The model 75.3 is a full triple horn with three independent ranks of tuning slides. It combines the dual bore aspects of the models 25 and 45 to give an even feel and response across the whole instrument. Like the model 45, the layout allows a completely independent f-alto side by means of the original Paxman valve in the mouthpipe. This means that the taper in both the mouthpipe and the branch can be designed solely for this side of the instrument and that the independent Bb and F basso sides are not compromised in any way.
Since 2012, the f-alto side has also featured a mouthpipe with a longer taper, giving improved intonation and a tone which blends more easily with the Bb and F basso horns.
The model 75.3 the Paxman compact valve section fitted as standard, making it both lighter and more precise in action.