Roberts RMB Output Trans - UK Vintage Radio Repair and Restoration Discussion Forum

Niechcial,Steve · 27th Feb 2023, 5:46 pm

I have one of these with an o/c output transformer. Can anyone suggest a suitable replacement please? I'm assuming the speaker is 3 ohm impedance?
Thanks,

Steve

cathoderay57 · 27th Feb 2023, 10:13 pm

Hi Steve, the DL94 wants to see a 10k anode load so for a 3 Ohm speaker you want a turns ratio of approximately 60:1. RS Components still supply a multi-tapped audio transformer that will do the job so long as you have space to fit it https://uk.rs-online.com/web/p/audio...ormers/2106475. Check the data sheet at this link for physical size and how to connect it. They aren't cheap though. If you are lucky somebody on the Forum might have a spare up for grabs. Jerry

Niechcial,Steve · 27th Feb 2023, 11:54 pm

Thanks Jerry.

27th Feb 2023, 5:46 pm	#1
Niechcial,Steve Hexode Join Date: Jan 2007 Location: Beckenham, London, UK. Posts: 373	Roberts RMB Output Trans I have one of these with an o/c output transformer. Can anyone suggest a suitable replacement please? I'm assuming the speaker is 3 ohm impedance? Thanks, Steve

27th Feb 2023, 10:13 pm	#2
cathoderay57 Nonode Join Date: Oct 2017 Location: Bristol, UK. Posts: 2,382	Re: Roberts RMB Output Trans Hi Steve, the DL94 wants to see a 10k anode load so for a 3 Ohm speaker you want a turns ratio of approximately 60:1. RS Components still supply a multi-tapped audio transformer that will do the job so long as you have space to fit it https://uk.rs-online.com/web/p/audio...ormers/2106475. Check the data sheet at this link for physical size and how to connect it. They aren't cheap though. If you are lucky somebody on the Forum might have a spare up for grabs. Jerry

27th Feb 2023, 11:54 pm	#3
Niechcial,Steve Hexode Join Date: Jan 2007 Location: Beckenham, London, UK. Posts: 373	Re: Roberts RMB Output Trans Thanks Jerry.