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Conversion to miniball or Dubro linkages

Posted: Tue Oct 13, 2009 10:00 pm
by jmerring
Is the conversion in a kit form, with instructions? I am not overly mechanical; but I could take the horn I am getting, along with the kit (if one exists) to my local brass tech.

Re: Conversion to miniball or Dubro linkages

Posted: Wed Oct 14, 2009 12:15 am
by Dan Schultz
jmerring wrote:Is the conversion in a kit form, with instructions? .....
It's possible that a conversion kit could be put together that is somewhat specific to certain brands and models of tubas. However... I've never done any two conversions that are EXACTLY the same.

Like Bloke said.... if your repairman is worth their salt... they'll know what to do.

That being said.... do you desire a conversion because your present linkage is noisy?.... or is it made up of those cheesy plastic ball connectors from the early 70's? If it's just noisy 'S' links, that can be fixed. Those old linkages can be just as robust as anything else out there.

Re: Conversion to miniball or Dubro linkages

Posted: Wed Oct 14, 2009 3:16 am
by Lars Trawen
Please have a look onto Rick Denny's excellent pictures and instructions.
http://www.rickdenney.com/valve_linkages.htm
If you are at all handy with tools, which you should be, this is all you need.
Good luck,
Lars

Re: Conversion to miniball or Dubro linkages

Posted: Wed Oct 14, 2009 9:16 am
by jmerring
Lars,


I thank you so very much for the information. It is WAY beyond my capability. I will show the whole kit and kaboodle to my repair man. If he could not do it; there is a guy in Miami, who is quite capable of this changeover. The horn I am looking at does not have clocksprings (thank goodness). Maybe that would make the job easier.

Jim

Re: Conversion to miniball or Dubro linkages

Posted: Wed Oct 14, 2009 12:32 pm
by Rick Denney
Lars Trawen wrote:Please have a look onto Rick Denny's excellent pictures and instructions.
http://www.rickdenney.com/valve_linkages.htm
If you are at all handy with tools, which you should be, this is all you need.
Good luck,
Lars
Both Joe and Dan are completely correct, though. Even if we narrow it down to one specific make and model, say, a Miraphone 186, we have a number of variations that each require a different strategy. Old Miraphones had S-links, then they had DVS ball links (those dreadful white plastic things), then there have been several variations of metal uniball links. Each uses a different stop arm configuration, and making the Dubro ball links mount on the stop arm is a little different in every case. I've done conversions on 6 or 8 tubas similar the one I picture on my web page, and each one was different.

Being able to work through the variations is the price of entry for doing it yourself. If that sets an unattainable standard, take to a tech. My pictures should be sufficient for any tech to achieve similar or better results.

Make sure the cure is better than the disease. I converted my Miraphone because it had DVS linkages, and the white plastic balls had cracked and could not be adjusted. The conversion was FAR cheaper than buying the repair parts from Miraphone. But it was the most difficult conversion I've done because the stop arms were not favorably configured. I converted a Cerveny-made Sanders that had already been converted by the importer. The importer had used cheesy and tiny 2-56-threaded ball links that bent every time I looked at them crooked. My conversion uses 4-40-threaded Dubro links with 1/8" brass tubing surrounding the threaded rod that were far more robust. I converted another Miraphone that had S-links that were severely worn, and the replacements have survived with only occasional adjustment and no breakage in about 20 years of professional use. I converted an early post-unification VMI that had used non-adjustable metal ball links that were rattly from the start. And so on. But I have not converted my newer B&S, which has the factory links that work perfectly.

Rick "whose standard is proper function and good durability" Denney