I have a solenoid to control the main water supply in my house.
I can turn the solenoid on with a wireless remote, a timer, a motion detector etc.
I invented a water sensing switch that if wet will send a signal to cut off the house water.
Cannon Water Detector Switch and House Water Leak Prevention
However, the quick operating solenoid valve created a bad water hammer.
I came up with a quick solution before taking out my torch, etc.
For $5 I bought a hose bib Y with SS ball valves made to control 2 hoses.
I put a vacuum break and the hose on one part as normal.
On the other part I screwed on a female hose to male 1/2 NPT adapter, a 1/2 female NPT to 1/2 PVC L, a 10 vertical piece of 1/2" PVC, and I capped it off.
(1/2" PVC is rated at 600 psi.)
The hammer reducer is adjacent to the solenoid valve.
Works perfectly, not a peep.
Should the air in the dead end pipe get absorbed, I would turn off the hose bib and drain it.
When I get a chance I might solder a 1/2" copper T to the hose bib, etc.