The Transcendence Six SLR was a vacuum tube preamp we built in the 2005 time frame. It was available factory wired or as a very complex do it yourself kit. It was available in our standard 12" wide chassis back then.
It used two 12AT7 tubes in the line section and two 12AX7 tubes in the phono section.
The "R" in the SLR designation refers to Regulated power supplies. The preamp had many regulated power supplies. It had separate regulated power supplies for each tube, regulated filiment supplies, regulated power supplies for the LM6321 current buffers for each audio section, and regulated power supplies for the headphone drivers. It was powered by a custom shielded toroid power transformer.
The unity gain current buffers following each tube provided low output impedance and high output drive current, allowing use of the preamp to drive low impedance power amp inputs and long cable runs. It also kept the tubes from interacting with whatever load the preamp was called to drive.
It was an excellent transparent and dynamic unit, but without much "tube sound" as the buffers let the tubes run much more linearity than normal eliminating their typical "tuby" harmonic distortion. Most users appreciated this, but a few did not.
They were very durable and easy to keep running so most are still in use today. I have not seen a used one in years, but if we had one to sell, assuming excellent condition, it would go for about $695 or thereabouts.
Frank
