Thiel Owners

most of the way to these speakers’ potential once I replace the resistors.

Super cool that you have Lexington boards and upgraded the coax feeds to ESAs. I am confident you’re getting better SQ than the SE version (FST boards plus SAs on the coax feeds).

My SEs had the FST boards with CYC MKT caps (other than the Clarity SAs on the coax), air core coils but with less than optimal winding integrity, and sandcast resistors (manufacturer unknown but similar construction to sandcasts from Xicon or Erse). Additionally, the printed circuit boards looked to have been somewhat burned underneath a couple of the resistors, so perhaps these were damaged by a previous owner playing very loudly.

During my upgrade, I did not listen to each single change I made so am unable to pinpoint everything. But I did pause at several stages and compared modified and reference channels in mono (using Roon to produce a mono mix). Comparisons I made were: 1) FST boards with sandcasts v Mills; 2) FST with Mills v “Tom Thiel boards” (CSAs though out, including on coax shunts, Lex-equivalent coils including Erse FoilQ in feed positions, and Mills resistors); 3) Tom’s boards with and without RTX Multicap bypasses on the coax feeds; 4) 160 v 250 V woofer shunt caps; 5) OEM binding posts and hookup wire v Cardas binding posts and hook up wire; 6) single v biwiring from the amp.

I heard at least some difference from each of these changes. In significance, I rank them: 1) CSAs + Lex/FoilQ coils (better resolution/textures/microdynamics; more open, clear, and transparent); 2) Mills MRAs (mitigated “glassy” midrange, improved bass impact/soundstage/“ease”): 3) Cardas wire and binding posts (more open/clear/holographic/“immediate”); 4) tie among biwiring (more relaxed/liquid/dimensional), coax Multicap bypasses (better “jump factor”, smidge more resolution), and higher voltage woofer shunt caps (bass “heft”, ease of presentation).

So, @sdecker I strongly recommend you upgrade the resistors. That’s a nice upgrade for short money. Several sources indicate the CSA improves on the ESA but is it worth your time and effort? I recall you kept the 1 uF bypass caps, so maybe “yes” (ie, get full capacitance in a single cap or, if forced to run parallel, have the smaller cap represent a larger portion of the total capacitance). In your shoes, I would upgrade the *feed* coils to FoilQ or Jantzen wax foil (one coil on each board). I did not directly compare the foil to air core but I think it’s worth trying this given that you can get all four foil coils for <$100. I would replace the 100uF coax shunts if only because electrolytics drift with age. The best solution is to go with film caps as they sound better and will last far longer but those are also far more expensive and larger. Sticking to electrolytics, I would pick the Jantzens.

The other changes I made fall in the category of diminishing returns (although I had a big smile on my face with the Cardas, it seemed to snap everything into focus). You might try a small bypass on the coax feed caps. Something like a 0.1 uF Audyn True Copper Max, Clarity CMR, or Jupiter copper foil. I don’t know that these are better than the more affordable Multicap but am curious. I have each coax feed, including the 43 uF subfeed, bypassed at ~1% but you might try a single 0.1 uF on the 28 uF cap.

@vair68robert 

So, you have installed Cardas hook up wire and compared it to “original” and “new” Thiel? 
IIRC, @tomthiel said that OEM was sourced from Straightwire (at least for “original” Thiel) but it was never resolved whether my SEs were equipped with that or sourced from FST. It did appear to be 18 ga and twisted per the Thiel recipe.

Note that I also replaced the gold over brass OEM binding posts with Cardas rhodium over silver. On paper, a notable upgrade. I cannot say to what degree the sonics are resulting from the wire versus binding posts. 

@beetlemania 
I too replaced the posts with the Cardas rodium/silver with the gold plated nuts , a lot of work for little if any gain .
To clarify I replaced the new Thiel wire and made the assumption 
that your 2.4se's came with Striaghtwire 18 guage solid wire ,
but either way the Cardas wiring was a big upgrade for both of us .
I used 17.5 awg for the tweeter and mid-range and 15.5awg for the woofer and to the inputs on the crossover boards .
I am curious about the new Straight wire configurations that Tom is experimenting with .
Did you use ERSE Fiol/Q for all 3 speakers ?

snbeall- The PCS was introduced in 2000. If yours has a double magnet on the woofer, that constitutes the upgrade. Interesting thing that double magnet. Its obvious purpose is to reduce EMF leakage for use near a video monitor. However, the reduced stray fields also reduce interaction with the crossover inductors and lead wires for more solidity and transparency, especially with complex and/or loud music.

Did you use ERSE Fiol/Q for all 3 speakers ?

I imagine you mean all three boards?

The 2.4 uses a mechanical crossover for the tweeter/mid, so only two boards. The coax and woofer boards each have one coil in the direct feed path and those are the ones Tom selected as targets for foil type.

But I’ve read, and now experienced, that caps in the shunt position can have audible consequences even on the woofer board. Some consider better components in shunts to not result in better SQ, all the more so on the woofer. To be fair, the 2.4 crossover is at 700 cycles (IIRC) and, with the low slopes, that woofer is really covering most of the midrange. But, my point is I will not be surprised to read reports of improved SQ using foil type coils in the shunt position.