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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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5th Mar 2021, 9:48 pm | #1 |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 417
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DAC90A speaker (later model)
Hi
This is the speaker from my 1957-ish DAC90A. Earlier models don't usually have a screw on the back of the magnet, but this one does. Does anyone know what this is for? Thanks Helder |
5th Mar 2021, 10:02 pm | #2 |
Nonode
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,820
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Re: DAC90A speaker (later model)
I would think it will be securing the pole piece, maybe other ones are glued instead? I must say I’d not noticed! I just looked at the one that I’d borrowed for my Ekco A22, and that has a hole where the screw should be! It works fine and doesn’t rattle or run, so I don’t think it ever had a screw fitted.
Regards Lloyd |
5th Mar 2021, 11:59 pm | #3 | |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 417
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Re: DAC90A speaker (later model)
Quote:
Helder |
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6th Mar 2021, 11:28 am | #4 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,580
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Re: DAC90A speaker (later model)
There might also be rust particles between the voice coil and pole-piece. You might be able to shift them with an airline (carefully) or worst case, remove the centre bolt and pole-piece, clean any debris away and use paper shims to reassemble.
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6th Mar 2021, 12:21 pm | #5 | |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 417
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Re: DAC90A speaker (later model)
Quote:
Helder |
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6th Mar 2021, 12:39 pm | #6 |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 417
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Re: DAC90A speaker (later model)
Here are a few photos. A very important improvement, especially because the cream urea-formaldehyde cabinet is particularly prone to cracking right above the dropper, was the addition of an aluminium dissipation plate - inspired by a photo on Yannis Karalis' website. The radio now runs only slightly warm. Bluetooth operation is indicated by a white LED mounted on the switching relay+BT board (by Colin Boggis), which gives out a soft yellow through the translucent cabinet.
Helder |
7th Mar 2021, 4:40 pm | #7 |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 417
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Re: DAC90A speaker (later model)
Glueing the spider seems to have fixed the issue. I still have some distortion/light vibration but only for very low frequencies and high volume, which I guess is normal as the speaker is probably being overdriven.
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9th Mar 2021, 12:35 am | #8 |
Triode
Join Date: May 2017
Location: West Midlands, UK.
Posts: 21
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Re: DAC90A speaker (later model)
Very neat restoration Helder Crespo
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9th Mar 2021, 11:34 am | #9 |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
Posts: 417
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Re: DAC90A speaker (later model)
Thanks bj Keet. This is actually my very first vintage radio and restoration. I got it also to learn and practice prior to working on my first Bush TV22. For some time it was the ugly duckling in my small collection (2 DAC90As and 2 TV22s), but it's looking and working quite well now.
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