Warburton Top Part 4 M Trumpet

For many years I have struggled to find good Warburton parts that screwed together perfectly. This latest top seems to have a slightly tweaked rim and cup, the blind hole threading has knurling at the bottom of the thread so it cannot jam. This sounds and plays very well. Warburton recommend their most common sale is a 4M plus 7 backbore which is what I play. This has a full enough sound on low notes but easier high register with a fairly small cup, it's almost magic versus other makes to compare the efficiency of note production and only a GR tech 65M-B feels less effort to me. The 4M is as Warburton describe, shallow yet good enough tone for any style (with an appropriate horn and backbore). If the rim is too flat and sharp try a Reeves 43 series in standard and W rim.