[Milsurplus] BC-348 Audio tube bias

[Bruce Gentry]

I think the negative bias is also needed for the RF gain control or AGC 
circuit on some models. I always let the B- float through the choke as 
originally designed.

    Bruce Gentry, KA2IVY


On 1/17/16 6:23 PM, John Hutchins wrote:
> John -
> B- is derived off the choke to ground; The choke, audio transformer 
> and a 0.05uf Cap are in a can together.
> Some units have this sacred can removed.  If this is  your case a 
> suitable resistor to ground will have to do.
> Hutch
>
> On 1/17/2016 12:52 PM, John Watkins via Milsurplus wrote:
>> Almost finished sorting out and rewiring/removing old mods, etc.  I 
>> have an AC supply in the radio, and the B- is grounded.  The VT-152 
>> (6K6) cathode would like to have a bit of negative bias to avoid 
>> distortion.  Read that it should be around -18V some where, and the 
>> B- is also ungrounded and connected to the VT-152 on the BC-348 
>> schematics.  Should I just pull the B- off of ground, or put a 
>> resistor in the cathode of the VT-152 (6K6)?
>>
>> thanks,
>>
>> John WD5ENU
>>
>>
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>
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