Cartrdige shim trick anyone?

[Folsom]

Do any of you use something between your headshell and cartridge?

I use cardboard from electronic part reels, but most probably don't have that. It's about the same as a cereal box.

The reason to do this is because your cartridge and headshell are not perfectly machined to go together. They're never going to mate perfectly. Now some Ortofons and other carts have a 3 point system that may be just as good as a shim. The shim needs to be something compliant so that it will crush a bit where the screws are, and compress where they are not. What the shim does is couple the cart to the headshell much better. The reason this is important is because the cart will take on a very low resonance as it becomes one with the arm. When it's not well mated to the arm it can have resonances right in your audio spectrum! The effect can be pretty powerful on a number of cartridges.

 

[tima]

I think you're talking about using a shim as a damper, and vaguely recall products meant to do this such as various exotic woods. Then there was a three pointed device intended as the notorious 'mechanical diode' and possibly level the cartridge.

Some cartridges such Lyras are designed to have their mechanical energy taken up by the headshell/tonearm. I wonder how a cardboard shim impacts this. Doe it change the arm-cartridge resonce frequency that was based on compliance and arm effective mass? Probably. Even if the cartridge-headsell mating surfaces are not perfect, I can't see doing this.

When an arm has no azimuth adjustment, some used a shim down the middle to facilitate azimuth via tightening the screws a bit more on one side or the other causing slight cartridge tilt. I think is was Wally Malewicz who suggested using a piece of mechanical pencil lead as the shim. Tradeoffs.

 

[ddk]

Do any of you use something between your headshell and cartridge?

I use cardboard from electronic part reels, but most probably don't have that. It's about the same as a cereal box.

The reason to do this is because your cartridge and headshell are not perfectly machined to go together. They're never going to mate perfectly. Now some Ortofons and other carts have a 3 point system that may be just as good as a shim. The shim needs to be something compliant so that it will crush a bit where the screws are, and compress where they are not. What the shim does is couple the cart to the headshell much better. The reason this is important is because the cart will take on a very low resonance as it becomes one with the arm. When it's not well mated to the arm it can have resonances right in your audio spectrum! The effect can be pretty powerful on a number of cartridges.

Using a shim to get Grado cartridges work with SME headshells. Years ago I remember some cartridges and tonearms used to come with a few shims or sticky shellac like compound, haven't seen it for years thought.

david

 

[Folsom]

Tima, no this isn’t about damping. You’re not trying to improve hysteresis, you’re trying to prevent it even happening. It’s also not for azimuth, but I guess on some arms you have to do that.

This is about increasing the coupling between the two. If coupling isn’t good then making it good can be like spending thousands of dollars for a better piece of equipment in results.

With cardboard I use, that’s more like thick paper as it isn’t corrugated or anything, it gets compressed to the point that it’s solid in the areas that already touched. Where it wasn’t touching well it now is firm.

The arms resonate frequency will dominate the cartridge bodies resonate frequency, since it moves along with the stylus. Many carts bodies have resonate frequencies that are very high, but they will act like a loose piece of a car vibrating when coupling isn’t good. Not all carts are effected equally, and many have the tripoint mount to help prevent this.

It’s worth a try for anything that tries to mount flat to flat. All you do is cut a shape like your cart and a couple U shapes for the screws.

 

[Folsom]

It could be thought of kind of like a car head gasket. The block and head are very flat, but you still need something to make them couple since it isn’t perfect via the nature of trying to pull them together.

 

[tima]

It could be thought of kind of like a car head gasket. The block and head are very flat, but you still need something to make them couple since it isn’t perfect via the nature of trying to pull them together.

That's more apt than the hysteresis comment.

I'm not clear on your theory that the arm's resonance frequency dominates the cartridge's because the arm moves with the stylus. what is meant by dominate? I'm assuming yr goal is sonic improvement, but why should a tighter (than normal?) coupling yield a positive effect ? Does it move the cart-arm resonance frequency to an inaudible frequency?

On what arm-carts have you experienced the issue where a shim improves your sound? How do the differences sound ?

 

[Folsom]

Hysteresis is the act of settling (like pushing a ball on a string, and waiting for it to come to rest). The goal isn't to make it settle faster (dampen). It's to stop the movement from starting. The reality is that anything that would have moved it, will still act against the entire tonearm and cart, but it just won't have any real effect besides hopefully moving the stylus to the groove of the record. Any resonance that will act is going to be on the tonearms very low resonance, that the cart doesn't really effect.

The tonearm resonance affects sound, as we know (generally speaking it must be sufficiently low to avoid impact of sound). The cart is stiff so it may have a natural resonance that's well above the audio range. If it's coupled well then all it did was slightly stiffen the tonearm overall, but not enough to change the tonearms SRF significantly (self resonate frequency that's mostly about length and bearings). The Tonearm's SRF can still be excited by the movement, but the stylus is effectively damping everything with it's suspension in the audio range because there's sufficient tracking force to stop the tonearm from flailing about to the tune of the stylus. But if the coupling is bad the cart can be excited essentially anywhere that isn't directly at the screws where it's good. The VTF can be there, but it doesn't matter if the stylus is pushing the cart to vibrate and not against the arm/the arm is reflecting it.

I use universal headshells. My midrange is so much cleaner with it that I expect to hear different parts of familiar albums sound different than they do with it. Overall resolution is up a lot, as well as volume tracking for midrange. Instruments sound more real as more character comes across in classical.