Opening rotor ports

[havard]

Anyone with experience from opening Bach 42 rotor ports? Improvements / drawbacks / risks?

[Lastbone]

Worked great on my 42. Opening the ports opened up the blow and improved the lower register. I've had this done on the 42, on my Conn 73 and on a Holton 180. I think the valve port mod is a pretty good one, and not very expensive.

Do not try this at home -- only use a trusted tech!

[havard]

Worked great on my 42. Opening the ports opened up the blow and improved the lower register. I've had this done on the 42, on my Conn 73 and on a Holton 180. I think the valve port mod is a pretty good one, and not very expensive.

Do not try this at home -- only use a trusted tech!

Who did the job?

[WGWTR180]

Worked great on my 42. Opening the ports opened up the blow and improved the lower register. I've had this done on the 42, on my Conn 73 and on a Holton 180. I think the valve port mod is a pretty good one, and not very expensive.

Do not try this at home -- only use a trusted tech!

Also curious as to who did this, particularly on your 180.

[Bonearzt]

Just MHO, but most rotors I see don't have enough material to remove enough to make a difference.

Polishing the passages does seem to make a bit of a difference though.


Eric

[BGuttman]

Just MHO, but most rotors I see don't have enough material to remove enough to make a difference.

Polishing the passages does seem to make a bit of a difference though.


Eric

Bob Osmun has been offering this service to Bach 42 players for at least 25 years. All the folks who worked there (including Steve Shires) are knowledgeable in the technique.

Osmun is located in Metro Boston (USA).

https://osmun.com/repair-services/

[Crazy4Tbone86]

In my opinion, the best candidate for this process is the Bach 42 valve because it is undersized and there is (barely) enough metal to work with that it can make a difference for a player with discerning tastes. On the Bach 42 with an open wrap, I like to remove a little more on the side that has the 180 degree bend so that AWFUL sharp bend has less of a impact on the resistance (Sorry folks.....I hate that Bach open wrap design!). That particular side of the port is not used when the valve is disengaged, so removing more on the one side only impacts the F-attachment notes.

I agree with Eric that are other things that can also help a horn blow more evenly. Smooth rotor port surfaces (many ports have rippled machine marks) and clean solder joints make a big difference. Nice clean connections under the ferrules in which the tubes are flush against each other (Matthew Walker of M&W mentioned this on a recent thread) can also make a difference.

[Peacemate]

(Sorry folks.....I hate that Bach open wrap design!).

The Bach/Conn open wrap is just the worst design. Why do people recommend it and specifically state that you should look for a 42BO or 88HO? Arguably any "resistance" taken away from the wrap is just put into the valve, and it sticks out so far.

Also, why do an open wrap on an 88H? It is so beautiful stock, at least compared to its counterpart, the 42B. Also, come on, there is no way anyone likes the stock 42B wrap.

[Crazy4Tbone86]

I believe an open wrap can be superior to a traditional wrap......only if the valve is a 90/90 degree configuration. Take a look at the design on all of the high-end horns with rotors (Shires, Edwards, M&W, Rath, etc...) .......they all have 90/90 or similar configurations.

[Matt K]

Also, why do an open wrap on an 88H? It is so beautiful stock, at least compared to its counterpart, the 42B. Also, come on, there is no way anyone likes the stock 42B wrap.

Agghhh... I am definitely the odd duck out. I actually really like the way the Bach rotors play and also dig the closed wrap Bach design. I had one installed on my Shires actually. At the time I had it installed, I had a spare rotor lying around so I had a dependent setup made out of it (Eric Edwards here did the linkages for it!). In hindsight... I should have kept it as-is. Memory serving, the Courtouis Jorgen van Rijen plays has the same wrap; if it works for him it works for me!

[Bonearzt]

Also, why do an open wrap on an 88H? It is so beautiful stock, at least compared to its counterpart, the 42B. Also, come on, there is no way anyone likes the stock 42B wrap.

Agghhh... I am definitely the odd duck out. I actually really like the way the Bach rotors play and also dig the closed wrap Bach design. I had one installed on my Shires actually. At the time I had it installed, I had a spare rotor lying around so I had a dependent setup made out of it (Eric Edwards here did the linkages for it!). In hindsight... I should have kept it as-is. Memory serving, the Courtouis Jorgen van Rijen plays has the same wrap; if it works for him it works for me!

IMHO, the "wrap" itself really doesn't matter as much as the valve quality/orientation and competent assembly!!
The 90/180 configuration DOES present more of a problem than the90/90 as Brian mentioned!

I've written previously that Larry Minick did actual dynamic flow tests to compare the two wraps and found no discernable difference.
But that's getting away from this discussion....

Eric

[spencercarran]

Also, come on, there is no way anyone likes the stock 42B wrap.

Stock wrap on the 36B seems perfectly fine to me, and it's literally the same parts. I've been told it doesn't fit the 42 as well as it does the 36 though.

[Crazy4Tbone86]

Also, come on, there is no way anyone likes the stock 42B wrap.

Stock wrap on the 36B seems perfectly fine to me, and it's literally the same parts. I've been told it doesn't fit the 42 as well as it does the 36 though.

One of my best instruments is a Bach 36 with a traditional wrap. Other than adjusting the bearing plate, which had worn a little bit, I have never opened up the ports or done anything special with the wrap. I simply took it apart and reassembled it with clean solder joints and no tension. I don't know if that valve section would work on a Bach 42......I only know that, as a .525 bore horn, it is an absolute beast!

[Peacemate]

Also, come on, there is no way anyone likes the stock 42B wrap.

Stock wrap on the 36B seems perfectly fine to me, and it's literally the same parts. I've been told it doesn't fit the 42 as well as it does the 36 though.

It's just too square. Those bell braces aren't beautiful either and aren't not be consistent in shape, since some are squeezed more than others when you compare different 42's, especially those double cone ones. They mix the design of brace types and flanges too. Some flanges are square and some are long hexagons. On the LT slide they have round brace flanges while on the non LT they have squares. It's like they played that kids game with the shapes and used them instead of thinking about how it looked up close. The design language of the 42B is just not consistent.

What I'm trying to get to is that the 88H wrap is beautiful, while the 42B could not be any worse, except for if they suddenly copied the Yamaha wrap. Ugh.

But yeah, it does play like a trombone. I might just be a Conn fanboy, even though I have owned twice as many Bachs. My opinion on the sound is not influenced by the looks though, and I do play an LT 42BG pretty regularly. I just cannot seem to choose between it and my 88HN (not HNV, please Conn, why choose that name).

[Crazy4Tbone86]

Peacemate,

I can see your point....the Conn 88H traditional wrap is more symmetrical than the Bach 42B traditional wrap. However, I have always disliked that very tight 180 degree bend in the Conn wrap. I have always thought that the 88H traditional wrap would have been a much better design if that piece was the same as the 180 degree bend at the end of the attachment tuning slide. For anyone who is not aware of it, those two 180 degree bends are NOT the same width.

Of course, all of this is not related to the original topic......opening up the ports of a rotary valve.

[tim]

I think Larry said open wrap was to keep condensation to a minimum. And easier to get it out when needed.

[Crazy4Tbone86]

From a construction standpoint, an open-wrap large bore tenor with modular connectors is BY FAR the easiest F-attachment bell section to buff and lacquer!

[Matt K]

That's actually really, in my mind, the primary reason for choosing to wrap modular horns as they are... with closed wrap/semi-closed wrap, etc. getting that 2nd bell brace can produce some weird results.

[ChadA]

Open wraps, whether you believe they help the sound/feel or not, must have been a financial boon to folks like Bach. Generally, those valve sections involve fewer pieces/solder joints and fewer bends with more straight tubes. I would think that would make them cheaper/easier to assemble, yet folks like Bach have sold them as an upcharge for years.

[Matt K]

Like the megatones, which are actually cheaper to produce but usually have something like a 25% markup?

[Crazy4Tbone86]

That's actually really, in my mind, the primary reason for choosing to wrap modular horns as they are... with closed wrap/semi-closed wrap, etc. getting that 2nd bell brace can produce some weird results.

Another reason to make them modular. With an "edge" brace design, there are NO braces connecting the F-attachment tubing to the bell or bell-side of the main tuning slide.