Soundbox adaptor, what's it for

[kirtley2012]

I've got this soundbox adaptor, I've seen a few of them around, but I'm not too sure what they're for, I know the slotted end fits into a No.4 soundbox, but what does it join to?, It won't fit onto a large bore HMV tonearm

[epigramophone]

These accessories were made in various sizes, to enable soundboxes to be fitted to tonearms of different diameter. Useful and worth keeping.

[Menophanes]

I bought an identical unit recently, hoping that it would enable me to fit a 5B sound-box to a Model 109 tone-arm* without packing it with bits of cardboard, but it did not serve this purpose. I fancy this type was intended instead to reconcile the No. 4 box with the fat tone-arms used in the previous generation of gramophones, between 1920 and 1925. Unfortunately all the adaptors I have seen listed are the same as this. Surely there must have been such things as 5A/5B-to-1925/1929-tone-arm adaptors? If so, where have they all gone?

Oliver Mundy.

*As this thread has appeared in the main 'Machines' section rather than in the 'British and European' division where perhaps it more properly belongs, I should explain that all references are to [British] His Master's Voice models and components. I suppose there must be Victor equivalents.

[epigramophone]

The rubber couplings on the HMV No.4 and No.5a/5b soundboxes are interchangeable by removing the grub screw and coaxing the coupling out. I have a No.5b with the coupling from a No.4, enabling it to fit the earlier tonearm of the 101 portable etc.

Great care needs to be taken to avoid breaking the old and fragile pot metal back plates. Most of the broken ones I see are the result of botched operations, so you have been warned!

Roger.

[Menophanes]

Thank you again, Roger! I still have the original No. 4 from my 109 and it is a good brass-backed example. I shall see if I can make anything of it without doing irreversible damage.

Oliver Mundy.

[Teak]

This adaptor converts from the early continental style connector (slit) to the hmv/victor style bayonet fitting.

[Inigo]

I bought several of those red rubber connectors for a Meltrope, and I discovered they also serve for HMV nos. 4-5a-5b, provided you remove their own rubber and sleeve connectors. The fitting neck on the backplate of those are all the same, so you simply slide the rubber inside et voilà! And the rubber is soft enough to allow fitting on a large or narrow bore tonearm. I use indistinctly any of the soundboxes on the HMV no. 127 or 101 (narrow) or on the 194 (wide) using the same rubber ring and they fit well...