Special thanks to transistor guru Bob McGarrah for lending his technical expertise to this page. Bob formerly ran a website called «Bob’s Virtual Transistor Museum & History». Now I’m not a ‘tech guy’ being primarily concerned with cabinet design and the cultural impact of the transistor radio so my commentary on chassis design is rudimentary (some would say primitive) at best. In saying that, there is culture and history in transistors and Bob’s enthusiastic commentary on the inner workings of the Roland 66 is a testament to that!
On the use of GTC Transistors: “After removing the chassis from its case I discovered a collectors dream from my point of view. Not only is the 6TR (66) hand wired with socketed transistors, but the transistors are not the typical «big name» jobs. Roland of course did not make transistors and had to purchase them from one of the available suppliers at the time. I believe this was Roland’s first transistor radio and they happened to choose to use devices made by another company which was a minor producer; General Transistor Corporation (GTC). GTC was among the early commercial transistor manufacturers and their products showed up in some pocket style hearing aids as well as a very few radios like the 6TR (66). GTC chose not to use the more typical RETMA «2N» numbering scheme for some reason, but for me this is actually another collecting «plus»».
On the electronic design and chassis components Bob states: “The Roland 6TR is a typical super heterodyne design and uses six transistors, three PNP RF and three PNP AF. Roland used a combination of miniature and conventional sized components to produce the most compact and efficient layout that they could. The whole thing is just a bit over 4″ square (excluding the control shafts). No doubt in 1957, just two years after the transistor radio era began, it was close to being state of the art construction”.
I’ve not removed the chassis from this example as I fear damaging the leather case. With regards to chassis design, Bob points out that some of the wiring on the Roland 66 is shielded by a metal tube, he says “This is the first transistor radio I’ve seen which uses such a design. It is more typically applied to high end audio equipment. I’m not sure what the engineers were thinking here, but it’s a nice touch”.
Bob finishes his commentary on the Roland 66 by saying “It is a fine example of a first generation transistor radio which proudly carried the label «Made in U.S.A.» I heartily agree.