UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

198 kHz · 25th May 2020, 5:50 pm

It was to prevent transmitter noise on short exchange lines or PBX extensions.
The jack units in my TRS used them, as we were just across the road from the exchange.
My recollection is that there wouldn't necessarily be noise without it, but without cuent limiting by the 6B the transmitter insert in the headset could 'fry' in the long term.

25th May 2020, 5:50 pm	#2
198 kHz Triode Join Date: May 2014 Location: Worcestershire, UK. Posts: 37	Re: GPO Jack unit 1B and regulator 6B It was to prevent transmitter noise on short exchange lines or PBX extensions. The jack units in my TRS used them, as we were just across the road from the exchange. My recollection is that there wouldn't necessarily be noise without it, but without cuent limiting by the 6B the transmitter insert in the headset could 'fry' in the long term.