Pre4, valves too high for using the cover

[pefa]

Hi,
After building the Pre4 I found some modern made ECC82 types too high to use with the cover on, and decided to try to do something about it.
(Ordered a new cover from Matthew, just in case it wouldn't turn out well

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Got chromed "tube protectors", and used rings above and below the cover plate.
Used a 1 inch hole punch that fit the holes in the tube protector rings.
The punch need a 10 mm hole for the bolt, so I used a step drill for the left one and a Dremel 9903 cutter for the right one where there are ventilation slots so diffcult to drill.
Covered the cover with masking tape to save the paint. Marked out the centre, the 10 mm hole for the punch bolt, and the outer diameter of the punch upper part. Useful to align the punch holes because the 10 mm hole among the ventilation slots was rather irregular.