[Hammarlund] 6AH6 vs 6C4

[Richard Knoppow]

----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
To: <Hammarlund at mailman.qth.net>
Sent: Thursday, June 09, 2011 1:41 PM
Subject: [Hammarlund] 6AH6 vs 6C4


> Both are 7 pin miniature:
>
> 6C4 6AH6
> 1 & 5 P 1 G1 (Grid)
> 2 IC 2 G3 (Suppressor)
> 3 & 4 Filament 3 & 4 Filament
> 5 & 1 P 5 P
> 6 G1 6 G2 (Screen)
> 7 K 7 K (Cathode)
>
> Looks like minimal rewiring at the socket.
>
> Heater current for 6C4 is 150 mA and for the 6AH6 is 450 
> mA.
>
> Ken W7EKB

     Beware that the output level of the ECO is likely to be 
different than from the 6C4 plus its circuit loading will 
likely be different which _may_ affect dial calibration. The 
stability of an ECO depends on finding the right balance of 
screen and plate currents. When the correct ratio is used 
the circuit is essentially immune to voltage variation over 
a very wide range. This also confirs some immunity to 
filament voltage variation which I find is a serious 
contributor to drift in some receivers.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com