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Mira linkage

Posted: Sun May 06, 2012 5:45 am
by Lingon
Appoximately when did Miraphone start to use straight links instead of the older S-links?

Re: Mira linkage

Posted: Sun May 06, 2012 6:42 am
by imperialbari
Miraphone like other German, Czech, British, Japanese, and possibly whatever nationality of brass makers used modular production, where some basic elements were used in all variants of a model. Most often the bugle and bell. Whereas number of valves, complexity of linkage, Kranz, amount of nickel silver trim, or number of valves would vary from student/amateur models through various step-ups-through professional models.

My galleries hold at least one scan of a catalogue showing how the Miraphone in the German market used a numbering system to tell the level of the outfit. There also were variants in the US market, where the TE models were known to have less nickel silver than the the U models.

Klaus

Re: Mira linkage

Posted: Sun May 06, 2012 6:23 pm
by Dan Schultz
I don't know exactly when Miraphone changed from the 'S' links to the to the 1st generation miniballs that had the 'cheesy' plastic housings. But I've seen Miraphones from the early 70's that had those nasty plastic parts that like to crack where the internal threads are.

However... as Klaus noted... Miraphone did different things for International markets that we didn't see here.

Personally... I prefer the old 'S' links. They have gotten a bum rap. The noise from the Miraphones rotors generally comes from sources other than those links.

Re: Mira linkage

Posted: Sun May 06, 2012 8:13 pm
by Cameron Gates
I played a 184 CC - sn 10307 -
that had the white plastic connectors. It was made in 1976. A fellow student had a later model 186 CC with "S" linkage.

BTW, I really like the white plastic connectors. Never had a bit of trouble and they were silent.

Re: Mira linkage

Posted: Sun May 06, 2012 9:12 pm
by Ken Herrick
Dan's comments remind me of the first Mirafone I ever did any work on. Another student at Northwestenr in 65 had a new 186CC which had noisy, S linkage valves. The problem wasn't so much the linkages, though using a slightly heavier oil made things better. The real problem was that the valves had not been seated in to the correct depth and the bearing plates were not driven home correctly. A good clean up of the valves and a light lapping then proper adjustment fixed not only the clanking noises but also made the horn play a LOT better. Proper adjustment and lubrication was all that was needed to give beautiful valve action. Got called on to go over a lot of tubas and horns after he was so pleased with having his valves set up right.

Re: Mira linkage

Posted: Mon May 07, 2012 2:51 am
by imperialbari
Point is that Miraphone didn’t go from S-links to anything more advanced at any given date. These scans from a circa 1993 catalogue tell that S-links and the ball&socket options were both offered simultaneously for decades. The current Miraphone site indicates that the S-links are no longer offered as an option.

Klaus

Re: Mira linkage

Posted: Mon May 07, 2012 9:19 am
by sceuphonium
I have an ancient Mirafone 186 which of course has the S-linkage. The 3rd valve is a bit harder to press than 1, 2, and 4. Seems like there are 4 or five bearing places along the linkage where things rotate or turn... what's the most likely source of the problem?

John Thompson

Re: Mira linkage

Posted: Mon May 07, 2012 9:36 am
by Dan Schultz
sceuphonium wrote:I have an ancient Mirafone 186 which of course has the S-linkage. The 3rd valve is a bit harder to press than 1, 2, and 4. Seems like there are 4 or five bearing places along the linkage where things rotate or turn... what's the most likely source of the problem?

John Thompson
It could be anything ranging from the rotor itself to the spring. The best way to find out is to pull the offending linkage/paddle assembly off the horn.

First... take the screw out of the top of the stop arm, pull the stop arm off, and make sure the rotor turns freely. If all is well there and there is no binding... go to step two. As a note... it is possible for the rotor to be rubbing the inside of the housing if there is too much clearance in the bearings. Try moving the rotor stem up and down and back and forth. Anything over a few thousanths of clearance is too much. The 'fix' is nearly impossible to do with written instructions. Take it to someone who is well-versed in rotor repair/adjustment.

If the rotor appears OK and the linkage is loose from the stop arm... move the linkage in all directions to see if any of the pins/tubes are binding. Check the main pivot where it mounts to the paddle bar. If there are tight spots... try working some oil into the joints rotating them as far as possible. I've seen that failure to keep these points oiled is a common problem. If oiling and movement beyond the normal range does not loosen things up.... again... take the horn to someone who routinely works on rotors.

Re: Mira linkage

Posted: Tue May 08, 2012 5:30 pm
by Lingon
Thanks for the comments and knowledge. Unfortunately it seems that it was not as simple as I had hoped for... On the other hand, why should it be?!