[Amps] Sweep tube amp

[Roger]

ny9h wrote:
> Big bucks,,,,,  for thi classic  "10 meter" amp....
>
>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=190316129891
>
> Now that's funny. CB amps are becoming collectable?  Big bucks for a relatively useless amp that now uses expensive tubes if you can find them.
>   

73

Roger (K8RI)
> \bill
>
>
>
>
> 06:37 AM 6/27/2009, Felipe Ceglia - PY1NB wrote:
> Hi Angel,
>
>   
>> I one recent CQ DL magazine, may 2009 (the one with the CW op YL on
>> cover), there is a project for a funf-tube PL519 amplifier. If I recall
>> it correctly it does not use a HV trafo, but for sure the output tank
>> was PI.
>>
>> If anyone have any information about the Fuchreis tuning network, I
>> would like to hear about it.
>>
>> 73,
>>
>> Felipe - PY1NB
>>
>> Angel Vilaseca wrote:
>>     
>>> Gentlemen,
>>>
>>> I just bought an old amp that uses 5 PL 519 TV sweep tubes in parallel.
>>> As it reads on the box, it was home made on June 1983 by HB9 AWI.
>>> The amp does not work anymore, but it is superbly built. The builder,
>>> HB9AWI, obviously put a lot of effort into it.
>>>
>>> I would like to restore it. It is so well made and so typical of ham
>>> state of the art at the end of last Century.
>>> No inexpensive Russian power tubes were obtainable at these cold war
>>> times! On the other hand, old color TV sets with sweep tubes still alive
>>> were plentiful. The PL519 had the reputation of being quite rugged. Most
>>> frequently, it was the line output power treansformer of the TV set that
>>> failed, not the tube.
>>>
>>> Unfortunately, there was no schematic included with the amp..
>>>
>>> The seller told me the design of the circuit was by DL9AH. It is quite a
>>> non-typical design:
>>> For one, the tank circuit is not a Pi, nor a Pi-L! It is called a
>>> Fuchkreis. It seems it was invented by an Austrian ham called Fuchs. I
>>> never saw anything like it.
>>> The power supply is a transformerless design. Apparently, it delivers +
>>> and - 300 Volts. So needless to say, the cathode circuit of the five
>>> PL519s is quite unconventional too. The bias circuit uses two pentodes,
>>> a PL 504 (a b&w TV sweep tube) and a smaller one. Never saw anything
>>> like this either!
>>> There is a separate 10-turn potentiometer for each PL519 to adjust the
>>> current through each tube. Quite sensible when you use five second-hand
>>> tubes, that may have already lived a number of years as sweep tubes in
>>> TV-sets.
>>> The power supply, the bias circuit, the relays circuit all have lots of
>>> VK200s and decoupling caps everywhere.
>>>
>>> As I just said, in a true ham spirit, it may use cheap tubes, but
>>> obviously a lot of care was used to design and build this piece of
>>> equipment.
>>>
>>> So, really, I would like to restore it. I tried finding the DL9AH design
>>> on the web, but no luck!
>>>
>>> Does the phrase " Sweep tube amp, DL9AH design" ring a bell? Especially
>>> for european hams?
>>>
>>> Any information about the design, or schematic welcome.
>>>
>>> Vy 73
>>>
>>> Angel Vilaseca HB9SLV
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>       
>> --
>> Felipe Ceglia - PY1NB
>> -------------------------------------------------------------------------------------
>> PR1T team member /// Rio DX Group member /// Araucaria DX Group member
>> http://www.dxwatch.com /// http://reversebeacon.net ///
>> http://riodxgroup.dxwatch.com
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>>     
>
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