Hi Steve,
Because you'd lose the isolation provided by the transformer.
skipp
--------- Forwarded message ----------
From: ab2et@juno.com
To: amps@contesting.com
To: <amps@contesting.com>
Date: Fri, 19 May 2000 12:18:38 -0400
Subject: Re: [AMPS] conversion of 6.3 volt (6LQ6) tubes to 31 volt
version
Message-ID: <20000519.121840.-4179921.0.ab2et@juno.com>
If you Series up the four 31 volt heaters why not just use the "mains"
or one leg with a simple 1/2 wave rectifier ...
I have done this on a couple of "low budget" conversions that have
worked out quite well.
And now I am off to Dayton.
73's
Steve
AB2ET
On Wed, 17 May 2000 22:27:49 -0700 nospam4me@juno.com writes:
>
> Alek,
>
> The heater for the average sweep tube (6LQ6) consumes
> about 16 watts of power. Yes, you can run an out board
> transformer, or an inboard additional transformer in a few
> different types of circuits.
>
>
> 1. You can remove the 6.3 volt paralleled leads from the tube
> sockets. Add a 24 volt ~2 amp transformer secondary in
> series with the 6.3. The primary wired parallel with the other
> xmfrs primary, the proper leads connected "in phase" to the
> 117 vac for an approx 31 vac secondary, just what you need.
>
> 2. If an amplifier has 12.6 volt heaters, you can secondary
> series another 18 volt transformer to obtain the ~31 volts.
>
> 3. Series up the four 31 volt heaters (`124 volts) and you'd be able
>
> to run a filament transformer in reverse off the original amp
> windings. Not realistic since you require a 12 amp xmfr for this
> "trick".
>
> cheers
> skipp
>
> ####
> From: Alek Petkovic <vk6apk@eon.net.au>
> ps: I ended up with 8 x 31LZ6's at $14.00 each so I think I got a
> reasonable deal.
> They are supposed to be like the LQ6's.
>
>
> At 10:48 PM 16-05-00 -0700, you wrote:
>
>
> >Hi Alek,
> >Marv is right, my spec sheet for that tube (RCA Brand) states the
> warmup
> >as 11 seconds min. Typical
> >of sweep tubes. Be sure to go over to my http://sonic.ucdavis.edu
> >server and down load my Dentron
> >Cathode current cutoff mod for the Dentron. Save your tubes.
> There
> are
> >two Dentron Download available
> >on the site, one is a copy of an old Ham Radio Mag article, the
> second
> is
> >my work up with the circuit
> >diagram.
> >cheers
> >skipp
> >
> > > On Mon, 01 May 2000 17:54:45 +0800 Alek Petkovic
> ><vk6apk@eon.net.au>writes:
> > >G'day from "Down Under.
> > >I've just ordered 2 sets of 4 x 31LQ6 tubes for my little Dentron
> >GLA-1000
> > >amp. These will replace the tired 6LQ6 tubes presently in the
> unit.
> > >The tube swap will of course necessitate an extra transformer to
> run
> the
> > >heaters of the new tubes.
> > >
> > >Does anybody on the reflector have an idea of the current drawn
> by the
> > >heaters in these tubes?
> > >... so I figure on around 2A total for the four tubes in
> parallel.
> > >I have a transformer rated at 100VA which I hope will do the job
> with
> a
> > >generous safety margin.
> > >Am I correct in the above assumption?
> >
> >:Hi Alek,
> >:Yes, that's the way it works -- should be right around 500 mA per
> >:tube. The 31's also have a "controlled" warm-up time which was a
> >:requirement for their original application in series filament
> string
> >:style TV's.
> >:73, Marv WC6W 310 649 3111
> >
>
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________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
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