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

[J. Forster]

I like regulation because the raw DC can have much more ripple w/o any
ripple on the DC. You can also use a Beta-C configuration, but regulators
are cheap.

-John

===========



> 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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>>
>>
>>
>
>