CS2.7 upgrading update .
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 .
I said almost finished because I am waiting for Clarity to release the PUR series capacitor , can it get any better ? Some say that the 1uf bypass cap is very influential so I'm hoping for a yes .
Tom just mentioned that he is replacing the steel screws with brass , do it it does make a slight improvement , I also installed reinforced nylon screws on the coaxial speaker , as for the washers I had to grind down brass ones to fit using them on the woofer , I did see that McMaster Carr has some #8 washers as small as .375" OD but I think they might still be a little to large . I also discovered that the screws holding the boards inside the speaker were of ferrous metal and replaced them with brass .
This project has not been easy but it is well worth it .
