The Hoffman 706 series Trans-Solar radio was one of the first mass-production solar radios and actually the first to be purchased by the general public in very large numbers. It was released in 1958, a year after the Hoffman P411 series in 1957. The radio was powered by 12 solar cells and could operate from lamplight as well as direct sunlight or, when neither was available, by an internal 4-volt mercury cell. The top mounted solar panel could only be used to power the radio and it did NOT act to recharge the internal battery as was the case with its’ predecessor Hoffman P411 series Home & Travel Solar Radio. A slide switch on the back side allowed the user to choose from “solar” or “batt” (battery).
Initial list price of the Trans-Solar radio was $75 (which was but half of the initial price of the earlier P411 Home & Travel Solaradio) and many were bought by consumers over the next few years at that price and then as the initial price was periodically lowered to compete with the many other transistor radios coming onto the market; particularly those from Japan. It measured 3-1/4” x 5-3/4” x 1-3/4” thick. A chromed carrying handle would extend the overall height to 5” but that handle could also be folded underneath the radio or set at a 30 degree rear angle for an attractive display and a useful direction of its’ sound. The radios were offered in seven colors. Oyster White (OP-706), Ebony (KP-706), Mocha (BP-706), Red (RP-706), Turquoise (TP-706), Espresso (CP-706) and Pink (PP-706).
From time to time an example will appear today in a light or mint green color and is often assumed by the owner or potential buyer to be a rare color version. This model was NEVER made in “green” and all such examples are actually turquoise cabinets which have been discolored over the years (probably from exposure to ultraviolet or sun light). A quick inspection of the very bottom surface or the inside of the cabinet (seen by removing the battery door cover) will confirm the true original turquoise color. (Some of our pictures here will include both the “mint green” and actual turquoise sets).
This radio was a very good performer with excellent sensitivity, selectivity, and sound. Many original examples are still playing well today and, although now a “senior citizen radio” a high percentage of the solar panels will be found to still be providing sufficient energy to power the radio. This model Hoffman, like it’s predecessor “Solaradio” was entirely USA-made. The plastic from which the cabinets were made was quite suitable for a portable radio and seldom experienced significant damage under ordinary usage and reasonable handling.
The generally used 1/4 pie-shaped solar cells are the same shape and size as those found in the earlier Admiral “Sun Power Pak” which was made in 1956 and used in conjunction with Admiral’s 7L Series radios (the FIRST solar powered radio). Hoffman had (as is explained in our History of Early Solar Radios article) in mid-1955 purchased the company who marketed the first commercially manufactured solar cells and which had also been used in Admiral’s revolutionary solar radio.
A few oddities of the 706 series are known, such as a factory-made example with the solar-battery rear switch and the word Trans-Solar on the tuning knob but with a plastic insert across the top where the solar panel would ordinarily be mounted. Some sets are also known with a different appearing solar panel – like those found on the later 709 series sets. An paper label inside the battery cover shows the model number based on cabinet color – but some sets have been seen with a wrong model number label pasted inside.
Radios photographed from MOSE and the Bill Burkett collection