Review: Krell FPB-700cx Amplifier

Category: Amplifiers

It was a puzzling realization when it occurred to me that my speakers and amp cost almost as much as the rest of my system. Since I have been a proponent of starting at the source and working back, I expect to take some abuse. Although I might argue that I wasn’t starting, I was upgrading my weakest link. I didn’t think that would work.

I have owned four pieces of Krell gear over the last several years and have been happy with each of them in their time. I guess many readers tuned out after that sentence. I had two pre-amps, and I am now on my second amp. I started with the Full Power Balanced series so I can’t really address the “Krell Sound” issue of the earlier amplifiers.

The Krell FPB 700cx is currently the top of the line stereo amp in the Class A series. They do have another series which, if you can believe it is much more expensive and supposedly, much better.

The first surprise I experienced was lifting the amp out of the shipping truck, and into my truck. It is a job for one large strong person, or two people of average size. With the shipping box the 700cx weighs in at 200 lbs. My son was less than excited at the prospect of helping me wrestle it into the basement listening room. This was not to be my last surprise.

The shipping material is very good, and Krell designed to amp to be easily removed from the carton. Okay, as easily as any 180-lb. amp can be removed. Keanen and I wrestled this monster out of the box and into position between the speakers. The power cord is semi-permanent so it is still in place. I connected the amp to the system via a 9 meter pair of Purist Venustus balanced interconnects.

Cosmetically the FPB 700cx is much different than the FPB 200. The face of the amp in no longer flat as it has been since Krell released their first product. The amp looks much nicer, and can I say, more expensive.

The entire line was redone cosmetically when the CAST series was developed. Since I do not use a KCT pre-amp, I cannot use the CAST technology, but my understanding is that it works very when to transfer the signal in the current mode.

I know that no amp is going to be anywhere near peak performance right out of the box, but who among us has ever started running pink noise, or a burn-in CD without listening first? Oh you liar! The amp had obvious potential. Soundstage was small, and lacking in inner detail and clarity, bass and treble were both thin, and rolled off, but it still sounded pretty reasonable. For the next three days I alternated between brief listening sessions and running the new Purist Burn-in CD 24 hours a day. Purist claims that the new CD works twice as fast as the older model, and based on what I heard after three days I would have to agree with their claims.

On Saturday, four days after the amp arrived several friends and a couple of acquaintances arrived for a ‘listening session.’ We are trying to organize a Northeast Wisconsin Audiophile Society, but that’s another thread! Comments began to flow almost immediately. The first was, “This wine is a little too sweet for my taste.” He was right; the wine wasn’t very good, so we moved on to another bottle. People seemed to settle down after that. We took turns listening to the music people had brought with them.

Greg has heard my system a lot of times was suitable impressed. He even commented that he heard things that he did not hear at home. Other things mentioned where the increase in soundstage size, and detail, but everyone seemed to come back to the increase in the bass level. Since I had not had much time to listen on my own yet, I did not argue with their assessments.

Over the next few days I formed my own opinions, but they did not differ much from what my friends had said, although I think they are more in- depth than what had been said during that session.

Upgrading from an FPB 200 to the 700cx doesn’t seem like it should be as dramatic as it turned out. The 700cx isn’t just bigger and heavier, it is completely different. Sure the bass goes a lot lower, and is considerably more fleshed out, but there is a lot more than just that. The midrange is so clear that sounds and images seem to float out of the speaker rather than being driven.

The Krell/Kharma’s do not have the most liquid midrange I have ever heard. That award went to a pair of Revel Studio’s being driven by Levinson electronics. I still would not trade the Revel/Levinson combo for my Krell/Kharma since the latter just does too many things right, or better than the former.

Krell has been accused of making bass heavy and overly bright sounding amps in the past. I did not hear any of that in my room. The treble was grain free and smooth, never shrill. I have yet to turn the system of because I found it fatiguing. I have to admit I have been resentful of other priorities that forced me to stop listening when I still wanted to spin just one more LP.

My biggest priorities when listening are ‘pure midrange’ and a palpable soundstage. I will give up the lowest bass registers to get better midrange, and a solid soundstage. The Krell offered me not only great bass, and smooth treble, but the midrange I demand, and soundstage with height, depth, and width, full of detail and air.

One of the first LPs I used after the amp had been running for a reasonable period, was the new Norah Jones on 180-gram vinyl. When she began singing “Sunrise” I had the idea that there was air in front of her, and behind. She was singing in a definable space rather than just floating somewhere between the speakers. I joked to Greg later on the phone that I could almost tell what color dress she was wearing.

Driving in neutral
The 700cx has less sonic signature than any piece of electronics gear I have ever owned. I hear more of the source, and less of the amp, than I did with the FPB 200. For those who have written off Krell equipment because of the claims of others, or even experience with the ‘Krell Sound’ you really need to listen to this amp. It is unlike anything I have ever heard. I have had my Sota Star Sapphire/Rega RB 900/Benz Glider, and my Sony SCD 777es for a number of years. I have always been happy with them. Since adding the Krell FPB 700cx, I can’t help but wonder what better sources might sound like in my room.

I am self-employed and anything but wealthy. I save up money to buy my stereo equipment. If I don’t have cash the purchase doesn’t happen. I did borrow money to buy my speakers though, but anyway… The Krell FPB 700cx costs $14,000. I paid $50,000 for my first house, for cryin’ out loud!!! Is the amp worth what I paid? In a word, yes. Any purchase is going to be a personal thing, and there are going to be even more people who think I’m stupid after reading this review than there were before, but this amp does so many things so well that it demands attention. That kind of quality costs money to build.

So you have one of two choices: either start saving, or start arguing!

Associated gear
Click to view my Virtual System

Similar products
Krell FPB 200
Cary V12 monoblocks
Aragon 8008st
Thanks for the review. I'm especially interested to hear your comments on the midrange quality and the non-fatiguing nature of your setup.
You said:

"Soundstage was small, and lacking in inner detail and clarity, bass and treble were both thin, and rolled off, but it still sounded pretty reasonable."

What do you consider reasonable?
The point was that it showed potential based on the performance of the FPB 200.
Nrchy: you know I'm a fellow Krell fan and fellow audio cynic, owning both the 400cx and the KCT connected via CAST. I've gotta a very strong predictive sense that if you were to put a KCT in your system and connect it via CAST to the 700cx you would realize sonic nirvana that you have not realized with this very, very fine amp. There's a good reason Dan engineered it this way and synergize with their pre; to configure the 700cx any other way just doesn't allow it to provide its full potential. Like I said, I've gotta strong hunch (based on my experience) about this..My .02 anyway...enjoy!
Steve, I've wondered about this, and have considered going to the KCT, but I'm so happy with the Krell/Klyne right not that I don't know that I need to change now.

Ultimately I plan to go another direction with my pre-amp anyway, so adding the KCT would only be placing another step in the way of the larger goal.

Don't think that I am disagreeing with you though. In the short term I would be looking more at my front-end rather than other gear. I sure like the FPB 700cx!
Get the KCT and call it a day...none better all things considered. I had the 400cx wt the KCT and it is transforming...I REGRET GIVING THE COMBO UP...ALOT!!!
I believe that Nrchy no longer has those 700cxs...correct?
No, I sold them to Squidboy about nine months ago. I replaced it with a Classe Omicron. Wow it quite an amp! You have a good memory Steve!
That Classe amp is quite something too. I remember being at the Montreal audio show back in 1998 and there was a room with Omegas powering Puppy 5s with ML front end pre and cdp. That was the closest yet I have heard to live music. Of course they had treated that hotel room to the nth degree.
Hi, this response might come in late, but perhaps "better late than never" should count? ;-)

I don't own a 700cx but an FPB-200c driving my nutty/naughty Sonus Faber Concerto Domus, a 2-way floorstander that seems power hungry it "sort of" killed my Sonic Frontiers Power 2 @ 110WPC!

I was ampless for a couple of months so i bought an integrated amp - and then the FPB came along: i simply forgot i have an integrated, and connected the 200c - MARVELOUS! Exactly what i wished my system would sound in a fairly large (20sqm) but low (attic) listening room.

In my condo, the Domus sounded "OK" with the Power 2, but now the Krell made it sing pretty well... and like what youe said, "the music just floats" - it's feels almost like i have a surround system, especially when i'm playing movies soundtracks via CEC CDP.

But via analogue playback... i could cry in happiness.

I can relate with you, in a way, although my amp was your starting point; for me this is "it"... for the next 10 years (hopefully).

I am fully settled with my analog playback (my digital is simply for background music when i am working), my Sonus Faber Concerto Domus (anything bigger is too much for me), and my Sonic Frontiers SFL-2 preamp. The rest of my system are simply icing.

Thanks for an encouraging and admireable post ;-)

Best wishes from Manila!
Egay .e.
I suppose the op back then did not know what he was doing, running cast is good, If you really want to hear this amp sing?, I recommend some Taralabs zero gold i/cs, omega gold speaker cables, this is what I did, the most profound amp you will ever hear useing the correct cables! Happy listening!