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Re: [Amps] Sweep tube amp by DL9AH, made by HB9AWI

To: Angel Vilaseca <>
Subject: Re: [Amps] Sweep tube amp by DL9AH, made by HB9AWI
From: Felipe Ceglia - PY1NB <>
Date: Sat, 27 Jun 2009 07:37:56 -0300
List-post: <">>
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.


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

Felipe Ceglia - PY1NB
PR1T team member /// Rio DX Group member /// Araucaria DX Group member /// ///
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