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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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10th Jun 2020, 7:00 am | #21 |
Hexode
Join Date: Mar 2012
Location: East Yorkshire, UK.
Posts: 354
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Re: RS Audio Transformer
Many thanks for the comments folks. Thanks for the video Kevin, that's very useful. It certainly gives good results from that demonstration. I think Dave did mention that by taping the laminations some bass response would be lost?
I am a bit vague about saturation though. What effect does it have audibly and electrically? Does it cause any damage? All help appreciated!
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Howard |
10th Jun 2020, 8:29 am | #22 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,902
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Re: RS Audio Transformer
I would leave it as it is. On a set running only a smallish quiescent current (<40mA) it ought to be far enough outside saturation. By my calculations from the datasheet, it is already going to be a bit light on bass even for a small radio, so rearranging the laminations to create a gap to keep it further away from saturation will not be of great value, while the loss of bass may be noticeable.
Saturation sets the onset of distortion and puts an ultimate limit on the power a transformer can pass. David
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10th Jun 2020, 10:18 am | #23 |
Heptode
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
Posts: 631
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Re: RS Audio Transformer
I also recommend that you don't try to re-arrange the laminations in this particular transformer - I have already tried to do this but had to give up... they are not only tightly clamped together but the varnish used is like a strong glue and they simply will not come apart : I tried solvents as well to no avail.
I have modified certain 100V line output transformers which came apart easily but as has already been stated, the inductance reduces and with the majority of these, it is not particularly high to start with. The earlier version of this transformer that RS used to sell (different part no.) did have stacked 'E' and 'I' laminations with an insulating gap but the current one, as you've noticed, is interleaved. When this changeover occurred I 'phoned RS technical help line to enquire about these differences but they didn't know what I was talking about... Andy
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10th Jun 2020, 10:55 am | #24 |
Hexode
Join Date: Mar 2012
Location: East Yorkshire, UK.
Posts: 354
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Re: RS Audio Transformer
Saturation sets the onset of distortion and puts an ultimate limit on the power a transformer can pass.
Like an automatic limiter by the sound of it. So no adverse effect on the radio itself. So I certainly need to leave it alone which I'm more than happy with. You've all been really helpful and informative, thank you very much!
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Howard |
10th Jun 2020, 3:24 pm | #25 |
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Re: RS Audio Transformer
It won't damage the radio, but you might not like the sound.
David
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10th Jun 2020, 4:12 pm | #26 |
Hexode
Join Date: Mar 2012
Location: East Yorkshire, UK.
Posts: 354
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Re: RS Audio Transformer
That was my main concern David, thank you.
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Howard |
10th Jun 2020, 4:31 pm | #27 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,274
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Re: RS Audio Transformer
If it's going into a DAC90A then I wouldn't hesitate. Certainly mine, and I'm not blowing my own trumpet here, is one of the nicest sounding AM-only valve radios I have. I have quite a handful of DAC90/90A's but none restored, so I can't compare it to an original transformer.
Maybe I should try and make a better video.
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Kevin |
10th Jun 2020, 5:13 pm | #28 |
Hexode
Join Date: Mar 2012
Location: East Yorkshire, UK.
Posts: 354
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Re: RS Audio Transformer
I think the video was very helpful, it gives a good idea, always difficult to get exact sound with the variables involved. I also have a DAC90a awaiting attention which I know has an O/C transformer. I agree, very interesting to compare.
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Howard |
10th Jun 2020, 7:40 pm | #29 |
Heptode
Join Date: Sep 2013
Location: Ellesmere, Shropshire, UK & Co. Cork, Ireland.
Posts: 502
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Re: RS Audio Transformer
I've used the RS output transformer in a Bush BS35. It performed well and I did not notice any change when l managed to mend and replace the original transformer back. This set overall sounds superb when fed audio from a Bluetooth receiver.
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10th Jun 2020, 7:48 pm | #30 |
Octode
Join Date: Mar 2006
Location: Watford, Hertfordshire, UK.
Posts: 1,270
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Re: RS Audio Transformer
There are places on the internet where this transformer was used as a transformer in a low power push-pull headphone amplifier. I guess having no air gap would be a bonus here, using tags 1 & 4 to feed the Anodes with tag 2 providing the HT.
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