Note
The SC-10 was an empty cabinet in which you could mount you own speaker. The first reference to the SC-10 can be found in the 1940 Allied Radio catalog, page 129, and is associated with the HQ-120-X receiver.
The PSC-10, dates to about 1942, and can be found in the 9th edition of the Radio's Master Encyclopedia, page H-59. It is associated with the Super Pro 200 series. It too, is just an empty cabinet.
By 1947, at the latest, speakers of the kind shown here can be seen in the 1947 Allied Radio catalog, page 155, advertising for the HQ-129-X and the SP-400. In each case the speakers are shown sitting behind the receivers, while text clearly states that a 10 inch speaker is included with the receivers.
The grill patterns of the speakers shown in the catalog may or may not match the pattern shown in the lead photo. Photo resolution makes it hard to determine.
