Thiel Owners

but its anomalous behavior is limited to its stability into low impedences, BUT if it does become unstable, it tells you via indicators

This may "save" the amp if the protection circuit is fast enough if it oscillates and there’s not too much storage capacitance, as you’d be crazy to put relays/fuses etc in the speaker outputs or power supplies. (another sound quality no no)
I did say just one of the negatives was stability and low impedance drivabilty, there are many more.

Cheers George

Rory at Benchmark says that many customers have requested such an AHB-3. I tried my hand at it. John is adamant that the AHB-2 has enough power. Engineers can be that way.

We wouldn’t be talking about this here if Thiel speakers had 4 ohm minimum impedances.

They are more like 2ohm, and at 60hz where the -phase angle meets the 4 ohm could represent even less EPDR load to the amp.
https://www.stereophile.com/images/archivesart/1208T37fig1.jpg

What the member who’s thinking of bridging should do if he must get another ABH2, instead of bridging it, which will be a step backwards with these CS3.7’s in all parameters except total wattage.

He should vertical bi-amp the two ABH2 amps, that way the whole power supply energy is available to just one bass speaker of one channel instead of two. The amp/s remains stable and able to drive these nasty loads.
https://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George

This same AHB2 conversation was had in another A'gon thread in 2018 where John Siau participated. I don't think the folks responding to him realized he was the amp designer.

The vertical bi-amp will not work with the Thiel CS3.7 since it only has 1 set of speaker inputs.

As it stands:

1) The designer of the amp told me by email that the amp will be good with the speakers. He looked at the speaker specs.
2) The founder of the speaker company mentions that he has been testing 2 AHB2 for the last 2 years.
3) @unsound makes a great point about finding something else that does not shut down. I think there will another amp in the future to have in the stable.

At this point a second AHB2 is an easy buy for me. I love the sound of this amp. They are said to work with the 3.7's, issue is how well. One thing I have learned the last 2 weeks is that the CS3.7 is not a speaker to be played crazy loud. That is fine for my current application in my office. A little more grunt from the 2 amps will take me to an ideal spot.

^With the right amp you can play these speakers pretty loud. Jim recommended up to 600 Watts per channel and used a Krell FPB 600 for them.