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You would thing even with the Handmade label, parts that were cast would at least be the same. Here is my page on the Expert 4-spring. They are all slightly different.
http://www.gramophonemuseum.com/expert- ... ndbox.html

Without an advert or labelled picture of "The Expert Dynamic", it's difficult to say for sure what the difference was. I assumed "The Expert Dynamic" was just the label given it later.
Thanks for the January 1935 review. I had missed it completely. It clearly compares it to it's predecessor.

Here is a picture of what may well be "The Expert Dynamic". It is completely different from the rest. It's also a lot heavier and does indeed sound better than the rest.

Thicker front plate to increase weight?
Note the wider flat gasket rubber at the front
A miter cut-out of the corner
A different chuck

The technical report is excellent, I have heard an All range, and indeed it is an excellent gramophone, though interestingly an EMG Xb oversize despite it's slightly smaller horn (33 ½" vs the All Range's 36") did win out in a comparison, though that was a hot jazz record, different records may well turn the tables, I still love the all range though, such a striking machine to see, interestingly the image in that article seems to represent a Senior.

Regarding soundboxes, here are my two Expert 4 spring 'Dynamic' soundboxes, these could be an example of the newer and older versions.
The one on the left is from my Junior (10a Soho Square 1933-36) and the right from my Senior (64 Frith Street 1936-1939), the difference is slight, but the later one on the right is ever so slightly larger, possibly with a slightly larger diaphragm? I haven't my calipers here to check currently, with a slightly different shaped body, notice how the earlier body is longer with a cut out for the needle bar, the later is flat bottomed, this doesn't seem to be an isolated thing as I previously rebuilt another later Expert 4 spring which was also of the larger type, perhaps they started like mine on the left, progressed to the slightly larger one then became the type Chunny has (Of which I have never seen another, very interesting!) in the war time and post war years? all speculation however.

I have two Expert 4 spring soundboxes just like Alex's one on the right. The catalogue drawing that I uploaded earlier, dated ~1935, shows this same design and calls it the "Expert Dynamic". This name was, therefore, already in use long before the 1940 review. I know that one of mine was purchased from 10a Soho Square in 1935. Chunny's newer one certainly fits the description in the 1940 review so I think this can reasonably be described as the "New Expert Dynamic" soundbox. As Chunny says, all of these soundboxes are slightly different indicating that Ginn's "hand-made" claim is accurate.

The Dynamic was the generic name Expert used to describe the 4-spring soundbox, in all its multitude of variations of size, weight, gasket thickness etc.

Thanks Steve, that's what I thought.

Judging from the multiple postings of the soundbox in this thread, it is probably very hard to find two that are identical!

Thanks chunny for posting the pictures-especially the top one. I had forgotten the flat gasket design, which we used to call the "jam pot ring" This must be where George Overstall got the idea of including these flat ring gaskets in some of his boxes.
Frank, I am sure, mentioned years ago that Mr. Creese or Crease,(cannot remember the correct spelling) was the chap who thought of the "Dynamic" design. He was the bloke who "tuned" the boxes to customers personal preferences.Is the tempered stylus bar thinner on these?
Yes, because they were different. It must have been a bit like a cottage industry. I remember Joe Ginn, in the letters I have here, that soundboxes were made in small numbers by someone whose name I cannot remember. Also Joe's "famous" weight adjuster were made in small numbers at a time. I have one fitted to my machine, and a very nice bit of equipment it is too!

I do not want to spoil the thread of this very interesting thread, but while I remember, here are two "Overstall" boxes made years ago, the two spring was originally fitted with the fat, flat gasket, but I changed it to a conventional rubber gasket of 3mm.
The four spring is an unusual design regarding the stylus bar springs. It has it's original flat rubber gasket still fitted-and the soundbox is very heavy!

This is the four-spring soundbox which came with my pedestal Expert Senior owned by Geoff Hide on the Wirral for over 50 years and sold to me via Frank about fifteen years ago. Frank related that this 'box had not been touched since David Phillips last tuned it so, I too, have left it alone. It also has the flat-section "jam pot" front gasket (cylindrical at the rear) which begs the question as to why this design was envisaged in the first place ? Ostensibly, it would not appear to be a sensible way to go as it considerably reduces the operating surface area brought to bear on the air column. However, as with all things, there must have been some very good reasons or it would not have been done. It is such a shame that contemporary empirical results were not written down---due, one supposes, to secret commercial interests.

It is also interesting to note that there are no washers between the backplate and the main casting---indeed there appears an unusually large (but consistent) gap ! There are three very narrow washers between the stylus protection plate and the main casting.

The other noteworthy difference between the soundboxes shown in this thread concerns the variation of diaphragm annular rings. It would be fascinating to have had David Phillips' thoughts and experience in this respect. It is now down to us to reinvent the wheel.............and post our experiences for the benefit of posterity.

And probably due in some measure to Ginn himself - I seem to remember Joe Ginn in his book describing his father wilfully destroying company records and such.