-The valve is a different design with a much smaller external case and different port spacing.
-The wrap is moved around. I'm guessing this was for George Roberts for the E pull. My 169 will not easily pull out far enough for a proper E. The wrap also doesn't seem set up to fit a "Bird's nest" valve, as the tubing is much closer to the main tuning slide.
-Possibly the most valuable change is that the instrument is much shorter in the bell section. The slide is nearly identical length. With my 169, I am in tune only when pushed all the way in. The 183 has the “Ideal” length for base tuning.
-The bell is also lighter towards the flare. The stem of the bell feels almost the same between them, but the 183 thins out similar to the Shires “T7” treatment.
Interestingly, the parts are almost interchangeable. The hand slide for the 183 will fit the 169, but not the other way around (?). Also the tuning slides can be swapped from the 183 to 169, but not the other way around because of larger outer diameter. The 183 slide also fits the tenon taper of my Edwards and M&W somehow
The way they play seemed very different until I swapped slides. I had to force the smaller taper of the 169 slide onto the 183, but once I did the character that I really like from the 169 started to show through. The difference felt like it was mainly down to a different leadpipe Venturi.
If I missed anything please chime in. I am really starting to enjoy these older Holtons, and I’d love to learn more about them.
