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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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11th Jan 2008, 1:51 pm | #1 |
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Mains filter cap - Bush DAC90A
I've been looking for an X2-class mains filter cap for the Bush DAC90A. The service data for the radio indicates that it is a 0.1uF 500V cap. However, I have not been able to find any 500V rated X2-class caps. All the ones I have found have been rated 250 or 275 VAC. How critical is it to stick to the original specification for this cap? can I get by with the lower voltage rated caps?
Don P.S. I found a couple of X2-class caps in a defunct computer power supply with the following markings: 0.22K 275V and 0.33K 275 volts. I am presuming that the 0.22K cap is a 0.22uF and the other is a 0.33uF cap; am I correct? Can these be used instead of the 0.1uF cap in the radio? |
11th Jan 2008, 1:54 pm | #2 |
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Re: Mains filter cap - Bush DAC90A
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11th Jan 2008, 1:56 pm | #3 |
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Re: Mains filter cap - Bush DAC90A
That was an awfully quick response! you replied before I posted my edited message. What do you think about the 0.22 or 0.33K caps that I have mentioned?
Don |
11th Jan 2008, 2:04 pm | #4 |
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Re: Mains filter cap - Bush DAC90A
You can use the 0.22uF cap, or use both in series. The value isn't critical. Most (all?) scrap switch mode PSUs will contain suitable X2 caps.
In most cases the radio will work perfectly well with this cap removed altogether. Paul |
11th Jan 2008, 2:15 pm | #5 |
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Re: Mains filter cap - Bush DAC90A
Although without it, you may get more interference, buzz, clicks, from your DAC90A when you switch on items like fluorescent lights.
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11th Jan 2008, 2:49 pm | #6 | |
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Re: Mains filter cap - Bush DAC90A
Quote:
In the 50s there were still lots of trams and trolley buses about, all with electromechanical speed controls I would replace this cap myself as a matter of principle, but I've run sets for extended periods with it removed and haven't noticed either excessive impulsive interference or modulation hum. Paul |
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11th Jan 2008, 2:52 pm | #7 |
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Re: Mains filter cap - Bush DAC90A
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11th Jan 2008, 3:32 pm | #8 | |
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Re: Mains filter cap - Bush DAC90A
Quote:
Paul |
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11th Jan 2008, 3:57 pm | #9 |
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Re: Mains filter cap - Bush DAC90A
It's neater and easier to mount the new cap on the back of the mains switch thus:
It's also cooler there. Nick |
11th Jan 2008, 4:34 pm | #10 |
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Re: Mains filter cap - Bush DAC90A
I have to confess that before I knew better I replaced the filter cap in my DAC90A with a 1000V Polypropylene type like the yellow one in the picture. It fitted the clip nicely. I have no intention of changing it.
I use the correct X2 items on new restorations.
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11th Jan 2008, 5:45 pm | #11 | |
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Re: Mains filter cap - Bush DAC90A
Quote:
Don |
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11th Jan 2008, 5:46 pm | #12 |
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Re: Mains filter cap - Bush DAC90A
I wouldn't worry Graham, it may not meet current safety requirements but I'll bet it's a much better component than the original cap, even when it was new!
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11th Jan 2008, 6:00 pm | #13 | |
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Re: Mains filter cap - Bush DAC90A
Quote:
Paul |
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12th Jan 2008, 12:24 am | #14 | |
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Re: Mains filter cap - Bush DAC90A
Quote:
Mains filter caps fitted to modern equipment (such as computer power supplies) are fitted to help prevent 'hash' from the SMPSU getting back onto the mains. Cheers. Simon.
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