[Milsurplus] BC-348 Audio tube bias

John Hutchins jphutch60bj at gmail.com
Sun Jan 17 18:38:06 EST 2016


john -
IF this is a Q model;   The B- off the bottom of the choke runs into the 
DET can,  and through a 50 ohm resistor to ground.  AS well as R108-2 
which is also 50 Ohms.   Look at your schematic! All these models can 
and are different.

My 2 Cents -
Hutch

On 1/17/2016 4:47 PM, Dennis DuVall wrote:
> Just make sure you do one the other.
>
> Dennis D.  W7QHO
> Glendale, CA
>
> ************
>> On Jan 17, 2016, at 10:52 AM, John Watkins via Milsurplus 
>> <milsurplus at mailman.qth.net <mailto:milsurplus at mailman.qth.net>> 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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