[Amps] Need Zener for 2KD-3 - Part Deux

[Bill Turini]

Folks:

On 2/2/2015 2:36 PM, Bill Turini wrote:
> I need a zener for my 2KD-3.  It's a 1N4561.  It appears that they are 
> really hard to find and exorbitantly expensive when you do. Has anyone 
> found a source for a replacement at a reasonable cost?
>
This request generated many wonderful replies and suggestions to fix my 
problem.  Last night I was RTFM when I noticed something very strange - 
the zener diode I had removed from the amp was not the same as 
identified in the schematic, and it was connected totally differently 
from the schematic.  Remembering the wise post from the Henry web site, 
I decided not to trust my eyes or the schematic and asked the learned 
group for their opinion.

First, the zener diode I removed from the amp was a 1N4561, a 5.6v 50 
watt device.  The schematic calls for a 1N2804, a 6.8v 50 watt device.  
Since the removed device was not wired in any way close to the 
schematic, I assume that this was an attempt at a repair or 
"improvement".  So, what should the voltage be?  5.6 or 6.8volts? Or 
should it be something else?   Since most of the other Henry 3-500z amps 
have 10 volt zeners, I would vote for the higher voltage 6.8v device.

Second, as for the wiring in the amp, I think it is just wrong, since 
all the other Henry GG amps have the cutoff circuitry the same.  So, I'm 
going with the schematic.

And, in case anyone is wondering, the 1N2804 costs just about the same 
ridiculous price as the 1N4561, so I'll probably opt for the zener and 
transistor route.

73's and thanks in advance.

Bill

-- 
Bill Turini
KA4GAV