UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Simon SP5 Hybrid Reel to Reel Tape Recorder Restoration

DMcMahon · 20th Mar 2023, 1:13 am

The ERT Service Sheet shows the SP5 as a Hybrid machine with just 2 valves verses 16 transistors, grid coupling capacitors is not such a potential issue as an all valve machine.

Looking at the schematic it looks like there is only 1 true grid coupling capacitor C38 (0.01uF) coupling the anode output of V1a (EF86) microphone pre-amp first stage through (via potentiometers) to the control grid input of V2a (ECC83) pre-amp second stage.

However your photos shows more than 2 valves so that is confusing, maybe there was a early build SP5 with more valves/all valves ?

David

20th Mar 2023, 1:13 am	#5
DMcMahon Dekatron Join Date: Apr 2019 Location: Worthing, West Sussex, UK. Posts: 6,604	Re: Simon SP5 Valve Reel to Reel Tape Recorder Restoration The ERT Service Sheet shows the SP5 as a Hybrid machine with just 2 valves verses 16 transistors, grid coupling capacitors is not such a potential issue as an all valve machine. Looking at the schematic it looks like there is only 1 true grid coupling capacitor C38 (0.01uF) coupling the anode output of V1a (EF86) microphone pre-amp first stage through (via potentiometers) to the control grid input of V2a (ECC83) pre-amp second stage. However your photos shows more than 2 valves so that is confusing, maybe there was a early build SP5 with more valves/all valves ? David