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Old 7th Jul 2019, 4:05 pm   #1
space_charged
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Default Ferguson 204 XL wireless

I have acquired a Ferguson short wave wireless. It covers HF in four bands and also has MW. I can't find any service or other information about it. The wireless I have is just the chassis screwed down to a plank of wood! It has an extra RF amplifier stage and combined with HF split into four bands it is almost a communications receiver. It has a magic eye tuning indicator. The valve line-up suggests an American connection - 6SK7, 6SK8.

I have searched for Ferguson 204 XL but can't find anything about it. Was this maybe a kit sold to radio amateurs ? I'm wondering if it ever was in a proper cabinet. Also possibly army/forces?

I have restored it to good working condition. Also checked the calibration of the scales. They were remarkably close to what they should be. There is a board with lots of beehive trimmers and coils to adjust them. Thankfully the board is marked to indicate which applies to what scale.

Any information about this set would be appreciated. I can live without a circuit diagram for it, but would be nice to have one.
C
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Old 7th Jul 2019, 4:49 pm   #2
HamishBoxer
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Default Re: Ferguson 204 XL wireless

Possibly export or Irish. Same model (204) for a television too.
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Old 7th Jul 2019, 5:02 pm   #3
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Default Re: Ferguson 204 XL wireless

I agree it's probably an export set given the wavebands and RF amp. Ferguson used Mullard valves, but these may have been replaced, especially if it's spent time in foreign parts. Irish sets normally cover LW as listeners wanted access to the BBC Light Programme as well as RTE.
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Old 7th Jul 2019, 5:04 pm   #4
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Default Re: Ferguson 204 XL wireless

Interesting thought. There might be an Irish connection. I got the wireless from a friend of a friend so I know a bit of its history. The original owner of it was a monk and it is my understanding that he used it to listen to Vatican Radio on HF, amongst other things.
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Old 7th Jul 2019, 5:18 pm   #5
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Default Re: Ferguson 204 XL wireless

The valve line-up as it was when I acquired the wireless was:

5Z4G (HT rec)
VR65 (audio preamp?)
EL33 (audio output)
6SK7 metal clad (if amp)
6SK8 metal clad (mixer/osc)
6SK7G (RF preamp)

Interesting mixture, but after WW2 there were lots of surplus valves around. I have no way to be sure they are all the original valves, but the above is how it was when I got it.

The set is fully functional now, except for the magic eye which is working but the phosphor is badly burned. I have obtained a modern (Russian?) close equivalent but fitting that needs a slight circuit mod which I have not decided to do. The original works well enough.
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Old 7th Jul 2019, 5:27 pm   #6
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Default Re: Ferguson 204 XL wireless

Those are almost certainly not the original valves.
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Old 7th Jul 2019, 5:31 pm   #7
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Default Re: Ferguson 204 XL wireless

Just taken a couple of photos of the set, on and working.

Note that I have replaced the metal 6SK7/8 valves with their GT variants. The originals were fine, but I like to see my valves glow...

I have added the speaker and the speaker output transformer. I assume the original output transformer was in the speaker unit.

C
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Old 7th Jul 2019, 5:36 pm   #8
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Default Re: Ferguson 204 XL wireless

Quote:
Originally Posted by paulsherwin View Post
Those are almost certainly not the original valves.
Yes that is what I thought when I saw it for the first time.
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Old 7th Jul 2019, 5:54 pm   #9
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Default Re: Ferguson 204 XL wireless

I can't see any detector/agc diodes there. The 6SK7s and VR65 would originally have been EF39s.
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Old 7th Jul 2019, 6:05 pm   #10
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Default Re: Ferguson 204 XL wireless

There might be an early solid state detector, such as was used in the Wartime Civilian Wireless, or of course the pentode I thought was an AF amp could be detector/amp.
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Old 8th Jul 2019, 9:46 am   #11
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Default Re: Ferguson 204 XL wireless

The VR65 doesn't have any diodes in it, and any other detector type would be unusual.

Of course, it's possible that the original valve in that position was an EBC33 and somebody has just fitted the wrong type, but that would stop the radio working.
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Old 8th Jul 2019, 4:32 pm   #12
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Default Re: Ferguson 204 XL wireless

The wireless is very much working, and quite sensitive too.
None of the valves (excluding the ht rec) is a diode. I'm currently thinking its a grid leak detector based on the VR65 pentode. Still possible it's a solid state device and I'll have another look with that in mind.

As to the magic eye valve I've not decided if I'll bother to fit the Russian new one I bought. That needs a small circuit change to work. In the existing one the phosphor in its "low signal" state is lower brightness than the parts illuminated at high signal.

Hmm, you don't think the magic eye could be being used as a detector...? It is used to display the AGC voltage after all!

C
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Old 8th Jul 2019, 4:56 pm   #13
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Default Re: Ferguson 204 XL wireless

Not likely. Though trace back from the grid of that and the volume control to find the detector / final IF.
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Old 8th Jul 2019, 5:16 pm   #14
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Default Re: Ferguson 204 XL wireless

Quote:
Originally Posted by Mike. Watterson View Post
Not likely. Though trace back from the grid of that and the volume control to find the detector / final IF.
Yes it was meant as a laugh! Mind you, the magic eye is a double triode.

realistically it has to be a solid state device, something like the "wsector" used in the Wartime Civilian Wireless?

C
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Old 8th Jul 2019, 5:48 pm   #15
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Default Re: Ferguson 204 XL wireless

Or someone added a 1N34 or a 1N60 or something so as to use a plain pentode for the audio preamp. The 1N34: 1946! 1N60 is still maybe the most sensitive detector, 1956. Not much different to 1N34.
Germanium diodes existed during WWII.
TVs used EAA and EB parts because they were cheaper. The Battery valve AM/FM sets used semiconductor diodes for FM (DAF96 on AM) long before Mains valve sets, due to filament power saving, even the first ones using a DC90 VHF-Mixer. Later the DF97 triodiesed were used.

There are Magic eyes with accessible amps, the EM34 and the single triode cousins aren't. The EAM86 magic eye even has a diode! https://www.radiomuseum.org/tubes/tube_eam86.html

I used a Russian 1j24b and an 1N60 to replace a DAF96 as an experiment. Two 1j24b Pentodes wired like a Triode/Pentode will replace a Triode /Hexode, Heptode or Octode with no changes to the original circuit, just an adaptor.
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Old 8th Jul 2019, 6:03 pm   #16
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Default Re: Ferguson 204 XL wireless

Also, I think all sets for the Irish market had LW. So likely this was bought overseas (A mission?) and brought back to Ireland.
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Old 12th Jul 2019, 8:22 am   #17
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Default Re: Ferguson 204 XL wireless

Ferguson had a very strong relationship with the United States.
It is possible that the odd ones here are the VR65 and the EL33. The American valves would normally require screening cans due to the lack of metalizing so the mystery continues.
Ferguson produced some first class receivers immediately after WW2 including a 200 series radio/radiogram using twin EL32's in push pull, no doubt purchased for pennies on the war surplus market. John.
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Old 14th Jul 2019, 2:37 pm   #18
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Default Re: Ferguson 204 XL wireless

Thanks John. Yes, I too think all the valves would have been American types. What do you think would have been fitted as output valve and the signal pentode?

In other sets with American valve line-ups the output valve would often be a 6V6. EL33 seems to be pin equivalent with KT61, so maybe that. I guess a beam tetrode could be a direct replacement for a pentode. Most often the suppressor grid is internally hard wired to the cathode. Of course that spoils all the fun you can have with a pentode - thinking of my favourite oscillator; the Miller Transitron! 6V6 looks to me to be pin compatible with EL33/KT61.

When I get space on my bench (currently occupied by a Sony KV9000) I'll have a look and see if I can see any solid state detectors.

C

Last edited by space_charged; 14th Jul 2019 at 3:00 pm.
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Old 14th Jul 2019, 3:06 pm   #19
Mike. Watterson
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Default Re: Ferguson 204 XL wireless

A KT61 works in an EL33 socket, though reverse might not be always true.
6V6 is different bias etc.
Many sets in 1945 to 1947 used a mix of USA and European type number valves.
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Old 14th Jul 2019, 3:07 pm   #20
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Default Re: Ferguson 204 XL wireless

I think you are mistaken, and this started off with E series valves. That was standard Ferguson practice at the time. A 6V6 is pin compatible with an EL33 but has different characteristics and bias requirements.

(Crossed with Mike)
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