View Single Post
Old 11th Dec 2020, 5:16 pm   #1
_Cosmic_
Pentode
 
Join Date: Oct 2020
Location: Washington, Tyne and Wear, UK.
Posts: 125
Default Grundig Electrostatic Tweeter Repair Tutorial

The Grundig Electrostatic Tweeter.

I am writing this to hopefully guide someone, just like me, who would like to try and repair their electrostatic tweeter.
This unit was commonly utilised by many manufacturers of radio, radiograms and record players during the 1960's. They sounded fantastic. Quad even made electrostatic speakers at one time, but these were huge free-standing units that I resisted the temptation to buy, due to the astronomical cost of them and their size, when I bought my Quad 33/303. Size is often a problem, as seen today with the amount of radiograms that are discarded and that remain unsold on the well known auction site.

Often new acquisitions such as radios and record players sound pretty good when first heard but sooner or later an enthusiast, for various reasons, will come to investigate the sound and discover that the small speaker, situated separately but close-by the main speaker isn't working.

Although I'm not an electronics or electrical engineer, I have owned a great many record players over the years since the 1960's so have a great deal of experience using them and keeping them maintained with new styli and cartridges. Just lately, I have been renovating a couple of Bush SRP 31D's. This was because I was forced into it after buying the first one on the well-known auction site, and it arriving damaged and parts of it not working, then another for the parts to fix the first one. It's usually because I have been conned so to speak by at least 2 sellers to date who said that the players were "working". They certainly were not damaged in the post.

One part in common that didn't work at all in both players was the Grundig electrostatic tweeter.

Immediately I did a bit of research on them and discovered you can no longer buy them, either new or second-hand. I discovered a video on the well-known tube site but it wasn't very clear exactly how to go about repairing them. I also discovered a thread of an owner making enquiries about how to go about repairing one and actually breaking it beyond repair in the process which was very sad to hear.

So after being prompted by one of our vintage-radio fantastic members I am going to attempt to go through the process of reviving your tweeter and not doing as some have suggested, discarding the Grundig and replacing it with a modern tweeter unit.

You will know when you have got it right because when they are working correctly they make a real difference to the frequency range and the spatial projection, in that the sound is spread a little more to the LHS of the speaker grill.

So here we go..just bear with me as it might take a little time to post with the photos and thinking about how I did it, and I might have to edit it a few times..
_Cosmic_ is offline   Reply With Quote