2. amps-preamps
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Input impedance issue?

Hello all,
I have a PrimaLuna Prologue Premium power amp driving KEF LS50's and a Rotel RB-880 power amp driving 12" NHT subs.
I'm using an NHT X2 crossover on the subs and going direct on the KEF's. I don't like the sound I get on the KEF's going through the high pass on the NHT. They are both being driven by an Audible Illusions L1 preamp. The pre has 2 sets of outputs. Seems when I have one output connected to the NHT and the other to the PrimaLuna the high end on the KEF's drops off. It's there but no sizzle. The only way it seems to sound right is to connect to the NHT via the tape outs on the pre for the subs. Then it's kind of a pain to keep moving the level on the subs all the time. Does any of this make sense? Any ideas? Thanks in advance.
Ben
honashagen
honashagen OP
137 posts
 
Any other suggestions on buffer amps? $350 for the Musical Fidelity! Ouch. What about the tube buffers from Yaqin? Any other recommendations?
honashagen OP
137 posts
 
How about this one?

http://www.ebay.com/itm/Silk-Audio-SD-CD3-Tube-Buffer-from-same-factory-as-Yaqin-/321865403164?hash=item4af0ac4b1c
almarg's avatar
almarg
9,670 posts
 
On paper, at least, the Silk Audio buffer and the similar Yaqin model look like they would probably be reasonable choices. Although I do have a bit of concern about the lowish 60 db A-weighted signal-to-noise spec on the Silk unit. And I would suspect that the Yaqin is no better in that regard, with its stated 75 db performance (no weighting specified) just being better on the basis of "specmanship."

Normally I don't attach any significance to signal-to-noise specs, because they can be defined in numerous different ways that are usually not indicated. But in this case the 60 db A-weighted number is low enough to raise a bit of a red flag, although it's quite possible that in a subwoofer application it won't matter.

Also, I note that there is no spec on output impedance. Which I would assume is low at mid and high frequencies, but depending on the value of the coupling capacitor that is most likely used at its output could conceivably rise to unacceptably high values in the deep bass region, which is what is important in this case.

Good luck. Regards,
-- Al
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