Congratulations, you've discovered Nelson Pass. As mentioned earlier your amp is using his earlier design that was licensed to Nakamichi. There is a nice upgrade path from his later designs when you are ready for an upgrade.
Nakamichi PA-5 driving NHT 2.5i
Thumbs up to this combination.
I have tried to power the relatively demanding NHT (86db, 3.6ohm lowest impedance) with different units which i thought were "good value": Acurus DIA-100 (100wpc), Carver Premiere AV-705x (185wpc in 2-channel), even CJ Sonographe SA250 (125wpc). The CJ came quite close, but I have always felt that something's missing - the voices would turn harsh at elevated volumes, the bass was emphasized and muddy (to my ears). Based on other feedback on NHT i kept thinking that it has to do with room placement (sure enough the bass output can be tuned with room placement, but could never get it to clear up).
I even wanted to sell the 2.5i - with the intent to get something "less demanding".
Boy am I happy i didn't.
In comes PA-5 which i got because it was "too good to pass up". Did not think I would actually need it... First I hooked it up to power the tweeter/midrange drivers of the NHT 2.5i while keeping the Carver for the subwoofer. The highs cleared up nicely, but the subwoofer still felt somehow underpowered and muddy. Oh well - room placement, I said, but on a whim i removed the Carver and hooked both posts to the PA-5 only.
And I was in for the most pleasurable surprise.
Gone were the "room placement" issues. The highs and mids kept their newfound clarity while the subwoofer now presented a taut and fast bass with flawless integration to the overall sound envelope. Gone was the perceived "dip" in the mid-bass - which i previously thought is a "given" of the design - now i understand that it was artificially created by the lower bass over-emphasis and sluggishness.
What did i learn?
1. 100wpc is "less" than 185wpc. However if the speaker feels underpowered - throwing more power in might not help.
2. The quality of the power component is more relevant.
3. Room placement issues might sometimes be a reflection of inability to power appropriately one driver or another.
I can now confirm that the NHT 2.5i is a worthy speaker of a great design - and I'm happy to have found the Nakamichi gem to drive it with.
I have tried to power the relatively demanding NHT (86db, 3.6ohm lowest impedance) with different units which i thought were "good value": Acurus DIA-100 (100wpc), Carver Premiere AV-705x (185wpc in 2-channel), even CJ Sonographe SA250 (125wpc). The CJ came quite close, but I have always felt that something's missing - the voices would turn harsh at elevated volumes, the bass was emphasized and muddy (to my ears). Based on other feedback on NHT i kept thinking that it has to do with room placement (sure enough the bass output can be tuned with room placement, but could never get it to clear up).
I even wanted to sell the 2.5i - with the intent to get something "less demanding".
Boy am I happy i didn't.
In comes PA-5 which i got because it was "too good to pass up". Did not think I would actually need it... First I hooked it up to power the tweeter/midrange drivers of the NHT 2.5i while keeping the Carver for the subwoofer. The highs cleared up nicely, but the subwoofer still felt somehow underpowered and muddy. Oh well - room placement, I said, but on a whim i removed the Carver and hooked both posts to the PA-5 only.
And I was in for the most pleasurable surprise.
Gone were the "room placement" issues. The highs and mids kept their newfound clarity while the subwoofer now presented a taut and fast bass with flawless integration to the overall sound envelope. Gone was the perceived "dip" in the mid-bass - which i previously thought is a "given" of the design - now i understand that it was artificially created by the lower bass over-emphasis and sluggishness.
What did i learn?
1. 100wpc is "less" than 185wpc. However if the speaker feels underpowered - throwing more power in might not help.
2. The quality of the power component is more relevant.
3. Room placement issues might sometimes be a reflection of inability to power appropriately one driver or another.
I can now confirm that the NHT 2.5i is a worthy speaker of a great design - and I'm happy to have found the Nakamichi gem to drive it with.