Perhaps the term high needs some definition
My vk5i total output imp was 800 ohms, 400 per phase
the vk32 has an output imp total of 600 and the Rex is 200 per phase or 400. .. Im figuring the VK 51 is in there somewhere between 400 & 800 ohms total..
Unless I read an article reviewing the CJ 350 Premiere solid state amp in error, one of the two mainstays, either Mr. Conrad, or Mr. Johnson said a ratio of 10:1 is sufficient for preamp to amp matching. So if the preamp in question has an output imp of say 1000 ohms total, then the amps input imp needs to be 10,000 ohms or better
. Many amps, even the modest input impedances of Spectral amps, would meet that criteria.
My single ended thor output impedance is I think 400. its driven every amp Ive connected to it with eease. 60wpc tube amps, 250wpc SS amps, 100 wpc SS etc
in to speakers with low impedances of 1.8 ohms, 4, 6, and 8ohms. With eff ratings from as low as 85 db!
So whats a high impedance output for an active preamp??? 1100 ohms? 1500?
All the BAT amps I just looked at have input impedances of 90K +. Tube or SS.
I doubt seriously youll run into trouble in that preamp > amp, regard.
BTW none of the BAT amps double down in their power outputs
they just have enormous power reserves. Others use negative feedback to ehlp out there.
and lets face it
exactly when will one need to have an amp which produces 500 wpc
or 600, or 1000 wpc?
90% of the music is made in the first 20wpc anyways.
It will all come down to what your aim is for driving your loudspeakers. Wanna peel paint? Produce live rock and roll shows?
Ive got a pair of 87db, 4 ohm speakers which drop to 2 ohms
I can run them easily with a pair of 120 wpc tube amps
very well
.. or with a 150 wpc SS stereo amp too! Even with my SS HT receiver which questionably put out 110wpc!
Kevin Hayes of VAC told me once he runs many of his amps on a pair of Thiel 2.6s
. even his 30wpc SET amp! Check the specs on some of the VAC amps which are very well regarded, and you will notice they dont double power with halved impedances.
This deal aint that hard. A quality amp will do well
. And heres a thought
. Call thiel and ask them what amps on your short list they would recommend.