Thiel Owners

I tried and almost loved the AHB2 with my Thiel CS3,7’s. I tried a single AHB2 in stereo and also 2 in mono. My room is small so I thought the lack of power at 2 Ohm region with the AHB2 would be OK. On most music the sound is incredible. However, with some very powerful music I felt like it was missing some grunt.

I emailed John Siau at Benchmark about the low imeddance ability of the AHB2 with the CS3.7. He said it would be great. I think it can be bettered with a more powerful low impedance amp.

I am keeping my Benchmark stack downstairs with my KEF LS50’s, a LA4 preamp, a DAC3B, and AHB2 amp (need to re-buy a 2nd AHB2 later). This will be used with a KEF Blade META much later in the future. The Blades are not as hard to drive as the CS3.7.

On the Thiel system I tried many amps that were better at 2 Ohm. These included the following:

- LSA Voyager GAN 350 (modified by EVS)

- Parasound A21+

- CODA #8

- KRELL Duo 175XD

- D-Sonic M3a 800s.

All these amps had more ’grunt’ with the music I found the AHB2 lacking. I only have the CODA #8 and the KRELL 175XD left on the Thiel system. I rotate the 2 amps between my RAAL SR1a headphones and Thiel CS3.7 speakers. I am finding it difficult to take the KRELL out if the Thiels because it sounds so good, 175 watts in Class A. However, I will force myself tonight because I want to hear the RAAL again with the KRELL.

BTW - the modified LSA Voyager is very similar sonically to the AHB2 but with more overall power (better for Thiel). I kept the CODA #8 over the Voyager mainly because I already had the AHB2 and preferred it over the Voyager with the LS50s.

Happy Friday! All

@tomthiel   Thanks for the detailed response to my questions. You may consider yourself an electronics layman, but you still know a lot more about this stuff than I do.

Given that the 2.2 appears to be easier to drive than the 3.7, it sounds like the AHB-2 should have enough power to handle my 2.2s if I decide to try one. (By the way, my room is about 3800 cubic feet, though with some large openings on two sides.)

I'm still trying to learn more about the distortion profiles of amps and their audible effects. The Benchmark website has a lot of interesting info on its products, and I even understand some of it. Jon Siau at Benchmark talks about providing electronic compensation to reduce second and third harmonic distortions (through their DAC, I think) as part of the attempt to reduce all types of distortion as much as possible. In contrast, Nelson Pass says that his listening tests at Pass Labs have shown a general preference by many listeners for the sound of amps that don't work too hard to suppress lower order distortions. Ralph Karsten at Atma-Sphere says that second and third harmonic distortion is not annoying to most listeners and actually helps mask the higher order distortions that give so many solid-state amps a harsh or overly bright sound. Siau, Pass, and Karsten are all highly regarded designers who use both measurements and listening tests to design their amps.

On the surface, it would seem best to reduce all distortions as much as possible, and this appears to be part of Siau's approach. On the other hand, there seems to be general agreement that the harmonics in recorded music reproduction are not identical to the natural harmonics in real-life musical instruments. This raises the question whether sound would seem most natural and real if all distortions are as low as possible or if the harmonics profile of the gear used to play back recorded music needs to come closer to matching the harmonics profile of real instruments. This sounds like a situation that will demand some actual listening!

Thanks again for your help in thinking some of this through.

Thanks guys, IMO a single Coda#16 would easily outperform 2 AHB-2s driving CS 3.7s.

Anyway i will start by demoing the Gryphon Essence stereo pre-power combo and see how that goes against my Diablo 300.

Since i now have Cardas Clear Beyond IC and SC in my system this has brought my Diablo 300 Thiel CS 3.7 combo to another league, absolutely insane level of performance!

In small bites. Jim chose the big Krell FPB600. Other muscle amps no doubt 'outperform' the AHB-2. I like the 'grunt' of my bridged Classé DR9s (1100 watts / 2ohms.) Bill Thalmann is presently hot-rodding them. And Nelson Pass is a hero of mine. So then, what's my AHB problem?