Krell FPB vs Plinius SA-103 vs Pass Labs XA60.5

Advise needed for power amp upgrade please. Current setup is Modwright 5400ES player; Aesthetix Calypso pre & Krell FPB300c power amp driving Von Schweikert VR-33s. I'm very happy with this setup; only minor gripes is a touch of hardness on a few older CDs, a bit of congestion on complex musical crescendoes and sometimes I can do with a bit more sparkle in the top-end at low volumes. Then the Krell went up in smoke! After repairs, it just wasn't the same.
I've narrowed replacement power amp options within my budget down to:-
1) Used Krell FPB400cx;
2) Plinius SA-103;
3) Or maybe I can stretch to a pair of Pass Labs XA60.5.
Grateful for advise, especially from members who have owned at least 2 of my above options. Many thanks.


You have ( or had ) a Krell FBP300c that put out 300 wpc @ 8 ohms. You say that it got congested on complex passages. The VR-33s are rated at 90DB sensitivity. If it was because it ran out of headroom, you need to know that.

The XA60.5 amps put out 60 wpc and the SA-103 puts out 125 wpc. If the FBP300c wasn't enough, will these be enough?

If it would work, I would try the Plinius first. It's reputation is sparkling, although it's not pushed like the Pass and Krell amps. I'd have one but I'm in a small room and can't take the heat.

My old XA30.5 had me sweating and was congested in complex passages from running out of steam. My KSA-50S was in a larger room, so I didn't notice the heat and I really didn't notice it being congested although it certainly wasn't the amp that the FBP300c is.

Chuck, many thanks for your input.
I really do not think the congestion is due to the amp. running out of steam. The FPB300c is rated at 300 watts steady state but is likely to be a lot more when playing music. And as you said, the VR-33s are 90dB sensitive and while I listen quite loudly, its not at excessive levels - room size is (28 x 23) ft.
I have heard some audiphiles remark that this tendency to congestion with complex music is a trait of Krell amps? Also, Krell does have the reputation for a bright edge to its sound. Having moved onto the FPB300c from a KSA150, I would say the FPB is vastly better in these respects. And I should put into perspective that my comments is really nit picking as I've been very happy with the system until the FPB300c went pop.
One other point, my inclusion of the FPB400cx is probably a case of playing safe as the FPB300c was so good. I suspect the Plinius and Pass options is probably overall better than the FPB400cx (?) though I do not know how they will gel with the VR-33s.
Grateful for your comments & advise. Many thanks.

I know that you didn't ask about any other amps, so just disregard this if you want.

I tried to find a replacement for my Spectron Musician III Mk2 in the Pass XA30.5. Although I loved the bloom of the XA30.5, it didn't work out for two reasons:

1. The heat in my small room
2. The running out of power in complex musical passages.

I went back and bought another Spectron because it's to me, hands down, the best amp that I've had in my system, and I've had Krell, Pass, Karan and Burmester amps over the years.

I run my Wadia S7i directly into the Spectron, but the reviewers all say that adding a tube preamp to the Spectron is the icing on the cake, and you have a tube preamp.

A new Spectron is only $4,000.00, and has a 30 day return policy to be sure they fit your preference. They also say that running a second one so that they're in a monoblock configuration is even much better.

I'm just saying that this might be another option, and at 600 wpc @ 8 ohms ( 1800 wpc @ 8 ohms in the monoblock config. ), they won't run out of steam. The added plus side for me is that it runs cool, it doesn't even get warm. The price of $4k for one or $8k for two is probably not above what you'd be paying for the other amps either.

Sometimes it is just the recording that is at fault.
I agree with Unsound. I have owned a 400cx for ten years now and 1) it is not bright and 2) it handles complex passages just fine with excellent detail and three-dimensional resolution.
I agree with Stevecham. I had a 400cx for a few years and did not find it bright or congested at all. The 400cx had total grip and control. Much prefered it to the Pass XA series amps that I heard, but that's my opinion. I recommend listening to Pass and Plinius before switching away fom Krell.
Solentgreen, what cables are you using? I had 3 Krell amps, KSA100S, FPB300 and FPB600 and found MIT ICs and SCs worked best. Some cables such as Nordost can make them sound thin and harsh. I don't like Krell pres and have always mate them with tube pre.

What tubes are you rolling in the MW 5400ES? I had a MW Transporter and you can improve congestion by rolling TS NOS 5u4gb and BT CV-181 ... my favorites.

I'm sure you know PCs can help the congestion problem too.
60 watts of class A is totally different than 60 watts of Class A-B or D. Ask Pass Labs, they say 60x5=300. But I had much more drive with these mono's compared to my older MF Nu-Vista 300 power. Which was modified. Gave more than 2x 350 watt by 8 ohm. Pass labs gives a more deep and wide stage than Krell does. It will be all about personal taste. Some people prefer Vanilla ice over Chocolate ice....
Thanks guys for all the comments & advise.
Chuck, I will look into the Spectron, which I think is a class D amp? I have to say my first audition of a class D amp (a Linn) was not so favourable; the sound was clean & clear but a bit sterile. But then the Spectron may be different.
Thinking about it, Unsound's idea that the congestion may be in the recording is probably correct, as not all CDs had this problem. It’s a nice surprise in a way to see so much support for the Krell option; after all I really enjoyed my time (almost 8 years) with the FPB300c; it’s a safe known option and the 400cx should better the 300c.
Knghifi, my signal cables are Pure Note Vanguard from player to pre-amp; Pure Note Alluvion balanced from pre to power amp, and VH Audio Chela speaker cables. Power cords are a Virtual Dynamics Master from the wall to a Hydra 8 conditioner. Then a Lessloss DFPC to the Modwright player; a Black Sand Silver Reference Mk V to the Modwright power supply and another one supplying the Calypso pre-amp; and a separate Virtual Dynamics Master from the wall to a separate Hydra 2 conditioner used solely for the FPB300c. None of these cables are to my knowledge bright or thin. I also extensively use Herbies supports for all components and speakers.
As for tubes, I am using Sylvania 6SN7 GTB valves in the Modwright 5400ES, and a Create Audio 5AR4 rectifier tube in the power supply.
At this point, I really should emphasize that the issues I raised re congestion and brightness are very minor and in the main are only from certain CDs. As Unsound said, more than not, its an issue with the recording rather than the system that we are talking about here. Remember prior to the FPB300c going up in smoke, I was very happy with the system and had no intention nor inclination to upgrade. Its just that I am forced into replacing the 300c as it was just not the same after repairs.
It will be great to get some advise from Plinius and Pass Labs users though before I decide; any of you guys out there? Especially those who might have done comparisons with the other and also Krell FPB power amps? Many thanks.
Solentgreen, If you go with Krell, get the monos and smearing problem will improve further.

I would also checkout Evo series. I find the darkness improved from KSA to FPB and I heard it was further improved in the Evo series.
I have owned a Krell FPB 300cx for more than 10 years. I am astonished to hear it becomes congested on complex passages. This is something I never noticed, and I listen to a fair amount of claasical music. Also, whatever hardness may have been present in the "c" generation was eliminated with the "cx." So I would go with the Krell. Have not had anything but stellar performance from the day it was delivered and installed in my system.