Thiel Owners

This was from Tom  5/25/2018

"The 2.7 midrange is fed through a 400uF electrolytic cap, albeit with a PP and styrene bypass in parallel. The 3.7 uses a bank of 75uF polypropylene caps with a styrene bypass. Multiple smaller PP caps provide faster reactions and less distortion than a large electrolytic. "   "I believe this could be the main reason for the improvement in detail and smoothness in the sound  "  Rob

From me 7/3/2022

A few months ago I had finished upgrading the woofer board and heard some improvement but nothing earth shattering , I am almost finished with the coaxial and the improvement is way beyond anything  I would have thought possible . 

I kept things simple , replaced the resistors with Mills , upgraded the capacitors , bringing the electrolytic capacitors within  and/or lower tolerance specs , making only one change suggested by Tom , replacing the 400uf capacitor with 4 100uf caps .

What I discovered was that the electrolytic capacitors used on the shunt or negative side were out of tolerance , the 68uf cap used on both the tweeter and woofer were up to 20% over while the 330 and 220uf used on the mid was about 7% over .  The 68uf caps were replaced by Mundorf caps that were about 3% over but replacing the 330 and 220uf caps was a bit of a problem .  First I replaced them with ERSE " 5% " tolerance caps that turned out to be over 11% over ! I didn't even try to listen to them . Then I  tried Jantzen " 5% ' caps , they were about 6% over .  I listened to them for a while and was happy with hearing the improvement that the other upgrades made but it bugged me that Tom was telling me that Thiel's tolerance max was 5% and mostly within 3% , so after asking Tom's advise I went with a 300uf Jantzen cap that together with the 220 I was able to achieve a 2% over tolerance .

Since I replaced/upgraded the resistors and capacitors ( except the 1uf's ) on coaxial boards at the same time I can't say how much the replacing of a 400uf cap is improved by using 4 X 100uf caps would be , I used Jim Thiels philosophy and Tom Thiels suggestion , if I had the room I would have replaced the 330 and 220 caps with 100uf max caps .  Also I can't say how much better the 100uf Mundorf caps are than Solen or Jantzen caps would have been , the same for the Jantzen used on the negative side .   I will say that the 1uf Purity cap on the tweeter made a large improvement in the sound stage and definition so I'm hoping/exception  that replacing the 1uf " Made For Thiel " cap on the mid with the new 800v Purity cap will take the sound to a whole new level .

vair68robert

Thank you for taking the time to answer my questions. I would think any film cap would be better than the 400uf electrolytic cap that was in there. 

The large values 220uf and 330uf are tough to find replacements that would fit in the confines of the cabinet. 

Was going outboard not an option for you?

Rob - kudos on the update and great info!  Kinda wonder about getting 4x100uf on there.  Wonder if standoffs to another board could have top and bottom mounted 100uf caps. Likely a bad idea with vibration, extending the path, etc...  Think you mentioned PartsConnexion will have PUR in July.  Going to get the 1uf caps for existing coax board and other parts needed for a VTL project.  

duramax747 - are you going outboard with the 2.4s?  I have a feeling that is the route that will be taken but the stubbornness in me wants to explore the internal crossover further.

There have been recent posts sending me down rabbit holes.  Similar to what Rob posted above, it seemed beneficial to create a schematic and studying the crossovers design.  Been toying with an internal 2.4 coax board layout with electrical components on both sides.  Tom Thiel mentioned "signal chaos", point-to-point and two-sided layouts so it seemed worth jogging that path to learn more.  The design considers a short path with input/output separation, component orientation, star ground (simple) and hopefully sufficient thermal management.  

Another rabbit hole was the mechanical and electrical vibration discussion then how to edge mount a two-sided layout.  Since using simulation software is not likely in the cards, perhaps an accelerometer will work.  Not sure how to avoid custom brackets and can print TPU to see how that measures.  TomD mentioned a mechanical approach to vibration but couldn't figure what it was or how it could be modified for this design.    

Those rabbit holes certainly reaffirms previous "it's complex" comments.  Good grief it is and it must have been an exceptional team to create Thiel products for so long.

Think a few of you are on the Facebook page and might reach out there if interested in seeing the layout.  Never fails I post photo watermarked "Do not use, designed by a 5 year old Lego expert" and creates confusion.  Still can't direct message here.

Summer Solstice