[Amps] Re: AB1 v. AB2

mark mark@sandlabs.com
Sun, 1 Dec 2002 11:13:07 -0500


In professional designs, the Grid Bias is applyied through a tap on the
secondary of the input tuned transformer.
Mark




----- Original Message -----
From: "bearlabs" <bearlabs@netzero.net>
To: "Rich" <2@vc.net>
Cc: <amps@contesting.com>
Sent: Sunday, December 01, 2002 10:37 AM
Subject: Re: [Amps] Re: AB1 v. AB2


>
> ----- Original Message -----
> From: Rich <2@vc.net>
> To: <bearlabs@netzero.net>; AMPS <amps@contesting.com>
> Sent: Saturday, November 30, 2002 11:07 PM
> Subject: Re: [Amps] Re: AB1 v. AB2
>
>
> >
> >
> > >Rich wrote:
> > >
> > >> ...
> > >> >> >> **  so increasing drive will not eventually cause grid current
in
> a
> > >well
> > >> >> >> designed AB1 amp?
> > >> >> >
> > >> >> >it can't. If it can then it is an AB2 amp.
> > >> >> >
> > >> >> So an AB1 amp can be AB2 if it is overdriven, and an AB2 amp can
be
> an
> > >> >> AB1 amp if it underdriven?
> > >> >
> > >> >Nonsense.
> > >> >
> > >> **  please explain
> > >
> > >You can build an audio amp or modulator that is capacitively coupled
> > >to the grids of the output tube and there is nothing you can do to
drive
> > >it into AB2 (grid current).
> >
> > How is DC grid bias applied to the grids?
>
> Separate minus voltage power supply fed via high impedance (resistors) to
> prevent loading down the drive voltage...
>
> >
> > >You have to DC couple it or use a transformer to
> > >drive it into grid current.
> > >
> > >Either the circuit supports AB2 or it doesn't.
> > >
> > >            _-_-
> > >
> > >>
> > >> >>
> > >> >> How would you design an AB1 amp that can not be overdriven?
> > >> >>
> > >> >> -  Rich..., 805.386.3734, www.vcnet.com/measures.
> > >> >
> > >> >
> > >> >
> > >> >
> > >> >--
> > >> >  _-_-bearlabs
> > >> >
> > >> >   http://www.bearlabsUSA.com
> > >> >    - Silver Lightning Interconnects & Custom Mods -
> > >> >
> > >> >
> > >> >
> > >>
> > >> -  Rich..., 805.386.3734, www.vcnet.com/measures.
> > >
> > >
> > >
> > >
> > >--
> > >  _-_-bearlabs
> > >
> > >   http://www.bearlabsUSA.com
> > >    - Silver Lightning Interconnects & Custom Mods -
> > >
> > >
> > >
> >
> >
> > -  Rich..., 805.386.3734, www.vcnet.com/measures.
> >
> >
>
>
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