Consolette orthophonic soundbox

[burke]

Just sharing a random thought that came to me. The deterioration of potmetal in these soundboxes seems generally be attributed to moisture and temperature fluctuation accelerating the degradation of an already poor formula. This seems logical to me [my day day job is in the museum world ... I'm NOT a conservator but I'm familiar with general principals]. I did a search on silicon dioxide [aka silica] to see if this had been floated before but only saw references to the preservation of wax and bamboo. If you are not familiar with this stuff, its whats inside those little white 'DO NOT EAT' packages you find in some foodstuffs and is a desiccant [absorbs moisture].

This falls under the category of 'may not help, but can't hurt' but maybe worth having one or two inside with the lid closed. They are easy to buy, but you can also revitalize them by putting them in the oven on the lowest temp for an hour or so and for larger spaces you can use silica cat litter wrapped in J-cloth ... yes I have done this

[dennman6]

Ron Sitko (and maybe others) is selling complete new castings for orthophonic soundboxes (back, front and ring). You only need your old needle bar I think. He also sells the ball bearings, gaskets, diaphragms etc.

Andreas

This I would think is great news for owners of Orthophonics. It seems one can completely build up an Orthophonic soundbox and restore performance quality to the Victrola. Walt Sommers rebuilt the soundbox for my 1926 Credenza, and replaced the cracked back with either a good original or perhaps a newly cast back. The rest of the soundbox was original. I realize this Sitko solution isn't the same as having an original soundbox, but if these replacement parts spec as original and look nearly as good I would be very happy to have such a good sounding unit on an Orthophonic Victrola. To me the look of the thing must look good and as close to original, but even more important is that the Victrola must be a good audio performer. This seems to be a win-win situation, and I wasn't aware of the new parts being available until now.

[JerryVan]

Just sharing a random thought that came to me. The deterioration of potmetal in these soundboxes seems generally be attributed to moisture and temperature fluctuation accelerating the degradation of an already poor formula. This seems logical to me [my day day job is in the museum world ... I'm NOT a conservator but I'm familiar with general principals]. I did a search on silicon dioxide [aka silica] to see if this had been floated before but only saw references to the preservation of wax and bamboo. If you are not familiar with this stuff, its whats inside those little white 'DO NOT EAT' packages you find in some foodstuffs and is a desiccant [absorbs moisture].

This falls under the category of 'may not help, but can't hurt' but maybe worth having one or two inside with the lid closed. They are easy to buy, but you can also revitalize them by putting them in the oven on the lowest temp for an hour or so and for larger spaces you can use silica cat litter wrapped in J-cloth ... yes I have done this

Darrell,

Pot metal decomposition is due mainly to the presence of lead in the original mix. Over the years, the lead promotes a process called intergranular corrosion, which apparently produces oxides that grow and thereby swell the entire structure until it essentially bursts. I don't know if humidity accelerates the process. I have always assumed that whether or not a casting decomposes was due mainly to pure luck. Driven by the amount of lead in the original mix. I believe lead was added purposely to aid in the casting process, with the eventual result not being known to the original manufacturer. At the very least, it was not avoided, as it is today, with modern die-cast practice.

[Retrograde]

I have pot metal reproducers that were cracked but stable when I bought them 20+ years ago. They haven't changed since Ive owned them as far as I can tell. I think the damage happened early on and has not progressed after the environment was stabilized. And I've done nothing special in my home to control humidity and temp other than normal heating and cooling. I don't think putting desiccant in a phonograph is going to do much of anything, it's not sealed.

I do put the "do not eat" packs in with my bamboo needles that are in small jars.

[burke]

intergranular corrosion

That led [no pun] me down a few rabbit holes this evening.

Including some sort of a home shop machinists forum where they were discussing 'Zamac' [apparently a less disreputable cousin of potmetal]

Near the end one person posted this:


"Or worse, a crucible used to melt lead, a few ppm of lead will cause explosively destructive intergranular corrosion to begin almost immediately. This is the cause of the strength loss and disintegration seen in aging Zamak parts. Even being in contact with lead after casting can be destructive. I was given a Craftsman lathe years ago and the change gears were in a tinned steel can with a bunch of other stuff. The gears and other Zamak parts in contact with the bottom and sides of the can had crumbled, starting at the contact points. Those not touching the can were fine. Moisture accelerates the process."

Now I'm not arguing that moisture is definitely a factor ... I honestly do not know. But like I said earlier this is just speculation on my part and its in the category of "Can't hurt, may help" ... probability makes no difference.

If I lived in Yurt near the ocean, then I would definitely try this.

[TonyJ]

This I would think is great news for owners of Orthophonics. It seems one can completely build up an Orthophonic soundbox and restore performance quality to the Victrola. Walt Sommers rebuilt the soundbox for my 1926 Credenza, and replaced the cracked back with either a good original or perhaps a newly cast back. The rest of the soundbox was original. I realize this Sitko solution isn't the same as having an original soundbox, but if these replacement parts spec as original and look nearly as good I would be very happy to have such a good sounding unit on an Orthophonic Victrola. To me the look of the thing must look good and as close to original, but even more important is that the Victrola must be a good audio performer. This seems to be a win-win situation, and I wasn't aware of the new parts being available until now.

Early on I bought a reproduction Ortho from Shenandoah and believe I later heard that they may actually get their castings from Ron Sitko. Having said that, I've never compared the performance of it to reproducers I've acquired since then. They sure do look nice though!

http://www.shenandoahrestoration.com/motor.html

[burke]

Hi all

An update and a new problem.

I obtained another soundbox from a member. It is in much better shape but like the original is just frozen solid. I tried all the techniques I could find [mainly a long soak in penetrating oil & some time in the deep freeze] but to no avail.

So I bought a new case from Ron Sitko and a new problem became immediately apparent. How to remove the needle bar from old case and then install it in the new. This picture shows the shaft that goes through the needle bar comes out and that is the solution.

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I destroyed the first case to get the needle bar and diaphragm out, but that shaft does NOT want to come out of the needle bar ... I have tried as much force as I dare with vice grips and plier combos and in this case even some blow torching/heat ... but its in there good.

Any secret methods or suggestions?

Thanks

[burke]

Figured it out myself a short while after posting.

I remembered I had a small jewelers vise so I put the end of the needle bar in it and with a small hammer and a nail punch I tapped on the end of the post and it popped out.

On inspection I see that no amount of heat or oil would have helped. The center of the post is ridged and its pure friction holding it in place. Reversing the process will be finicky, but now that I know the situation - quite doable.

Both foil diaphragms have holes and lots of crinkles and dings so I found a replacement on ebay and just purchased it.

Basically once I'm done the only original parts will be the needle bar and spider.

[burke]

A new diaphragm arrived last week and I attached the spider today [maybe went a little heavy on the epoxy]. I also un-soldered the bars that connect the needlebar to the spider and realized there is an indentation to make sure you connect it in the right place.

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The crossbar was hard to get out and really didn’t want to go back in … I ended up filing it down a smidge … not sure if that’s what most folks end up doing or not, but it’s still ‘snug’.

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You use epoxy to re-attach the spider --- can you do the same for the needlebar bars … or is solder an absolute must for some reason?
One of the backs survived and with it the phase plug. I did not realize the phase plug was detachable.
There is some on the forum who say the phase plug makes a significant difference and Ron Sitko’s does not have one.

I figure there are 3 options:
1. Build it without
2. Use the old back and plug with the new front case
3. Or use the detached phase plug in the new back … that would mean epoxying it and that would be difficult or impossible to reverse … unless I used something like silicon [which could be switched with epoxy later once I was sure it was the correct option.
Thoughts … or even better actually experience doing something like this?

[JerryVan]

The fourth option is to drill & tap the 3 tiny holes and mount the phase plug the correct way.

However, you could epoxy it. That's not irreversible since you can heat the heat the back piece to melt the epoxy. Just be sure that the new back plate allows enough room for the phase plug to be there without hitting the diaphragm. Chances are, it wont make a terribly noticeable difference either way.

You can probably glue the needle bar as well, but if you find that to be unacceptable at some time, you now have a mess to clean up before you can solder it. I would solder it, being very careful to not melt the epoxy holding the spider to the diaphragm. I use a small, electronics soldering iron. Let it get to full heat before you begin and solder the joint as quickly as you can, before heating the entire spider and letting the epoxy melt.