Stumped on a Buzzing brass Reed

[apprenticeOF]

The A pull reed on my brass reed Lachenal English buzzes.

 

I went through everything I could think of: cleaned, checked clearances(in and out of the slot about 10 times), checked for loose screws, put paper shims in the slot (tried 1 at the tip, 1 at the base, and 1 at both), put a little plasticene on the adjacent pan support block both to check for clearance and to dampen, held the pan up to the light with the valve back and gently pushed down to check clearance on the pan slot, retuned and checked for burrs. Replaced the valve - even though it was new.

 

I was left with the thought that the reed must be toast, and was about to send it off for replacement. I then swapped the A reed into the Ab slot and vice versa. The A reed doesn't buzz in the Ab slot, but the Ab reed now buzzes in the A slot. The fit seems nice and tight.

 

Any thoughts as to what I'm missing?

Edited February 13, 2011 by apprenticeOF

[SteveS]

The A pull reed on my brass reed Lachenal English buzzes.

 

I went through everything I could think of: cleaned, checked clearances(in and out of the slot about 10 times), checked for loose screws, put paper shims in the slot (tried 1 at the tip, 1 at the base, and 1 at both), put a little plasticene on the adjacent pan support block both to check for clearance and to dampen, held the pan up to the light with the valve back and gently pushed down to check clearance on the pan slot, retuned and checked for burrs. Replaced the valve - even though it was new.

 

I was left with the thought that the reed must be toast, and was about to send it off for replacement. I then swapped the A reed into the Ab slot and vice versa. The A reed doesn't buzz in the Ab slot, but the Ab reed now buzzes in the A slot. The fit seems nice and tight.

 

Any thoughts as to what I'm missing?

Have you recently replaced the valves on this instrument?

 

Did the reed buzz before you did any retuning or other reed work?

 

Is it a metallic buzz?

 

One thing you can try is check the clearance between the reed and the valve adjacent to it - sometimes a reed can buzz against a valve if the clearance is too little. If it looks too little, trim the edge of the valve closest to the reed with a sharp knife.

Edited February 13, 2011 by SteveS

[Greg Jowaisas]

First i would make sure the reed shoe is not too tight in the slot. Snug is just right. Too tight in a slot that is not entirely straight can distort the shoe enough to allow the tongue to bump into it. You should be able to hear a clear "ping" by gently lifting the tongue tip to sound the reed.

 

If you are getting a clear ping then I would check the slot clearance beneath the buzzing reed again. Large reeds can be pulled deep into the slot. So it pays not to just check the tip but further up the reed.

 

There have been occasions where simply filing the venting slot did not provide enough clearance. I've had to move the reed in its dovetail slot by shimming one side and removing material from the other. If this is necessary remember to maintain the 8 degree dovetail so the reed shoe is pinned snug.

 

Seems like you are working carefully and methodically. Sometimes you just have to put things down, walk away for awhile and then the probable cause and solution will pop into your head.

 

Good luck,

 

Greg

[apprenticeOF]

First i would make sure the reed shoe is not too tight in the slot. Snug is just right. Too tight in a slot that is not entirely straight can distort the shoe enough to allow the tongue to bump into it. You should be able to hear a clear "ping" by gently lifting the tongue tip to sound the reed.

 

If you are getting a clear ping then I would check the slot clearance beneath the buzzing reed again. Large reeds can be pulled deep into the slot. So it pays not to just check the tip but further up the reed.

 

There have been occasions where simply filing the venting slot did not provide enough clearance. I've had to move the reed in its dovetail slot by shimming one side and removing material from the other. If this is necessary remember to maintain the 8 degree dovetail so the reed shoe is pinned snug.

 

Seems like you are working carefully and methodically. Sometimes you just have to put things down, walk away for awhile and then the probable cause and solution will pop into your head.

 

Good luck,

 

Greg

 

 

I removed some material from the slot but am reluctant to take much off. No change. The reed "pings" nicely. I also tried shimming the reed back in its slot about .015" to check if it was hitting the curve in the slot. No luck. Visually, it does not appear that the reed can hit the slot, although it was tight to one side.

 

This reed pan was badly warped (it had been left for years with only a couple of support blocks) and the shoe had been badly corroded (to the point of white zinc salt deposits). The reed pan has also shrunk a fair bit, I had to shim about .030" under the new gasket I installed - but the shims are on the opposing side.

 

I'm going to check the flatness of the slot, and also the straightness. I've had this apart so many times I'm worried about wearing out the end bolt threads!

 

Any other thoughts?

Edited February 15, 2011 by apprenticeOF

[apprenticeOF]

Gaaah! Finally found the problem. Because of the corrosion problems with this concertina I started with about a dozen buzzing reeds. All of them were caused by various shoe and pan issues. So naturally this last one I assumed that the issue was the same. The old saying about when you assume...

 

We had selected this instrument apecifically because it had the spruce baffles and brass reeds. Our steel reed concertinas make my wife's ears buzz. Anyway, like everything else on this concertina the spruce baffles were warped and the felt pads that support it had been eaten by bugs. When I replaced the felt pads I used some felt I had on hand. On what seems like my fiftieth attempt to fix this buzzing reed, I noticed that if I didn't fully depress the key - the buzzing stopped. I suspect that I put extra pressure on the key on the pull and was levering just enough against the baffle to spring the hook and loop slightly - which then buzzed in sympathy with the reed. The metallic sound was just like a buzzing reed. A thicker felt washer on the baffle and an extra button washer - eh voila! No more buzzing.

 

By the way, this instrument does NOT make my wife's ears buzz and she is happily playing away.

 

Thanks for your help folks.