[Amps] Warrior power amplifier

[John Lyles]

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 at yahoo.com>
> To: <amps at 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?