Yamaha CA - What are these 'covers' on the rca jacks?

[Majestyk]

Behind the Yamaha CA series amplifiers one set of RCA jacks seems to posses them, as pictured below (PHONO 2).

What are they for?

 

[rottalpha]

Behind the Yamaha CA series amplifiers one set of RCA jacks seems to posses them, as pictured below (PHONO 2).

What are they for?

RCA plgs would shunt potential noise coming in via inputs not in use.
you have them over one of the phono section inputs which is super sensitive to noise.

 

[Majestyk]

Thanks for the quick reply. So I take it they came with the unit? Do people ever use more than just one set?

 

[N8Nagel]

Thanks for the quick reply. So I take it they came with the unit? Do people ever use more than just one set?

My recently purchased CR-820 has them as well, also on Phono 2.

Some people use them on any unused input, it can't hurt, although theory says the phono inputs will be most susceptible to interference due to the extra gain stage(s).

 

[avionic]

Behind the Yamaha CA series amplifiers one set of RCA jacks seems to posses them, as pictured below

Phono shorting plugs.

 

[Majestyk]

It's a CA-600.

https://www.canuckaudiomart.com/details/649311978-yamaha-ca600-recapped/images/1371702/

 

[Blue Shadow]

Most are shorting plugs, a short circuit between pin and outside edge. This to keep the unused phono input from injecting noise into the phono system. I've seen some that are not shorted and they are just plugs keeping the input RCA jack clean as are the covers some had on their units from new.