Looking at the picture you will notice the Huashen is slightly higher and narrower. Huashen about 21" high, 8" wide at bottom bow and the Melton 20" high, 9" wide. Also notice the larger valve paddles on the Melton. I believe the Huashen may be fitted with horn, or baritone valve paddles, while those on the Melton are full tuba size. The routing of the piping is very different with a complete loop of the leadpipe before entering the valves on the Melton while on the Huashen the leadpipe goes straight in to the valves like a normal tuba. The fact that the valves are so much earlier in the bugle on the Huashen against the Melton may explain the much narrow valve bore in the former.
Also notice the different coloured brass - although not sold as gold brass the Huashen is more red in colour against the Melton and has a nickel silver leadpipe, while that on the Melton is yellow brass. Both tubas have nickel inner and outer slides.
The valves work excellent, smooth, quiet and fast on both models - I have no criticism with either. Playing the different size paddles seemed to make little difference. Both have got a very similar adjustable angle thumb ring which on the Melton it is necessary to turn to remove the 2nd valve slide.
Bells are both the same diameter at 220mm (8.7") with the Melton being detachable for travelling. The valve bore between the two is very different 15.5mm on the Melton and only about 12mm on the Huashen as can be seen in photo.
My perception looking at both tubas is that the Melton is more cylindrical through the whole bugle and the Huashen more conical - meaning the latter is more tuba like, while the former makes better cimbasso substitute.
Both tubas seem well made, although there is a strange kink in pipe on the back side of the Huashen as can be seen in photo below. I heard while in China that they always make changes to instruments 'copied', so the kink may have been deliberately included to make different from the Jestaedt 80 on which it is based. I can see no other reason. I want to look at the Jestaedt 80 next year at Frankfurt and see if that has kink?
The two travel tubas come in very different cases - the Melton in an adapted horn case with back-straps and the Huashen in a hard sort of brief case. The Huashen case is 67 x 35 x 30 cm against 56 x 40 x 25cm for the Melton. Weight loaded with tuba is 6.8kg for the Huashen and 7.5kg for the Melton (the tubas alone are 2.7kg Huashen and 3.2kg Melton). Which sort of case is preferable is personal - the Melton case is nice for long hikes using the back straps, but for carrying in hand the handle of the Huashen case is more comfortable. I have now flown with both tubas as cabin luggage and had no problems with the airlines carrying either. I think either would be strong enough if had to go as checked luggage - in fact one of the Huashen did so come from China (wrapped to stop scratching) and survived unscathed keeping tuba safe.
Now onto playing - they feel and sound remarkably similar considering the difference in bore size. I at times while testing forgot which I was playing. Looking at the sound wave profile in Audacity after having recorded on H2 I cannot detect a noticeable difference. The Huashen feels more stuffy after playing the Melton, but after a few minutes I found I soon got used to the extra resistance. Both models have reasonably good intonation with me finding no wonky notes. Tonally I liked the Huashen better in the high register, no problem playing Bydlo on this tuba. While the Melton has the better low register, by which I mean down in 4th valve territory. The low C is no problem on either tuba, although slightly more open with the Melton.
Now is the Melton worth the considerable extra cost? Well that all depends how you want to use and if you have the money. If you want to use as substitute cimbasso then the Melton is the only one to get, it has an incredibly effective practice mute and is a great little tuba to play and oozes quality.
However as a handy mini tuba to take travelling to keep ones lip in, or to avoid having to carry around full size tuba the Huashen does the job nicely, is surprisingly well made, fun to play and at a price affordable to a lot more people.
