LF Transformers - UK Vintage Radio Repair and Restoration Discussion Forum

E93AFAN · 18th May 2022, 9:33 pm

Has anyone found a suitable, inexpensive modern alternative to the 3:1 and 4:1 LF transformers often specified in pre-war and early post war circuits. Sometimes Lissen, Marconiphone etc., transformers are advertised on trading websites but I'm not stupid enough to pay £60 or more for an (often) untested item where the seller does not accept returns!

I have read that removing an LF transformer is "doable", but would this not reduce overall gain.

Thanks for your help as always.

Ed_Dinning · 19th May 2022, 8:58 am

Hi, yes there were various fixes used in the war years when the transformers were not obtainable. This involved reverting to R-C coupling with a subsequent loss of gain.

There were RS parts available through the 60's, a bit smaller but worked well enough.

They can be rewound, not difficult, just tedious

Ed

18th May 2022, 9:33 pm	#1
E93AFAN Tetrode Join Date: Mar 2022 Location: Chippenham, Wiltshire, UK. Posts: 71	LF Transformers Has anyone found a suitable, inexpensive modern alternative to the 3:1 and 4:1 LF transformers often specified in pre-war and early post war circuits. Sometimes Lissen, Marconiphone etc., transformers are advertised on trading websites but I'm not stupid enough to pay £60 or more for an (often) untested item where the seller does not accept returns! I have read that removing an LF transformer is "doable", but would this not reduce overall gain. Thanks for your help as always.

19th May 2022, 8:58 am	#2
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: LF Transformers Hi, yes there were various fixes used in the war years when the transformers were not obtainable. This involved reverting to R-C coupling with a subsequent loss of gain. There were RS parts available through the 60's, a bit smaller but worked well enough. They can be rewound, not difficult, just tedious Ed