lI have owned several Krell amps over the years and have to say this is the best I have heard so far with the possible exception of the new Momentum amps; in fairness the Momentum is a different animal. I will probably own these for the rest of my life. They are tremendously good at just about everything, they sound best on 220 or 240 volt power with a 20 amp circuit for each one or better, you cannot judge them until you feed them some serious power.

I just never think about the sound of them anymore they never stress over anything, stringed bass, electric bass, movie type bass is there anything better? Tighter and more tuneful on the planet? My MBL speakers have kind of sloppy bass to be honest and this amp tightens them up nicely, my 801N are just tough to drive in the bass but this amp makes the 15" woofer dance a like an 8". Nothing else can make bass like this except for maybe a digital amp but I don't like that sound of digital amps; it’s just effortless with the FPB750MCX. To me the mid-range is their best strength; it's not syrupy but it’s very natural, it’s pure class A with the power of god. Through the cast connection I don’t think there is a better balance than this between tubes and transistor, it’s just lovely. The treble is not quite as pronounced as say an AR but now days they are very close to each other anyways, fairly sweet and natural, extended but not pronounced or in your face. The wall socket voltage not only strengthens the bass but the voltage level can somewhat effect the treble, we are talking splitting hairs here, but the voltage can make a slight difference, too high and it can sound a little hard. In California here the voltage at times in the summer can be abnormally high 250+ volts.
The imaging through a great preamp is just jaw dropingly grand, huge with the MBL’s, I like the Krells driving the MBL’s more than the MBL amps. With these Krell amps the soundstage is even bigger, the bass is tighter, I feel like the FPB750MCX has less personality and is more neutral and musical but neither set of amps strain at all driving these speakers, even at concert levels.

Just for fun the other day we hooked some small monitor speakers with 6.5 inch woofers to them, WOW, the soundstage opened up, they could handle crazy power all the sudden and they thumped your chest, balanced in and balanced out, nothing else can do that and squeeze so much musical enjoyment out of a modest speaker.

The question is not how good this amp is and it is tremendously good, but why aren’t more amps this good? Through hole construction, 6000+ watts of transformer in each one, pure class A, CAST which was a huge bold step forward. Dan is an amazing guy to buck the norm with CAST and I know he endured a lot of crap from the industry for it, he’s an innovator and this is a perfected product thanks to his bold efforts.
MONO is the way to go with FPB amps, it’s in the details but the difference is obvious and we have had both. You don’t have to be an audiophile to hear how good and graceful these amps are, they are all about the music. They do not shove detail in your face, they do not exaggerate dynamic swings nor do they compress anything. The detail with the CAST connection is beyond or equal anything I’ve ever heard, hard to say, but it’s at the level of the Momentum amps and FM acoustics, the detail is not exaggerated it’s just all there.

It’s amazing what Dan has done with Krell and Shameful, what the investment company did to him and his family. The evolution of the products over the years is very significant from one step to the next, the quality is always outstanding. I hope Dan D’Augustino never lets all this get him down; Dan is an icon to this amazing wonderful hobby like Nelson Pass and others. Few men are so passionate in any industry, the Krell FPB750MCX was created out of perfection and passion and you can hear it! It is worth the extra effort to integrate into your house and system, it does need good (lots of) power, and it does generate heat, but like the Porsche 993 it’s the measure of everything else, it is the high standard. If it’s really all about the music, you have to listen to a pair of them and judge for yourself.

Rob