<snip>
> >2. Also assume the 47k resistor via the relay is for cutoff bias on RX
also
> >via the relay.
>
> yes - but a g-g amp will work fine business without one.
If I recall from my old Heathkit Warrior Amp manual, the reason you cut the
tubes off is so that you don't produce shot noise when in listening mode.
Mike(y)
W3SLK
----- Original Message -----
From: measures <2@vc.net>
To: Ed W3NR <w3nr@vol.com>; Amps <amps@contesting.com>
Sent: Friday, October 13, 2000 12:50 PM
Subject: Re: [AMPS] ClippertonL Help
>
> >
> >Recently picked up a well used Clipperton. Has 4 new 811A's that I plan
on
> >using with the lower plate voltage.
>
> With a rated diss. of only 65w, 811s do better when tuned with a tuning
> pulser. However, if you have a free supply of new tubes, you needn't
> bother.
>
> >Have some questions that hopefully can
> >be answered here.
> >1. I assume the 9.1 Zener is used for idling plate current via the relay
on
> >TX.
>
> correct
>
> >2. Also assume the 47k resistor via the relay is for cutoff bias on RX
also
> >via the relay.
>
> yes - but a g-g amp will work fine business without one.
>
> >3. I used a 47ohm/220pf combination on each grid to ground as did Collins
in
> >the 30L1. That should get 4.7 volts bias on each grid with the thought
that
> >with about 1700 volts on the plates some bias would be needed.
> >4. Why no filament center tap. If I need to, can I use a 22 ohm resistor
> >from each side of the secondary to make one ??
>
> not enough conductivity. A pair of 2.5-ohmers in series make a better
> semi-CT.
>
> >5. What is the recommended safety for spikes? I used 10 ohms in the B+
line,
> >are back to back diodes still the cure on the B- ??
>
> For limiting the drop across the grid-current meter shunt R, 3A diodes
> work fairly well. 1a diodes are prone to fail.
>
> >6. Tuned input, can anyone send me the values needed for 10-160
especially
> >160 as the HB has 10-80 that I guess would be OK.
> >7. Can a parallel tuned circuit be used on the input rather than a pi. or
is
> >the bandwidth too narrow without a pi?
> >
> pi networks with a Q of 2 is what works best.
>
> cheers, Ed.
>
> - Rich..., 805.386.3734, www.vcnet.com/measures.
> end
>
>
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