The one-year-old HMV reproduction instrument, worth £75, was taken from LP's Paradise in Victorian Arcade, Walsall.
A man and a woman aged in their 40s and 50s entered the store and distracted manager Lisa Powell while a younge man, believed to be their son, stole the record player.
Miss Powell said: "I was in the shop on my own because my mum had popped out and the man and the woman surrounded me at the till and began talking really loudly blocking my view.
"I thought it would be wise to stay by the till because we have a lot of our expensive items around that part of the shop but I saw the couple's son put his coat over the gramophone and take it outside.
"I confronted his parents who denied all knowledge and said they didn't even have a son.
"The record player isn't even that expensive so I can't see why they would just take it. I am really upset.
"I have contacted the police who are going to dust the shop for fingerprints. I just want to get it back."
The 25-year-old from Coalpool opened the shop in July last year after receiving help from Walsall Council's Innovation Fund to reduce the number of empty units in the town. The shop is the first of its kind in the area and sells LPs, CDs, second hand vinyl and band merchandise.
Miss Powell's 53-year-old mother Jackie, who also works in the store, said: "Lisa has always wanted to have a little shop selling vinyl and it hasn't been open long.
"It is a lovely little shop, so to think that someone could do this is terrible. You don't expect it to happen in broad daylight. This is our livelihood. Lisa is only small and this was a big man and his wife who towered over her to intimidate her. The couple also had two little girls who were picking up everything and messing with things."
West Midlands Police said it had received reports of a gramophone being stolen at 1pm on Monday afternoon.
Spokesman Peter Edney said: "A man and a woman aged in their 40s and 50s entered LPs Paradise and distracted a member of staff while a younger man stole the record player."
Anyone with information should call 101 or ring Crimestoppers anonymously on 0800 555 111.