Amp upgrade for Thiel CS 3.7


Hi everyone,

At the moment i am using a Classé CAP-151 int amp to drive my Thiel CS 3.7
The amp is doing ok but a much bigger amp would obviously be more appropriate to drive my Thiels.
I've seen a very nice Krell FPB 700CX  for sale at a reasonable price.
Would that be a good investment or not ? would it be overkill ?
Let me know what you guys think.

Thieliste



128x128thieliste
At first, I'd say overkill for the 3.7's-But if you are getting a good deal, what the heck. But Krell yes!  Thiels should have double down power. FPB 300 would do real well, and would be half the money. The 700 is in 5i territory, or 7.2. Lots of mass and lots of heat!. I had an fpb 300 with my 2.4's, which was great, but more than I needed. But at the price, I could afford the extra power,  I'm  going to use a pair of fpb 250 monos for CS 6's, which should be ideal. I've had 2.2, 2.3's 2.4's, cs5i's, and finally CS6's. Would really love a pair of 3.7's!

The Theil's need an amp with current, solid state that can "almost" keep doubling it's wattage to 2ohms
EG:
8ohms-100w
4ohms-200w
2ohms-400w
This means a solid state amp that uses BJT (bi-polar) output transistors, Tube, Mosfet, and Class D need not apply. See impedance v -phase angle graph.
http://www.stereophile.com/images/archivesart/1208T37fig1.jpg

Quote from Stereophile's measurements
The sensitivity is usefully higher than average, which is a good thing considering that the CS3.7's impedance remains between 2 and 3 ohms over much of the audioband (fig.1), and that there is a demanding combination of 3.8 ohms and –40° capacitive phase angle at 60Hz. Thiel specifies the impedance being nominally 4 ohms, with a minimum of 2.8 ohms. I actually found the minimum impedance to be 2.4 ohms at 125Hz.
The difference between 2.8 and 2.4 ohms is academic, either mandating use of an amplifier that has no problem delivering high currents.

Cheers George


The CS 3.7 is a very fine loudspeaker from Thiel.
Not only does it require a large listening space (20x20, 25x25...)
it craves a high -current power amp to boot.  Choose wisely and you will be sonically rewarded.

As of recent, I keep seeing Classe' integrated amps pop up for various speakers. It must be pretty good to excellent in receiving the coverage.

I have auditioned the CS 3.7 w/ an Anthem 225 integrated and there was plenty of power and current to rock this speaker. Just another brand to consider.

Happy Listening!