The Hammarlund HQ-140-X is a single conversion general coverage receiver. It covers 0.53 to 30 MHz in 6 bands and is equipped with a Lamb single crystal filter. The IF frequency is 455 kHz instead of the 465 kHz used by earlier SP-200 receivers. It's also a relative lightweight, coming in at only 50 pounds, 23 pounds less than the SP-200, but still 15 pounds more than the later HQ-145. The HQ-140 was manufactured from 1953 to 1956.
The HQ-140 is a great sounding radio, as are all the general coverage Hammarlunds. Image rejection suffers a bit above 20 MHz, but it remains sensitive and stable up to 30 MHz. While not designed for SSB, the generous electrical bandspread and stability make tuning and listening to CW and SSB easy once you learn how to adjust the RF Gain to prevent overload.
N1TI's YouTube video/audio demonstration of a HQ-140
"HQ-140-X Communications Receiver, Technical Description and Operating Instructions", The Hammarlund Manufacturing Co., Inc.
"Communications Receivers, The Vacuum Tube Era 1932-1981", 3rd Edition, by Raymond S. Moore
"Shortwave Receivers Past & Present", 2nd Edition, by Fred Osterman