Tuning a Model C / H reproducer, the Why and How

[MicaMonster]

Ok. Everyone (EVERYONE!?!?!?) is probably either tired or lightly amused by my obsessive behavior, but I'm Back. And I have a new discovery to share.

1mm O.D. medical grade silicone tubing.

Used for drawing blood, or for your morphine drip at the Wayne or Union show when someone offers you $250 for a machine you paid $3000 for less than 2 years ago. (more on that, later).

My biggest gripe (hahah....gripe is such a light and fluffy word) about cylinder reproducers is the lack of public knowledge in how they actually function. For all intents and purposes of explanation I will use my humble Edison Model C cylinder reproducer as an example. For those that have disassembled one, they contain two natural rubber gaskets that are each sandwiched with paper gaskets. The paper gaskets kept the rubber from sticking to the diaphragm and the reproducer shell. I've always felt that the 33mm Edison diaphragms were too small for the job....and they are, if you install them tightly between new rubber gaskets and clamp the life out of them.

The diaphragms need freedom. Wiggle room, with enough hold to keep them vibrating at the frequencies that they are trying to represent while not loose enough to distort and cause uneasiness or sea sickness in your listening parlor. For a long time, I used my own cut paper gaskets to achieve this, but the paper itself would swell with temperature and humidity changes, and yes....call me crazy (again), but I can hear the change in tone.

We need to focus on technological improvements. For over a decade I have been a crazy supporter of silicone and butyl rubber as a modern replacement for gum rubber in reproducer mounting flanges and gasketry. I'm the guy found lobbying for this, often flowering my language with purple prose and vitriol, at any phonograph event where they'll take my admission money.

The problem I have with gaskets is that I have become finicky with how records sound when reproduced. (Mr. Edison, if you are out there floating in the ether.....save me a position at the machine shop after reviewing my fountain penned job application). The results are inconsistent, and I am never really satisfied.

SO. Here is where I explain the virtues of silicone tubing. More specifically, the 1mm tubing I sourced from the medical field. I replaced the gaskets in a Model C with it, but to make it work, I had to file off the little alignment ear from the friction washer that sandwiches above the gaskets (between gaskets and clamping ring). Then, VISUALLY, I slowly tightened the clamping ring down until it made contact, then about ¼ turn more. Results may vary. The idea is that there is gentle contact, but the hollow gasket should NOT be allowed to smoosh closed. And that is how I set my Model C up.

The headache is adjusting the wire diaphragm link. It will need to be made about .5mm longer so your needle bar doesn't bottom out on the wax cylinder. Use a test record for adjusting the needle bar. There is a lot of back-N-forth in this game, so put some time aside.

Play a few test recordings. I use brown wax, black wax, and celluloid 2minute cylinders.

Diaphragm adjustment rings work like a TONE knob on a 1950's phonograph. TIGHTENING increases TREBLE, and decreases BASS. . LOOSENING increases BASS, and decreases treble. There is a sweet spot. This is how you adjust an Edison Standard Speaker or Automatic reproducer. NEVER put a slip-on horn on an Automatic.....it will apply its weight to the bottom of the diaphragm (possibly cracking it if it is French glass!). Always use Standard Speakers and Automatics with a floor crane suspended horn or ear tubes (preferred by myself). Ok. But this only works if your diaphragm ISN'T sticking to the gasketry. If it is, you won't hear any difference at all, other than distortions when the diaphragm becomes too loose. (exhale). I'm being a Dutch uncle. And I need to stop it.

My Model C has one of those 3-disc "wedding cake" mica diaphragms in it. The results on an orchestra cylinder were ear opening. My only criticism, other than the amount of time I invested in this experiment, is that the clamping ring will sit up about .5mm from the reproducer body. Simple adjustment.....loosen the hinge block by 1 full turn to acommodate.

No Graphophones were hurt during the run of this experiment.

[Jwb88]

So you can't stop adjusting and fiddling with reproducers? Neither can I!

I currently have gaskets I cut out of craft foam sheet in my model c. It has a copper diaphragm. I think there was an improvement, but not huge. I think the foam sheeting doesn't have enough resiliency and it tends to mush down and just stay that way. I bought some red gaskets for a victor #2 from a dealer and they are the same foam. I admit they sound pretty good, which is why I tried them on the Model C. I think in the victor 2 they have more room and they're wider, so they work well.

I think silicone rubber is probably the best bet of modern substances so I'm sure yours probably sounds noticeably better. Next time I have some time set aside I'll probably mess with it some more. Can't help it.

[barnettrp21122]

Have you tried this silicone tubing in Diamond A-C or Diamond Disc reproducers yet?
Bob

[edisonclassm]

The biggest problem with optimum performance in phonograph reproducers is aging and stiffened diaphragms. When diaphragmatic movement is hindered by age hardening(DiamondA,A,C,DD) and in the case of the copper diaphragm, work hardening. You get optimum performance out of a reproducer when the diaphragmatic movement is at it's peak. This is why the Higham reproducers on the Columbia BC's work so well when they work. Higham reproducers use mechanical means to increase the diaphragmatic movement resulting in an exponential sound increase. Copper diaphragms on the Edison reproducers are not pure and contain some alloy to rigidize the material. It really is a form of Red Brass. Anyone who knows materials science knows that brass will work harden as many materials do. Years of playing records actually hardens the diaphragm restricting it's movement therefore affecting it's performance. Other reproducers that are affected by work hardening are the Victor Concert series with their tiny eyeglass shaped torsion spring supporting the needle bar.(Early Zonophones too) These torsion springs break over time because the material reaches what is known as it's ultimate strength from the twisting back and forth of the needle bar when playing the modulated recordings. The best solution would be to replace the aging diaphragms with new ones. Unfortunately there are no suitable replacements available. The only modern diaphragms that outperformed the originals were those found in the reproducers made by Paul Baker in the late 70's and early 80's. Glass and Mica Diaphragms found in earlier Edison and Columbia Reproducers were intended to be sensitive more than compliant. Glass was found to unsuitable due to it's fragility and was replaced by Mica which was more durable and when new and was nearly as sensitive.

[MicaMonster]

You are absolutely right, the Edisons are an alloy of brass and copper. Replacements from Overseas are usually found to be made of solid brass, which is waaaay too hard, or maybe stamped too thick. The Paul Baker diaphragms in his reproduction Model K reproducers are the best I have heard. In truth, I use a Baker Model K *INSTEAD* of the Edison Model K because it is built much much better. (tip of the hat to you!)

Rice paper diaphragms, that is an entire different chapter!

Here is a trick I use to eliminate rattle: cut the 1mm silicone tubing in half, then thread some through the eyelets. They act as dampers, and keep metal-on-metal with the wire link. No more rattling. In the photo the diaphragm silicone is on top...after the pic I rotated it to the bottom.

[edisonphonoworks]

Mica those are very good points. Most of the time I hear reproducers the clamp is too tight. I am going to have to try the silicone gaskets. I have used the Phonoboy diaphragm in my model C and it sounds great. I am also partial also to stepped glass diaphragms in C, H, reproducers. I like the trick with the tubing in the eylet.