Experimentation with an Exhibition Soundbox

[Governor Flyball]

Having recently rebuilt another Exhibition Soundbox and despite resplacing the gasket and/or diaphragm, the Exhibition soundbox has always sounded to me too bright and especially strident on electrically recorded discs. So this evening I performed an experiment replacing the stylus armature springs with more flexible springs. The aim was to gain more stylus compliance and improve the bass.

I read some in this forum making the stylus bar springs less rigid by grinding the existing ones. Tonight I went one step further and tried manufacturing my own springs from razor blades.

The resulting springs were less stiff than the originals. I fitted the spring to my Exhibition on my VV-VI to test.

The sound quality changed noticably. The stridentness was suppressed and the bass response improved. An electrical disc sounded less strident. The highs were attenuated somewhat but not unduly. I shall try making the springs stiffer to see how it will affect the highs

I am curious if any of you have tried the same and have had varying degrees of success making this or other modifications? I am also curious if the springs across the soundboxes across the Victor models used a standard design or if the springs are softer on other models?

[Inigo]

I'm one of them... I've reattached the original springs differently, so they only hold a bearing ball each, placed on top and pressing the needlebar fulcrum plate against the knife supports. This arrangement is similar to emg-expert, but instead of points, mine press through steel balls housed within the spring holes. It's only a relocation of same elements (introducing the steel balls). An image tells more than 1,000 words.... I'll post it later
I'm also experimenting in the same soundbox with different quality metal diaphragms. Later I will extend my explanations if you are interested.
Colleague jamiegramo and others herein have shown other experiments to update the design of the exhibition.
There's much to say here... A lovely soundbox the design of which, I believe, we feel was incomplete, because they changed to the no2 and no4 and then the orthophonic, so the exhibition evolution was halted. It's clear that it could have been further improved, as EMG people proved, using it as a base to develop their soundboxes.
It's a little marvel, small and heavy, powerful and simple, and I don't resign to leave it as it is... My dream is to understand it and evolve it to a superior thing by means of small reversible changes.
I believe this feeling is common to some of us...

View from the needle chuck, the springs holding the balls in the holes. Note the 15º elbow for tracking correction

[JeffR1]

Here's a thread you may find interesting, unfortunately all the photos from Wyatt, are gone except mine.
The idea was to get rid of the Victor support springs all together and create a central pivot point of the needle bar to allow better motion of the bar.
This in turn created a deeper tone and electrical recordings sounded better.

It was tricky trying to find just the correct gauge of wire that was bendable.

viewtopic.php?t=31451&hilit=exhibition+ ... dification

[jamiegramo]

There have been some good threads on the subject but their attachments are lost and a picture really can be worth a thousand words. The above link I was going to recommend as well.

Part of the problem is the poor tracking error found on the machines that are period to the Exhibition. You can never hear this reproducer at its best until you have sorted this problem or you place it on a later machine with less tracking error.

[Governor Flyball]

I'm one of them... I've reattached the original springs differently, so they only hold a bearing ball each, placed on top and pressing the needlebar fulcrum plate against the knife supports. This arrangement is similar to emg-expert, but instead of points, mine press through steel balls housed within the spring holes. It's only a relocation of same elements (introducing the steel balls). An image tells more than 1,000 words.... I'll post it later
I'm also experimenting in the same soundbox with different quality metal diaphragms. Later I will extend my explanations if you are interested.
Colleague jamiegramo and others herein have shown other experiments to update the design of the exhibition.
There's much to say here... A lovely soundbox the design of which, I believe, we feel was incomplete, because they changed to the no2 and no4 and then the orthophonic, so the exhibition evolution was halted. It's clear that it could have been further improved, as EMG people proved, using it as a base to develop their soundboxes.
It's a little marvel, small and heavy, powerful and simple, and I don't resign to leave it as it is... My dream is to understand it and evolve it to a superior thing by means of small reversible changes.
I believe this feeling is common to some of us...
IMG20240920233446.jpg

I am glad others have been surprised at the tracking error at the beginning of the disc. I like the 15 degree correction. However to provide a a good average tracking correction, you would need to move the needle arc forward ahead of the spindle. This would then mean that the tracking force towards the center of the disc as there would be no anti skate force to counteract ir. It begins to get more and more complicated! I made a similar compromise in a Columbia Grafonola 50 to reduce the tracking error at the record outer start and accepting a slightly increased error at the record center.

I wonder if they thought about such things in those far off days?

[Governor Flyball]

I recall in "From Tin Foil to Stereo" Victor prided itself in its bright sound whereas Columbia and Edison were focussed on trying to get better bass. To achieve the bright almost strident sound, that is why the original stylus bar springs were so stiff?

I have been playing a variey of discs on my modified Exhibition. The softer springs certainly has provided more bass. There is no rattle and even thirties records sound better and are more enjotyable to listen to as is. The two most important things to achieve this so far for me are the extra soft gasket and the stylus bar springs replacement.

[Inigo]

Very interesting.
My experiments go in that direction, also trying several home made diaphragms made of metal, plastic and cardboard:

[Governor Flyball]

Very interesting.
My experiments go in that direction, also trying several home made diaphragms made of metal, plastic and cardboard:

Haha. I did the same on an old Edison Diamond A reproducer. I have a nice clean original Diamond A with rice paper diaphragm I rebuilt with new gaskets for my Edison Triumph and the one with my aluminum diaphragm with a cotton thread link. I prefer listening to my Blue Amberols with the aluminum diaphragm. Never thought of doing that with the Exhibition because I like the diaphragm transparency to see the printing.

[Hoodoo]

I have been thinking lately about the hardness of the Exhibition isolator rubber. Even the new ones I have purchased are not very soft, especially when compared to the very squishy red one that is in my Meltrope III.
Were the original isolators softer than the newly-made ones?

[Inigo]

Never thought of doing that with the Exhibition because I like the diaphragm transparency to see the printing.

me too... That's why when I got my first and only machine equipped with an Exhibition, I bought another two Exhibitions, one as backup, and another for experiments.