[AMRadio] : Apache audio Real good - Use of 6146's

[Gary Schafer]

Larry Knapp wrote:

> Gary - It's totally up to you whether you wish to use 6146B's in place of
> 6146A's.  I refer you to G Zook's recent article in Electric Radio.  It's
> possible they do work in some early transmitters, but in others, using 6146B's
> in place of the original design for 6146 or 6146A's will cause severe
> parasitics and improper neutralization.

I have used the B's in lots of transmitters with no problem. I remember one or two
collins transmitters that I did have to change the neutralization components on to
get it to neutralize properly though. Any time you change tubes you should check
the neutralization. I have also seen several transmitters with 6146A's in them that
were not properly neutralized also.

The DX-100 was never manufactured with any neutralization in it that I know of.
There was a mod that a lot of people did to neutralize them. Very simple to do.
When properly neutralized you will find that you may be a little short on grid
drive on 10 meters. I have never seen any more parasitic problems with the B's than
with the A's when properly neutralized.

The VHF and UHF radios the Glen spoke of are more of a problem because of the
frequencies that they operate at. In those radios inter electrode capacitance plays
a bigger roll in fixed circuit component values than it does at HF.

> The 6146B's were designed primarily
> for SSB operation, not AM.

Who told you that?


> It's up to you.  I prefer the 6146 and 6146A's in
> my DX-100B, Valiant and Heathkit Marauder; all before 1963.
>
> 73, Larry KC8JX

I wouldn't think twice about using 6146B's or W's rather than A's or plain 6146's.
If I were buying tubes I would pick the B before I would the plain or A version.
More plate dissipation in the B.

73
Gary  K4FMX


>
>
> --- Gary Schafer <garyschafer at attbi.com> wrote:
> > Yes you are right Larry. I can never remember that the DX-100 was advertised
> > 100 watts output and the Apache was advertised 150 watts INPUT. You end up
> with the same output on both. I first see the 6146B advertised in QST around
> 1963 or 64. I think the Apache appeared in 1959?
> >
> > As far as using 6146B's in place of the A's though there is really no problem
> > doing
> > so.
> >
> > 73
> > Gary  K4FMX
>
> =====
> May your days be full of sunshine and good thoughts fill your head.
> From: Larry Knapp, KC8JX, St. Joseph, Mi  49085
>   Best 73's
>
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