HMV (British) v. Victor No. 4 Soundbox - Interchangeable?

[fran604g]

If the back is brass, then the front will be too. After undoing the four screws, try very gently to seperate the two halves. Sometimes the old gasket sticks to either the back of the soundbox or the diaphragm, sometimes both! Rough handling will cause the mica to delaminate.

Thank you. I'll be very careful. Maybe I'll use the very slightest bit of penetrating oil to help unseat the gaskets from the diaphragm.

Best,
Fran

[OrthoFan]

It still sounds fairly decent, but loud high-frequency passages break up, due to either the old gasket material, or the mounting isolator -- or both. Do you have a recommendation for both the gaskets, and mounting isolator?

I'm not sure if the one-piece rubber gasket is still available. You could probably check with the Antique Phonograph Supply Co. -- http://www.antiquephono.com/ or George Vollema -- http://www.victroladoctor.com/

In addition to a frozen gasket, another thing that will cause a #4 (as well as a #5a or #5b) sound box to break up on loud passages is a mis-adjustment of the needle bar pivot. The needle bar should be free to move in the direction required to track the record--to move the diaphragm back and forth, but should not move in the opposite direct (or in the direction of the lugs holding it in place). If there's even a trace of movement, or shake, when you move the needle bar sideways, it could cause buzzing, blasting, etc.

Years ago, I posted a description of how to adjust the needle bar pivots, on this page -- http://forum.talkingmachine.info/viewto ... f=2&t=4465

OrthoFan

[Retrograde]

Regarding Gaskets:

It's been awhile since I rebuilt my #4s. A couple of times I used a red one-piece gasket from Soundgen. I don't know if those exist any longer. On others I use two black gaskets from Ron Sitko. These black ones and the mica are made for the Columbia Grafanola, I think. The black gaskets are ~1.64mm thick. A quick check of my spares shows that the total thickness of gasket/mica/gasket is ~3.5mm

[Phono48]

Thank you. I'll be very careful. Maybe I'll use the very slightest bit of penetrating oil to help unseat the gaskets from the diaphragm.

Best,
Fran

No! If penetrating oil gets of the edges of the mica, it will seperate the layers and you'll need a new diaphragm.

Barry

[fran604g]

Thank you. I'll be very careful. Maybe I'll use the very slightest bit of penetrating oil to help unseat the gaskets from the diaphragm.

Best,
Fran

No! If penetrating oil gets of the edges of the mica, it will seperate the layers and you'll need a new diaphragm.

Barry

Thank you for the tip. I'll try to separate them another way, if the problem arises.

Best,
Fran