My HMV 5A has LESS bass than my 5B - EDIT, FIXED! (Sticky bearings).

[EdgarFB]

I've just picked up a 5A at a really nice price, but on testing I have to say its not what I expected! Its just a thinner sound that my 5B, whereas I expects it to be more bass heavy, sacrificing treble based on what I've read.

Is this just because its more worn/poorer condition than my 5B? Or does the production quality just vary so much that the usually bassy soundbox has less bass than usual? I can't see any damage, but it does have some spots on the diaphragm.

[EdgarFB]

Ive also spotted that there is much less movement on the stylus bar on the 5A, while it is very fresh and springy on the 5B... is this a design difference with 5A's being less flexible? Or is this another sign of age (and possible cause of the loss of bass).

[EdgarFB]

aaaaand another question, any thoughts on whether this 5A is duller chrome or nickle plated? I think they made both.

[EdgarFB]

Apologies for this rambling one man conversation... but I think the needle bar pivot is actually seized/stiff which is why there is very little movement, its just the natural flex of the bar that's left. So I guess I'm looking at how to free and adjust a needle bar!

[Inigo]

It looks as in need of a complete overhaul. These can sound very well, indistinguishable from the 5B, but need to be in perfect condition, flexibility, cleanliness, soft gaskets, soft back neck collar, etc. Everything contributes to the sound, and it can be as good as any of the praised EMG or Expert soundboxes, but when it is in perfect condition. The diaphragm must also be cleaned from dirt and oxide, and any pores sealed with lacquer or a tiny drop of glue. Better if renovated (spares can be found). If you don't dare to do it yourself, there are specialists here that can overhaul it for you, as Wyatt, named MicaMonster herein.

[JerryVan]

It looks as in need of a complete overhaul. These can sound very well, indistinguishable from the 5B, but need to be in perfect condition, flexibility, cleanliness, soft gaskets, soft back neck collar, etc. Everything contributes to the sound, and it can be as good as any of the praised EMG or Expert soundboxes, but when it is in perfect condition. The diaphragm must also be cleaned from dirt and oxide, and any pores sealed with lacquer or a tiny drop of glue. Better if renovated (spares can be found). If you don't dare to do it yourself, there are specialists here that can overhaul it for you, as Wyatt, named MicaMonster herein.

Agree!!

I would bet money that at least a few of those spots on the diaphragm are corrosion that has caused a tiny hole, or holes.

[Inigo]

holes in the diaphragm or other air escapes kill the bass more than anything else

[An Balores]

I agree with all the above but would add that I have noticed differences in these soundboxes, even when appearing to be in tip-top condition. I did swap one over from a table model to my 102 when I sold the table model because it had a much fuller sound with better bass response .

[EdgarFB]

It was mostly just dirt on the diaphragm, It's cleaned up quite well. I've also partially freed up the needle bar as it was rock solid and it sounds a lot better, very similar to my 5B, but still just very slightly weaker bass response (nothing like as bad as before). I'm still not happy with the tighness and limited movement of the bar though, I could only remove one sleeve, on the other side the end screw comes undone but the sleeve seems fused in place.

On my beautiful sounding 5B the bar rocks very freely (with no side movement obviously) to the touch and the diaphragm is very flexible, the 5B you have to apply a lot of pressure to see it flex.

That said its very nearly there now and almost the same as the 5B... I was just hoping it would exceed the 5B's bass as I'd been led to believe they did. If not I'll just move it on, I only have one machine that uses 5s any way!

[leels1]

You might struggle getting the back off the 5a as they seem to be a poorer quality pot metal than later 5bs.

That said, you can get away with taking the front off and throughly cleaning the diaphragm and then sorting the pivot bars. They can be very tight and it’s easy to snap the outer screw if it’s rusted into the collar, so some penetrating oil may help, but just be very careful.

The gaskets on these are felt so shouldn’t need changing. If you feel there’s air escaping through them, a slight bit of oil round the edge inside should seal any gaps in the felt.

When resetting the needle bar pivots. Make sure there’s no side to side stress on the needle bar itself, the pivots should just touch the inner ball bearing (also make sure the ball bearing is still there!) and give back and forth motion freely.

I have wondered also if excessive swelling of the backs can cause the diaphragm to contort and not operate correctly on some of the soundboxes which would give a thin, less bassy response. I have one like this where all seems correct but as the back won’t come off it’s hard to say. It sounds really bad though.

A 5a should sound no “worse” than a 5b in theory as they’re more or less the same, they will sound different though, but I reckon no two 5a or 5b sound 100% the same. There are differences between different ones.