Steel or Aluminium for casework?

[Clive197]

Just arrived at Clive towers is a PS Audio Stellar Phonostage which is cased in steel. All my other kit is cased in Aluminium. If I tap the Phonostage it rings slightly. If I tap my other kit it doesn’t ring. I know that steel is heavier than aluminium. I also know steel can be bent easily while aluminium can’t be bent. Thinking about this is giving me a headache and I wonder if any of you guys have any pearls of wisdom.

[Macca]

I think it's the other way around, I know steel is stronger than aluminium weight for weight.

[Stryder5]

Steel is good for rejecting interference and cheap to manufacture into cases, perhaps allowing more to be spent on the internal components.

It’s resonance can be nullified by judicious use of sound deadening material. Remember this can be insulating too, so take heat into consideration.

IIRC there was a thread on here recently about suitable materials.

Gary

[Stryder5]

Oh, and you’re wrong aluminium is more ductile than steel so is more easily bent.

Gary

[struth]

aluminium or copper are better for magnetic field shielding

[Barry]

For magnetic shielding, the order is: steel (the best); copper, then aluminium.

For 1/16 inch thickness, the shielding factor (in dB) at 1KHz is:


Steel, 23dB
Copper, 7.2dB
Aluminium, 5.8dB


whereas at 10kHz the figures become:


Steel, 34dB
Copper, 29dB
Aluminium, 23.5dB


The problem comes in trying to shield against magnetic fields at low frequencies (< 100Hz). You need to use steel or copper of greater thickness (say 1/8 inch). At 50Hz the figures become:


Steel, 32dB
Copper, 4.5dB