last_lemming - about CS2.4 XO upgrade. That model has been done several times at various levels with good results. However, my explorations have revealed that Jim’s stock XO parts are quite well optimized per cost. A complete rework could cost as much as the entire original bill of materials. I have been working on some cost-effective substantive upgrades at moderate cost, all having to do with orderly propagation in the electrical and fluid dynamic realms.
Electrically we replace the input terminals with GR Research Electra tube terminals as well as the internal cable with something I have developed. We're presently searching for a manufacturer willing to take on its idiosyncrasies. I predict you’ll love it, and it will be available this year. The 2.4 has its crossover in the cabinet bottom with enough room to house larger, better caps, as well as away from the dirty fields generated by the drivers. We have addressed orderly wave propagation in the crossover layout with the circuits running linearly rather than dense-packed.
Also, I have developed a new cap with multiple sections in the Golden Ratio. It’s extraordinary and should be in production this year. And, you can replace your resistors with Mills MRA-12s, especially in the series-feed positions. I can help you identify or implement various aspects as you might choose via PM.
The fluid dynamic wave-launch solution is coming along nicely. We control the interface between the high-density energy at the driver / transitioning into the limp air mass in the room. The sonic improvements are as thrilling as they are unexpected. We are presently running beta tests on the SCS4.
January 2023, our efforts shifted focus onto the SCS4 due to its friendliness to upgrade work by multiple participants. All new solutions developed on the SCS4 will apply to all Classic Thiel models. The work as been long and slow, but progress is being made.
I can suggest what might be best for now vs wait for later.