Original amplifier made and used by the Building Research Station in vibrating acoustic strain-gauge experiments
Penultimate r.f. amplifier from No. 1 sound transmitter, Croydon (less valves) Penultimate r.f. amplifier from No. 1 sound transmitter
Dual-trace amplifier unit type 3A6 serial no.100859 for use with Tektronix Oscilloscopes, by Tektronix Guernsey Ltd., CI. Dual-trace amplifier unit type 3A6 serial no.100859 for use with Tektronix Oscilloscopes 1970-1984