To my HW-101 I use the SB-600 speaker unit with the HP-23B power supply built in. To my HW-100 I use the power supply HP-23A but I don't have any SB-600 to place it in. So I have made my own counterpart with the same functionality, but made of 8mm plywood and painted in Heathkit green color. The SB-600 is equipped with an oval 6"x9" speaker driver. I don't have any of the same kind but I have a Philips 9710 M/01 full-range speaker driver with an AlNiCo magnet. The speaker driver is approximately of the same age as my HW-100. The Philips 9710 is circular shaped and 8½" in diameter so the cabinet has to be slightly higher than the SB-600 but the width is the same, so I can place them on top of each other.


The Philips 9710 is probably the best full-range speaker driver ever made. It came on the market in the mid 50's and was still in production until the early 80's. During the years the magnet system has been improved but already the first version had very good characteristics. The 9710 M/01 had an AlNiCo magnet system but the later 9710/M8 had a ceramic magnet system. There was also high impedance versions for use whith transformerless tube amplifiers. 9710/AM was 800 ohm and 9710/BM was 400 ohm. 9710/M8 was later designated AD9710/M8. The 9710 has been used in High End HiFi Speaker Systems such as several versions of the Carlsson/Sonab speakers.


My 9710 hade a few holes and fractures in the cone and the suspension showed that it had been used for several years. I impregnated the cone by appying a thin layer of water based glue for wood and I reinforced the suspension by applying a couple of layers of rubber glue.


To use such a full-range speaker driver in SSB/CW apparatus is really not the perfect choice, but you use what you happen to have  ;-)