Sterling Mag Cylinder Mystery


Well-Known Member
Ward posted this to the MEPD and the blaster builders but I though the RPF might be interested too so he asked me to post this here.


I have been emailing with Paul Harrison of Elstree Studios (One of the men who worked on building the Landspeeders and Mouse Droids for ANH)

Here is what he had to say:


We built the originals but the art department did a lot of the dressing up. Most greeblie parts came from Elstree Electrical, which was an old store on the high street that had old oscilloscopes, valve radios etc.

But those parts I think were just spark plugs with the porcelain knocked off with tender tap from a hammer. We helped John Stears on the mouse droids too, we had it running around the workshop, based on a Datsun 280 RC sports car from what I remember. I think it was old valves on there. Most glass bits were broken off as we knew they wouldnt survive shipping, it was easier to remove them and repaint.

Hope this helps,

Cheers, Paul

I then went online and located a PDF schematic for a RCA Victor Radiolette R-5 and CHECK OUT WHAT I FOUND ON THE SCHEMATIC..

We need someone that can determine what this part is.

Does anyone know? This could be the last real-world part of the E-11 that has yet to be uncovered.



Ward Jones
Moisture Farm Patrol
Garrison Tyranus
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Interesting, though, that he suggests two different sources for E-11 and Mouse Droid parts when we know they are the same.

What led you to the Radiolette R-5? I don't see the progression from what he said to what you found.
We need someone that can determine what this part is.[/b]

If you look at the schematic and documentation in your PDF file you will see that C2, and C9 the parts you have highlighted are capasitors... Adjustable capacitors to be exact...

Lineup Capacitor Adjustments

Two adjustable capacitors are provided for aligning the two tune circuits at the high frequency end of the scale.[/b]
My reply to Ward when he e-mailed me about this:

What we really need to look for is a whole rack of these things. The prop department cut them down into pairs. They came as full racks of 6.

Interesting info, but I can tell you they were racks of 7-pin vacuum tubes. Those are the fragile glass parts Paul remembers removing.
The large empty sockets were identified by the MSE droid builders forum.
Audio equipment is likely the correct direction. I've been focusing my research on amplifiers (which use 7-pin vacuum tubes, often in sets of 6).
Maybe you could ask Paul about amplifier equipment. Chewie's bowcaster and Luke's hunting rifle both have Fender amp knobs on them.


We may be looking for some similar form of capacitor mounted in these racks of vacuum tubes.
To me the diagram doesn't really look very similar.
They are cylinders and it does look like they have nuts at one end. They might be roughly the correct size although I don't see anything to determine scale.
you dont actualy need access to an old marshall amp. I have seen many opened up and have a couple myself, even an old Gretch tube amp with Tremolo, and have never seen those inside them. What you can do is email some old skool guitar/amp/musical repair shops with the picture of the item and ask if they know what part/make/brand it is.
I dont think it would be from an amp but I have been wrong before.
Chris, I emailed those comments of yours to Paul and he responded with this:

That makes sense, the shop always had big old radios and "portable" amps for musicians which were big things. They had those other amps that went between a record deck and speakers too, I think marshalls were going well by then ?
Sent from Paul's Blackberry phone

Hopefully, we are closer to finding out what they are. :)

As for the progression from the initial email and finding the radio schematic . . . . Paul's original response to me mentioned oscilloscopes and valve radios. I did a GOOGLE search on valve radios, found several sites with schematics and diagrams, and began pouring over them looking for anything that appeared to match.

Based on the second email from Paul, I would say that an early Marshall vacuum tube amplifier is probably the best bet at this point. Anyone have access to one? :)
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

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.
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
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Erv´ from where you take so much time to make such an awesome detective research and so many other projects in the same time :)

absolutly stunning :eek
Here's his last set of information :
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

Hi Erv - I just started this quest up again over at FISD with my suggestion that E11 cylinder had 3 capacitors in between the main cylinders (I started off calling them fuses because I'm no electrician.) Did you get any further with your research? I think we're having some new ideas and I'd welcome your thoughts over at the thread. It'd be great if everyone pooled their knowledge & we could finally get an answer to this 34 year-old mystery! :)

3 central "fuses" on E11 Blaster Cylinders? - First Imperial Stormtrooper Detachment - Page 3

I'm hoping to buy one of your excellent BlasterCores in the near future too! :)

All the best, Andy
I noticed that myself and indeed it's pretty obvious on the speeder engine !

IIRC, I think some have only 2, other 3, those caps are easy to rip off from what I see.

I haven't been further in my investigations. Most people I've talked too are positive that this unit probably comes from military RF equipment. Many suggested an IF stage in a radar or something like this. Next step would be to visit a specialist and/or a junkyard dedicated to those parts to put a final point to that mystery.

As it's been seen in several props, there's a chance it was installed in those changeable aircraft racks that were gutted. That would explained why they got so many of them. The construction of the racks suggest the military use too (def not consumer electronics)

The number of pins of the valve socket don't provide so many choices for the valve type, due to the period of use, hence EF92. I have no doubt about the distributed amp topology neither for the use of the device : It's can't be audio (as confirmed by other people) as it's a super linear + *wide* bandwidth amp for RF instruments (radar, video, ILS why not). This is also (with no surprise) it's found in oscilloscopes as it's exactly the same purpose (large BW and linearity).

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Thanks for that Erv - I've no idea what your last paragraph means because I don't know electronics but it's given me some more words & ideas to research.

LonePigeon from The Parts of Star Wars has joined the discussion I linked to so I'm really hoping we can all finally solve this! :)
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