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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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21st Feb 2019, 10:39 pm | #1 |
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Dynatron Nomad
Hi all
Does any have or know of a good loudspeaker replacement for a dynatron nomad Tp11 Many thanks |
22nd Feb 2019, 8:04 am | #2 |
Rest in Peace
Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 4,100
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Re: Dynatron Nomad
Loudspeakers were very often not specific to a single radio. Why not give the spec. of the loudspeaker you want, to save everyone having to look it up before they can potentially help you, Overall dimensions, fixing centres, impedance, depth front to back may also be important.
Mike |
22nd Feb 2019, 11:40 am | #3 |
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Re: Dynatron Nomad
Morning
Yes .. good point. Have included a picture . The unit is 7 inches by 4 1/8 . The circuit diagram states 50 ohms. Many Thanks |
22nd Feb 2019, 11:46 am | #4 |
Rest in Peace
Join Date: Mar 2011
Location: Basildon, Essex, UK.
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Re: Dynatron Nomad
That one is pretty unusual, what exactly is wrong with it, is it open circuit, have you checked the solder connections the the flexible braid that goes to the speech coil.
Mike |
22nd Feb 2019, 12:11 pm | #5 |
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Re: Dynatron Nomad
The coil is rusted up and there is no movement in it.
It's showing as open too. Its got left in a very damp garage for a few years most of the unit was damp inside but have been able to get it working . Just the speaker to go. |
22nd Feb 2019, 12:35 pm | #6 |
Octode
Join Date: Feb 2006
Location: Bristol, UK.
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Re: Dynatron Nomad
I got one for my Dynatron from here:
https://www.ebay.co.uk/itm/Replaceme...m1c7a10bd34:m: The speaker on mine was open circuit. I know eBay is sometimes frowned upon here but this just a link to a part nor a sale Malcolm |
22nd Feb 2019, 12:38 pm | #7 |
Dekatron
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Location: Leominster, Herefordshire, UK.
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Re: Dynatron Nomad
Finding a 50R 7*4 loudspeaker may be difficult.....
Maybe fit some beefier output transistors- AC128 or similar and use a 15R one? You might need to tweak the bias. Silicon PNP TO220 would be bombproof but would certainly need to be rebiassed. Alternatively, you could simply (reversibly?) fit a cheap audio amp module to do the same job again with 8 or 15 ohm speaker. A secondhand Hacker one would be nicely insulting to the set Edit: just seen the Ebay link but it seems to refer to 8R speakers rather than high impedance ones.
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22nd Feb 2019, 1:40 pm | #8 |
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Re: Dynatron Nomad
Thanks for the feedback.
Just a thought.. would having a 15 or 8 driver with suitable resistor in either parallel or series work? The driver would need to quite sensitive I would imagine. Last edited by opus242; 22nd Feb 2019 at 1:51 pm. |
22nd Feb 2019, 9:47 pm | #9 |
Dekatron
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Re: Dynatron Nomad
Yes...... but even a15R driver, padded up to 50R would get less than 10% of the audio power.
A 2:1 stepdown audio transformer would turn 15R into 60R- not a bad match. You would need to be careful with dc though- a 1000uF cap between the output of the amp and the TX primary would be a wise precaution. I'd go with siliconising it myself_ BTDT with a Hacker which was much trickier to rebias being a directly coupled amplifier. You can keep the old bits safe in case the real deal speaker does turn up.
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22nd Feb 2019, 10:49 pm | #10 |
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Re: Dynatron Nomad
Hi all
This may be a project too far for me. I have not worked with transistors before and it end well. Cheers Last edited by AC/HL; 23rd Feb 2019 at 12:50 am. Reason: Forum rules |
23rd Feb 2019, 8:08 pm | #11 |
Octode
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Location: Harrow, London, UK.
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Re: Dynatron Nomad
I have one of these radios which is of no interest to me. I will check out the loudspeaker and if it is what you need, it's yours for p&p.
'Will get back to this thread with further details soon. Chris |
23rd Feb 2019, 8:25 pm | #12 | |
Dekatron
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Re: Dynatron Nomad
Quote:
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23rd Feb 2019, 11:28 pm | #13 |
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Re: Dynatron Nomad
Simpson's . Pm sent. Many Thanks
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23rd Feb 2019, 11:32 pm | #14 |
Dekatron
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Re: Dynatron Nomad
Looks like an incontinent rocking horse has pitched up! Hopefully it can be sorted fairly easily now.
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26th Feb 2019, 9:50 am | #15 |
Octode
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Re: Dynatron Nomad
Hi Rob
Please find attached photos of the loudspeaker as promised. Is Techman a Friend? The speaker is funtioning well and as it has been removed from a Nomad, I am confident that it is what you need but just in case have a look and confirm. Best wishes Chris |
26th Feb 2019, 10:01 am | #16 |
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Re: Dynatron Nomad
Morning
looks perfect. many thanks |
7th Mar 2019, 10:10 pm | #17 |
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Re: Dynatron Nomad
Many thanks to Simpsons radio is up and running.
Many thanks |