mike c said:
1) we dont have returns here ...
2) in your opinion, will my movie watching benefit from a separate amp
Hi Mike,
I can't say whether there would be enough difference to make it worth the additional cash for you... but it did (and still does) for me. Some of it will depend on your speakers and room, some on your choice of movies and music, and some on the associated equipment.
My first home theater system was based upon a Marantz SR-4200 receiver (70 watts per channel). At the time I had two pairs of speakers in the house, and decided that I’d build a surround system around one of the two. I had a pair of Klipsch Forte’s and a pair of KEF Q75’s. Both of these speakers are efficient, and neither is seemingly a difficult load. The Forte is a 96dB (1 watt/1 meter) speaker with a nominal 8 ohm rating. The Q75 is a 91 dB (1 watt/1 meter) 6 ohm nominal speaker.
With 96 dB sensitivity and an 8 ohm rating one would think you could use pretty much any amplifier with the Klipsch Forte’s. This, however, is not the case. Apparently, in order to match the output levels of the midrange and tweeter drivers (those horns, you know) to the 12” woofer, Klipsch used a transformer in the crossover circuit. Transformers are inductive by nature; which means that while the amplifier doesn’t have to have a high power output, it does need to be able to deal with a very difficult load caused by the inductor’s presence. Using an inexpensive receiver with these speakers is entirely the wrong approach. What’s needed is an amplifier that can deal with difficult loads without any problems. Not high power… high current… or at least a design that has “grunt” as I call it.
Therefore, my Marantz receiver/Klipsch experiment failed miserably; muddy, tubby, and generally unappealing sound was the result. Luckily, the KEF’s sounded very nice with the Marantz, which allowed me to begin building my home theater anyway.
My point, however, is that impedance and sensitivity are not the only parameters in the speaker/amp interface to be concerned with. Phase angle and inductance must also be taken into account, at a minimum.
After several months of enjoyment with my new system I wondered how it would sound with a separate outboard amp instead of the internal amps in my Marantz receiver. Not that it wasn’t loud enough… just that I wanted a more dynamically realistic presentation for both music and movies. Therefore, I grabbed my battleship amp (a Harman-Kardon Citation 22) which is rated at 200 watts per channel.
The difference was obvious (to both my wife and I). Not as great as the difference between the Klipsch and KEF speakers of course, but significant none-the-less. Even with the relatively mild-mannered KEFs there was greater dynamics and impact, greater detail and clarity, greater growl in the bass, better low bass extension and accuracy, and overall, a much more lifelike and exhilarating presentation. This was true both on music and watching movies... though admittedly some albums and some movies showed the differences more clearly than others. And where the Marantz wouldn’t play nice with the Klipsch Forte’s, the separate Citation amp made them sing!
Now I truly understand that not everyone wants to spend the additional money for a separate power amp. Not everyone wants those extra boxes hanging around. Not everyone seems able to hear a difference, or the difference just isn’t great enough to warrant the expenditure for them. But there is a difference; and in my opinion, for the better.
For me, it was indeed enough to warrant the cost. YMMV
