Can anyone out there help me with some advice please?? I've been playing bass trombone for almost 15 years on my Holton TR181 bass trombone. My band has a Yamaha YBL 612 dependant bass which I have used on occasions and found I can get more sound out of. I've recently bought an old Yammy 322 single valve bass which has been a revelation...I can really growl on it and for longer than I've ever been able to on the Holton. It obviously has the limitation of a single valve and for some of the stuff we play I really need the 2 but have become accustomed to the independant valves on my Holton and don't like the dependant valves on the band's Yammy.... Here's the question...do I keep the Holton, or swap it for a 613R or H? These seem to be like gold dust and I don't have the money to do other than a straight swap really....or does anyone out there have a 613 they want to swap for a Holton bass?