NHT 2.5i Amplification Questions

Discussion in 'Archived Threads 2001-2004' started by Justin Schneider, Aug 26, 2002.

  1. Justin Schneider

    Aug 25, 2000
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    I've been bitten by the upgrade bug recently and a have a few questions about amplifying the NHT 2.5i's.

    Currently the are powered by a Parasound 2200II, which puts out 250 watts to each speaker. I've come across a couple of NHT SA-2 amps for cheap that I've read work great for biamping the 2.5i's. They are rated at 120 watts. My questions are:

    1. Would it be overkill to power the subs in the 2.5i's with the SA-2s and the mid and highs by the 2200II? This seems like a lot of power for the speakers, but I've read NHTs thrive with lots of power.

    2. What about the difference in power between the SA-2 and 2200II? Will the sound be unbalanced as the highs/mids will be getting more power?

    Any suggestions? Has anyone played around with a similar setup? Thanks for the help.
  2. Bob Ahlberg

    Bob Ahlberg Agent

    Apr 29, 1999
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    well, having owned 2.5i's for 6 years, I can respond to this. You will probably reap just about as much sonic benefit from biwiring them with good cables as you will biamping them in the manner you suggest.

    What my experience has been with biamping is that you will pick up a bit more width and depth in the soundstage. This is true only if you are able to match the amp outputs very closely so the woofer amps are putting out the same power as the mid/hi freq. amp. If you can't control the output of either one of the amps or another, you will actually lose sound quality and coherence of soundstage.

    By using a smaller amp on the woofer portion, you will limit the output of your system to whatever you can cleanly produce out of the woofer amp. BTW, the bass line usually takes alot more power than the mid/hi freqs...so you have that to consider as well.

    Your 2.5i's are fairly revealing of the quality of your source .... both in terms of amplification and your cd/dvd player. Pair them with good amps and they will overachieve. Your parasounds sound match well with them. I like tubes and found that that a tube preamp with a smooth solid state amp is a very happy pairing.

    my .02
  3. Will Gatlin Jr

    Will Gatlin Jr Stunt Coordinator

    Mar 7, 2002
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    I bi-amp my VT-2's (front&rear) with 225 watts to the highs and mids, and 250 watts for the lows. The bass is not as boomy, and the mids really stand out like new money. I would try and get the amps closer together (power wise). Good luck!!
  4. Haru

    Haru Stunt Coordinator

    Aug 9, 2002
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    In the last 7 years, I have owned 18 NHTs of various types.

    I do not have golden ears and I see no advantage with fancy cables, nor any influence of an adequately powered, competently designed amp on the nature of the sound of a speaker. I can't say anything about anyone else's expereinces, but I will tell you what I would do. I would continue to drive them with the Parasound and forget about the SA-2.

    The simple fact of the matter is that the SA-2 is a very worthwhile addition if your regular amplification is limited in quantity. But the parasound is NOT limited. It does not need the sort of assistance that the SA-2 can give it. Now, if you had a 100-150wpc amp that could be used to drive the upper range units while the Parasound drove the bass units, there might be some benefit, IF you used a pre amplification crossover. But, frankly, I probably would not even do that. The 2.5i simply does not have a bass section that can use such superb amplification as the Parasound to any better effect that it could something more modest.

    In short, it is my conviction that the Parasound is a good enough amp that it can drive the 2.5i as well as the 2.5i can be driven. Short, there is no point in buying 5 gallons of milk, if your container can only hold 2.

    Speakers maybe capable of being bi amped, but bi amping is only beneficial if your amps individually can not drive the speaker to its best advantage. the Parasound you have can drive the 2.5i as well as it can be driven. A single Parasound 2200 is already more than enough amp than the 2.5i needs.
  5. Mark R O

    Mark R O Stunt Coordinator

    Nov 2, 2001
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    The advice from Bob, Will and Haru is solid. We currently use 2.9's as our HT mains. The upgrade that has by far made the greatest impact overall was the addition of an NHT SUB TWO subwoofer.A great piece both musically and for films.
    Should you do the same, you will significantly increase your amplifiers "percieved" power capability, plus add bottom octave reach that the 2.5's could never hope for alone. I've seen the SUB TWO used for as little as $400.00 on Audiogon. You'll be stoked with the combo.
    Bi-wire your 2.5's with a respected cable pair.(This will increase your amp's output to about 400+). Try tilting them backwards about 5 degrees too!(The soundstage and midrange will change considerably) If there is no danger of them being knocked over(kids, etc.), lose the crossbars and spikes and put metal cones on the bottom for feet!
    If you have'nt already, measure speaker placement with precision. Small adjustments yield big payoffs. And of course, no grills!
    Listen to Haru, and blow off the SA-2's.
    I too have used Parsound amplification, excellent results for not much money. But by far the amp of choice IMHO is Sherbourn. If you ever get a chance to try a set of mono blocks (or the 5 channel if need be) you will be amazed.
    Have fun playing and listening!

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