[ARC5] Receiver Power Supply

[Bill Cromwell]

Ho Mac,

I don't think he wants a full wave bridge, either. I run mine at 90 
volts B+ because they run a little cooler and will probably last a 
little longer. When I go as low as 45 volts the performance falls off 
noticeably but not intolerable. I have to increase the gain. Others say 
they have found something close to 180 volts just about perfect. At the 
lowest voltages some biasing resistors have to be changed and the screen 
voltage divider has to be undone. I run mine on a stack of 9 volt 
batteries at about 15 mA for the total load. At 45 volts the current 
drain is half that.

I get better results with DC on the heaters. Current draw will under ~ 
half amp for all six tubes at ~24 volts. "24 volt" heaters will be happy 
with anything under about 30 volts and likely work well in receivers 
down under 20 volts. My DC heater wiring is picking up some AC hum from 
nearby utility wiring (I run batteries). When I switch off the heaters 
the hum and background noise drops instantly but the receiver keeps 
playing for a minute of so. More chokes and filters coming right up.

73,

Bill  KU8H


On 04/28/2015 02:36 PM, D C _Mac_ Macdonald wrote:
> I believe some folks here on the ARC-5 list, recommend keeping the B+ voltage down around 175V or lower to ease stress on the old capacitors in the receivers.  Using a choke input filter setup with this transformer should probably get you into that "safe" territory at a minor cost in audio output power.
>   
> * * * * * * * * * * *
> * 73 - Mac, K2GKK/5 *
> * (Since 30 Nov 53) *
> * k2gkk hotmail com *
> * Oklahoma City, OK *
> * USAF & FAA (Ret.) *
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>   
>
>   
>> From: carpenterpa at tds.net
>> Date: Tue, 28 Apr 2015 13:43:44 -0400
>> To: arc5 at mailman.qth.net
>> Subject: [ARC5] Receiver Power Supply
>>
>> Has anyone on the Forum built a power supply for the ARC-5 receivers using a Stancor PC-8417 power transformer?
>>
>> This transformer has three secondaries:
>>
>> 220-0-220v @ 50mA
>> 25.5v @ 0.5A
>> 6.3v @ 0.6A
>>
>> I was thinking of using a 6X5 as the rectifier for the B+. I assume a full wave bridge would work for the 24v filaments to the Command Set receiver? What is the current draw for the receiver filaments at 24v? Is the 0.5A close enough?
>>
>> If someone has seen a power supply circuit using the PC-8417 power transformer please send it my way (by direct reply with attachment) and/or fill me in on the details.
>>
>> If the current ratings are OK, this would make an excellent PS for my receivers!
>>
>> Thanks in advance to all you respond!
>> Respectfully
>> Phillip W4RTX
>>
>> Sent from my iPhone
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