Thiel Owners

I don't have full vs 1uF bypass comparisons, but I do have some relevant history. When Thiel developed the bypass configuration, caps were relatively primitive, and smaller value, higher spec bypass caps made a significant improvement. We developed that 1uF tin foil x styrene cap as state of the art and used it for nearly every station. Note that the CS3 had teflon nF double bypasses and the CS2 and 3.5 had styrene ultra bypasses. As caps got better, the ultra bypasses became effectively obsolete. Note that multiple caps help and hurt. They hurt timing precision, since their discharge rate is faster than the larger value, and each station must be tuned. Effectively cost-prohibitive in our particular niche. 

When Jim was developing the SE, Gary and Rob report that they listened to and measured many, many configurations of bypasses and brands of caps including darling  audiophile cost-no-object ones. They chose the then-best Clarity SA for its rightness, both measured and heard. The single (non-bypassed) value was chosen as sonically superior to the bypassed version. Note also that the CSA, with its copper spluttering, is said to be a league ahead of the ESA, which was a relatively small advance over the SA.

Beware that the incision of these higher grade components comes with its own set of potential perils. In Lexington last week I saw Rob's 7.2 XOs in which he had replaced all series feeds with ESAs to compare with stock. He (and his cohorts) preferred the stock parts. The point is that the whole thing is a pot of soup, and "improving" something may require other compensations. When converting Beetle's 2.4s, I was relieved that every upgrade resulted in upgraded performance. As he mentioned, his SE's were late Chinese manufacture with room for improvement by reverting to old methods, from which we also upgraded layouts and coils. All his parts were very carefully selected, and synergy ruled. My own path is with Mills resistors and Clarity caps on old-style point to point boards with new layouts and heat managemnt. I am considering those electronic upgrades as end of project decisions. My focus is on re-bracing and re-baffling which is progressing well.

   It turns out I *did* post to this forum about my 2011 XO upgrades on 2/2/18 (pg 49), with beetlemania and others acknowledging my relatively early surgery. 
   My 2.4s are fairly early production (SN 611,612) so I can confirm the high(er) quality original XO parts (including the inductors), point-to-point boards (literally), and wiring. 
   Due to nobody posting about 2.4 XO specifics in 2011, I had to wing it with only the schematic and XOs in front of me and Thiel telling me their use of Clarity Cap SA.  So I wasn't about to second-guess their use of film 1uF bypasses.  I had evidence the ESA I ended up using was a better-sounding cap than the SA, the CSA wasn't available yet, and the 630V caps and far-more-expensive Mundorfs et al were simply too big for the space on the XO board, so I used 250V versions.
   I don't doubt the XO can be improved well beyond what I've done, but as Tom Thiel points out, there are risks and pitfalls to just throwing the best and fewest parts at such a carefully-modeled 2-way XO.  I look forward to reading what Rob Gillum and team can accomplish with more resources than were available to me at the time!

   And I'm still waiting for informed comments about the compromises of the 2.4 baffle versus the smoothly rounded 2.3.  The 2.7 did away with the baffle discontinuities and should sound that much better due to both the baffle and certainly the 3.7 coax.

sdecker - I don't have those models to inform any opinions. But I am messing with the CS1.5 and 1.6, which exhibit similar baffle differences. The 1.5's grille board mates with the baffle to form a flush surface with 1" radiused round-overs. The 1.6 has much larger round-overs outside of a shallow (1/8" - 3mm) pocket which holds the metal grille panel with cloth over it. I believe the 2.4 and 2.7 are like the 1.6. Within all those variables, I have isolated a sonic and measured glitch caused by that grille 1.6 pocket, either the edge of the metal panel or the edges of the pocket with the grille off. Filling that pocket with 1/8" F11 wool felt eliminates the glitch and the speaker sounds larger, the image lifts and comes out of the box. With the felt in place, the treble balance sounds right without the attenuation of the fabric. The grille magnets work through the felt for protection when needed.

This discussion segues into the grille cloth thing. A manufacturer must decide how to present its products to market, and Thiel chose wood cabinets with fabric grilles, for better and worse. Reticulated foam (model 01, and a Wilson special order) is more transparent, but not very cool-looking imho. Our fabrics got more and more sheer as they became available, but it is still there as Andy mentioned. I believe most audiophiles would prefer no fabric. In fact Thiel offered grille frames with no fabric and extra finishing to match the baffle. Nice, direct sound, but with more high-end sizzle. We could have, but chose not to modify the XO to knock down the treble. A hot-rod shop such as Thiel Renaissance could offer such mods to make the purist happier. I am presently experimenting with solutions that optimize sound quality and aren't physically objectionable.

Hi All,

I have a couple of CS5 questions for the Thiel experts. 

1. how does one determine if they have CS5's or CS5i's? I read somewhere, I think on this thread, that there is no marking on the outside of the speakers to tell? My serial numbers are 1225 and 1226.

2. When I turn my system on with the preamp allowing no volume, I can hear different sounding "hisses" from each of the three small speakers on the top. This is audible only with my ear within six inches of each speaker. Is this normal? Or is it a sign that something is wearing in the crossover, etc. Or could it be coming from another piece of equipment like a tube preamp?

Thanks for listening,

Dsper, 

Thanks for your post, Tom.
Interesting that Rob found the ESAs to sound worse. My experience was that nearly every change improved the sonics. Perhaps because I had a good coach ;^)

I am considering those electronic upgrades as end of project decisions. My focus is on re-bracing and re-baffling which is progressing well.

As you know, I'm a big fan of upgrading the passive parts. And I think a lot of the improvement I hear can be had for less money. That said, I'm looking forward to trying your baffle treatment.