อันนี้ไปอ่านเจอเข้าเลยเอามาลงให้เป็นความรู้ดีมากสำหรับนักเล่นที่ชื่นชอบ CCa Siemens โดยเฉพาะ Gray Plate VS. Silver Plate
1950's to early 60's "Gray-Shield (or refered to a PLATE)" (left) compared to Late 60's-Early 70's "Silver-Shield" (right)
The earliest and what the tubemuseum audiophiles vote as the best-sounding Frame-Grid Construction* E88CC are the "Gray-Shields or Plates" packaged in Yellow-Blue boxes made between 1951 - 1966. The gray-shield is the horizontal plate above the body of the tube or immediatly below the top frame.
This shield is an electrostatic rectangular shield treated with gray coating (left picture) or uncoated and silver (right picture). The vacuum environment increases the likelihood of life-shortening electrostatic discharge when operating at peak. This "shield" is designed to protect the electrostatically sensitive component and ground and deflect the tube discharge through a resistance in the "gray-plate". These tubes may have the date/production codes on the glass, this doesn't matter as the code method or placement has no effect on sound quality.
Second generation are the "Silver-Plates or Shields" with the un-coated silver electrostatic shield and originally packaged in Orange-Blue boxes which were made between 1966 - 1979. Both series say Siemens-Rohren(tube). These silver-shield E88CC are great tubes too! They have the codes on a silver tag inside the tube. The reviews you read were written with the intention to warn you away from the newer production non-frame-grid design or single-stem attached to the halo design.**
