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Old 17th Mar 2018, 8:41 am   #31
Craig Sawyers
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Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,999
Default Re: Pre-amp for Golden ears

Quote:
Originally Posted by Radio Wrangler View Post
Air springs can give an escape from the deflection relationship. The force they exert is proportional to piston area and gas pressure, but the spring rate involves the volume behind the piston. Add in active control and the world is your mollusc of choice.

David
Same equation. Imagine the piston sealing a chamber at atmospheric pressure. Now you apply a mass. The piston moves downwards to balance the mass with an increase in pressure in the chamber. That distance is B in my original equation.

I guess your comment comes from the design of optical honeycomb tables, which are fitted with a number of vibration isolation options for the legs, including active control. Last one I specced was an 8' x 4' with super-invar skins, and earthquake bump stops on the legs. That was for an astronomical spectrometer on Gemini South. Unfortunately big telescopes are sited on mountain tops, which are generally in earthquake zones - so immunity is built into all aspects of design. I was system engineer for that, and Maggie Aderin (now the Sky at Night host) was project manager.

Craig
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