The Heathkit DX-35 appears in Radio-TV News Heath ads from July 1956 to December 1957. Designed for the 80 to 10 meter ham bands, including 11 meters, it uses stacked B+ for the 12BY7 oscillator and 12BY7 buffer tubes. Plate power input is 65 watts on CW and up to 50 watts on AM from a 6146. AM operation is screen modulated using a 12AX7 for audio and a 12AU7 as modulator. A switch on the rear panel selects one of three crystals or the jack for an optional external VFO. A typical VFO is the Heath VF-1. An accessory power socket for the VFO is also provided on the rear panel. The DX-35 was replaced by the DX-40 which was first advertised in the January 1958 Heath ad in Radio-TV News.
Try this link for Heath catalog info on the DX-35.