that's going to be some necroposting but I think it's somehow worth it.
I'm working on my own E11 project right now and I decided to be a bit of a detective on those mag cylinders.
I appologize if the discussion about those has been continued somewhere else :confused
I started with the hypothesis presented here thanks to the answers from the Elstree studio person.
I rejected the music amp. As a (bad) guitar player, I'm familiar with amps and even some tortured preamps don't have this sort of valve topology. For the output stage, it's usually a simple push-pull, nothing like the aligment we have here.
I also considered the fact it could be a DOUBLE rack from the same unit, then cut in two.
I started talking with a workmate whose hobby is vintage tube audio amps, to see if it would ring a bell. He said pro electronics (not consumer, and music amps, even if in the pro field, aren't made like that). He though military or industrial. Pro. 100% sure it's not a consumer radio.
Someone mentionned the IF strip, which made sense, aside of the fact they usually use less tubes and are coupled by transformers. But since tube electronics isn't my generation (I graduated as a EE in the 90's) I asked my mentor (87, who built a LOT of tube devices he authored) and also people like Alan at the Radio Museum website he runs, Phil @ Old Radios and someone at Pye Electronics History website.
IF strip was mentioned a lot, especially since it was a "classic" in surplus shops. Then my mentor mentioned "or on the opposite, a wide band amplifier in the distributed form.
I started my research *again* from that point and focused on the topology of the racks. They have very few components and tubes seems to be cascaded thru coils.
Here is the schematic of a distributed amplifier (I stored all the files on my website for a better convenience) :
you'll notice how close it is, one sort of coil which is the one under the racks, the other one being in the famous cylinders (the ones with the cap and bolt).
Then 2 different (decoupling) capacitors, on our case one value made of 3 of them in // (one seems to have been cut on the E11 targeting sensors) and the other one in inserted in a small tube.
Those cylinders aren't fuse, either I or any of the people I contacted (familiar with that sort of electronics) said the same. It's almost for sure a coil (inductance) protected by a screening can.
I looked for the use of a Distributed Amplifier topology and discovered it was used in certain oscilloscope. The point is getting a wide band, flat response and high gain with this sort of amplifier and it happens to be used for the vertical amp (the one in charge of moving the beam up and down on the CRT to display the amplitude).
That was a interesting lead as you can see on those pics I search for a long time. You'll also notice that in a distributed amp in an oscilloscope comes in a double structure, and most often a 2x6 tube set.
the tektronix 551 is a very good example. You will even spot some vertical coils held in place with a screw between the 2 rows of valves, very similar to the ones in the landspeeder rack (minus the screening can/tube).
It's more detailed in the tech manual of that Tektronics 545A on page 17
http://www.plecterlabs.com/Media/E11/MagCylinders/545_3.pdf
The only issue is that the style of the racks aren't of the style of what you find in an oscilloscope :cry, which is a desktop device you're supposed to take care of. No valve protection at the base, and less "bullet proof" mounting which takes us back to some military use for our unknown set of parts.
I tossed the question with my mentor being more specific of the use of a distributed amplifier v.s. the fact it wouldn't match for a narrow band device like a comm receiver (which isn't wide band per say, but rather narrowed to an Intermediate frequency to make the design simpler).
He mentionned that it could be a video amplifier, for a Closed TV circuit (in a military boat ?) and the person from the radio museum proposed again an IF strip for a radar, in this case it would be more for the number of amp stages that this distributed topology would be used, and less for the wide band feature.
Here's his last set of information :
Hi Erv
I don't think it's an IF strip for a conventional radio receiver for speech. It could be an IF strip for video and to have a fairly wide bandwidth using staggered flat tuned coils. If you open one of the cans with the nuts on top and remove the coil then measure its inductance you should find it suitable for 9.72MHz which was the standard IF used in RAF equipment. There were several ex-RAF equipments around in the government surplus shops in the early 1960s.
The IF strips in these use up to 4 or 5 EF91 or EF92 valves with an EB91 detector.
Some radars used more than one IF strip. Maybe one for elevation and one or more for azimuth and another for noise reduction.
Mostly the equipments in the 1950s were modular.
The front end, IF strip, audio etc were all bolted into a common chassis, like the transmitter/receiver shown on my website. That is an AM set for 118-135MHz. You can see the different modular chassis.
There were also landing aids which had two or more receivers driving a meter showing the pilot whether he was right or left of the centre line. The large number of amplifying stages were to give a steep sided flat topped response with very high attenuation of off channel signals.
Your particular IF strips (I think were called Type 373) and were sold for about 7/6d which in todays money would be 37pence.
cheers
Allan
That's where I am today after 2 weeks of search. I'm afraid now I must pass the ball to someone able to pay a visit to a person familiar with those aircraft / radar device.
hope this will help finding the right device. I think we have the right "schematic" now, we "just" need the device :unsure
