Tritonus from Mannheim are sometimes compared to Emerson, Lake & Palmer, but they were definitely independent. At the keyboards - including the Mellotron - was Peter Seiler, who later had a good run with many of his own releases and gigs and is still active today, mainly in the field of electronics. Here is the new vinyl edition of their first LP (from 1975), taken from the master tapes. It comes with a booklet of 24 pages in LP size.
tritonus