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70/100V speaker / amp questions...

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Richard Hedderly:
Hi,

I'm doing a tech refresh on our UK church audio setup. Going over from analogue mixer to digital / Dante.

Our existing passive speakers are fine and want to keep them. Each 300W 8Ω. The old analogue mixer /amp is a 300W per channel at 4Ω.

On new replacement amplifiers they are listed as 70/100V compatible, yet nowhere in the speakers' or the mixer's manuals is there any mention of 70/100V, just the ratings. Neither speaker has a tapping dial.

The speakers are Yamaha S112IV (very retro) and made in the USA. I suspect being made in the States, they are 70V.

Am I OK getting a new amp, setting it to 70V and feeding 300W 8Ω to the speakers?

Cheers

Richard

John Roberts {JR}:

--- Quote from: Richard Hedderly on December 30, 2020, 11:16:37 pm ---Hi,

I'm doing a tech refresh on our UK church audio setup. Going over from analogue mixer to digital / Dante.

Our existing passive speakers are fine and want to keep them. Each 300W 8Ω. The old analogue mixer /amp is a 300W per channel at 4Ω.

On new replacement amplifiers they are listed as 70/100V compatible, yet nowhere in the speakers' or the mixer's manuals is there any mention of 70/100V, just the ratings. Neither speaker has a tapping dial.

The speakers are Yamaha S112IV (very retro) and made in the USA. I suspect being made in the States, they are 70V.

Am I OK getting a new amp, setting it to 70V and feeding 300W 8Ω to the speakers?

Cheers

Richard

--- End quote ---
no...  a 70v line feeding 8 ohms would be a lot more than 300W, if it didn't release its smoke.   

you need to find better manuals...

JR

Kevin Graf:
Let's see:
70 Volts and 8 Ohms is 600 Watts.
70 Volts and 300 Watts is 16 Ohms.

Are those the only two settings on the amp?

* * * * * * * * * *
Rod Elliott on Commercial 70 Volt systems:
https://sound-au.com/articles/line-amps.html

Rane Note on 70V Constant-Voltage Audio Distribution Systems:
https://www.ranecommercial.com/legacy/note136.html

Richard Hedderly:

--- Quote from: Kevin Graf on December 31, 2020, 08:35:38 am ---Let's see:
70 Volts and 8 Ohms is 600 Watts.
70 Volts and 300 Watts is 16 Ohms.

Are those the only two settings on the amp?

* * * * * * * * * *
Rod Elliott on Commercial 70 Volt systems:
https://sound-au.com/articles/line-amps.html

Rane Note on 70V Constant-Voltage Audio Distribution Systems:
https://www.ranecommercial.com/legacy/note136.html

--- End quote ---

---------------------------------------------------------------

Hey Kevin,

This is certainly a "trying to understand what they had / have got" scenario.

Some background.

The church is over a hundred years old and when I went under the floor near where there the speaker cable feed is, there was a label around the cable of 70V.

Now, the current sound system is circa mid 1990s. That's not to say they didn't have a old 70V distributed system before in the 60's until then and reused the speaker cables.

I'm new to the PA side of things. I wanted to make sure that there wasn't a hidden setting somewhere that needed to be enabled.

Given they only have one set of FOH speakers and a smaller stereo pair in a side room, I'd prefer to use this Behringer which has no mention of 70/100V setup.

https://www.thomann.de/gb/behringer_nx4_6000.htm

So if it's a case that there are non 70/100V systems and 70/100V systems, that's great.

It points to that they did reuse the old 70V speaker wire and that the 90s kit is in fact a non 70/100V system.

Would love your take on that.

Best wishes

Erik Jerde:

--- Quote from: Richard Hedderly on December 31, 2020, 11:41:13 am ------------------------------------------------------------------

Hey Kevin,

This is certainly a "trying to understand what they had / have got" scenario.

Some background.

The church is over a hundred years old and when I went under the floor near where there the speaker cable feed is, there was a label around the cable of 70V.

Now, the current sound system is circa mid 1990s. That's not to say they didn't have a old 70V distributed system before in the 60's until then and reused the speaker cables.

I'm new to the PA side of things. I wanted to make sure that there wasn't a hidden setting somewhere that needed to be enabled.

Given they only have one set of FOH speakers and a smaller stereo pair in a side room, I'd prefer to use this Behringer which has no mention of 70/100V setup.

https://www.thomann.de/gb/behringer_nx4_6000.htm

So if it's a case that there are non 70/100V systems and 70/100V systems, that's great.

It points to that they did reuse the old 70V speaker wire and that the 90s kit is in fact a non 70/100V system.

Would love your take on that.

Best wishes

--- End quote ---

It would probably be helpful to know exactly what equipment is currently installed and (as beat you can determine) how it is hooked up.  The suspect 70v line may be appropriate for high voltage audio or it may not.  Knowing what the cable is will help with that.  For instance you can run 70v systems through a building on category cable and often be fine.  A high voltage system would have major problems doing that.

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