First, the 5th supply is for control. It provides a voltage to the on-off
switch of the Herc II, and that in turn turns on the 4 12-volt supplies when
the Herc II is switched on.
Second, there is a margin of 20 amps to supply the transciever driving the amp.
My biggest reason for using the 9420, however is the protection that it
affords the Herc II. TenTec has a very good history of providing over-voltage,
over-current, high-swr, etc protection to prevent eating up the finals of its
equipment. You only get this if you use the power supply that is designed to
provide it. Great insurance IMHO.
The Herc II manual provides all the info necessary to size and connect another
brand of supply, as well as feeding it directly from batteries.
As for 20 amps rather than 25 for each amplifier, you should have no problem
there.
Dave
WA3MKB
----- Original Message -----
From: "Tom Macon" <tmacon@wi.rr.com>
To: kb9lie@yahoo.com
Cc: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Wednesday, August 5, 2009 2:04:24 PM GMT -05:00 US/Canada Eastern
Subject: Re: [TenTec] possible power supply for Herc II?
At first look, it seems like this supply is a fairly good match but the
devil may be in the details. The 9420 is made up of 4 - 25amp supplies
while the AA978 contains 5 - 20 amp supplies. While both add up to 100
amps, there's more to the story. As you probably know, the Herc contains
four parallel rf amplifiers, each fed by one of the four supplies in the
9420. The first question is whether you can get by with 20 amps instead of
25 for each amplifier.
The 9420 also has a fifth small supply that's always on. Maybe the fifth
supply in the AA978 could be adapted for this or add a separate, small 14v
supply. After that, there are many questions as to how the control and
overvoltage protection circuitry can be adapted. This would all take some
work to figure out - hopefully someone out there has already done this.
While I have a Herc, I have no experience running it on anything but the
9420.
Hope this helps a little.
- Tom, K9BTQ
----- Original Message -----
From: "Peg Haese KB9LIE" <kb9lie@yahoo.com>
To: <tentec@contesting.com>
Sent: Wednesday, August 05, 2009 10:26 AM
Subject: [TenTec] possible power supply for Herc II?
>
> I have an Omni V rig and HERC II amp with the companion 9420 power supply.
> They work great.
>
> Paul K9OT liked it so well he got another Herc II but no PS. Now we have
> found a used Audio Authority Model 978-100 switching power supply. Will
> this work okay for the second HERC II which would be used for a Corsair II
> or possibly other rigs?
>
> The fellow selling it uses them for a VHF repeater system. He says it may
> need filtering for HF but didn't have any details. Does anyone know if
> this will actually work out and what to do, or should we look elsewhere?
>
> 73 de Peg KB9LIE in sunny SW Wisconsin USA
>
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
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