Ideal tonearm length ?

[Daithi]

Could the shorter tonearm cone from the 103 small tabletop? I don't know that machine, but if its rectangular plan dimension is smaller or equal than the 101 case, and the tonearm in the tabletop is centered as in the greater machines, them the tonearm must be shorter, for the 101 is placed diagonally to the case...
What a mystery!

I suppose duty calls me to find out what machine its from and how rare it might be before I chop it up and ruin it for its original purpose. So if anyone knows I'd be much obliged. Its a paltry 7 inches from the center of the tonearm pivot to the center of the soundbox mount. Hardly useable and must be savage on records. It wouldn't be from a kids gramophone or one of those compact miniature gramophones by any chance?

[AZ*]

I'm not sure about the HMV 103, since mine is packed away and inaccessible currently. However, I can state with absolute certainty that the HMV 32 uses a short 7 inch arm similar to the one in your photo.

[Daithi]

And soundgen is right. There's a fundamental difference in the tonearm of a 101, and it is the downwards angle at the soundbox end. This is to allow the tonearm being installed much lower in the 101 than in the other machines, to reduce the case height..... The tonearm base in the 101 is installed below the motorboard...... All the other machines have the tonearm base installed on the motorboard..... So these don't need the downwards angle, and the soundbox neck section is straight. The tonearm is at the same level as the soundbox centre, but in the 101 the tonearm gooseneck raises up to catch the soundbox neck.
Very good! For the rest of dimensions, they look the same, at least in the photos.
So if you use a 101 tonearm for the new gramophone, either you install it lower than the motorboard, or you insert the gooseneck of another machine with straight end.

My intention is to purchase a Pelican case iM2450 which has internal dimensions of 18.0 x 13.0 x 8.4 in inches. So I may have to do exactly as you suggest and drop the tonearm pivot below the level of the deck board. Time will tell. I have to save up for the case since they cost more than a good HMV portable, so the cost is currently delaying progress. Time will tell.

[Daithi]

I'm not sure about the HMV 103, since mine is packed away and inaccessible currently. However, I can state with absolute certainty that the HMV 32 uses a short 7 inch arm similar to the one in your photo.

Thanks Az, so if I modify this tonearm, am I chopping up a difficult to find part, a priceless relic from the golden age of steampunk music or is it just another tonearm. I'm nearly of a mind to try and persuade someone to make one from scratch in stainless steel but even if I do that it would be nice to provide them with a version in nickle plated brass and carbon fiber so they know what to aim for rather than a bunch of drawings on the back of an envelope.

[Daithi]

I found a large tonearrm on eBay curtesy of Soundgen. I think he put it up there just to keep me out of trouble. I nearly died of fright when I opened the package. A brute of a thing compared to the 101 and 161 tonearms that I am used to. It sounds completly different too when popped at the soundbox end with the palm of the hand.

[Inigo]

Mmmm... Would you delight us with a photo?

[Daithi]

Mmmm... Would you delight us with a photo?

Here it is in a dismantled state.
The bearing has 19 balls in it. I'm dreading reassembly.

[Marco Gilardetti]

Well, it looks pretty much like the standard tonearm that equipped HMV re-entrants.

A tip that maybe you already know about ball bearings assembling, is that a huge layer of thick grease has to be put in place first. It will hold the balls in place like "glue" while you put each in its own place.

[Daithi]

Well, it looks pretty much like the standard tonearm that equipped HMV re-entrants.

A tip that maybe you already know about ball bearings assembling, is that a huge layer of thick grease has to be put in place first. It will hold the balls in place like "glue" while you put each in its own place.

I have never seen a re-entrant tonearm before so it was a surpise to me. How does this tonearm compare in sound to a normal narrow one? Its only slightly longer but much fatter. Its girth must make a big difference

[Marco Gilardetti]

How does this tonearm compare in sound to a normal narrow one?

Neither better nor worse. As usual it depends on the horn to which it is connected to. It will play good if attached to a horn properly designed in order to match its characteristics, and awfully if attached to a horn designed for a different type of tonearm.