Astell & Kern sp 1000m gold edition

Alex An (director at Astell & Kern) writes: "As we already experienced, different material affects sound signature of the DAP and this is the reason we have variation models with different material like SS or Cu for SP1000 and previous models. Same to the SP1000m, its original version is made of aluminum but its gold edition is made of brass with pure gold plating which improves electric ground connection and it makes improvement of sound."

"But some friends questioned me its inside area is also covered by gold plating otherwise its grounding is not efficient enough. actually it is more difficult not to cover specific area without plating during the process but anyway let me share photos of sp1000m gold edition body for your request. For your info, our sound engineer describe its sound signature as below compare to sp1000:

- sp1000 ss : wider stage with more accurate sound. its overall sound signature is clean and clear. 
- sp1000 cu : deeper sound especially better expression of bass. sound signature is warm and bold which is character of copper. 
- sp1000m gold : sound stage is smaller than sp1000 but sound depth is better. sound signature is warm and has both character of sp1000 ss and cu.