That story was very funny desmo

"twin phono / RCA cable with 3.5 mm jack at the other end" should be "cable RCA de doble canal con una clavija de 3,5 mm en el otro extremo" (it's very difficult!).

But in El Escorial you may go to the Gigante Supermarket or to the Carrefour of Villalba. Then you may find the cable for yourself hang somwhere in the market. Thus you won't have to explain it to anyone

Anyway, why do you think is embarrasing not to speak spanish? Noone is born knowing everything... You will find that it is usually that when you say "No hablo español" someone will start speaking in english... Also, the number of forgeiners in El Escorial is quite high.

Regards.

Fernando