On Dec 9, 8:00�pm, Paul wrote:
When the hot water flow through my kitchen sink sprayer is low or on
full, it is quiet, but when the flow is at about 75%, it "sings" very
loudly with a loud high-pitched tone. With cold water, it is quiet at
all flow rates. I have taken the faucet apart and don't see anything
wrong with it. It is a single faucet with a lever type handle that
delivers both hot and cold water from the same faucet. Any ideas on
what could be causing this?

my delta does that now and then, try replacing the diverter assembly
or soak diverter in vinegar. i suspect it cruds up.....