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Re: [Amps] Eimac tube on the 'bay

To: "'Alek Petkovic'" <>
Subject: Re: [Amps] Eimac tube on the 'bay
From: "Gary Schafer" <>
Date: Mon, 12 Oct 2009 23:15:01 -0500
List-post: <">>
Hi Alek,

I also have one of the TMC IPA units that I took out the driver stages and
ran a 8295A with a grid resistor for the input. I used a 100 ohm resistor in
order to be able to drive the 8295 to full power.  Had that for many years.
Recently took that tube and socket out and put in one of the 4CX1000A
sockets that I got from you to test some tubes I had laying around. 

Now converting that amp to an 8877 GG. I thought about a GS35 but it is a
little tall for the TMC chassis.

Also going to put together a YC156 amp after this one is going.

Gary  K4FMX

> -----Original Message-----
> From: [] On
> Behalf Of Alek Petkovic
> Sent: Monday, October 12, 2009 6:27 PM
> To: Roger
> Cc:
> Subject: Re: [Amps] Eimac tube on the 'bay
> No, the amp deck we are modifying is the driver amp or IPA from the
> 10kW Technical Materiel Corporation, 10kW transmitters. The same
> units can be seen in photos of the WWV site. We have,what used to be
> a US Navy communications base here in Western Australia,located at
> North West Cape. These units were used there and became surplus and a
> heap of local hams were able to get hold of them. This was about 20
> years ago and there a still quite a few floating around.
> The amplifier module uses a 6CL6 followed by a 6146W followed by the
> 8295A. From memory, with that lineup, we used to run 100mW into the
> front end and get our 1500W out at the tail end. It was of course a
> real chore to change bands with that setup so we did away with the
> first 2 stages and stuck 50 Ohm at the grid of the 8295A and so we
> were able to feed in 100W and only have to do the output tuning when
> we changed bands. The grid was biassed at -120V so with 100W drive
> into the 50 Ohms, we never went into grid current.
> We, (my local club) decided to strip one of these units down (donated
> by VK6JX) and just use the RF deck in a new enclosure and plonk a
> GS35B into it. It is a works in progress and we hope to have it on
> the operating desk by Christmas this year.
> That is why we have the tube, socket and chimney surplus. They are
> now sold and will be heading to a new home in Florida this week.
> On the subject of the bigger tube, we are also stocked up with all
> the parts necessary to build a YC156 amp. This will be for 80, 40 and
> 20m only. This project will commence immediately after the GS35B is built.
> Cheers from soon to be sunny, Perth
> Alek. VK6APK

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