Plastic vs. Aluminum headshell

[cgutz]

I have a KD550 turntable with the original headshell. I also have a headshell that is made of well constructed plastic (not the cheapy ones with all the holes you see on ePay). The plastic headshell is a few grams lighter than the stock aluminum headshell. The plastic also has a metal grounding plate mounted inside.

Is there any sonic disadvantage to plastic headshells? I was surfing the internet about turntables and came across some obscure reference about aluminum being preferred for headshells over plastic, but can't find any other references to this.

Anyone have any thoughts or information? Aluminum or plastic?

 

[Stanton681EEES]

A plastic shell would be preferable with a say heavier cartridge or a very compliant cartridge. It's Ok trust me there is a lot of info out their on the information highway that is nothing but BS............. and it seems to keep getting passed on and passed on etc......... If you get my drift

 

[cgutz]

Stanton681EEES
Thanks. I have a high compliance cartridge, which is why I used it. The lighter weight of the headshell brings the calculated resonance from around 7hz to over 9hz, which I understand is more satisfactory.

You mean I shouldn't believe it just 'cause its on the internet????? Next you are going to tell me the banker from Nigeria that sends me an email that he will share his millions with me is a fake....

 

[Nat]

I don' think there is one correct answer to the question. Plastic is lighter and probably better damped than metal, but its also less rigid, and the addition of the metal grounding plate might introduce exactly the sort of resonances that the metal headshell might have had (but maybe worse, because now there are two objects vibrating, or, perhaps better because they damp each other, but of course the cartridge would also be doing the same thing, so who the hell knows?). Which is why you have to actually listen, and to different types of music, to see which works best in your system.
I'm curious what you think about both headshells -- my impulse is to think that moving the resonant frequency may not matter much (and I wonder if in practice the change is actually that large), whereas the different sound of the shells might matter. But what do I know? Let us know.

 

[ETI_5000]

I'm curious what you think about both headshells -- my impulse is to think that moving the resonant frequency may not matter much (and I wonder if in practice the change is actually that large), whereas the different sound of the shells might matter. But what do I know? Let us know.

Weight can have quite an effect on the resonant frequency of the tonearm, thereby affecting the tracking. It can have a significant influence on sound. I once heard a very expensive ADC cartridge (late-1970’s AUD price $100+, comparative 2010 value $600-1000) badly matched to an expensive tonearm (resonance well away from the ideal 10 Hz) on a top-of-the line JVC turntable (maybe $3-400 without arm). It was trounced in sound quality by a combination at the bottom end of the price scale (70’s prices: Empire cartridge about $5, turntable & tonearm $100), where the arm and cartridge were well matched! The same ADC cartridge sounded really superb on a well matched (light) tonearm – it was much better than the Empire cartridge, which was a “throw in with a turntable” model. It was just a matter of matching it with the right tonearm for it to sound how it was designed to, but if you didn’t, the result was very disappointing. I wouldn't have believed it until a hi-fi salesman I knew (played cricket with him!) demonstrated it to me when there weren't any customers around. He'd had an older salesman show him how drastic the difference was.

One of the best ways to get a lighter headshell that's still rigid is to get one of the magnesium alloy ones from the 70's and 80's, such as the Denon PCL-5 (6g) http://www.audioinvest.no/denon/index9.htm . They often show up in Ebay. They are very light, rigid and non-resonant.

-Don

 

[Flammaster]

I have always liked the look of those Ortofon wood headshells.

 

[Nat]

Obviously mass has a significant effect on the resonant frequency of the arm/cartridge compliance, and at other frequencies also. But I think that this difference is most likely to matter a lot with high compliance cartridges (and very few were higher than ADCs, which you use as an example), but such cartridges are less common nowadays, where moderate compliances are more or less the rule.
Certainly a lighter headshell might make a marginal match better, but I doubt if a gram or two difference (whcih is what the OP saysis all that significant, especially in the context of the excellent, but not low mass, arm of the KD 550. I don't think the difference will be that large a percentage of the total mass.
Another way of looking at this is that cartridges themselves differ by a great deal more than a gram or two in their masses, so there is more wiggle room there than with these two headshells.

 

[majick47]

I have a number of headshells for various cartridges/tonearms and when checking specs/materials I havn't run into any headshells made of plastic. I'm sure there are some plastic headshells out there and you could give it a try but I'd be leaning towards alloy headshells that match your cartridge/tonearm.

 

[Nat]

A lot of the headshells for straight arms are plastic, usually carbon fiber filled, so fairly stiff and well damped. Some of the plastic headshells I've seen for SME/japanese bayonets are earlier, so perhaps before carbon fiber was common, and I think they are plain old plastic plastic. The fact that the OPs plastic headshell has a metal plate in it makes me wonder if it isn't earlier -- at any rate the metal plate makes me nervous about flexibility and vibration. But there are lots of suprises out there, so actually trying it is probably a good idea.

 

[cgutz]

I've been using it with my VMS20e MkII (with a replacement VMS15XE stylus - lower compliance than the stock stylus) with the plastic headshell. Seems to sound very fine and musical. I haven't tried the same stylus/cart combo on the aluminum headshell as the cartridge mounted on that one has a well adjusted alignment.

The headshell is quite rigid, and the metal grounding plate is very well attached. I do think the thing is old, got it for next to nothing on ebay.

I was calculating the resonance using the various formulas found online. The extra couple of grams does make a difference in this case in bringing the calculated resonance for the VMS15 stylus into the normally accepted range).

Thanks for all the information.