UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Two or three IF stage Chinese radio kits.

Dual Standard · 31st Dec 2016, 4:06 pm

I agree the biasing of VT2 & VT3 looks a tad odd.
In the diagram R4 has an ‘icky’ just above it which to me means ‘read the notes’. The bottom line of text(?) on the diagram also happens to have ‘R4’ half way through. I wonder if R4 should be selected for best performance? I would temporarily substitute R4 with a 47K or 100K pot and try adjusting it for 0.5mA at ‘B’ (VT2 collector), or perhaps just for the most pleasing audio.

Mike

31st Dec 2016, 4:06 pm	#10
Dual Standard Hexode Join Date: Aug 2005 Location: Cheshire, UK. Posts: 263	Re: Two or three IF stage Chinese radio kits. I agree the biasing of VT2 & VT3 looks a tad odd. In the diagram R4 has an ‘icky’ just above it which to me means ‘read the notes’. The bottom line of text(?) on the diagram also happens to have ‘R4’ half way through. I wonder if R4 should be selected for best performance? I would temporarily substitute R4 with a 47K or 100K pot and try adjusting it for 0.5mA at ‘B’ (VT2 collector), or perhaps just for the most pleasing audio. Mike