In addition to Carl, KM1H's, suggestions:
You shouldn't need step start with this, unless the power transformer became
much stiffer, heavier. The choke will resist a major current surge. Also, if
you do get rid of the choke and only have C, it will need to be a lot more
Capacitance, and will probably need step start to protect the diodes during
chargeup.
I wouldn't recommend mucking with the parasitic suppressors unless they failed.
811 and 572B aren't as hot in the VHF gain department as some other glass
triodes.
The zener bias is a good idea. As for grounding the grids, short connections to
chassis are usually a good thing, unless Heath did something wierd. If the
thing has neutralization, you may have to re-set that as it would probably
change with different inductance from grid to ground.
Someday I am going to get my Heathkit Chippewa KL1 working, I finally got the
original KS1 power supply for it. The amp was hacked up by someone and I just
need to trace the wiring and understand the mods (fixed screen power supply
instead of string of VR tubes and dropping R). Now that was a stout Heathkit
power amplifier!
73
John
K5PRO
> ----- Original Message -----
> From: "Allen Jones" <w9dz@yahoo.com>
> To: <amps@contesting.com>
> Sent: Saturday, February 23, 2008 9:47 PM
> Subject: [Amps] Heathkit HA-10 Warrior
>
>
> >I am in the process of refurbing a Heathkit HA-10
> > Warrior amp. I have looked at some of the old threads
> > dealing with this amp and have a couple of questions.
> >
> > The 866's will go in favor of plug-in solid state
> > replacements. Am I going to end up with a lot of
> > extra B plus? The power supply is choke input to a 8
> > Mfd capacitor. Would a step-start circuit be of any
> > value or will the choke be enough to limit the surge?
> >
> > Are the original parasitic chokes sufficient or should
> > I replace them with something different?
> >
> > This amp has had two plate transformers fail for the
> > previous owner. He used the amp on RTTY. I got a new
> > transformer from Heyboer and asked them to build it
> > for CCS. The vast majority of my operation will be
> > SSB. I plan to scrap the fixed bias supply and go with
> > a zener in the center tap of the filament xfmr in
> > series with a high value resistor which will be
> > shorted with a relay in transmit. I will ground the
> > grids of the 811's directly to the chassis with heavy
> > braid or copper strap.
> >
> > Any other suggestions?
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