Audio Cubes II has original replacement earpads for the SR404 for $40 + $17 shipping to the USA: http://www.audiocubes2.com/category/Headphone+Accessories/product/Stax_Replacement_Pads_for_SR-404,_Lambda,_Nova_Signature.html
I purchased replacement earpads for my 1980's Stax Lambda Pro's from them last year, which worked out very nicely. In my case I never had any slippage with either the old or the new pads, though. I replaced them because the foam that covers the electrostatic element was deteriorating. (The foam pieces are included with the earpads, at least in the case of the Lambda Pros).
Regards,
-- Al
I purchased replacement earpads for my 1980's Stax Lambda Pro's from them last year, which worked out very nicely. In my case I never had any slippage with either the old or the new pads, though. I replaced them because the foam that covers the electrostatic element was deteriorating. (The foam pieces are included with the earpads, at least in the case of the Lambda Pros).
Regards,
-- Al