Sign in to follow this  

New to 70 Volt Systems

Recommended Posts

Hello everyone,

I've been building live sound systems for nearly 20 years (8/4/2 ohm systems), and only in the last month have learned about 70 volt systems, due to the fact that I have a client who wants build an outdoor system for them.

They are, obviously, very different. But I think I understand 70 volt systems now, and they're actually pretty simple -- assuming my research was done correctly. But I wanted to confirm with the experts I'm sure are browsing this board.

The speakers for my system will be JBL Control 29AV. I want to use Crown Amps

These 70 volt JBLs have Transformer taps @ 110W, 55W, 28W & 14W

For my question, I've assumed that I'll use them at the 110w settings

Config. #1: So, if I buy the CTs 600 amplifiers, and use them in 70v dual/two-channel mode, I can get 2 speakers per channel and be 80 watts under the power rating. Is this correct?

Config. #2: Or, conversely, if my final design needs more speakers, I can buy the CTs 1200, and put 4 speakers on each channel?

In the long run, this outdoor system will have between three and five geographical zones. Since I'll control audio through a Matrix audio switcher, I'm thinking that I'll need something like 16 speakers, and up to 4 amps.

Have I gotten the calculations right, or horribly wrong?

Thanks in advance!

Share this post

Link to post
Share on other sites
Yes, yes, and right. Generally you assign one channel to each zone in a 70V system, but your thinking looks all correct.

Hi Kevin,

Thank you so much. I just ordered a CTS1200. I have a question, though. I couldn't seem to find an answer in the manual, and I didn't see it in any of the diagrams.

How do you select 70V mode? On the old Com-Tech series, there was a sliding switch on the rear of the amplifier that said something like "8/4/2" on one side and "70 Volt" on the other. I haven't seen any sort of selector switch on the CTS series amps. Where is it located?


Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this