Help Diagnosing Bach 42A Valve and Assemble Issues

[meaningofhome]

Hi folks,

Long time lurker here ! Looking for some help with diagnosing some issues with a used Bach 42A (Hagmann). I've played other Hagmanns and loved it, finally got my hands on one but the valve and the assembly of the whole horn seems a bit janky. Looking for advice on what to fix with the tech or what I can do on my own before taking it in. I've attached some pics showing the issues.

1) I'm assuming the notches on the casing are for alignment, so for one I know it's not aligned which I imagine is just putting on and dialing in new rubber stoppers. When I play with the valve aligned (manually holding it) it plays a bit better but it's still not what I expect from a Hagmann, still a bit stuffy.

2) After oiling the valve there's still a scratching metal sound which sounds like the barrel is rubbing against the casing.

3) The cross braces are all not parallel, especially the big diamond one connected the bell, it's less than 90 degrees. I have a feeling the horn was dropped, bell shows some old crease marks (unless that's lacquer wear).

4) The neckpipe and the connection to the valve at the slide receiver when peering inside doesn't look flush - I'm not sure if this is intentional, can anyone confirm?

I read on the forums that it would be beneficial to have sub-par Bachs rebuilt/de-stressed by an experienced tech since it's mostly assembly issues, i.e. parts are decent. Wondering if people have experience with doing that and if it's recommended in this case, a 2006ish horn that currently doesn't sound too hot.

Thank you,

Kalun

[Burgerbob]

looks pretty normal to me, other than the valve obviously not being aligned.

[Blabberbucket]

1) I'm assuming the notches on the casing are for alignment, so for one I know it's not aligned which I imagine is just putting on and dialing in new rubber stoppers. When I play with the valve aligned (manually holding it) it plays a bit better but it's still not what I expect from a Hagmann, still a bit stuffy.

Yup, the valve is not aligned. These are finicky to set up properly, I would recommend against trying to adjust it yourself. They can leak pretty badly entering/exiting the F tubing if set up wrong.

2) After oiling the valve there's still a scratching metal sound which sounds like the barrel is rubbing against the casing.

Again, needs to be cleaned and properly adjusted.

3) The cross braces are all not parallel, especially the big diamond one connected the bell, it's less than 90 degrees. I have a feeling the horn was dropped, bell shows some old crease marks (unless that's lacquer wear).

Bach trombones are built this way - look at a picture of any Bach trombone and the cross brace will look like that.

4) The neckpipe and the connection to the valve at the slide receiver when peering inside doesn't look flush - I'm not sure if this is intentional, can anyone confirm?

I read on the forums that it would be beneficial to have sub-par Bachs rebuilt/de-stressed by an experienced tech since it's mostly assembly issues, i.e. parts are decent. Wondering if people have experience with doing that and if it's recommended in this case, a 2006ish horn that currently doesn't sound too hot.

I wouldn't worry about this. Get the valve set up properly and the instrument leak tested first before you go down the "de-stressing" rabbit hole. You could ask your tech to scrape the excess solder out of the receiver joint.

[elmsandr]

The perpendicularity and parallelism you note is actually kinda good…. If the pipes were straight and not conical, that would all be spot on. With tapered tubes, they need to be at least slightly off or you’re forcing something. Also, with Hagmann valves the braces are also off in clock position when looking from the tuning slide or handslide receiver. Most poorly assembled 42As I see are from them being built too square and not following the different necessary geometry of the valve.

To the point, I agree with it getting a good cleaning and alignment first before diving into surgery.

Cheers,
Andy

[hornbuilder]

Not at all uncommon for the cross braces to not be parallel on Bach factory horns. There is a LOT of "close enough" work in these horns.
Ignore the markings on the casing. Look down the handslide receiver to confirm correct alignment. Re the scratching, have the instrument professionally serviced. This may involve a.little.light lapping.

[meaningofhome]

That's reassuring! Even with the mis-aligned valve the horn plays really well - 80% of the time it plays almost as expected when engaged but 20% of the time it doesn't seem to seal properly and sounds stuffed up. Looking forward to getting the valve fixed and bringing the horn up to spec.

This horn has a gold brass bell and LT slide, lacquer still on. It plays a bit too broad and warm throughout (in terms across both range and dynamics). I'm looking for more front and this kinda unadorned austere sound, or the option for that when pushed, basically more colour range. I tried a friend's Conn 88H Hagmann, double-o wrap with a Bach 42 bell which sadly wasn't for sale. It had that range of austere to mellow + the open but not too open response from the Hagmann, basically my ideal horn albeit it would be even more perfect in a medium bore outfit. So that leads me to this purchase and the potential mods to come.

I'm open to recommendations from the forum and from my research, I've read about folks using 42 slides on 36s, and the other way around (less common). Since I want a Hagmann and I have this 42A, my idea was to put a 36 slide on it (swapping the 36 slide tenon to fit), and potentially put a 36 bell on it so it would be like a 36A.

I had thought of doing it the other way around by getting a 36b and getting the Hagmann conversion package, especially knowing they make a smaller bore 36-specific Hagmann valve but there was a good deal on this 42A and the conversion route, parts alone costs as much as the 42A.

If anyone has experience with these kinds of mods I would be open to any advice, and for notes to pass on to a tech!

[LeTromboniste]

Based on your pictures looking down the tubes, your valve looks very slightly out of alignment, but really not by much. On mine, just how adjusting the tightness of the set-screw attaching the linkage to the rod behind the valve was enough to move the alignment this much.

The step in bore between the slide receiver and valve is normal. Your slide tenon is thicker than that step, and it's shorter than the receiver, so there's a bigger step up in bore before that, which effectively creates a short "chamber" inside the receiver where the bore is wider and slightly reverse-conical between the end of the tenon and the start of the valve assembly. Hagmann provides two different size inserts with his conversion kits, that one can slide into the receiver to reduce or remove that "chamber".

[meaningofhome]

That's some deep intel with the little chamber!

In checking the screw area though, I realized the linkage arm is setup on the outside instead of on the inside like that majority of pics I found of the 42A. I did find two horns that had the arm on the outside so I imagine it's not exactly wrong, or is it...

[LeTromboniste]

I've seen both. I'm not sure it makes a difference. Dual-valve basses are usually set up with the linkage to one valve on the inside and to the other on the outside.

[hornbuilder]

On a single valve horn, it doesn't matter if the connecting rod is "inside" or "outside". Outside makes access to the screws easier.

[Kbiggs]

The step in bore between the slide receiver and valve is normal. Your slide tenon is thicker than that step, and it's shorter than the receiver, so there's a bigger step up in bore before that, which effectively creates a short "chamber" inside the receiver where the bore is wider and slightly reverse-conical between the end of the tenon and the start of the valve assembly. Hagmann provides two different size inserts with his conversion kits, that one can slide into the receiver to reduce or remove that "chamber".

I remember seeing those inserts on his old web page. I wasn’t able to find them on his redesigned webpage, but my college French was 40 years ago.

I’ve often wondered whether the gap between the tenon and receiver on a trombone acted in a similar way to the gap between the end of the mouthpiece and the end of the receiver on a trumpet. (Aside from King and some Benge trombones, leadpipes are usually one-piece.) Would the Hagmann insert negate an important acoustical feature?

[LeTromboniste]

The step in bore between the slide receiver and valve is normal. Your slide tenon is thicker than that step, and it's shorter than the receiver, so there's a bigger step up in bore before that, which effectively creates a short "chamber" inside the receiver where the bore is wider and slightly reverse-conical between the end of the tenon and the start of the valve assembly. Hagmann provides two different size inserts with his conversion kits, that one can slide into the receiver to reduce or remove that "chamber".

I remember seeing those inserts on his old web page. I wasn’t able to find them on his redesigned webpage, but my college French was 40 years ago.

I’ve often wondered whether the gap between the tenon and receiver on a trombone acted in a similar way to the gap between the end of the mouthpiece and the end of the receiver on a trumpet. (Aside from King and some Benge trombones, leadpipes are usually one-piece.) Would the Hagmann insert negate an important acoustical feature?

In my experience it didn't change the sound much, but it did noticeably affect the feel of the instrument (the inserts made it feel a bit more compact and direct), and as far as I can remember it had a very small effect on intonation. Back then I preferred the feel with the "normal" set-up without inserts. With what I like now and how my approach to playing has evolved, I think if I played that horn today I would probably use the inserts.

[Burgerbob]

Bach Artisan A47s also come with that spacer. I found the horn to just be better overall without it.

[meaningofhome]

Thanks Matthew and Maximilien for clarify the valve link arm position.

Based on your pictures looking down the tubes, your valve looks very slightly out of alignment, but really not by much. On mine, just how adjusting the tightness of the set-screw attaching the linkage to the rod behind the valve was enough to move the alignment this much.

The step in bore between the slide receiver and valve is normal. Your slide tenon is thicker than that step, and it's shorter than the receiver, so there's a bigger step up in bore before that, which effectively creates a short "chamber" inside the receiver where the bore is wider and slightly reverse-conical between the end of the tenon and the start of the valve assembly. Hagmann provides two different size inserts with his conversion kits, that one can slide into the receiver to reduce or remove that "chamber".

Found the thread about this topic and Hagmann's explanation from Swisstbone's post on that thread:
viewtopic.php?t=6866

here's a (not to scale) diagram of where the "chamber" is



Note that Hagmann follows the McCracken design philosophy that the receiver/valve/ f-attachment bore should be the same as the slide bore, where most other designs have a larger bore starting at the end of the tenon.

I noticed on custom Hagmann horns that their slide receivers have an extra notch - I wonder if that's part of the design for fixing that spacer issue. Then I noticed that OE Thayer sells a multi-taper slide receiver part: https://thayervalve.us/store/Multi-Tape ... p719000338.

Any idea if this multi-taper part has anything to do with addressing this?

[pfrancis]

Yes Clontz is solving that with his multi taper slide. No the trim ring, on the Hagmann and Thayer products, is not solving anything - aside from lock ring abuse to the exterior of the instrument. The slide tenon (when inserted) no longer creates a cylindrical section (chamber) in that part of the instrument.

This is a typical “your mileage may vary” moment, while reversed slides are almost standard on orchestral trombones they are certainly not on trumpet, or even small bore trombones. This design phenomenon is not a “problem”, it is simply an attribute. An attribute that some people will (perhaps unknowingly) prefer and others will decry as “the problem” because they read something on the internet/have anecdotal experiences that support their opinion.