[Milsurplus] 6K4

[WF2U]

Ray,

The Russian 6K4 is the equivalent of the 6SG7 and not the 6SK7. The 6K4P is
the equivalent of the 6BA6W/5376.

What Russian receiver are you working on?

73, Meir WF2U
Landrum, SC

> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net
> [mailto:milsurplus-bounces at mailman.qth.net]On Behalf Of Ray Fantini
> Sent: Wednesday, March 08, 2006 10:29 AM
> To: milsurplus at mailman.qth.net
> Subject: [Milsurplus] 6K4
>
>
> I have been working on a Russian military receiver that uses a tube
> called a 6K4. This tube in no way resembles the US version of a 6K4, it
> appears to be a remote cut off pentode maybe the Russian equal of a 6SK7
> The tube is a octal base and just about the same size as a 6SK7, except
> only a tiny bit shorter. The tube is used in both RF and IF amplifier
> circuits. the IF deck has been modified for 7 pin miniature tubes, and
> they appear to be 6K4P tubes.
> Both the octal and seven pin miniature have the same number and not
> having good Russian substitute guides several questions come up. First,
> can the 6K4 octal be replaced directly by a 6K4P mini? Second, the only
> tube base diagram I have found for the 6K4P shows it as a directly
> heated cathode where the octal one was indirectly heated, yet I am lead
> to think that the 6K4P will directly replace a 6BA6 and I always thought
> a 6BA6 has a indirectly heated cathode? and last but not least, will the
> 6BA6 directly replace a 6SK7? If the Russian 6K4 is a 6SK7, and the
> receiver was modified to use a 6K4P that is the same as a 6BA6 will the
> tubes have the same characteristic and respond the same way in regards
> to AVC control? I can see that their are some small differences in the
> capacitance but don't see that as any big issue. I do have to replace a
> couple of the IF tubes and do not know if I should go with the Russian
> 6K4P that I will have to buy or just stuff America 6BA6 tubes in their.
> Ray Fantini KA3EKH
>