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

Mike. Watterson · 28th Jan 2019, 7:56 pm

So HT of a 90V nominal set might be designed for 100V down to 54V. Certainly 75V to 85V is fine for mains derived HT or using disposable lithium cells (tricky!). Typically HT is less critical so per cell endpoint is 0.9V per cell.
Maximum volume will gradually degrade with falling HT.
The set will simply stop with too low LT on the mixer/oscillator.

28th Jan 2019, 7:56 pm	#17
Mike. Watterson Heptode Join Date: Dec 2014 Location: Limerick, Ireland. Posts: 901	Re: Roberts R66 diode MR2 So HT of a 90V nominal set might be designed for 100V down to 54V. Certainly 75V to 85V is fine for mains derived HT or using disposable lithium cells (tricky!). Typically HT is less critical so per cell endpoint is 0.9V per cell. Maximum volume will gradually degrade with falling HT. The set will simply stop with too low LT on the mixer/oscillator.