Class D Amp

[Ajani]

Ok, I placed the amp in my reference system with mixed results. I had to roll some tubes because the amp sounded flat with the RCA Black plates in my preamp and sylvania's in my DAC. Once I did this the amp came a live. I am running Amprex 6CG7's in the preamp and Tung Sols in the DAC.

First off. The amp is dead quiet. No hiss and blacks are black. Compared to my Parasound A21 the amp is more quiet and there is no grain what so ever ( my one beef about the A21 is that it has a touch of grain). The amp also has more air, transparency and a wider sound stage. Bass seems a bit tighter and more controlled but there is a little less bass slam so its a trade off. The sound is more smooth but the midrange is not as prominent, probably due to the airiness of the sound. The A21 has better dynamics, deeper bass, more depth to the midrange and better treble resolution. The CDA-254 good treble but not harsh in the least, it sounds different but not in a bad way. People have commented about this on other reviews. Vocals are excellent very natural. The overall sound is very liquid. One thing about both amps are the dampening is excellent and noticable. These are both well controlled and fast amps. The dampening factors of Class D amps are in the thousands as is the A21.

Here are the Pro's and Con's for the CDA-254S

PRO'S-
Smooth well controlled sound
Tight well controlled bass
Wide sound stage, very transparent, airey sound
No Grain what so ever
Neutral souding
Very black background
Good dynamics but not on par with the A21 (more on this below)
Good treble with no harshness

CON'S-
-It needs the larger 400va power transformer that the CDA-254L comes with. The CDA-254S comes with the smaller 300va. I have read that with the larger transformer that the amp has much more slam, more powerful bass and is more dynamic. Note that when I used the amp with the PSB speakers, dynamics and bass slam was excellent. It was only when used with my more demanding Magnepans that the amp could have used the bigger power transformer.
-Midrange could have used a little more weight to it.
-Treble could use a little more detail and resolution

I don't think that I will be using this amp in my reference system but I probably will go ahead and buy th SDS-470 amp that puts out 600wpc at 4 ohms (the CDA-254S is 250wpc at 4 ohms) and has a massive power transformer. The SDS series is supposed to have better treble, dynamics and be of higher quality. I like the smooth sound, air, wider sound stage and very tight bass that this amp has. It has some of the qualities that the new Van Alstine 400R and 600R amps have, but they are out of my price range at $3K plus.

Overall the Class D amps are a bargain at $200-$400 for the kit versions. They give you a taste of audiophile sound at bargain prices.

Nice review... Maybe the SDS-258 or 470 will correct the cons you found with the CDA...

Anyway, between Feanor's comparison of the SDS-258, your comparison of the CDA to the Parasound and all I've read, I'm sold on trying out either a SDS-258 or 470...

I'm going to e-mail Tom at Class D to determine which is better... As I'm a bit confused... I know the 258 doesn't double into 4 ohms, while the 470 does, however since the 470 is slightly cheaper I'd assume it trades off some quality for that ability to drive more difficult loads...

Thanks again for the review!