The SB-401 transmitter was a variation on Heath's earlier SB-400 (1965). Almost identical, it added the ability to change from separate transmitter operation to "transceiver" operation from the front panel (vs. opening up the lid on the 400). Internally, the 6BZ6 oscillator tube was replaced by a 6AU6, and a sidetone level control was also added.

Crystals were NOT supplied with the rig on the assumption you would be using this with it's receiver "mate" the SB-301, thus un-necessary. Dimensions: