# Yamaha RX765 and ohms...



## gtamayo (Jun 21, 2011)

One technical question...

I have a Yamaha RX-765, connected to 2 Infinity Clasia C336, each of 8hms, and an Infinity Subwoofer. Initially I just wanted to hear my music, so the set up satisfied much of what I wanted. 

But then I purchased the OPPO BD83.... And I felt the need to move to a 5.1 system at least.... I purchased the center and two bookshelves PSB Image B, each of 4 ohms....

I was wondering what will be the correct set up in the receiver to hear the system, without burning anything!!!!

Some advice?

Sent from my iPad using HTShack


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## Andre (Feb 15, 2010)

Your Yamaha likes speakers over 6ohms. Your Infinities are 8ohms nominal (they will dip below this), your Images are 6ohms nominal with a 4ohm minimum. Set the Yamaha to 6ohms, this may limit voltage output but will help protect your amp, keep an eye on how bad it heats up as compared to just running the infinities.
Because impedance difference, when balancing the volume of the system the mains will need to be cranked up a bit more as compared to the others.


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## gtamayo (Jun 21, 2011)

Thanks!

I will do so. Actually, there has been a pair of occasions in which the Yamaha powered off. :T

I was giving it extra-thoughts: purchasing a pair of Image B bookshelves, and program 2 zones; one of 5.1 and the other of 2.0. One for HT and the other for music. I guess that I have to purchase an additional subwoofer to have a 2.1 instead, yet the room will get really crowd onder:

Giselle


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## Andre (Feb 15, 2010)

If your Yamaha is shutting off it is clipping and going into protection mode because the amp is stressed. Not good for the amp adding more low ohm speakers to zone two will only stress it more.


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## gtamayo (Jun 21, 2011)

I thought that if I program two zones, both will work independent? Isn't the whole idea of the 2 zones?

Zone 1: Infinities (8ohms) 2.0 or 2.1
Zone 2: PSB (4ohms) 5.1 

?????


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## gtamayo (Jun 21, 2011)

gtamayo said:


> I thought that if I program two zones, both will work independent? Isn't the whole idea of the 2 zones?
> 
> Zone 1: Infinities (8ohms) 2.0 or 2.1
> Zone 2: PSB (4ohms) 5.1
> ...


I mean, I thought they were two independent circuits.... Or are they interconnected?

What would be a good receiver for the PSBs?

Sent from my iPad using HTShack


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## gtamayo (Jun 21, 2011)

gtamayo said:


> I mean, I thought they were two independent circuits.... Or are they interconnected?
> 
> What would be a good receiver for the PSBs?
> 
> Sent from my iPad using HTShack


I get it. Yamaha and 4ohms do not get along. I checked the settings and there only two impedance settings: 6 and 8. The setting was on 6. even with 6, from time to time the yammie powers off.... hummm

Sent from my iPad using HTShack


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## Andre (Feb 15, 2010)

The circuits that connect the zone to the sources my be different (i.e. you can listen to one thing in zone 1 and another in zone 2). However, the amplifier is the same (i.e. there is not a dedicated amplifier for zone 2). The more speakers you attach to the amp the less power it can provide to each speaker, turning the amps volume up makes it draw more current, which makes it heat up, then if it has to push that power to a reistance it wasn't designed to handle it will heat it up more. More amps have a failsafe that rather then blow up they will shut off at a certain temperature.

If you amp is in a wall unit or some other stand that doesn't let it breath very well (i.e. there isn't at least 4 inches between it and the sides/top of the unit then it is probably starving for cool air. You may have to take it out of that area. If it is in a open area you could try a fan.

If none of this helps with the shut offs, then I can only recommend changing the speakers to those that are 8ohm, or keep this current Yamaha as a zone 2 and get another dedicated to HT.


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## gtamayo (Jun 21, 2011)

Thanks Andre! You have been very kind! By the way, I send you an e-mail with the long story.... Hope you find a chance to look at it.

Cheers!


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