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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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13th Oct 2018, 9:49 pm | #1 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 773
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TCS Receiver Output Transformer
Hi All,
Does anyone have a AF output transformer removed from a TCS-series receiver? If so, I wonder if they could give me the resistance values of the windings, particularly the primary. Regards Roger |
13th Oct 2018, 10:37 pm | #2 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,998
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Re: TCS Receiver Output Transformer
Don't worry about the DC resistance - if anything 'the lower the better' applies.
Rather, focus on the impedance-ratio/match to your intended load. The 12A6 output-bottle in the TCS8/12 is pretty much the same as a 6V6 and so you need to present a load-impedance of something around 5-7K at the anode. The TCS I've got here - which I bought from "GWM Radio" as a kid in the 1970s - has a generic 5K-to-3-Ohm output-transformer which I fitted in place of the original (which was designed to drive a 500-Ohm load). The transformer in question I actually salvaged from a radio I found dumped in a stream near Ivybridge in Devon while on holiday with my parents. [I got a 6AT6 and a couple of other valves from it too]. |
14th Oct 2018, 10:55 am | #3 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 773
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Re: TCS Receiver Output Transformer
Many thanks for the comments. I'm fairly sure that the primary winding of the TCS transformer is O/C but I just wanted to check that it wasn't some very thin, high resistance wire in use. I've used an AVO8 to check and can't get any reading, which is fairly conclusive, I feel.
I have a couple of generic valve output transformers here which will do the job, including one I bought for use with an HRO receiver, so I will be trying one of those. Next step is to find out if another fault took out the original iron! All the best, Roger Last edited by G3VKM_Roger; 14th Oct 2018 at 10:56 am. Reason: add |
14th Oct 2018, 11:37 am | #4 |
Octode
Join Date: Oct 2008
Location: Littlehampton, West Sussex, UK.
Posts: 1,465
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Re: TCS Receiver Output Transformer
Roger,
I do have one of these transformers I'm sure but it's buried in one of 6 really heavy boxes of transformers and my strength ran out before I could find it. However, my TCS 12 instruction book on page 99 states:- T201 Primary 7500 Ω, Sec. 500 Ω CT. 2.4 W 200-5000 CPS. Part No 677N227. When I was playing with TCSs I found that almost any average audio output transformer was ok assuming you wanted to drive a speaker. Hope this helps, sorry I'm a bit late. Jim |
14th Oct 2018, 2:46 pm | #5 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 773
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Re: TCS Receiver Output Transformer
Hi Jim,
I'd just found the spec on the transformer but thanks for confirming it. I think a lot of these items failed during the life of the set. I do have a couple of others I can try, so will not bother you with digging out an original. Hope you're well, 73 Roger |