9.5 Sound


9.5mm Sound

Click Here for The Lost Chord - my history of trying to improve 9.5 sound.

Click Here for Silent to Sound - about conversion of silent machines to sound. Some sound-on-disc material.

Click Here for Pathé Vox - about my long history with the Vox and Super Vox.

Click Here for Joinville Equipment - about the late (1950's) Pathé machines like the Pax and a report on a sound conversion

Click Here for Cinegel Royale, an interestingly different approach to 9.5/16 sound.

Despite my natural aversion, there are even some pix of the Son (Ugh!) at the foot of this page.


Pat Moules has come up with some literature about French Sound film on 9.5, of which I have never even heard. In some ways, they are much more like some of the Pathescope Monthlies than is Cinema Chez Soi.



FrSdJan38a     FrSdJan38b     FrSdJan38c     FrSdJan38d


FrSdAv38a     FrSdAv38b     FrSdAv38c     FrSdAv38d     



 FrSdSep38a     FrSdSep38b     FrSdSep38c     FrSdSep38d     FrSdSep38e


FrSdNov38a     FrSdNov38b     FrSdNov38c     FrSdNov38d     FrSdNov38e


One problem with 9.5 sound was that the soundtrack stole some of the picture area. Obsessed as they were with claiming that 9.5 used the maximum possible percentage of the total film area, and that its picture size compared well with 16mm, Pathescope carried this approach thru onto sound films (see pic below, after the Comète). The result was a very square format for 9.5 sound, yet it was not to be that long before the professional cinema was rapidly disappearing over the horizon in quite the opposite, letterbox, direction. The French arm of 9.5, however, went for a more rectangular picture, no doubt as being aesthetically more pleasing, even if it did "waste" some of the film area above and below the image - an early form of "black bars"? Interestingly, the proposed but never realised standard 8 mm optical sound system also involved stealing a bit of the picture area. 

TQ1 Conversion


 TQ1a      TQ1c    TQ1d     TQ1b     TQ1f     TQ1e           

This is a Bell and Howell converted to 9.5, reportedly by Burgess Lane, many moons ago. It ran, but with poor volume and all sorts of extraneous noise from the amp and controls. The job was in some ways well done - the sound reader lens had been moved across so the film was the right way round for projection. However, the gate is decidedly dodgy with the sprung portion comprising a lower and an upper section, joined by a piece set back from them to give clearance. And while the sound reader had been moved across, the exciter had not! A peculiar little mirror-cum-lens had been bolted to the inside of the exciter lamp cover to direct the light across. I suppose it must have worked to deliver any sound at all, which it did. It was not helped, however, by the fitting of a 6v exciter lamp when there was only 3.9v going into it, giving a very orange light. I decided to move the lamp across, and doing this kept me happily occupied for many hours over a number of days.

It is now many months later, and I have finally done some pix for you. You can see how I have moved the exciter lamp over (ie outwards). To make room, I cut a hole in the exciter cover (see last pic) and covered this with a thick piece of aluminium, which had a hole excavated into it to provide the remaining room needed. Given the damage already done, I had no qualms about this - that little door flap was already there.

The gate is really quite unsatisfactory. What they seem to have done for the back gate is to cut thru the centre line of the 16mm gate vertically and take a piece out of the middle. So there are now four "edge" runners, two of which are right in the middle of the 9.5 picture. The gate mask is wrong, too. And as for that 2-piece front gate......

Apart from the exciter lamp, I have also made a simple change to give a little bit of scope for adjusting the position of the sound track. I removed the upper of the two "noses" on the sound jockey roller assembly and replaced the roller with a 9.5 one (actually an 8mm one which I adapted). This has a spring behind it and the "nose" replaced in front of it, with a small brass spacer as the screw is otherwise too long. It need careful screwdriver adjustment and I suppose technically there ain't a lot to stop the screw coming undone, but as a quick and dirty fix it worked OK. Trouble is, the precise shape of the bracket for the diode/cell interferes and prevents very much movement of the film, but to adjust would have meant substantial dis-assembly. My final change was to swap the volume control pot for another, which worked much better. I also replaced a 16k ohm resistor across the input to the amp with a 33k one, which seemed to improve the sound. I tried 67k, but that seemed a bridge too far and I felt the sound was starting to deteriorate in quality.

There is a lot that needs to be done to make this a really high grade machine. The sound lens is held by a single screw and can pivot, which it no doubt will in use. The spool noses are dreadful, relying on araldite to hold crude adapters in place. The gate is a major area needing work. There is still not enough volume from the sound, although quality is good. I think, too, that the way they have adapted rollers from 16mm is not very good. I think the Comète below is a much better job in most ways.




 Comète1     Comète2     Comète3     Comète4


The Comète, as I understand it, is a French conversion of a Chinese 16mm. This appeared at the Group 9.5 auction, where I bid on behalf of Patrick Moules and got it very cheap as it had mechanical and amp problems. The mechanical problems were easy to fix, but I had to pass it to a radio repair man for the amp. I also had to improve the exciter lamp set-up. There is some provision for moving the film in relation to the sound reader, but it's a bit crude and tricky and could do with a major re-think. That said, the conversion is a quality job and the results I can only call superb, with plenty of "top" and great clarity from the sound.  


Here is a superb pic of the sound film dimensions from McKee's "Home Cinema". 

Some dimensions for other gauges can be found near the end of Big Brother 1 and now in Film Standards.

Here for those interested in such things is a circuit diagram for a Vox amplifier, plus an even more technical thing about valve voltages.

Voxamp1     voxvalves




sonugh1     sonugh2     sonugh3     sonugh4     sonugh5     sonugh6     sonugh7     Sonugh8

These are pix produced for someone who actually wanted a pic of the Son(Ugh!)! Plus a couple of odd bits. However, more recently (Autumn 2016) I have somehow found myself with two or three Sons (") and being sucked in. I shall have to be careful or I could easily end up giving the Son(") its own page. Ugh!

I started with a much-modified affair, with a new motor and a new solid-state amp. Sadly, these things did not come together in any very satisfactory way. The basic flaws of the Son ("), as we all know, were:-

1 A motor wound for 160v yet run on 240v (as well as having dodgy "rubber" mounts prone to failure). This was apparently in part at least so it would go fast enough from cold to approximate to sound speed;

2. The motor was a standard, rheostat-controlled variable-speed type, constant speed being achieved by means of governor contacts at the rear of the motor. This was not necessarily bad of itself, but together with 1 above,gave rise to a situation where, as the motor warmed up, it went faster and made the governor work harder unless the speed control was gradually reduced to match the increase in speed from the warming process. Burnt-out contacts were a frequent cause of return to the Pathescope workshops for repair.

3. The amplifier was poor, effectively just thrown together, down to a low price, 
by unskilled labour, in someone's garden shed  and very prone to fault.

4. The film path was very poor. A single, small sprocket is not ideal for a sound machine, especially when it required at least one very tight bend, nearly 180 degrees in half an inch, as the film met the sprocket for the second time.

5. Smoothing at the sound drum was poor.

6. I have heard reference to "Son-stroke" as a cause of film damage, in connection with the claw/gate combination, but I am not wholly convinced. The claw is in principle very similar to that in the Pax and the Elf and I am not clear why this would damage film - that tight bend in the film path is a much more likely cause. As for the gate well, it was cheaply made with poor aperture and masking but, again, no obvious opportunity for damage.

This particular machine has obviously had an adventurous life. It's a bit battered, with lots of paint chips, and some screw threads that no longer hold - inevitable when they are in a fairly soft casting. The lens mount has been enlarged to 1 inch (Specto or old B&H) and, as mentioned above, a new amp has been fitted. The new motor installation is a bit of a bodge, with over-flexible mountings and imprecise location. Getting the right tension on the belt seems to drag the shaft across and put extra strain on the motor. A new circular rheostat (like in the Specto 500) seems to have some kind of associated circuitry that means it responds relatively slowly to changes in the speed setting. It is still, however, very much subject to speeding up as it warms up. Hammerite have a lot to answer for: a new side plate has been fitted to cover the amp and some benighted fool has manually applied Hammerite. This is NOT a good look and has been removed.

I have had a lot of trouble with the sound drum. The ball bearing race immediately behind was well past its sell by date and ran very rough. Unsurprising; it is unsealed and it seems in fact that it is impossible to find sealed ones as it just isn't thick enough, so my new one is unlikely to enjoy a long life. And lubrication is difficult because of access problems. I also found that the re-routed supply to the lamp (I forgot to mention the lamp is now a 24v 250w halogen peanut. This is fed from an external transformer, the mains supply to which comes from the projector rather than having a separate mains connection), was rubbing on the flywheel and causing a surprising amount of friction. The perspex light tube from near the film to the photocell has been replaced by a rod in which is fixed some form of diode, but it looks to me to be at the wrong angle to catch enough of the light from the exciter (a 12v 20w halogen)(!) and will need re-doing. I have so far failed to get the flywheel running freeely enough, or the motor for that matter, and the only way I get decent-ish sound is by adding considerable pressure to the sound drum by hand; even then speed is very unstable and volume is low. And the lateral adjustment for the sound- reader is sloppy. Every time I need to tweak something, I have to do a fair bit of dismantling, and then re-assembling before I can test. I got bored with this and have put it on one side until stocks of patience are restored. I may have to go the whole hog and fit a B&H motor, as the current one does not seem man enough for the job.

I have also discovered the danger of playing with a Son ("). I hadn't finished messing with the first before I moved on to a second. This has now had the amp and tranny removed, a B&H DC tachograph controlled motor mounted and a B&H diode fitted in place of the PEC. There is a lot more left to do, like a power supply for lamp, motor, amp and pre-amp and exciter, plus fitting the exciter (it was part of the amp wot I have removed) and finding stuff to do the electronic bits. I still do not know what voltage the motor runs on or how its speed is controlled. However, it fits quite neatly once the old tranny has gone and yes, the side will go back on round it. There is bags of room in the base to put the B&H tranny that I hope will provide most of the supply voltages I need.

Dismantling the projector showed what a dog's breakfast both motor and amp were. I will do you some pix.

Sonamp     Sonmotor     SonBHmotor

You will see I have severely truncated the support brackets for the B&H motor and fitted alu angle to provide a way to fix it down. If I ever do this again, I would be able to cut the brackets to a more precise length, and have them in contact with the base, rather than supported off the base by the alu brackets as here.This would avoid having to cut into the alu to match the curve of the housing for the rubber mounts at each end of the motor. I would probably have the front alu angle pointing backwards, so the flange is under the motor rather than in front. This would make it easier to fix to the plate with which I have filled the hole where the original motor was. The B&H motor shaft is 5mm, where the old motor shaft was a nominal 0.25" (about 6.3mm). I made a brass extension piece, the hole sized to be a fairly stiff push-on to the B&H shaft, with an external diameter to match the original fan and inching knob cum pulley.