Krell KAV-400xi vs. Parasound A21+P3

I haven't listened too the Parasound at all, and therefore cannot make any comparisons which is usual here at Audiogon. But I do think I can offer some insight none the less. I own the Krell 400XI and love it but I want to clear up a few things.

1. The Krell 400XI has a decent power supply (large) but suffers from inadequate heat sinks. If you actually look inside it's quite sparse. I have driven a pair of Dynaudio 52SE's and Aerial Acoustic 5's with no problems. The Dynaudio's are a fairly easy load impedance wise as it's rather liner, the Aerial's are more difficult but made for a good pairing with the Krell. I haven't found heat to be a problem yet, although I've often wondered.

2. The Balanced 'myth'. I have used this Krell with both the RCA and XLR's and I think most people hear the +6db increase and assume balanced is superior. This is where I get rather annoyed. Matching dB levels between balanced and single ended the differences are there but not as striking. Also, the Krell 400XI isn't fully balanced as some marketing suggests. Sorry Krell owner's this is fact not fiction. It uses Balanced Differential Circuity as opposed to a completely balanced design. While I agree this does improve low level detail (and I prefer it) some would argue that Krell is simply adding a circuit and therefore adding a stage which can be audibly heard.

I like my Krell don't get me wrong. It's done nothing but given me good music. But as much as I get irritated by the anti-Krell 'they make statistical amplifier's not musical components' crowd I find a lot of mis-information gets thrown about by both sides. At the end of the day it's a nice Integrated for a fair price which looks appealing to the eye and measurements that help sell the product. Some of these measurements are taken out of context (Balanced Design) or sometimes exaggerated (4 Ohm rating). I still plan on keeping mine.

I thought that there was a conclusion on an earlier
thread that the Krell was balanced. I DO know what you mean
by matching the db levels but I have used Mcintosh, Esoteric and Musical Fidelity sources with my Krell. Note that the MF does not have XLR outputs. I noticed a difference in detail, imaging and bass with the balancd inputs. I do admit my XLR cables are far superior to any RCA cable I have.
Yes this thing gets hot. But I never have had to turn the volume to anywhere near where it can go. I do run it at low listening levels most of the time.
It is great for listening to music.

I knew nothing of this amp from any thread when I bought it.
I listened to it and thought it was a good buy at the asking price point. I do run it with 4 ohm speakers.
I am not arguing about being a true balanced player. They do advertise that for what it is worth.

For what they go for used on this site...GRAB ONE.

It sounds darn good with my stuff. It will only be as good as the rest of the system. We all know that.

I read that Stereophile review several times before I decided to take a chance on the 400xi because I too had concerns. According to John Atkinson's measurements taken of the Thiel 2.4: "Not only does its impedance drop to 2.73 ohms at 600Hz, but it stays significantly below 4 ohms from 100Hz to 50kHz, and there is a difficult combination of 4.5 ohms magnitude and –45° electrical phase angle at 80Hz."

After two weeks of serious listening in the evenings, sometimes at SPLs from 8 feet from the Thiels up around 85 to 90 dB, the 400xi gets hot, but not so hot that I cannot keep my hand on top of the amp. So it seems that even 2.73 Ohms minimum and a nominal less than 4 Ohms is OK for the Krell 400xi.

Also, according to the Krell's measurements and for other amps, Atkinson's test regimen puts amplifiers through some quite serious stress; music is a very different source signal than pink noise or 1kHz/10kHz square wave tones. And look what he did to thermally stress this amp so that it was cranking 500 Watts before he got the fuse to blow into 2 Ohms! Also, Atkinson points out that, "Concerned about the temperature-dependent nature of the amplifier's linearity, I measured the manner in which the KAV-400xi's THD+noise percentage varied with frequency at a moderately high level (16V) into 2, 4, and 8 ohms. The results are shown in fig.5: the audioband distortion is nicely below 0.1% into 8 ohms, with the right channel a little more linear than the left. A rise in THD above the audioband gets more severe into the lower impedances, but this is nothing to be concerned about."

The other thing too is that he thermally stresses the amp and does the waveform analysis when maximally thermally stessing the amp, something he does not routinely do for other products. That seems a bit unfair and I wonder if he has some chip about Krell that we don't know about.

He concludes that one should not partner the amp with speakers less than 4 Ohms (I conclude nominal impedance) but in my experience all is well.

Music does not stress an amplifier the same way as Atkinson does in the lab. And while I admire some of the punishing tests he puts SOME, NOT ALL amps through, readers will also remember that he admits that some of the tests he performs requires that he stand well away from any amp he puts them through some of these tortuous experiments. Gee I wonder why and what does that tell you?

I'll bet Atkinson has seen his share of dazzling fireworks.

The 400xi could probably use a bit more heat sinking, but under "normal" listening conditions (I mean are you guys risking your hearing in excess of 90 dB routinely???) and even a tougher load, this amp seems to have no issues. I'm not gonna lose sleep over this but instead enjoy how great it sounds. And great it does sound!

Cheers!
Steve

Hi Steve,

I never heard the A21 or the A23 Parasound .. but I own the Thiel 2.4 and two Parasound Halo JC1 and believe me these amps are one of the best amps to drive these Thiels
I should give thanks everyday to Audiobroke and some other guys here that suggested me to buy the JC1s!

My cent!

Stevecham - high appreciations for your input and further clarifications of JA measurments...

However, I could not live with amp proclamed at 200/400Wpc (8/4 ohms) with a smallish 750VA transformer. Cooling devices aside...

If I were asked, I would create a Krell integrated between heavily compromised KAV-400xi and absolutely non-compromised (and insanely priced) FBI... At some 5-6k dollars, this one may be the killer...