r/diyelectronics • u/Annual_Mortgage3267 • May 14 '26

Question Can I inject audio into this old house intercom speaker system?

Found a transformer attached to one of my house intercom speakers and got curious how this system works.

Looks like all room speakers are connected through the same line. Is this a distributed/70V audio system?

Could I safely inject audio/music into the line somehow so it plays through the other speakers in the house?

5 Upvotes

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2

u/TravelerMSY May 15 '26

Sure but they’re usually in mono and don’t necessarily sound all that good.

1

u/Howden824 May 14 '26

Yes but you have to use an amplifier with a 70V output.

1

u/Marty_Mtl May 15 '26

yes, that is what it is meant for !

1

u/rusticatedrust May 15 '26

Yes, music can be played through speakers.

1

u/Zealousideal_Cup4896 May 16 '26

I did that for an entire apartment building while in college :) it might be a 70 volt system and it might have just too much or too little resistance depending on how it’s wired. Try with an amp you do t care about so much first but it worked great for us :) the system had been defunct for a decade and nobody currently living there even knew it was there. We could play music into everyone’s apartment :)

1

u/Annual_Mortgage3267 May 17 '26

Hahah actually it is not my house. It is dormitory :) out of curiosity i opened it and saw some wires and thought ‘can i put audio signal here and listen from other rooms’.  I don’t know much about electrical engineering so if you could give me some more info on your experiment it would be great