Do not know about the VTL MB125, however, the ARC VT100MKII can be tricky and expensive to re-tube. Try
http://mycollins.net/audio/ He goes through the re-tubing procedure for the ARC. (Nice detailed pictures) Last time I checked with ARC, the cost to retube the 100MKII was in the $800-$1000 range plus freight.
http://mycollins.net/audio/ He goes through the re-tubing procedure for the ARC. (Nice detailed pictures) Last time I checked with ARC, the cost to retube the 100MKII was in the $800-$1000 range plus freight.