The Talking Machine Forum — For All Antique Phonographs & Recordings

It is currently Sun Jan 17, 2021 6:25 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 14 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: Early EMG 2 Spring soundbox
PostPosted: Mon Dec 28, 2020 7:10 am 
Offline
Victor I
Joined: Mon Nov 14, 2011 6:06 pm
Posts: 180
I agree, but I imagine with a "varnished" diaphragm-may have even been shellac coating, is there a chance that the non-metallic material of the diaphragm's composition may be better protected from such as atmospherics? Or even the break down of the coating could have effects on quality of reproduction?
Certainly an interesting subject. It is bad enough with aluminium diaphragms suffering with oxide degradation. I wonder if the good old mica or Bozon's patent tortoiseshell may be the only ones not badly affected by the atmosphere, but they could certainly be affected by internal stresses through use and adjustments. This is a subject I know little about, and would like to know more of.


Top
 Profile  
 
 Post subject: Re: Early EMG 2 Spring soundbox
PostPosted: Mon Dec 28, 2020 7:57 am 
Offline
Victor IV
Joined: Sun Mar 15, 2009 6:18 am
Posts: 1256
Location: Luxembourg
old country chemist wrote:
I agree, but I imagine with a "varnished" diaphragm-may have even been shellac coating, is there a chance that the non-metallic material of the diaphragm's composition may be better protected from such as atmospherics?


Alastair, the closest example to the Astra diaphragm that comes to my mind is the Edison diamond disc, made of layers of shellac-coated rice paper. They all aged badly, even NOS pieces. This is demonstrated by the vast increase in quality of reproduction when they are replaced with newly-made diaphragms made by a couple of very creative enthusiasts, both forum members. It becomes then guesswork to speculate how a brand new Astra soundbox would have performed. The scarcity of extant pieces also limits the comparison among differently-aged diaphragms.


Top
 Profile  
 
 Post subject: Re: Early EMG 2 Spring soundbox
PostPosted: Tue Dec 29, 2020 9:57 am 
Offline
Victor I
Joined: Mon Nov 14, 2011 6:06 pm
Posts: 180
Thanks Carlos for your information. I think this is a subject that could be of interest to quite a few of us.


Top
 Profile  
 
 Post subject: Re: Early EMG 2 Spring soundbox
PostPosted: Tue Dec 29, 2020 7:22 pm 
Offline
Victor Jr
Joined: Wed Nov 07, 2018 6:02 pm
Posts: 33
Location: Hampshire, England
Re Astra diaphragm:

Because mine had a tear, I could see a web of threads inside it. I'm sure I've read somewhere these were a silk composite?

Mined didn't age well either, and came in rather deformed (dished). I used steam to try correct that to some extent, but will never know what it sounded like new. One of those days I'll fiddle about with making a new diaphragm for it

Re EMG spacer padding:

Out of curiosity, I've been playing around with small bits of standard gasket tubing squeezed between the soundbox body and platform to see what that does. Depending on where I placed them, the effect ranged from not much to dialling down treble a notch, and perhaps made the sound a bit less open. So much fun tinkering with this thing!


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ]  Go to page Previous  1, 2

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: alang and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Content © 2009-2020 by The Talking Machine Forum and the respective posters.
Americanized by Maël Soucaze.