I have never heard one, but was told that it is based upon a David Berning EA-230 tube amp design...check it out.
http://www.milbert.com/
http://www.milbert.com/
12 volt tube amplification?
If anyone has any thoughts regarding tube amplification for car stereo or can recommend a manufacture please do let me know. A google search reveals a few possibilities. All older type car radios used to be valve driven. Is it possible there is a kit for those with schematic/soldering skills?