[ARC5] Converters for Q5-ers (PS hum)

[Dennis Monticelli]

FYI.  My re-cap'd BC-453B pulls 10mA off 60V.  Not much at all.  Of course
you pay some price in terms of overall gain and audio output, but the
sensitivity is still good enough that antenna noise dominates.  As I drop
B+ further (heading for 24V) I find that the first function that dies is
the BFO.  Some radios are still running OK at 24V and some lose the BFO.
Maybe a fresher tube would make the difference.  I know some folks run them
that low successfully.

Dennis AE6C

On Tue, Jan 20, 2015 at 1:39 PM, Bill Cromwell <wrcromwell at gmail.com> wrote:

> Thanks Dennis,
>
> I'm takings notes here and looking at what I have. My Kenwood doesn't
> "seem" to bothered as much so I will look at the power supply schematics
> but I suspect I am *hearing* less of the crud because of the system
> passband and much more is seen by the front end - bad! I was surprised by
> the small amount of current drawn by six tubes from the B+ at 45 and 90
> volts. I suppose I have become used to larger numbers for the plate current
> in transmitters. I have several hours on the batteries on the BC-453 now
> and the batteries are still chugging away.
>
> I thought I had a used power connector with the built-in filters left from
> a swap-fest purchase that included two or three of those units. They are
> reasonably priced from places like Mouser, etc. I might purchase the
> individual parts and put them together to handle higher current for
> transmitter power supplies. A filter built heavier will surely not be
> harmed by *ANY* receiver.
>
> 73,
>
> Bill  KU8H
>
>
>
> On 01/20/2015 12:31 PM, Dennis Monticelli wrote:
>
>> On my BC-453 I either run batteries as you do, Bill, or I use HP bench
>> supplies, which have excellent output noise specs.  The local noise
>> environment is bad enough as it enters from the antenna without having to
>> worry about direct feed of line noise into the receiver circuitry.
>>
>> Dennis AE6C
>>
>>
>