Thiel Owners

Beetle - thanks also from me for your steady, careful implementation, especially when backing out of blind allies.

You all may be interested to know that the 03, 03a/b, CS3, CS3.5 and CS2 had styrene micro bypass caps (0.01 and 0.015uF), similar to (but not as good as) the RTX bypasses. They were dropped @ CS2.2 and CS3.6 and onward. Those earlier models also used the French polypropylene Solens @ 400 volt and German polystyrene x tin foil 1uF, both best in world at the time. Those companies ceased making film, and replacement caps gradually became more ordinary. I suspect that some of the love for the CS3.5 might be attributable to those pristine caps and double bypasses.

In this project we are using best of form caps that exceed anything Thiel had ever used, including those described above.  Thanks again to Beetle for making various controlled comparisons. I will be making more.

tomthielLooking forward in reading more about your observations as well as Beetle's configurations. Over the years, reading across multiple Audio forums, I have read about the right phase angles. In the models CS 2.4, 2.7 and 3.7, the first right phase angle occurs at 200 Hz. A second right phase angle occurs at 100 Hz. Have you guys (Andy, Beetle, Holco or Tom) found this problematic for your personal system power amps to drive? As I understand it, this is correlated in drops between 4 Ohms down to 2 Ohms across much of the speakers' frequencies. 3 Ohm nominal.
This is one indication as to the value of using a 2 Ohm stable power amp to (hopefully) prevent clipping and distortion within the mid-bass/mid-range regions.  Thus, reducing damage to crossover and driver.

Happy Listening!

@jafant
I have never noticed any stress from my Ayre AX-5 at any SPL in my 18x19 room (vaulted ceiling with large openings on rear wall). With my combo of amp and DAC, clipping sets in at an indicated “40” on the volume with a typical CD. Even for something like Zeppelin or The Who, “32” is plenty loud for me. I have plenty of headroom.

Mr. Beetle - I have routinely used Mills wirewounds in my own crossover rebuilds and upgrades over the years. And they have routinely been an improvement in nearly every instance. I am glad that your experience has confirmed my own. They are quite good.

But I will add this. I have learned that materials and parts selection, and their implementation, is as much of as an art as a science. That process of ’voicing’ more approximates a very complex cooking recipe, where some ingredients balance and offset against others, and must be combined in a careful blend.

While normally the superior materials and parts prevail, some of the critical listening outcomes can be quite surprising, indeed.

As an example, I am always reminded of one of my favorite stories involving David Hafler, who many years ago was voicing one of his amplifier designs, and was working out the selection of one particular coupling capacitor. While the design team had access to every conceivable exotic capacitor design, including those with copper and silver leads, a very simple, very humble, and very inexpensive steel-leaded model always prevailed in every single listening test. The amp went to production with that inexpensive steel-leaded capacitor.

sgmlaw - your Hafler story represents the approach of a wide range of designers, and practically the entire DIY community. I will offer a different perspective which included Nelson Pass, John Dunlavy, Benchmark's John Siau and Jim Thiel to name a few.

That Thiel approach says that in a situation where an inferior part creates a better sounding outcome - that is evidence of another problem. Something else is going on which has not yet been identified.

Your Hafler experience happened routinely in Thiel product development. As a matter of process, we took that outccome back to the lab to figure out what was happening. Usually that "fix" was masking something much like dither noise masks or randomizes artifacts of digitization. Our MO was that a solution had to both sound better and measure better or our work wasn't finished.

I recognize that I am speaking anathema to many or even most of you. But I offer it as a signpost along the Thiel road.