Krell FPB 600 or 400cx?

I have owned several Krell amps and pre-amps. I love Krell performance, sound, looks and buld quality. Never had a problem. They really know how to build amps and preamps.Love their products!

I agree, Krell monblocks definately sound better than their stereo amps. I have A-B'd the Krell 750mcx (stereo amp) with the Evo 400 (stereo - not the e series). They are very very close. They both sounded great. I had great difficulty picking one over the other. The Krell MCX amps are superb, especially the monoblocks and the big 750mcx. I think the MCX amps sound much better than the prior generation Krells. I love my Krell Evo 600e's, but I also loved the 450mcx. They are great, great amps.

I have owned Krell equipment for many years. I currently have two Krell Evo 600e's and 2 S-275's and the Evo 707 processor. The amps and the processor are superb. I have never had a problem with Krell amps. I have had a few quirky functional issues with the Evo 707, but Krell has been incredibly responsive and it now functions perfectly. The Evo 707 sounds so good it was worth the minor inconvenience while they ironed out a few minor issues with HDMI handshakes. I love the build quality and the performance of my Krell equipment. The 600 model is the generation before the 600c. It does not have cast capability. I owned the 450MCX (extended frequency range)a few years ago and loved them. I have A-B'd Krell's mono to stereo amps and easily noticed an improvement in 3-dimensional sound staging and instrument seperation (air) with the mono blocks. I felt the MCX (450 MCX)generation high frequency reproduction was brighter (in a good way) and more pristine than the earlier generations (which tend to be a bit on the dark side). The 450 MCX also did a better job on transients. If you can find a pair of reasonably priced 450 MCX (monoblocks) in excellent condition, you should buy them. They will perform better than the two pieces you are considering. They are great sounding amps. If you do not match up with equally high end pre-amp, you are wasting your money.

I am using two Krell Evo 600E monblocks for R/L channels with music and home theater. The Evo 600e is a stunning amp. I use two Krell S275 amps for home theater only. One S275 amp is used to bi-amp my center channel speaker (my processor has 2 center channel outs) and the second S275 for the two surround channels. The S275 replaced my Krell 3X250 amp. I use cast for the 600E's, balanced connections for the S275's. The S275 is a much better amp than the 3X250 Krell. Since I don't use them for music, I don't have a feeling for their ability to create a 3 dimensional sound stage, dynamics, tight bass, transients, speed as I do with the Evo600e's. I have had no problems with the S275's, I like them very much. They are dead quiet and they provide more power than I need. They probably perform much better than the small Krell 150 monoblocks, which recieved very positive reviews. They are compact in all dimensions except for depth and weigh 50lbs each. The S275 is very nice, but it is not in the same class as the evo amps. If you plan to use the amps for music only and you don't want to pay the cash for a new Krell EVO e series amp, I advise looking for two Krell 450 mcx or 650 mcx monoblocks. I owned the 450 mcx's and loved them. They are great, extended frequency range amps (fast, detailed, 3 dimensional sound stage, great instrument seperation, nice highs, great tight detailed bass). They will not fit into a rack as well as the S275. You should be able to pick them up for a great price if you can find them. But keep in mind, you need a very good preamp and/or processor with the high end amps to get them to sound their best. I think the pre-amp/processor is every bit as important as the amp, if not more important. Hope this helps. Good luck.

I lived with the 450 MCX for several years. When I exchnaged it for the Evo 600 (now the Evo 600E) I did not notice a significant difference (I didn;t A-B them at home). Midrange,bass treble all sound great with both amps. Both have excellent 3 dimensional sound stage, instrument seperation (air). My dealer felt the treble was a bit more prestine with the Evo amp, but I am not sure that I agree. The sound is too close to compare without direct A-B. My A-B comparison at the store was a Krell Evo 400 stereo amp A-B'd to a Krell 750MCX stereo amp. The sounded very similar. i guess it is impressive that the smaller evo 400 could match the 750MCX. T really had to strain to detect a difference. I would not trade in the MCX for the evo amps unless you get a great deal. Both are superb. The thing that made a huge difference in audio performance in my hifi was changing my Krell KCT pre-amp and Lexicon MC12B processor for the Krell Evo 707 processor. This made an obvious enormous improvement in all aspects of audio both for music (2 channel stereo using the pre-amp bi-pass in the Evo 707) and for home theater. I noticed it immediately, no AB comparison was necessary. I have been involvrd in this hobby for over 30 years. Upgrading to the Krell Evo 707 is by far the single greatest upgrade I have ever done. The 707 uses a pre-amp section very similar to the preamp used in their top of the line Evolution 2 (retails for $55,000)in all channels. The sound is absolutely stunning. The Evo 707 is amazing, it completely blows away the Krell KCT and the Lexicon MC12B.

If you have a good Krell dealer, between trade-in and discounts, you should be able to buy the 707 for much less than $30,000. $30,000 is a lot of money. On the other hand, compared to the evo 2, which retails for $55,000 for two channels, the 707 could be viewed as a 'bargain' since it has almost the exact same preamp in all channels, along with the processing, EQ, video, etc. The improvement over the KCT (which I used in CAST mode and is a very good pre-amp) is enormous. I was shocked. Better instrument separation (more 'air'), better 3-d sound staging, faster, better dynamics, better transients, much better tighter (more accurate sounding) bass, more detailed but with an analog tube like bloom. The Evo 707 produced a more beautiful, life like sound. This also applies to replacing the Lexicon for HT use (I used the Lexicon for HT, the Krell KCT was used for stereo music).
Krell does have a less expensive pre amp/processor, but I have not heard it. I doubt it sounds as good as the 707.
What are you using for a pre amp/processor?

Ben,
CAST technology was developed by Krell and used exclusively by Krell. Krell has an excellent explanation of cast on their website : www,krellonline.com/cast.html

My understanding of CAST: all electronic audio equipment operates in current mode. The electronic current is converted to voltage, transferred by cable to the next piece of equipment where it is transferred back into current, modified as necessary, converted back to voltage, transferred by cable to the speakers. Everytime the signal converts from current to voltage and back to current some distortion/noise can occur. Krell CAST equipment uses an extremely high frequency bandwidth (>2 MHz) and transfers the signal in current not voltage. This eliminates distortion that can occur durring the conversion from current to voltage (and voltage to current). Also, Krell claims that since the signal is transferred along their special CAST cable as current rather than voltage, there is no signal degradation effect produced by the cable. They claim, with CAST, the signal remains unaltered from source to speaker. I believe the Krell amps ending with C (400C, 600C, etc) were the first generation Krell amps to use cast. They have CAST in their high end amps, processors, pre-amps, CD/SACD players. I believe the Krell KCT was the first pre=amp with CAST.
CAST is very interesting, innovative technology. It is a great idea. Does it work? I have never A-B'd to compare. Reviews state that it does make a significant improvement. My guess is that it probably does make an improvement. No one else has CAST, Krell owns it.

The S275 does not have CAST.

I don't know anything about the PS Audio DAC/pre-amp. Do you like it? It probably will be fine with the Krell S275.
The Krell 150 mono blocks probably sound very similar if not identical to the S275. But the S275 will give you more power. The choice probably depends on the speakers you will be driving.

Once you get into the 450MCX, Krell KCT level of equipment, things like cable (Krell CAST cable, etc) become important considerations, also, more expense.

SFSTEREO:
The pre-amp section for stereo music in the Krell Evo 707 is fantastic; far superior to the stand alone Krell KCT pre-amp I owned previosly. If you are able to audition one for music, make sure to go into the menu and sslect pre-amp for the CD player and/or record player. This bi-passes the digital processor. The Krell Evo 707 is an amzing piece of equipment. The sound is extraordinary for home theater and stereo music. I traded my Krell KCT and Lexicon MC12B when I bought the Evo 707. I cannot say enough about the Evo 707, you have to check it out.
Good luck.

Matti,
I don't understand what you are trying to say. Please elaborate.