Can 70V audio distribution system deliver decent sound?

[klettermann]

I just moved into a new house wherein the previous owner spent gobs of $$$ on various odd technologies. These include elaborately wiring every room for cable TV (75ohm coax) and speaker wires all through the house to run a 70V audio distribution system with in-wall and in-ceiling speakers all over. He could have hardwired the house for gigabit ethernet and used Sonos or something but went total 80's on it. Apparently he hadn't heard about the internet. Anyway, I don't know much about these 70V systems except that I associate them with cheesy, commercial venues for Muzak (grocery stores, shopping malls, etc). All I have left is a few in-ceiling speakers, the wiring and a bunch of in-wall transformer attenuators.

So: can this stuff possibly sound any good? And can such systems even play stereo or is it just mono everywhere? Obviously I'd need an amp to do anything at all. Alternatively I may just use the wiring and set up a few small class D amps fed by some kind of streaming source. Thoughs and ideas welcome. Thanks!

 

[Speedskater]

Is it one small diameter, two conductor cable, looped from room to room. Or are there more cables?

 

[JeffS7444]

When you are dealing with long runs of skinny speaker wire, high voltage is exactly what you want to minimize resistive loss. 70 volt PA amplifiers can be had pretty cheaply. I wouldn't expect really high fidelity, but it might be pretty decent for casual listening.

With a more modern cloud-connected solution like Sonos, you'll be lucky if you get 5-7 years of useful life out of the things before they're rendered obsolete.

How's about a mix of old and new? Like a 70 volt PA system with Sonos as a source? That gives you the convenience of apps and streaming services but keeps obsolescence-prone parts to a minimum.

 

[klettermann]

Multiple cables. There are 3 2-conductor cables where the old amp was. These go to 3 transformer-type volume controls on the wall. Each of those seems to feed a >>pair<< of speakers, . Looks like respective speakers were wired in parallel , nothing here seems to be 2-channel. He could have done so much better!

 

[TonyJZX]

there are 'higher performance' 70v systems

JBL Pro CSA series is better than many esp. the no name PA types... they use drivecore which is robbed from Crown I beleive.

 

[klettermann]

Thanks for the comments, which caused me to dig deeper. 4-conductor wires were used to connect the amp with the respective volume controls. Only 1 pair was used however, hence speaker pairs are all mono as noted above. It wouldn't be hard to get rid of the volume transformers and reconnect it all for 2-channels. So, this gives me 3 sets of skinny stereo cables nicely run through the walls. I'd be inclined to do it that way using one or 2 units like Bluesound Powernode instead of the 70V route. Among other things, I've already gort a couple pairs of suitable bookshelf speakers. That now raises the issue raised by @JeffS7444 - skinny speaker wire. But that's a topic for a new thread. Thanks and cheers,

 

[Speedskater]

Modern high power amplifiers can drive a 70V system without an output transformer.
Everything you need to know about 70V systems:

Constant-Voltage Audio Distribution Systems: 25, 70.7 & 100 Volts

Use a transformer to step-up the power amplifier's output, drive long lines, and use another transformer to step-down the voltage at each loudspeaker.

www.ranecommercial.com

High Voltage (70/100V) Audio

Elliott Sound Products - Commercial audio, 100V, 70V line systems, transformers, amplifiers and ancillaries.

sound-au.com

 

[egellings]

I just moved into a new house wherein the previous owner spent gobs of $$$ on various odd technologies. These include elaborately wiring every room for cable TV (75ohm coax) and speaker wires all through the house to run a 70V audio distribution system with in-wall and in-ceiling speakers all over. He could have hardwired the house for gigabit ethernet and used Sonos or something but went total 80's on it. Apparently he hadn't heard about the internet. Anyway, I don't know much about these 70V systems except that I associate them with cheesy, commercial venues for Muzak (grocery stores, shopping malls, etc). All I have left is a few in-ceiling speakers, the wiring and a bunch of in-wall transformer attenuators.

So: can this stuff possibly sound any good? And can such systems even play stereo or is it just mono everywhere? Obviously I'd need an amp to do anything at all. Alternatively I may just use the wiring and set up a few small class D amps fed by some kind of streaming source. Thoughs and ideas welcome. Thanks!

It's problematic, because small audio step up and step down transformers are carrying the sound. For elevator music, like the Hollyridge Strings plays the Beatles, then I 'spoze. For decent sound, look elsewhere.

 

[klettermann]

Thanks to all. Wow. It looks like maybe I can get some use or of one or two off the cable runs. Maybe. All this elevates the last, and maybe most interesting, question: why?? The previous owner was a retired cop who seemed to have LOTS of money to spend {that's another question in itself). Why do this in this day and age? Was he even listening to music? Now I imagine that it was lo-fi voice, podcasts perhaps, but that's would be newer tech. A police scanner perhaps? We'll never know but it's fun to imagine. Thanks again.