[ARC5] BC-375 Re-Tube Project- Scratch Three

[Mike Everette]

The 809 has a 7.5 volt filament if I remember right.

What about the V-70-D, which was used as the final in the old Globe King 400?  I don't know how readily available they are today, but probably about the same as the T40 and TZ40.  I have a good pair of V-70-Ds left over from a GK400 that bit the dust years ago  (good riddance if you ask me -- that thing was a deathtrap).

Or maybe the 572B?

One potential problem with using any of these tubes might be that the plate connection has to be lengthened due to the plate cap.  The 211/VT-4-C has the plate connection at the bottom, of course.

73

Mike
W4DSE





________________________________
 From: Geoff <geoffrey at jeremy.mv.com>
To: kgordon2006 at frontier.com; David Stinson <arc5 at ix.netcom.com>; ARC-5 List <arc5 at mailman.qth.net> 
Sent: Monday, November 18, 2013 4:13 PM
Subject: Re: [ARC5] BC-375 Re-Tube Project- Scratch Three
 

And then there is also the 809, T-40 and T-40Z, all of which are fairly 
available.

Carl


----- Original Message ----- 
From: "Geoff" <geoffrey at jeremy.mv.com>
To: <kgordon2006 at frontier.com>; "David Stinson" <arc5 at ix.netcom.com>; "ARC-5 
List" <arc5 at mailman.qth.net>
Sent: Monday, November 18, 2013 4:02 PM
Subject: Re: [ARC5] BC-375 Re-Tube Project- Scratch Three


> What about an 811 or 812, A or non A?
>
> Carl
>
>
> ----- Original Message ----- 
> From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
> To: "David Stinson" <arc5 at ix.netcom.com>; "ARC-5 List" 
> <arc5 at mailman.qth.net>
> Sent: Monday, November 18, 2013 11:47 AM
> Subject: Re: [ARC5] BC-375 Re-Tube Project- Scratch Three
>
>
>> On 18 Nov 2013 at 3:10, David Stinson wrote:
>>
>>> Three candidate tubes for the
>>> "Cheap Tubes for the BC-375" project have disappointed.
>>> 1625, 837 and 7984 will not "hold up" in this service.
>>> Once the screen voltages are dropped to spec,
>>> the tubes lack the gain to oscillate reliably, even
>>> with heavy "gimmick" cap coupling between grid
>>> and plate in the OSC stage.
>>
>> David: Have you yet tried connecting the screen to the GRID (G1). As I 
>> said
>> earlier, this results in a HIGH-MU triode, which SHOULD work much better
>> as an oscillator.
>>
>> Kenneth G. Gordon W7EKB
>>
>> "Courage is being scared to death but saddling up anyway."--- John 
>> Wayne
>>
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