[Amps] Eimac tube on the 'bay

Tue Oct 13 10:46:25 PDT 2009

Hi Alek,

The rating plates of our 3-phase transformers do not show the voltage of the
coil but the voltage between phases.
Current capacity will be the given current of 1.5A times sqrt3 which will be
2.6A CCS.
To obtain 6KV you will need a 6 diode bridge rectifier and the windings star
connected.

73
Peter  

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Alek Petkovic
Sent: Dienstag, 13. Oktober 2009 11:51
To: k7rdx; Roger
Cc: amps at contesting.com
Subject: Re: [Amps] Eimac tube on the 'bay

Yeah, we've got a very hefty 3 phase supply to give us 6kV DC.

Actually, I have a question regarding our transformer. Being 3 phase, 
it has 3 windings of 4200V AC and the nameplate says that they are 
rated at 1.5Amps.

Once rectified, we will have 6kV of course but my question is; at 
what current rating? Will it be 1.5A or do we multiply by that by 3 
because of the 3 phase working?

It doesn't really matter as the transformer is from a tv transmitter 
and so it is CCS rated and we should have enough grunt for our YC156.

73, Alek.

At 09:31 AM 13/10/2009, k7rdx wrote:
>Nice story Alek...When you get the yc-156 done the gs-35b will be 
>ancient history too...Providing you have a psu capible of handling 
>the 156...Cheers...Jim..K7RDX..
>----- Original Message ----- From: "Alek Petkovic" <vk6apk at bigpond.com>
>To: "Roger" <sub1 at rogerhalstead.com>
>Cc: <amps at contesting.com>
>Sent: Monday, October 12, 2009 4:26 PM
>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
>>
>>
>>
>>At 06:58 AM 13/10/2009, Roger wrote:
>>
>>
>>>Alek Petkovic wrote:
>>>>I have a good tested one (8295A) here out of VK6JX's TMC amp. It
>>>>comes complete with SK184A socket and chimney. It was doing 1.5kW
>>>>out when last fired up.
>>>>
>>>>We are doing a GS35b conversion
>>>To an HT-33B?
>>>
>>>>and so the tube, socket and chimney are surplus.
>>>Not the GU-73BB? It and the socket are a *little* more money, but it
>>>is certainly capable of surpassing a few GS-35Bs <:-))
>>>
>>>73
>>>
>>>Roger (K8RI)
>>>>Any offers?
>>>>
>>>>73, Alek
>>>>VK6APK
>>>>
>>>>
>>>>At 02:35 PM 12/10/2009, Roger wrote:
>>>>
>>>>
>>>>
>>>>>Roger wrote:
>>>>>
>>>>>>Larry wrote:
>>>>>>
>>>>>>
>>>>>>>    I wouldn't recommend powering up the HT-33b though, or you may be
>>>>>>>returning to the restoration bench... Larry
>>>>>>>
>>>>>>>
>>>>>>Yah, it looks like some of those pits are pretty deep and PL-172s are
>>>>>>notorious for going gassy while the 8295As have a good reputation.
Maybe
>>>>>>that's why a good tested 8295 runs twice the price of a good 
>>>>>>tested PL-172.
>>>>>>The PL-172s have a designator of PL-172/8295A, but the true 8295A is
>>>>>>metal ceramic while the 172 is metal with glass seals.  Neither one
goes
>>>>>>for much (on average) untested.  OTOH I sometimes see some untested
"as
>>>>>>is" tubes go for far more than I'd pay.
>>>>>>
>>>>>I should add that the 8295A is relatively rare and when found in tested
>>>>>and in good shape are worth a small fortune.  In addition to being
>>>>>metal/ceramic they are about a 1/2" taller than the glass/metal PL-172
>>>>>
>>>>>73
>>>>>
>>>>>Roger (K8RI)
>>>>>
>>>>>>73
>>>>>>
>>>>>>Roger (K8RI)
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>-----Original Message-----
>>>>>>>From: Roger [mailto:sub1 at rogerhalstead.com]
>>>>>>>Sent: Sunday, October 11, 2009 10:16 PM
>>>>>>>To: n1miw at cox.net
>>>>>>>Cc: amps at contesting.com
>>>>>>>Subject: Re: [Amps] Eimac tube on the 'bay
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>Larry wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>    Looks like this tube didn't sell the first time, so he's trying
>>>>>>>>
>>>>>>>>
>>>>>>>again...
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>Anyone have a sandblaster? Should clean up nicely with one of
>>>>>those! I bet
>>>>>
>>>>>>>>the vacuum would need to be "put back in" though! :-)   ...Larry
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>http://cgi.ebay.com/EIMAC-TUBE-8295-PL-172-Hallicrafters-Amp-more-NR_W0
QQite
>>>>>
>>>>>mZ370270597830QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item5635d8
f2c6
>>>>>
>>>>>>>We were talking about that one over on the Hallicrafters group last
>>>>>>>week.  I thought it'd make a good, colorful addition to a restored
>>>>>>>HT-33B while keeping it all original.  Don't spose that one had a bit
of
>>>>>>>exposure to salt water or was left in wet packing for "some time"?
It
>>>>>>>was also labeled another hurricane casualty.
>>>>>>>
>>>>>>>73
>>>>>>>
>>>>>>>Roger (K8RI)
>>>>>>>
>>>>>>>
>>>>>>>
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>>>>>>>>
>>>>>>>>
>>>>>>>>
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>>>>
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>>>>
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>>>
>>>
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>>
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