Paul McGowan writes: I was going to step off into the deep end this morning with the start of our cable series but many of you asked about the results of the latest amp shootout so I thought I’d give you a brief update on that progress.
The quick overview is that we made significant progress, but we have a ways to go. That’s pretty much how it seems to go on most of these projects.
The good news is that the amp has tremendous bass, midbass and midrange – something many power amplifiers never achieve – so I am pretty happy about that (of course, I knew that going into this). What it still lacks is the top end openness and, while we’ve made progress, my guess is that no amount of tweaking is going to get what we want. More drastic measures are perhaps in order.
Before rebuilding Music Room One, we relied for a long time on the great Magneplanar loudspeakers. The one problem I had with the Maggies is their lack of high frequency extension – something you just never quite notice when you own them – but something that becomes quite clear when you get a system that does have this extension. Without this extension a power amplifier lacking in this area doesn’t standout as lacking at all – in fact, it sounds quite natural – and you simply get used to that sound. This is why I never really noticed the lack of upper energy in the amp design – something painfully evident when compared with an amplifier and system that has it.
The new system in Music Room One has the capability of upper energy extension and will serve as a perfect design tool to hear what’s happening – or in this case – not happening.
The net result of this lack of extension can easily be heard in the pluck of strings, the strike of a cymbal or the knock on a wooden block in a piece of well recorded music. The pluck of a steel string sounding more like a quickly plucked taught nylon string, the cymbal strike having the body of the cymbal correct and full but lacking the upper shimmer and ringing cymbals have and the wooden block sounding more like a metalic block – when missing this upper energy.
Often described as a lack of rise time or transient attack I am not sure that has a lot to do with it. I have heard this extension properly presented on a tube amplifier whose frequency response is down a dB at 20kHz and, on the other side of the coin, missing in a power amp who’s flat to the same frequency. Even square wave response can be identical as well.
Tomorrow I’ll tell you what we did to get the improvements in this very area – improvements which, unfortunately, have yet to give us as much open upper energy as we need.