[Hammarlund] NuvistaPlug & more

[Eugene Balinski]

Carl,

  Do you happen to have a schematic and parts list
available ?   Could come in handy in a few radios.

73,
Gene K1NR

On Fri, 9 Nov 2007 12:43:58 -0500
 "jeremy-ca" <km1h at jeremy.mv.com> wrote:
> The 6BA6 was later followed by the 6BZ6 and Collins liked
> the 6DC6. All provided improvements over the 6BA6.
> 
> For ultimate NF improvement a FET with associated
> circuitry can be mounted on an adaptaplug or similar and
> require no receiver changes.
> 
> Carl
> KM1H
> ----- Original Message ----- From: <rrkrr at comcast.net>
> To: "ChasW3KC" <w3kc at verizon.net>; "hammarlund"
> <hammarlund at mailman.qth.net>
> Cc: <glowbugs at piobaire.mines.uidaho.edu>; "ChasW3KC"
> <w3kc at verizon.net>
> Sent: Friday, November 09, 2007 11:00 AM
> Subject: Re: [Hammarlund] NuvistaPlug & more
> 
> 
> > The stock 1st RF amplifier tube in the SP-600 was a
> 6BA6 - a remote cutoff 
> > pentode.  The 6BA6 has a relatively high noise figure
> which becomes a very 
> > significant limitation to receiver MDS above 20 MHz or
> so.  The 
> > "Nuvistaplug" used two 6DS4 remote cutoff Nuvistor
> triodes connected in 
> > cascode, which gave good gain, much improved noise
> figure, and high 
> > reverse isolation for the 1st RF amplifier.  The
> Nuvistaplug was sold as a 
> > tube socket plug-in replacement for a number of 7 pin
> tubes.  The tube 
> > socket connections of the Nuvistaplug must have been
> adaptable to the 
> > particular device to be replaced.
> >
> > The British companies Racal and Eddystone liked to use
> cascoded triodes 
> > for 1st RF stages in their receivers.  They used the
> ECC189 (American type 
> > 6ES8) which is a single 9-pin miniature tube containing
> two triodes that 
> > are designed to be connected in cascode.  In order to
> use this tube in an 
> > SP-600, the 7-pin 1st RF amp tube socket would have to
> be replaced with a 
> > 9-pin, and the resulting noise figure would probably
> not be as good as 
> > that for the Nuvistor.
> >
> > The 2nd RF amp in the SP-600 is also a 6BA6, but with
> the gain of the 1st 
> > RF amp in front of it, the noise of the 1st RF amp
> dominates, so it's not 
> > worth replacing the 2nd RF amp with a lower noise
> device.
> >
> > Bob K4ERR
> >
> >
> > -------------- Original message ----------------------
> > From: "ChasW3KC" <w3kc at verizon.net>
> >> For the SP-600, what tube type did the NuvistaPlug
> replace?
> >> Was it ever used in radios other than the SP-600?
> >> As I recall,  Ameco used to make a preamp that used
> >> nuvistors
> >> (the Ameco preamp I have is solid state and I think it
> came
> >> out later).
> >> TNX/73 de Chas W3KC
> >>
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