[ARC5] BC-453 Current Draw

[Dennis Monticelli]

OK guys.  Here is the report on current draw vs B+.

First the working conditions:
1) Western Electric BC-453-B in very good overall condition with the only
modifications being 12V heater wiring (not by me) and a complete re-capping
(guilty).  No changes were made to the biasing of any circuits.
2) FT-260-A adapter box
3) 12.6VDC filament power from HP bench supply
4) Variable source of B+ from a Heathkit PS (external accurate metering)
5) AF impedance transformer driving an 8 ohm speaker
6) Gain control set to about 3/4 with volume varying from soft to loud
depending upon B+
7) RF source was a magnetic loop with preamp (Pixel Loop)

*B+      mA       Comments*
24      3.5        barely alive
30      4.5        audio at a whisper
40      6.0
50      7.6
52                   the BFO starts up and stays on until the B+ drops
below 30V
60      9.2
70     10.9
80     12.6
90     14.2
100   16.0
110   17.5
130   21.0
150   24.3
170   27.8
190   31.3
210   34.8
230   38.3
250   41.8     audio is pretty loud now but distortion acceptable

Notes:
1)  The BFO has a very minor effect on current draw (small fraction of a mA)
2)  The audio output does boost the current draw when it gets loud but only
by a few mA
3)  Your mileage may vary, especially if your caps are original.  Leaky
caps at the higher voltages in particular would increase the draw.

Hope this data is helpful to the group.

Dennis AE6C


On Tue, Jan 20, 2015 at 7:01 PM, Bill Cromwell <wrcromwell at gmail.com> wrote:

> Hi Scott,
>
> Some of the ham modifications include installing a separate audio gain but
> most (that I know of) do not. In the discussion in this thread the OP has
> already corrected his question to your suggested intension.
>
> 73,
>
> Bill  KU8H
>
>
> On 01/20/2015 08:57 PM, Scott Robinson wrote:
>
>> I presume you mean RF gain not audio gain, yes?
>>
>> /scott
>>
>>
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