BOLEX G3 Sound

Whatever my view of the G3, I could not resist the much rarer sound version. Take a silent G3. Then add a huge amplifier and a large sound unit. You get...................................................this.

           

I have repeated the HMHT article in full size, as I supect it will not otherwise easily legible be (Yoda).

There is a quiet but determined emphasis in the advert (this being December 1939) on Swiss origin. And, a point I confess had not really registered with me before, the ability to show DIN films. Between the two small pix at the bottom of the ad is a particularly interesting reference to converting any Type G machine to sound with an add-on unit. This seems (particularly when taken with the transparently bolt-on design of the sound head) to make nonsense of the claim in the review, emphasised rather too much for conviction, that the whole thing was designed like that in the first place. Pull the other one. I wonder, too, if Bolex were pushed into producing at least the conversion unit by the success of a proprietary model - this is what happened to Specto with the dual 9.5/16 conversion by Cinesmith, or with Pathescope and the Aurator for the Gem.

     

As well as the machine itself, you get a splendid box of bits which, in addition to the usual G3 bits, has large sound sprockets, an extra picture gate for 9.5 sound, and sound gates - dinky things just like picture gates - for the optical sound. There is not usually room in the box for everything, one set of parts being on the machine. The exciter lamp is a festoon type, ie a bit like fuse. If you look at the close-up, the sound optics are in the right-angle thing on the sound unit. As far as I know, there is no sound slit; an image of the exciter lamp filament is used. After passing through the film, the sound light is turned through a right angle by a prism and fed down a tube to a photocell in the amplifier. The sound speed appears to be controlled by a mechanical governor behind the lamphouse. This is what makes the machine so ferociously noisy - I think it's about the worst I've ever heard. The whole set-up comes in two large cases, the second holding amp, speaker and various transformer thingies to do with the sound (note grasp of technical features). Apart from being very heavy and noisy, the addition of the amp underneath brings the projector much higher than normal. Hard to know how well it would have performed in its heyday, but I find it irresistible and aim to get it fully working - one day.

The most interesting point about this machine in some ways is that it was on the market by about the middle of 1939, if the piece above from Home Movies and Home Talkies is to be believed. Not sure they saw the same machine as I have!

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I returned to the G3 Sound several years later. 

I think I have mentioned the 16mm-only machine, built into a blimp, that I acquired a couple of years back in France. There are various indications that the machine is based on a tri-gauge original, as the sprockets are removable and there are a few parts stamped “16mm”, which of course is unnecessary for a single-gauge machine. One of these is at the back of the prism below the exciter; this does not feature on my tri-gauge and I don’t know what it does. (I noticed later that it actually does have “9.5” on the other side.)

 I decided it was finally time to get this machine up and running and, of course, the usual fun and games ensued trying to overcome all the problems. A major one of these was that a specially-shaped cover for the exciter lamp was missing, as well as another piece of cover for the sound tube that is purely cosmetic with no practical function. This is not terribly surprising, as both of these on my other machine are extremely fragile. 

The exciter cover is a weird shape because the lamp is one of those tubular, festoon-type lamps and, crucially, is rather wider than its mount (which is made of wood). I was lucky in having a cover from my tri-gauge machine to copy, which I did by cutting out a wooden reverse mould to fit inside the cover. Here are old and new covers and the wooden mould. I wrapped some thin metal round the mould and bashed it with a hammer, snipped bits off, adapted the mould etc until I got something that might do. After much use of filler etc and paint, what finally emerged seems OK, tho’ its grip on the machine is a bit tenuous. I think the colour of the original cover is an earlier attempt by me to match the colour of the machine, not terribly successfully – Bolex colours seem very hard to match – so I decided to not even try and went for silver. I’m not sure I shall bother with the other cover.  (I did in the end – but you expected that.)

Note the over-complicated strips forming contacts and wire connections of the exciter lamp base and the fact that the lamp is actually soldered into place into the spring brackets. This seems a strange and OTT belt and braces approach. Note also the two lugs on the side and the spring at the back. I am wondering if the unusual type of lamp is a hang-over from tri-gauge to cater for 9.5 and 16mm sound-tracks being on different sides and so needing a long filament to cover this range. I have come across a similar idea on a Cinegel dual-gauge sound machine. The lever at the bottom of the exciter mounting block is familiar as another device to assist gauge change – Heurtier sound machines have a variable sound slit with a similar lever.

 I am a bit suspicious about this exciter lamp because, in the minimal amount of documentation I have, the entire block with lamp is listed as a single spare part along with other “consumables” such as lamps, fuses and valves, suggesting it might have a short life. This makes me wonder if maybe there is not enough space left to dissipate heat; maybe the wood starts to char even! We shall see.

On my tri-gauge machine, the wooden block with the exciter simply screws onto its platform; the 16mm one is much more sophisticated (or do I mean complicated?). The pix below show details of the mount. There are two springs which have an upper loop as a sort of handle and when stretched upward, a loop further down engages with the tiny lugs on the side of the wooden block. There is another, horizontal spring at the back of the base, plus an alignment slot at the front, which fits over a pin on the mount. The pin appears to be mounted on a floating base(?!), but there is a more precise arrangement at the rear, with a locating pin fitting into a single, close-fitting hole at the rear of the base. You do wonder quite what it was those Swiss engineers were taking and where it might be available today.

A further problem with the exciter is that I did not actually know what voltage I should apply, as this is fed from the amp. I played safe and applied a low voltage of about 3.5 from one of those multi-volt adapters you can buy quite cheaply. It actually worked at first, then the filament went – a tiny, barely visible gap in the middle. Unsurprising, I suppose, given its age. Now, curiously enough, I had an identical spare, in the spares that came with my tri-gauge, the which, as I now know, it would not fit. However, I felt discretion was the better part of valour and went for a 12v 5w festoon lamp from Halfords, which was happily the same size and seems to work well, at least once I managed to un-solder the original!

In order to find out what the exciter voltage actually was, I decided to re-commission the tri-gauge machine, long laid up in mothballs in the Cinerdistan equivalent of the Devonport Dockyard. I started with the amp; a capacitor or two looked likely candidates for replacement and one large one had leaked several gallons of wax (I hope it was wax) over the base-plate but, with the usual advice from Paul Schimmel, I managed to get it up and running. It’s a fairly basic amp (U50, 2 x 6F6G and 6N7), but although not hi-fi, as a projector amp it is excellent, with plenty of top, virtually no hum or hiss and especially none of that irritating potentiometer track crackle one so often finds. (Signal source at this stage was a portable CD player.) I measured the exciter voltage as emerging from the amp and got a reading of 6v, not in any way surprising. However, when I tried the projector (which is another story), I got no sound. On checking, the exciter was extremely dim and the voltage across it read only around 1v. This I have yet to resolve, or to establish whether there is any link to the failure of the 16mm machine’s exciter. (Actually, I have found another original bulb that looks like it says 2.1v, so it is probably my fault.)

                         

With the 16mm machine, most of what I did was basic cleaning and oiling. The thing is an amazingly robust box– made out of girders, like Irn Bru. It has a solid plate base, on which is built a very strong framework of what one can only call angle girders with strong screw fixings, corner reinforcing brackets and thick side panels. This is necessary: a) because the top arm is mounted on the top of the box but mostly: b) because all 5 sides above the base are hinged and openable. A 4” square hole at the front (a sliding cover plate is included) allows film to enter and leave, guided by rollers. Opening the front panel allows the lower arm, fixed to the base inside the box, to be hinged out. There is even a special slot for the drive belt to the take-up. Both arms, incidentally, take at least 1600’ reels, unlike the tri-gauge which is limited to 800/900’. As you can see (pix 3 & 4 above),the droop snoot has been eliminated, presumably in the interests of greater spool capacity and smaller blimp. There is a blimp mentioned in the advertising material for the G3; how on earth did the fit it round that snoot? Pic 5 was taken while I had the power input socket removed. I was half-contemplating using a 240 to 110v converter I have, to enable the machine to be mains-powered, but I couldn't fit it in. Note also the care taken to give the entire sound head sprung mountings. I think I know this is suppposed to help isolate the sound from external influences, but for the life of me I can't see the point.

Getting what is a very cumbersome machine out of this box requires both side and top to be opened to manoeuvre it out of its confines. First, though, there are half a dozen screws to be undone from under the base. As there is no positive location for the projector other than the screws, getting it screwed down again is awkward, as you have to try to hold the machine in place within the box, with the whole thing on its side or rear, while you try to locate the first screw into a hole. I will not bore you with all my tribulations, but the machine was in and out like a jack-in-the-box and a forgotten feature, the still pic device, caused me much angst.

There being no amp to stand it on, I resolved the sound problem in my usual manner, using a 5mm square flat diode thing, mounted in this case on top of a nylon bar fitted up the tube that guides light from the prism (or is it a mirror – I ent looked) to the PEC. An axial hole takes the leads out the bottom of the nylon to wherever. Sound was good but a bit muffled; I may have damaged the diode which, foolishly, I purchased without flying leads. Suffice it to say my soldering skills are not world class; I shall have to re-visit this, but only after I have tried it on the tri-gauge amp.

First, however, I have some problems to resolve on the tri-gauge machine. I have discovered that both my memory and understanding of how the interchange parts work was deficient. In particular, I ignored to my cost an injunction I found only afterwards (I know, I know) in the basic instructions I got with the machine. This said “DO NOT REMOVE THE LOWER SPOOL SPINDLE”. I did, and have regretted it, and have yet to fix the ensuing problems.

Let me start with a couple of pix of the two machines together and the box of bits fror the G3 and an explanation of how it all works. The principal issue is that, unlike virtually every multi-gauge machine I know, the top and bottom spindles are not the same. The bottom one has removable drive dogs for each gauge, very much like those on Muray rewind arms, which are a push-click fit onto the spindle. This spindle is ultimately driven by a double spring belt hidden within the Concorde-style droop snoot. The lower pulley, which is on the lower spindle, incorporates a one-way drive so, in order to wind film on to the reel when threading, one must push the spindle from the back. This moves it a short distance, releasing the spindle from the one-way lock, so the spool can rotate. 

Now for my folly. I removed the spindle, but only with some force, then removed from the other side a sleeve and a spring, which together provide the travel to release the one-way mech. In the process, I stretched the spring irreparably. No problem, I have a store of springs various which can usually provide. However, when trying to refit the replacement spring with the sleeve, I made insufficient allowance for the fact that I have very little sensation in my finger-tips (heredity) and the spring went “SPOING” and the sleeve vanished from the face of the earth. I have turned that area of the loft upside down and I cannot find it. I have made a new one from memory and my best guess as to how it is meant to function, but I ent got it right yet. So far, I have only an intermittent drive to the take-up which frequently stops altogether. Let this be a lesson to ALL nerds to read the b****Y instructions first. I assumed it was just like any other G3 and it wasn’t.

This did explain some of the curiosities I found in the parts box, as in the pic above which is, incidentally, neither complete or accurate. I had initially wondered why there was only one 16mm spindle, but failed to think why. Normally, two sets of bits are in the box and one on the machine.

For 9.5 and 16mm, there should be two small sprockets and one large, one spool dog for take-up and a complete spindle for feed, plus a sound-reading gate (above) and a film gate; 9.5 has both silent and sound film gates. 8mm is significantly different. 9.5 and 16 use the same sprocket film guides; for 8mm not only do these have to be changed above and below the gate, but a special additional guide is fitted within the 9.5/16 guide for the large sprocket, the 8mm large sprocket being quite small (this latter guide does not appear in the pic). The 8mm spool spindles and sprockets work in the same way as 9.5 and 16mm. Another oddity in the parts is the presence of two 9.5mm large sprockets, two 9.5mm sound film gates and two 9.5 drive dogs. None of this could come from any other type of machine – they are unique to the Bolex tri-gauge. Curiously, I have what are unquestionably Bolex G3 9.5 and 16mm sound gates, adapted for use as optical sound gates for a Heurtier Superson; I wonder if somewhere there is a Bolex Tri-gauge sound machine missing an awful lot of parts………

 Anyway, after much fiddling, I was able to get the take-up to work and was able to try the sound. I think I have mentioned before what a noisy machine is a G3 Sound, especially not being blimped like the 16mm machine; subject to that, the sound seemed not half bad, but a bit low. I fixed this by switching to a 10w exciter lamp (still 12v ex Halfords). Irritatingly, the only way to change the exciter is to remove one of the securing clips more or less completely, but at least it is fairly accessible, if fiddly. Without replacing the PEC (either like-for-like or with a diode), I reckon this is about as good as I am going to get. I have also found that, with 1 or 2 millimetres to spare, I can just squeeze a 1000’ 9.5 reel onto the take-up.
Having read the instructions, such as they are, in more detail, I noted one or two differences between what they say and what I have found in practice. Most notable is the claw setting, which is by means of a knob at the rear. This, together with my surplus of interchange parts, suggests there must be one or two more of these behemoths in the country – it would be interesting to get in touch with anyone else who has one.