[Boatanchors] 6BA6 Tubes

[Al Klase]

Yes, all the tube substitution books say a 6AU6 is an acceptable sub for 
a 6BA6.

This is just WRONG!   It's OK in a pinch, but the 'AU6 is a sharp-cutoff 
pentode, while the 6BA6 is a remote-cutoff device.

Remote-cutoff is the magic that allows a communication receiver to 
control the enormous gain that's available is such a radio.  Loading up 
a radio like 75A3 with sharp cutoff pentodes is going to completely mess 
up the AVC resulting in distortion on strong signals.

Here's my list:  6BA6/W/WA - 5749 - 6660 (caution 1/2" taller)  6BA6's 
are cheap and available.  Why mess around?

6BJ6 - 6662 - 7694 might be OK, but gain is a bit lower and the heaters 
are 150 mA vs. 300 mA so be careful in series string applications.

Al



On 12/15/2011 9:29 PM, Mike McCarthy, W1NR wrote:
> 6BA6's can be substituted with the following:
>
> EF93, 7543, 7496, 6BZ6§, 6AU6A, 6AU6, 6BA6WA, 6BA6W, 6CG6, 6HR6, 6660,
> 5749, 6BD6
>
> The 5749 is the same as the 6BA6W. I think I used that one in a Drake
> restoration a while back. So, it looks like the 6AU6 is an acceptable
> sub according to the substitution guide. Of course, all of these have
> subtle differences that may or may not appear depending on the circuit.
> The 6BZ6 is flagged as not being compatible in some circuits.
>
> Mike, W1NR
>
>
> On 12/15/2011 01:51 AM, Joe Walden wrote:
>> Hello again,from Joe W. w5jdy in Norman,Ok 73069..  I am in the need of four
>> 6BA6 vacuum tubes for a Collins 75A3..  Not to sure why but the previous
>> owner put 6AU6's in the place of the 6BA6's??  I looked on Ebay but didn't
>> see anything like I wanted..  Would rather give the money to a ham anyway..
>> I would like new ones but even used tested-good would just be fine..  Please
>> contact me direct at:   w5jdy at cox.net     Thanks Joe
>>
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/