Feanor
10-01-2013, 04:56 AM
A couple of years ago I sold my tube preamp and replaced it with a passive. I was satisfied with the experience in combination with my Class D Audio SDS amp, however when I decided to experiament with a different sound in the form of a Forte 5 amp, I questioned the adequacy of the passive. Many people have stated that passives repress dynamics and, to be sure, the Forte really lacked "PRaT".
So I bought a new, active preamp, an Audio Research LS9. It's a solid state preamp; one might question that decision but let's leave that aspect aside. I wanted a clear, neutral, balanced preamp and that's what the LS9 is.
So what are are my conclusions to this point?
First, with the Forte 5 the increase in dynamic contrast is relatively huge. What I took to be an excessively laid-back if not down right boring amp is actually pretty decent thanks to the active LS9.
Secondly -- and surprisingly -- the SDS' PRaT is also somewhat increased. I'm not sure of the fundamental cause in this case: I'm using the balanced outputs on the LS9 and the SDS is optimized for balanced input, so is it purely the active preamp or is it the amp responding to balanced inputs? Dunno.
Thirdly the high frequencies seem very slightly boosted for both amps -- mostly a good thing in the case of the Forte 5, entirely a bad thing in the case of the SDS. Is the effect related to the preamp's improved dynamics or is it just that its got boosted (or distorted) highs? Dunno.
The think that does seem clearly confirmed for me is that an active preamp can significantly improve the dynamic contrast of the music depending on the associated equipment.
So I bought a new, active preamp, an Audio Research LS9. It's a solid state preamp; one might question that decision but let's leave that aspect aside. I wanted a clear, neutral, balanced preamp and that's what the LS9 is.
So what are are my conclusions to this point?
First, with the Forte 5 the increase in dynamic contrast is relatively huge. What I took to be an excessively laid-back if not down right boring amp is actually pretty decent thanks to the active LS9.
Secondly -- and surprisingly -- the SDS' PRaT is also somewhat increased. I'm not sure of the fundamental cause in this case: I'm using the balanced outputs on the LS9 and the SDS is optimized for balanced input, so is it purely the active preamp or is it the amp responding to balanced inputs? Dunno.
Thirdly the high frequencies seem very slightly boosted for both amps -- mostly a good thing in the case of the Forte 5, entirely a bad thing in the case of the SDS. Is the effect related to the preamp's improved dynamics or is it just that its got boosted (or distorted) highs? Dunno.
The think that does seem clearly confirmed for me is that an active preamp can significantly improve the dynamic contrast of the music depending on the associated equipment.