Need some Amp help - a little new to properly powering speakers

Amojan,
It was atmasphere who made the positive comment regarding tube amplifiers in his post yesterday. Did you not see this? I personally believe that the key issue here is amplifier "quality " be it tube or transistor. People suggesting just get a more powerful amplifier (quantity) and throwing more watts at the speaker aren't  helping moskaudio (OP).

Moskaudio, I don’t have experience with tube amplifiers in that particular price range. I would look into known reputable brands such as Cayin, Quicksilver and Primaluna on the used market. Those 3 come to mind but I’m sure there are other candidates as well.
1 Regarding tube amplifiers qualify output transformers and power supplies are essential for good sound and performance.
2 Push pull topology with minimum 30 to 35 watts and up (assuming good quality) should work well for you. If you have to exceed the budget a "bit" I’d do it to ensure that the quality of the amplifier is good.
Charles

Although I almost always agree with my esteemed Audiogon friends and colleagues Atmasphere and Charles, and although I am definitely a fan of tube amplification, I would be hesitant to pair a tube amp with these speakers, at least without an in-home trial having return privileges.

While the speaker’s published specs indicate a nominal impedance of 8 ohms, the measurements shown here indicate as follows:

Impedance reaches a minimum of 3.75 ohms at 66 Hz and a phase angle of –47.96 degrees at 83 Hz.

While that information is not nearly as complete as I would have preferred to see (a graph of impedance magnitude and phase angle covering 20 Hz to 20 kHz would have been more informative), it is suggestive that these are probably not tube-friendly speakers, especially when it comes to tube amps in a price range that would make sense. (As opposed, for example, to a vastly more expensive Audio Research Reference series amp, which I suspect would do ok with these speakers).

The problem with the 3.75 ohm figure is not necessarily that value in itself, but rather that given the 8 ohm nominal impedance there is likely to be a wide **variation** in impedance between the bass region and the impedance at higher frequencies. And given also the likelihood that the speaker was designed with the expectation that it would probably be driven with solid state amplification that variation is likely to result in unintended tonal aberrations, such as weak bass, if it is driven via the higher effective output impedance of most tube amps.  And the fairly severe -47.96 degree capacitive phase angle at 83 Hz would most likely add to the problem.

I can also say specifically that based on measurements I’ve seen in Stereophile many PrimaLuna models, especially the lower priced ones, have particularly high output impedances, even for a tube amp, which casts further doubt on their suitability for use with these speakers.

Good luck. Regards,
-- Al

@Almarg even more light shed and more difficulty added to the mix =).

Although, this would make sense. The tweeter and small mid woofer appears to be the same exact design as the LSI25s, which are rated at 4ohms.....most likely due to the woofer being self powered. 

So many fun things to play with =D. Now.....to study up on capacitive phase angles at certain critical sound frequencies.....

You do not need more efficient speakers for more detail. The most detailed speakers may well be Quad electrostats, and they are horribly ineffcient.

The first statement is true, the second is partially false. Quads are planar loudspeakers, and so the 1 meter measurement does not give their true efficiency. In general you can add 6 db to the measured figure and be a lot closer to their actual efficiency. This is true with any planar. 

Al, If a tube amp were used on this speaker, it would probably do fine if used on the 4 ohm tap and if also running about 20 db of feedback. The impedance curve would then present no worries.

I only mentioned a tube amps simply because the OP is dealing with a lower volume loss of detail. Low level detail is something that tubes can do considerably better than transistors. IMO this has to do with the linearity of the devices themselves; even pentodes are not that bad at lower power levels.

@kosst,

You completely misread my post. I was speaking of low-volume dynamics. I don’t know how you confused my statement unless you simply read it too fast. This is what I said,

His original post stated that he noticed a lot of "imaging" loss at lower levels. Maybe he was referring to imaging in the true sense of the word, but I’m betting that dynamics is the more appropriate adjective. I’ve never had an issue with low-level imaging, but all mid-efficiency speakers I’ve owned struggled to produce decent dynamics under 70db

Since you mentioned LS50s, I happen to own a pair, and they, like other low efficiency speakers, have weak dynamics at low volumes. It doesn’t matter if one feeds them tube, SS, class A, or AB power, nor does high or low damping factor make a difference. They simply need a certain level of voltage to open up and that means louder volume.

Anyway, the OP subsequently confirmed what I suspected, that he was actually referring to dynamics, not detail or imaging.

What folks here seem to fail to comprehend is that many listeners want the same "jump" factor (mostly regarding bass) at low volume that they get at higher (80db+) volumes. Amp manufacturers began to compensate for this with "loudness" controls once low efficiency speakers became the norm. Then the movement toward minimalism and home theater came about. AVR manufacturers know that most will only use these products for home theater, so inclusion of a loudness control is no longer worthwhile. The boutique minimalists swear that any such control compromises the sound, and/or the BOM for the rest of the amp. That leaves one the option of using separate DSP, an EQ, or high efficiency speakers to attempt to compensate for the loss of low-level dynamics.

Any honest speaker designer will attest that high efficiency speakers produce superior dynamics at low volume. I know you don’t like to read that based on the speakers you own, but it’s the reality.

I own both high and low efficiency speakers. I don’t consider either approach inherently superior. Each approach has strengths and weaknesses.