Suggestions needed for an SS Stereo Amp w/+175wpc

I am currently using a Sonogy Black Knight MkII with my KEF 105.1's. Solid state dynamics with the performance "air" of tubes.

Mapman, Bob, Maddoggy, and Butcherboy,
Thanks for your responses and recommendations.

Bob, I am not an expert. I was under the impression that one of the benefits of having a lot of power improves dynamics. (Of course, if it's not on the original recording, that's another story.) Also, I have been following the discussion on the thread re Ohms over in the Speakers forum, and I seem to recall that the Ohm's perform best with a lot of power. This was the basis for my statement. My musical taste is very broad-I enjoy almost everything but rap. Also, I do not not listen at very loud levels, except for some rock (The Who, Led Zep., etc)

Dante,

I believe it is true in general that you need more power to make the OHMs sing, but there is more to it tha that. Not all watts are created equal nor are all OHMs equally power hungry (though they are largely as a group). Some additional qualifications are needed

Here are the technical factors I know of that matter in selecting an amp for the OHMs:

1) input impedance. This is more of a factor with tube preamps which tend to have higher inherent output impedances in general than SS. Lower amp input/preamp output impedance ratios will theroetically tend to negatively affect low end (bass) performance and perhaps other areas as well. How much difference you might hear based on this spec alone is debatable, but higher is generally safer

2) watts. In general more watts will go louder but that is about all this alone assures.

3) amps - in general higher current delivery will enable the amp to take better control of the driver at any listening volume enabling better macro and microdynamics

4) efficiency/power delivery into 8 4 and perhaps even 2 ohms (power rating mostly doubles into these loads). Amps that do this better in general should be able to drive the OHMs consistently at various frequencies and deliver a more balanced sound even at lower volumes

5) Damping factor. This is the similar impedance matching issue but now from amp to speakers. Higher damping factors are generally considered better. If it were me I would avoid amps with less than 30:1 damping factor into 8 ohms unless there is an opportunity to listen first. Above this, I would not let this sway me, although in general higher damping factors should lead to tighter, more controlled bass, all other factors aside.

6) I have the biggest and hardest to drive OHMs (5s) and the smaller 100s. My Musical Fidelity A3CR amp at 120w/ch into 8 OHMs deos a very good job driving both, but has to work much harder for the 5s. In a good application (OHM is matched well to room size), I think there may be diminishing returns with 100s with more powerful amps than what I already have. I believe the larger OHMs in bigger rooms, like the 5s, can benefit from an amp that can deliver a well matched 250w/ch or even more.

BTW, I've had the big OHM5s in my smaller room where the 100s normally reside as an experiment and found no advantage soundwise there. In fact, the 100s worked better because they are smaller and had more room to breathe. Fitting the OHM to the room correctly is the other very important thing to consider beyond amp selection and such.

Hope this helps.

"In general, I'm a fan of more watts. They just don't help at low volume."

Agreed.

#4 above (efficiency into 8, 4 and perhaps even 2 ohms) is the main factor I have found that makes the biggest difference in regards to sound quality at lower volumes. You might not hear much difference at low volumes between a 60 w/ch amp and a 250w/ch amp at low volumes if they both do this well. #2 (Watts/Power) is probably the one factor out of these that is not a significant factor at lower volumes. Everything else can make a difference I believe.

BTW, I checked the specs on your Arcam amps, and it appeared to me that you can do much better in this regard as I did as well in my case, only in your case you might not benefit from more than 120w/ch, unless your goal is to go louder and cleaner than currently as well.

In my case specifically , I found my current 120w/ch Musical Fidelity A3CR does low to moderately high volumes (at which I mostly listen) much better than my prior 360w/ch Carver m4.0t, and the difference can be heard with all my speakers (OHM 5s, OHM 100.3s, OHM Ls, and Dynaudio Contour 1.3 mkIIs) which is why I made the change to 1/3 the watts I had prior. The Carver definitely went louder and sounded good loud, but that was it. The A3CR only cost me $600 used and was worth every penny.

Now, my goal for my next amp, primarily for the benefit of the big OHM 5s in the bigger room, would be to get back up to or past the prior Carver's power levels but with an amp that can do the other things that matter at least as well as the 120w/ch A3CR. That in theory would put me in the best position I can be in at all volume levels, from lowest to highest, even with the OHM 5s. I'm thinking the difference with the OHM 100s in the room they are in will be more marginal at best, but we'll see. First, I have to convince myself to spend more money to improve the sound of a system that is already floating my boat just fine in most every regard these days.

Also remember that technical specs and optimizations alone still do not tell the whole story nor guarantee good sound. Different amps will still sound different or have their own distinctive sound. These are just the technical issues that you can control that if done will put in in the best position to reap maximum performance out of your system overall. Some amps may still sound bad and some good. Some of that is real and some is a result of individual preferences.