Mike Zuccaro describes his Harvey 193-R model 47 FM HiFi receiver:
"This is a 17 tube, dual conversion high fidelity FM receiver, covering 85-115
MHz. A type 956 acorn tube is the RF amplifier, followed by a 9002 local
oscillator. Plate voltage to the L.O is supplied by a VR-150 regulator.
Ceramic tube sockets are used, and a massive tuning cap.The L.O runs 10.7 MHz below the incoming RF, and a 6AK5 mixer tube then
converts it to the first I.F of 10.7 MHz. This is then mixed again, via a 6K8
pentagrid converter with a 6.1 MHz crystal oscillator. The difference is 4.5
MHz, which is then amplified by 2 stages of double tuned I.F
transformers, driven by 2 6AB7 tubes, and then fed to 2 more tuned 6AC7
limiters.A 6h6 discriminator is used, presumably Foster-Seely. Another 6H6 tube is
used for the muting/squelch. The demodulated audio is fed to a 6AC7 voltage
amplifier, thru the bass and treble controls, followed by a 6SL7, 6SJ7, a 6J5
phase splitter to a pair of push-pull 6V6's.A large UTC output transformer is used, and can be strapped to drive an 8 ohm
speaker. The unit also has a phono input. a 5U4 rectifier tube is used.Interesting features - an antenna tuning control, a 2 position "mute" switch
(not variable), lots of negative feedback used in the audio stage. 2
meters, one for signal strength (50 uA) and one for center of station.
Anyone who has a schematic or manual for this unit? Please contact me!"
Email: Mjzuccaro@aol.com