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I received a super nice HMV No.4, all brass, reproducer today from England that sounds superb to my ears. The rubber gasket around the mica is very hard though. I almost hate to touch it because it sounds so good. Should I even mess with it?

If you think it sounds great why mess with it. I say don't touch it.

Dan

I agree. Leave it alone. As the old saying goes, "If it ain't broke, don't fix it"
Harvey Kravitz

Perhaps my earlier thread would better apply here regarding my recent HMV no. 4 rebuild: http://forum.talkingmachine.info/viewto ... 11&t=29050.

Both the one-piece diaphragm gasket as well as the mounting flange on my brass No. 4 were rock-hard and sounded terrible.

I've also been been a proponent in the past of "If it ain't broke, fix it 'til it is . . . "

Depending on the flexibility of the diaphragm, the only "sacrifice" I can see for not restoring it would be a somewhat restricted lower mid-range, or "upper bass." It would probably have a brighter sound compared to a restored #4. But, if it sounds good to you, leave it as-is. If you start to see any "black dust" accumulating needle tips, it might be time to change the gaskets.

OrthoFan

Ok Thanks.I actually removed the red one piece rubber gasket and it had no cracks. It was a little stiff so, I sprayed it with some silicone and heated it gently with my heat gun until it was almost as flexible as a new one. How much play should be in the pivot points on the diaphragm arm? Should it be on the loose side or tight side? I loosed the pivots and placed a drop of oil on them. I adjusted them to where the arm was perfectly centered on the mica and it was on the loose side but with no side to side end play at the bearings. It has more volume now.

hearsedriver wrote:Ok Thanks.I actually removed the red one piece rubber gasket and it had no cracks. It was a little stiff so, I sprayed it with some silicone and heated it gently with my heat gun until it was almost as flexible as a new one. How much play should be in the pivot points on the diaphragm arm? Should it be on the loose side or tight side? I loosed the pivots and placed a drop of oil on them. I adjusted them to where the arm was perfectly centered on the mica and it was on the loose side but with no side to side end play at the bearings. It has more volume now.

I was told, years ago, that you should be able to move the needle bar by blowing on it gently. (Obviously, when not connected to the diaphragm.) But from what you describe, it sounds like you have the pivot adjusted correctly. If it's too tight, the sound tends to be shrill, and if it's too loose, or if there's any side-play, you'll hear buzzing or rattling on louder notes.

OrthoFan

OrthoFan wrote:

hearsedriver wrote:Ok Thanks.I actually removed the red one piece rubber gasket and it had no cracks. It was a little stiff so, I sprayed it with some silicone and heated it gently with my heat gun until it was almost as flexible as a new one. How much play should be in the pivot points on the diaphragm arm? Should it be on the loose side or tight side? I loosed the pivots and placed a drop of oil on them. I adjusted them to where the arm was perfectly centered on the mica and it was on the loose side but with no side to side end play at the bearings. It has more volume now.

I was told, years ago, that you should be able to move the needle bar by blowing on it gently. (Obviously, when not connected to the diaphragm.) But from what you describe, it sounds like you have the pivot adjusted correctly. If it's too tight, the sound tends to be shrill, and if it's too loose, or if there's any side-play, you'll hear buzzing or rattling on louder notes.

OrthoFan

Great! Thank you.

CharliePhono wrote:Perhaps my earlier thread would better apply here regarding my recent HMV no. 4 rebuild: http://forum.talkingmachine.info/viewto ... 11&t=29050.

Both the one-piece diaphragm gasket as well as the mounting flange on my brass No. 4 were rock-hard and sounded terrible.

I've also been been a proponent in the past of "If it ain't broke, fix it 'til it is . . . "

Don't know how many "Red Green Show" fans there are here, but Red has an "If it ain't broke" saying that's my favorite:

"If it ain't broke... You're not trying!!!"

Red was the best. One of my favorites was "This is only temporary. (Unless it works.)"
Dave D