Jafant, TomThiel & Rob @ Coherentsourceserice.com, thanks so much for the responses.
Some Thiel fans for years have been looking for a replacement mid-range for the Thiel CS3.5. Several contenders apparently have come & gone. The 10F/8424G & G00 are highly respected drivers; however, there isn’t enough information floating around the web on the original 13M/8521 to make an informed comparison. Madisound replied to me that people have been happy with the 10F/8424G swap which is encouraging, but no specifics. Rob at rob@coherentsourceservice.com (thanks again Rob) just responded to my email that in his testing the 10F/8424G00 is the replacement driver of choice. The 10F-8424G00 is mounted onto a special plate that holds the driver and the trim ring for the CS3.5 mid. He offers the driver, plate & trim at at Coherent Source Service for $250 each, plus shipping.
Tom Thiel’s awesome response above nailed some of my questions on the 10F/8424G as a replacement. The two drivers appear a very close match, but Thiel’s design of the CS3.5 places serious demands on the mid-range, so several factors come into play when selecting a replacement… not the least of which is how it behaves with a soft 6dB slope, low 400Hz crossover, high power handling demands and a bass equalizer infusing a formidable power shift. However; for me, most important is how it sounds. If it sounds as good or better than the original, there may be subtle work arounds to meet my needs.
I’m still hoping to find Thiel owner who has heard either the 10F/8424G or G00 in the 3.5.
If the 10F/8424G or G00 work as replacements, I’ll try swapping out the original Dynaudio D28AFs with the Dynaudio ESOTAR T330D tweeters. I have a pair from another project that never materialized. I contacted Dynaudio concerning the possible swap and they felt it would be a good match. There wouldn’t happen to be anyone with experience replacing the 3.5 tweeter with the T330D? This isn’t a complex a swap as the mid-range.
Jafant, thanks for asking about my musical tastes? I guess they’re all over the place. I’m a product of the 60s fused with parental influence from the 30s to 40s. Beatles, Stones, Buffalo Springfield, Blue Cheer, Tull, Neil Young, Mayall to Nat King Cole, Louis Armstrong & Ella Fitzgerald. As time progressed got into country rock, blues, jazz, bluegrass and Americana. As I get older my tastes mellow, I now enjoy quieter more emotional music, but with exceptional detail & depth. Clean, clear intimate audio, able to hear a vocalist draw a breath between lyrics, fingers sliding down a 12 string guitar, a tad of darkness. This has led me to SET amps & high sensitivity speakers.
What it my system? As a hobby, I diddle with audio equipment. Finishing building a pair of OB Lowther PM6As (silver voice coils), Tone Tubbys and built in subwoofers (almost done). Also currently building some modified 4Pi’s, again with built in subwoofers (mid way through). Lastly, finishing a DIY turntable & Transcendent Masterpiece 300B preamp (almost done).
My main system - Merlin VSMs, Joule VZN-80 & Joule Preamp (on pause due to lightning damage). Active system - Transcendent Grounded Grid preamp, Welborne Lab 2A3 Moondog monoblocks and diy Tang Band W8-1772 OB speakers (with built in subs). I’ll eventually mate the modified Thiel CS3.5s and powered subs with my Marantz Estotec SM6 amplifier. As you might guess, my wife is a patient woman.
