Thiel Owners

I believe that it is the opposite. One ahb2 works fine but the mono. Ahb2 has a higher impedance and won't work. Check with benchmark.

"Running Benchmark AHB2 in bridged mode and 4 Ohm Speaker "

https://forum.audiogon.com/discussions/running-benchmark-ahb2-in-bridged-mode-and-4-ohm-speaker?high...

Here is the designer of the AHB2 addressing the posts on the thread linked above.

https://forum.audiogon.com/discussions/running-benchmark-ahb2-in-bridged-mode-and-4-ohm-speaker/post...

https://forum.audiogon.com/discussions/running-benchmark-ahb2-in-bridged-mode-and-4-ohm-speaker/post...

BTW - I think the Purifi amps from guys like March Audio in Australia could be similar to the AHB2.

@xyzsantabarbara, Though Thiel Audio is usually better than most at posting their specs, I think you'll find the following interesting:

https://www.stereophile.com/content/thiel-cs37-loudspeaker-
specifications

https://www.stereophile.com/content/thiel-cs37-loudspeaker-measurements

Whether it's due to different measuring techniques or rounding to standard numerations, I think the 4 Ohm nominal rating is a bit off. The Stereophile measurements suggest a low of 2.4 Ohms and the graph looks more like a nominal 3 Ohm rating to me. And with a difficult phase angle to boot. I'd suggest working from that 2.4 Ohm minimum impedance when gauging for appropriate amplification.

@unsound I saw your prior post on this and do have some concern that the amp may not work. Not a big deal if it does not, the CS3.7 is not going anywhere nor is the Benchmark stack. I plan on setting up 2 rooms once things get back to normal.

The Magico A3 speaker I demoed at a store with my old AHB2 sounded closed in with a single AHB2. I actually sold it after that demo since I was thinking I was going to get the Luxman. Though that changed when I bought the HPA4 and then re-purchased the AHB2.

I will find out soon enough. Unfortunately I do not have funds available to buy a second AHB2 in the short term.

BTW - Did you read the Benchmark designers comments on the links I posted above?

https://forum.audiogon.com/discussions/running-benchmark-ahb2-in-bridged-mode-and-4-ohm-speaker/post...

This is his profile on A’gon.
https://forum.audiogon.com/users/gearbuilder

Unsound - I agree that the proper rating for the 3.7 would be 2.5 ohms. Nominal impedance is by convention stated at or near the minimus after the bass anomalies. If that trough is deep and steep the rating can be upped a little, but the 3.7 does not bounce back and indeed stays below 3 ohms to 500 herz, where lots of power is required for mid-bass output.
I find Jim's adherence to low impedances misguided and limiting. Not many amps perform well into such a low impedance.