[ARC5] Simple Question Arc-5 receiver power supply requirements?

[Dennis Monticelli]

If you select a common 24 or 25.2Vac 1A transformer you can power the
filaments directly and use a simple half-wave doubler off the same
winding to give you about 60 to 70V.  This works because the B+ draw
is light.  I measure 10mA of drain on my BC-453B with about 60V on the
plates. That was AFTER I replaced a bunch of leaky caps.  With lower
plate voltage the overall receiver gain is lower and the max audio
output power is limited.  I consider neither of these issues to be a
bid deal.  If you wish to keep your caps original, then the radio will
definitely thank you for running it off a lower voltage. I do not
consider regulation to be necessary.

BTW, they run great off batteries too.  Use rechargeables for the
filaments (12V converted or virgin) and a stack of about 7
nine-volters for the B+.  If your caps aren't leaky, the nine-volters
will last and last.  Hum will be non-existant.

Dennis AE6C

On 12/4/12, J. Forster <jfor at quikus.com> wrote:
> Do you plan on building the supply in a separate box or to plug in place
> of the dyno?
>
> If I were not a pureist and partial to dynos and dynaverters, I'd build an
> AC supply to plug in where the dyno was mounted and put out oth the 250
> VDC and 28 VDC. Furthermore, I'd regulate both supplies, which is simple
> enough today with the semiconductors available now. Regulation will allow
> you to use smaller filter caps too. No modifications to the set would be
> required.
>
> I suspect the entire thing could be built on a single, single sided PCB
> with a hole pattern to match the dyno.
>
> Another thought. You could use a standard wall-wart that puts out 24 or 28
> VAC and use a little filament transformer wired backwards with a doubler
> for B+. This would eliminate having line appear on the unit.
>
> FWIW,
>
> -John
>
> ==============
>
>
>
>> Hello:
>> I started collecting ARC-5 receivers a few years ago and I find I have
>> accumulated  a nice heap.  I'd like to put them into operation but I need
>> power supplies.  Rather than source parts from my junk box and ebay and
>> build multiple different power supplies, I decided to do a clean design
>> from the ground up using ordinary Mouser- Digikey type parts which will
>> allow me to make several identical supplies.
>>
>>
>> I thought the simple part would be to look up the voltage-current
>> requirements but my efforts turned up a wide range of values.    The
>> median seems to be 250vdc-80 mA and 28vdc - 400 mA obviously for
>> receivers
>> still wired for 28vdc filaments.
>>
>> I have also read of using less than 250 vdc to reduce the component
>> voltage stress.
>>
>>
>> Filament voltage was of course dc in the original applications,  ham
>> conversion generally used ac but I have seen some comments about
>> returning
>> to dc filament operation.
>>
>> So what do you guys think is the ideal power supply operating
>> specifications?  250vdc at 80 mA for the plates or something
>> lower----28vac at 400 mA for the filaments or is there any practical
>> reason to use dc?  Current specs listed above are actual expected
>> receiver
>> power supply currents with no power supply safety margin
>>
>>
>> thank you in advance for your comments.
>>
>> bruce   KJ3Z
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>
>
>