[Drake] 6JB6A tubes

[Garey Barrell]

Joe -

The only place I'm aware of that sells matched pairs is RF Parts.

Drake matched only by cathode current for fixed element voltages.  
Generally new tubes of the same brand are close enough. 

You can check them yourself in the transmitter.  Either plug in one at a 
time and check the idle current.   As long as they are within 5% of the 
same idle current  _without changing the bias adjustment_  , they're 
"matched".

It's a good idea to check the cathode and screen resistors for the 
finals for value and match.  Also verify the meter shunt (2.7 or 3.3 
ohms, depending upon model) and series calibration resistor (on the 
"Meter" switch up top) are correct.   Check the calibration at 0.100 mA, 
the idle current, since the meters are not all that linear (whatta ya 
want for less than $2!?) and the idle current is far more critical than 
the plate current at full load.

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual
<http://www.k4oah.com>



Joseph Trombino Jr wrote:

> Howdy Drakester's:
>
> It's been a while since I purchased a matched pair of 6JB6's so am 
> wondering where can such a pair be bought at reasonable prices these 
> days??
>
> Thanks for any info provided.
>
>                                73, Joe W2KJ
>