Thiel Owners

Arvincastro - my comments might be from left field, since I don't have much direct comparison to hi fi gear. For my work upgrading classic Thiels, I wanted 3 dissimilar amps for cross-checking upgrades. My main amps are Classe DR-6 pre and a pair of DR-9 power amps, which I have used for 30 years, know very well, and mate well with Thiels. In 1990 they were pretty decent entry-level high end with strong reviews. In addition I recently bought an Adcom GFA-555mkII, which to me represents a mid-fi amp with some hi-fi cred. My reference amp settled as a pair of Benchmark AHB-2s. That amp is primarily a pro amp, turns up in a lot of mixing and mastering studios, plus got Class A ratings from Stereophile, Absolute Sound, etc. Its claim to fame is absolute neutrality and vanishing distortion in a small, affordable, Class H package. I don't know what hi-fi aficionados think of it; I have asked here to no response, and I haven't seen it in the chatter. I am pleased with it as a colorless, honest straight wire with gain. FWIW.  

Tom - I've been considering an upgrade to my Classe CA-300 that powers my 3.7s, so I checked out the specs to the Benchmark amp you listed. The short question I have is: is this enough power? Obviously you consider that to be the case, but in an arena where many consider the large Krells to be normative, would the Benchmark keep up? Thanks for your thoughts.Todd

Todd - I can't answer that question due to the radical divergence of individual needs. Big room and/or loud level can magnify power requirements by large multiples.
That said, unlike other circuit topologies, the power stays absolutely clean until it quits - limited by fast protection circuitry.My situation is unusual in that my studio has 2 real, exterior walls, but the interior walls are porous, allowing few reflections or standing waves. The ceiling and floor are normally framed and therefore somewhat lossy. The studio occupies a corner of a 30'x50'x8' space which is open to similar spaces above and below it. So my listening environment is effectively quite large. My peak listening volumes never exceed 100dB, usually around 85.

In normal 100w/c stereo mode, the clip lights have rarely flickered, but have never tripped. In 400w/c bridged mode I have not reached any limit. So, the AHB-2 acts like a larger amp than it measures, probably due mostly to staying clean all the way to max, rather than gradually increasing distortion as most amps do.

Benchmark offers a generous home trial audition. I suggest you A/B it in your system with full send-back guarantee.

tomthiel"I can't answer that question due to the radical divergence of individual needs"

What is "radical divergence" that does not make any sense to me but English is not my first language so I ask you politely, respectfully, and sincerely to explain this term.

What is "radical divergence"

Some people like to listen at very high SPLs and have large rooms. They will need a LOT of power. Some people have smaller rooms and listen at moderate levels. They will need hardly any power.

I did some calculations for my CS2.4s. Thiel claimed a minimum impedance of 3 ohms and three reviewers measured the minimum ranging ~2.7-3.1 ohms. Assuming a *constant* 2.9 ohm load (a worst case scenario as the impedance dips this low only for part of the frequency spectrum) and ignoring room interactions, I need about 5.5 watts for 85 dB at the listening position, ~20 W for 90 dB, ~50 for 95 dB, and ~180 W for 100 dB. I estimate my amp clips at ~97 dB. But I very rarely ask for more than 90 dB peaks and most of my listening probably only requires 2-5 W. My amp has plenty of headroom for my listening preferences. Others may need more power. If you demand 105 dB peaks (sorry for your ears), you may need 500-750 W with something like the CS2.4, depending on room interactions!

So, someone like me needs <50 W but some others may need an order of magnitude more power. Radical divergence.