Polk L800 and First Watt SIT-5
chatra
Posts: 6
I recently discovered the First Watt SIT-5, a true single-ended Class A amplifier rated at 65 watts into 4 ohms. While it may not be a powerhouse, I am interested in how it performs with Polk Audio L800 SDA speakers at typical listening levels. Has anyone used this amplifier with the L800s? Based on its specifications, it appears well-suited for the SDA. I currently use a Parasound JC5 A/B amplifier with these speakers and am considering whether the Class A single-ended design would provide a noticeably better listening experience.
Comments
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The SIT-5 is a monoblock amplifier at around $11K a pair. I haven't experienced that First Watt model myself but I'd agree that on paper they'll drive the L800s fine. Whether the experience will be better with the L800s than with a different amplifier will be an ear of the beholder kind of thing. The SIT-5 should sound different than the JC5. Having sufficient power isn't a significant concern with the amps even though the L800s are not a high efficiency design. I have a JC5 on mine. The first 12 watts or so is Class A before switching.
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Good point. I already knew about the Class A wattage for the JC5, but I wish Parasound had added an LED to show when it’s running in Class A. Maybe it does, but when I got the JC5, I just set it up and started listening. From what I’ve read, the SIT-5 exhibits distortion similar to that of tube amps. Since it’s a single-ended amp, it pairs well with the Polk L800’s SDA technology. You could say the SIT-5 was made for the SDA crossovers in the Polk L800s, except for the high-power recommendation. Based on the specs, the First Watt SIT-5 seems like a great match for the SDA crossovers, and it runs fully in Class A. The Polk L800 is recommended for 50 to 300 watts, and the SIT-5 puts out 65 watts into 4 ohms from a single-ended amp. I think this amp would be a great fit for the L800s if you listen at normal volumes, and maybe for older Polk SDA models too. The real question is whether I prefer the sound of the JC5. I think I would, but I want to find out more about the SIT-5 with Polk SDA. I’ve read that the SIT-5 does really well with jazz, opera, and orchestral music, but not as much with rock or country.
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There is also Class A push-pull, you know? It also offers freedom from crossover distortion. Class A PP can sound very, very good.
Single-ended amplification:
1) Operates in Class A by definition
and
2) For better or worse, does not cancel out even-order harmonic distortion, whereas push-pull does.
SE vs. PP is an age-old debate, but low-order, even-order harmonic distortion sounds good, whereas low order, odd-order harmonic distortion sounds bad. ... and higher-order, odd-order harmonic distortion sounds even worse.
The so-called second harmonic distortion product of a "fundamental" pure tone (note) is exactly twice the frequency of the fundamental; i.e., exactly one octave higher in pitch (frequency). This sounds pleasant by definition. Consider a four note "chord", where the fourth note is an octave above the fundamental. The C-major triad is C, E (the major third), and G (perfect fifth)... then add C an octave above for the four part harmony. Try it on a keyboard.
I.e., the issue of SE vs. PP ain't quite a trivial one, operating class notwithstanding.
I'd probably recommending getting some high-quality ears-on listening time before plunking down $11k.
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Steve Guttenberg did a, rather long-winded, review of the SIT-5 amps earlier this year. He did use them with a range of speakers from high efficiency to low efficiency older Magnepans.
https://www.youtube.com/watch?v=ongk4CApoKs
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I would like to hear that combination.
