My turntable sounds like the speed is too slow

Playing a 45RPM record at 33 1/3?

I bet I'm not the only one with a new and unheard record who forgot to change the speed and thought it sounded strange...

If you don't trust your cellphone app, maybe mark the platter, play a record and use the phone's stopwatch function to time 100 revolutions which you can count. Should take 180 seconds. If it does, time to look downstream starting with the stylus, the cartridge the mounting geometry etc.

First off make sure it is the turntable. Do your other sources sound normal to you?

If they do you have a problem either with your cartridge or phono stage. Look at the cartridge carefully, it the cantilever straight? It the diamond still there at the end? Does it look normal under magnification? If you have another cartridge set it up and listen. If it sounds fine the first cartridge is defective. If it sounds bad you have a problem with your phono stage. 

Good Luck 

@dogberry we’ve all done it. When Diana Krall sounds like Thurl Revenscroft, you know you’re playing her 45 rpm record at 33. Hit the speed button or drop the belt onto the second pulley. Depends on turntable.

The cell phone app is accurate enough that if it says 33 1/3 it’s close enough. Your ears would not hear the difference so it’s not the speed. I would check your cartridge setup as others have suggested.