[Boatanchors] Re: WRL LA-1 Linear

[Gary Schafer]

"Barry L. Ornitz" wrote:

> Gary Schafer,K4FMX, wrote:
>
> > >  Steve Wenger asked:
> > >
> > >  > Does anyone know a good replacement for the EL38's? What is
> > >  > a good replacement if I rewire the tube socket. Anyone have
> > >  > any EL38's for sale? Anyone interested in buying the amp -
> > >  > make offer.
>
> > I have one of those amps too. It works ok but it does not put out as
> > much power as advertised. Back in those days there was confusion of
> what
> > PEP really was. I haven't run mine in awhile and don't remember how
> much
> > power it puts out, somewhere around 200 watts at most if I remember
> > right. Maybe only 150. It was used with 20A's and the globe scout.
> >
> > The EL38 I think is the same as a 6CA7. Both equally hard to find. I
> > believe that they are popular with the audio people so the price is
> > rather high.
>
> The 6CA7 is an EL34.  Which is it, an EL34 or EL38?  The list
> of transmitting tubes for amateur transmitters posted recently
> said the tube was an EL38.
>
> > It could be converted to 1625,s or 837,s but would require a socket
> > change. Shouldn't be too hard to do as there is not much to the amp.
> The
> > power handling of those tubes would be equivalent to the EL38. If
> using
> > 1625,s you would need to modify them to disconnect the suppresser
> grid
> > from the cathode.
>
> Not all 1625 tubes are suitable.  This is discussed in the
> 1957 ARRL Handbook where they note that in some 1625 tubes,
> the suppressor grid is brought out from the tube envelope and
> connected to the cathode inside the base of the tube.  Here
> you just need to remove the base and clip the connection.  But
> in other 1625 tubes, the connection of the suppressor to the
> cathode is internal to the glass envelope.
>
>         73,  Barry     WA4VZQ     ornitz@tricon.net

Hi Barry,

You are right. It should be EL38 which is a 6CN6.  I get the EL34 confused
with the EL38 as the WRL amp is described in Stoners SSB hand book and
right next to it is another amp described that uses the EL34's which is a
6CA7..

None of the RCA 1625's can be modified that I know of. All had the
suppresser tied internally to the cathode. Most of the other brands could
be modified.

I always cut a slot in the tube base near the cathode pin and one of the
unused pins next to it. That way you can unsolder the two leads from the
cathode pin and put the cathode back to it's own pin and the suppresser
lead into the unused pin.
I have never tried using them by just cutting the suppresser lead and
leaving it floating.

73
Gary  K4FMX