review, just a promised followup to an earlier thread I posted about trying to find an affordable replacement amp for my broken Aragon 4004 amp to drive my Magnepan 2.7QR spkrs. For those who don't have the time or the inclination to read this entire thread, I'll identify the name of this affordable and excellent amp at the beginning: Class D Audio SDS-440CS that lists for $660 and has a 3 week in home trial period. For those who'd like the rambling details of my experiences with this amazing amp, please read on.

My Aragon 4004 class A/B amp recently broke down after many years of great service. The estimate to repair/replace the leaking capacitors in the power supply section was $300-400. The powereful Aragon(400 watts.ch @ 4 ohms) worked great with my older Magnepan 2.7QR speakers since they're relatively inefficient (87db) and need a lot of power to sound their best. So, since this amp was going on 23 yrs old (who knows what was going to go next), I decided to just buy a high powered amp to replace it on the used market.

I searched EBay, Craig'sLlist, Audiogon and other internet sites. I found out that used Aragon 4004s, even the less ancient MKIIs were going for about the same price that I paid for mine used 10 yrs earlier, around $1,000. This was more than I wanted to spend, so I changed stategies and found out, through the forums on Audio Circle and Audiogon, that a lot of people were switching to the new class D amps to drive the notoriously power hungry Magnepan speakers; this is true of owners of the small entry level MMG's through even owners of the top of the line and largest 20 series models.

I made an offer on Ebay to buy a used Wyred4 Sound class D amp, which was one of the first amps the company produced, that didn't meet his reserve price. The seller emailed me back stating it was sold but suggested I check out the new ClassD Audio completed amps. CDA began by supplying class D amp modules and related components to DIYers but has recently branched out by selling completed amps from their facility in Southern California.
I checked out their website and called them the next day. Tom Ross, the company'sowner and amp designer, answered the phone (must've been a busy phone day). He's a great guy;very knowlegable and interesting to talk to. He said he's not looking to get rich but just trying to make the best amps he can at an affordable price so he can build his small business. He told me he's currently relying on positive word of mouth, rather than expensive advertising, to help keep his products affordable.
He says he designs his amps to have the solid and well controlled bass characteristics of good solid state amps combined with the smooth, liquid midrange and treble of good tube amps. This exactly matched my tastes. After he asked me some questions about my system, he recommended either the 440 or 470 amp since either would be a good match with my system components. I chose the SDS-440 because it had about the same power as my old amp (440 watts@4 ohms) and was a little less expensive than the 470. When I opted for the brushed aluminum faceplate, rather then the black, he asked whether I'd like black screws on that or the new silver ones. I took the silver and he said, if I change my mind later, he would send me the black ones free of charge. He also said the fully balanced XLR circuit in the 440 is one of the best on the market and he would include 2 RCA to XLR adapters so I could take advantage of this (how's that for customer service?). The amp was ordered at the end of January and arrived, well wrapped and double boxed, on February 12th.I apologize for the long winded lead in but I thought it might be useful to some readers.

Before I get to how it sounds, I should tell you that this amp is quite a bit smaller and lighter than my old Aragon (about 1/3rd the size and weight). However, it is well built and doesn't look cheap in any way. It was a breeze to setup once I removed the 65lb Aragon from my rack.

Now for the important part: How did it sound?:

I'm not going to pull any punches and will relate my impressions as honestly as I can. For the first few days of listening, I was a little disappointed with the sound; it was a little too neutral and lean for my tastes. I always thought I preferred an amp to sound a touch to the warm side of neutral, without sacrificing details. I left the amp on since I wanted it to break in and it draws so little power while idling.
I called CDA on the 3rd day and related my impressions to Tom. He said his amps don't have any parts that really need to "break-in". But he said he's noticed that many people's ears/brains need time to break-in, especially if they're listening to class D for the first time. I thought that sounded a little unusual so I asked if it was OK to just return it and get my money back. He said: "no problem. You have a 21 day trial period, so just send it back with a copy of the original invoice and we'll give you a full refund, less shipping costs.". Then Tom suggested I keep it longer into the trial period to give the amp a thorough tryout and to see if I needed to adjust to the class D sound. He said I could return it at any time up to the 21 day limit. Since I only had the amp for 2 days, I agreed. As I hung up, I remembered that my preamp (VTL 2.5 with NOS Mullards) had been turned off for several days. I had disconnected the ics and shut it down when I brought my Aragon in for a repair estimate a few days earlier. I only turned it back on when I finished hooking it up to the new CDA amp. It wasn't even warmed up when I first listened to it. This could explain the lean presentation, woops.

So, since everyone is finally done laughing at my stupdidity, I'll continue. Now I had to give this amp another good audition since the preamp had now had plenty of time to warm up. I have always left my preamp and amp on 24/7 so there's normally no warm up time needed.

To give this amp a fair trial I pulled the 2.7s out about 5 feet from the front wall, past the front of my tv, to my normal 2-channel listening position. My listening position is about 15-16 ft away from the slightly toed-in speakers, which are 8-9 ft apart, with the left speaker 2 ft from the left wall and the right speaker at a roughly right angle to the open pass-thru to our dining room( no true first reflection point on the right wall due to the lack of a wall). Ocassionally,I move my chair forward a few feet to attain more soundstage depth on good recordings. The room is carpeted, with soft leather surfaced seating spread about(chairs and a couch). I have yet to convince my wife about the benefits and beauty of well placed diffusors,acoustic panels and other room treatments. I don't push it since she humors me by allowing me to turn our living room into a combination listening room/home theater. You can check out my room setup by clicking on the 'system' label below ( the pictures show the spkrs placed in their ht position, I just pull them another 3 ft further out from the wall for 2 channel listening).

As far as ht performance, this amp has been great since it was setup. Movies and tv sound excellent in DTS and Dolby 5.1. I relegated the one remaing good channel on my old Aragon to driving my passive subwoofer. The 440 is driving only the front L+R channels but does so flawlessly. I run the 2.7's full range for ht(set to large on prepro)and set the high pass filter on my sub to around 45hz(and leave ithere for 2 channel,too). The amp drives these spkrs well with great ambiant and detailed sound with surprisingly good bass from spkrs only rated down to 34hz.This amp is an excellent choice for ht.
As far as music, I had a revelatory experience on my 2nd extended listening session, after a few days of use (break-in?). This was on a Thursday night at about 11pm, a few days after delivery. I had just switched from Comcast to Directv the day before and they now offer Pandora free. I just signed up with Pandora that day and thought I'd listen to a few songs on Pandora before heading to bed. I know Pandora's not the best source in terms of fidelity but it gives me near cd quality without having to deal with changing cds.
I created a station,"Jack Johnson", because I'm very familiar with how many of his songs sounded on my old amp and thought it was a good reference test for the CDA amp. I switched the processor, being fed a Pandora wifi internet digital signal from a small 'client' server box via a digital coax cable, to 'stereo'. The processor then sends analog signals via RCA cables to my VTL preamp prior to the signals being passed to the CDA amp and finally to my speakers. Effectively, I'm using my Parasound AVC2500 preamp/processor as a Dac with analog output.
I know this is kind of a 'Rube Goldburg setup but it's just a temporary solution to get the Pandora signal playing on my system, until I come up with a better method. Anyway, the first song was "Staple it together" by Jack Johnson. The music emerged from complete silence and sounded unbeleivably good, bass was solid,, taut and textured. The best bass I can remember hearing from this often played well recorded song on my system. although there was a slight lower bass overemphasis. I think this was due to the 440's extremely high damping factor controlling the 2.7's woofer section much better than my old Aragon was ever able to. I remedied this by turning down the high pass filter crossover setting on my subwoofer to about 35hz from the 45hz setting I used with the Aragon. The midrange was a touch on the warm side of neutral and the highs were sweet and crystaline clear. The highs did not seemed to be rolled off at all. The soundstage was wide, deep and band members were clearly positioned in this acoustical space. The listening perspective was like I was sitting in the center about 15 -20 feet away from the performers. Now this was the type of system sound I was striving for ever since I got hooked on this crazy hobby/obsession 30+ yrs ago.
Pandora played song after song mixing in various artists with the ocassional Jack Johnson songs, mainly acoustic small group music. What was unusual, besides every song sounding incredibly real and like I was in the room, is that the perspective was consistently about the same for each recording:like sitting in an empty studio/nightclub in the middle and about 20 ft back from the performers. Personally, I like this non-forward presentation because it gives a very vivid sense of depth to the soundstage. But, how and why do all these various artists, at different studios/venues, recorded by different labels and by different recording engineers give such a consistent perspective on the music? One explanation might be that all the recording engineers were taught to mike these smaller groups with similar numbers of mikes in the same general locations. This is just a guess but it should be easy to check out by just seeing if I get a different perspective on larger ensemble recordings.
Anyway, every song I heard was so involving and fun to listen to that before I knew it it was 4am. So, of course, I couldn't resist playing 1 last song before heading to bed. Fittingly, the song was "Mr Jones" by the Counting Crows. It sounded the best I've ever heard this song sound, atleast in my system. Near the end of the song, the lead singer sings: "I'm just about as happy as I can be". This sums up my feelings about this excellent amp right now.
It was a dramatic sound turnaround; from 'too lean sounding' the first few days to the most incredible $660 amp in the known universe a few days later.

- Was it a magical, temporary alignment of cosmic forces? I don't think so because it has sounded just as amazing every day since.
- Was Tom wrong and his amp does need a few days to break-in?
- Was Tom right and my virgin class D ears and brain needed some time to adjust to such a different, distortion free,noise free, clean and natural musical presentation?

Given that Tom knows his amps so well, and how accurately he described how this amp would sound in my system after my 'ears burned-in': good solid state bass combined with a smooth midrange and treble that are also very detailed and revealing at the same time, I'm going to give the benefit of the doubt to Tom. However, I also think this amp benefits greatly from being paire with a tube preamp, especially if it's a fairly good one and is properly warmed up. My general thinking is that the SDS-440 sounds like nothing, it just very faithfully amplifies whateveris inputted to it. Like the proverbial 'straight wire with gain'. I'm not saying this amp only sounds good with a tubed preamp, just that I think a ss pre would likely be too neutral and lean for my tastes. You may call this coloring the sound, or a 'bandaid approach', but I don't give a f#@ck because this combo sounds organic,beautiful and just like music should to me. I'm just about as happy as I can be with this amp. Do you think the Counting Crows' lead singer was singing about his new Class D Audio SDS440CS amp? I am so glad that Tom had the wisdom and experience to know I just needed some time to adjust. After thinking about the sound of this amplifier and my adjustment to it's presentation, I've come to the conclusion that this amp comes very close to the audiophile ideal of " a straight wire with gain". It has no sound, in other words; it just takes whatever is inputted to it, amplifies it with minimal noise, distortion and coloration and passes the amplified product to the speakers no matter their impedance. If you want colorations in your amp, this may not be the amp for you.

Disclaimer: I have no affiliations with CDA or it's owner, Tom Ross. I'm just a very satisfied customer and fan of this newer company and thought fellow Audiogon members might be interested. The only professional review of the SDS-440CS I could find was printed in Stereo Times and the reviewer stated it was very similar sonically to his father's Wyred4 Sound ST-250 at 2/3rds the price.
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