Impedence switch on Yammie 2400

[theguy]

I am considering the Yam 2400. My main speaker towers are 8 ohms, but the centre and surrounds are 6 ohms. There is a setting that you can set for 6 ohm minimum or 8 ohm minimum. In the staff review on this site, he recommended using the 8 ohm setting regardless. Yamaha is quite adament that the 6 ohm setting should be used in this case to avoid over heating. Audioholics staff member suggested that dynamics would be limited with the 6 ohm setting. Anyone have any thoughts on this? I don't want to buy the yammie if I am forced to use the 6 ohm setting and it limits the quality of sound in any way. Yammie says it does not; Gene says it does. Who is right?

Thanks for your help

 

[gene]

Who is right?

We both are

In the case of the RX-V2400, it has built in thermal protection to limit power under heavy demands so even if you have the receiver set at 8ohms, it will limit power to its set threshold when multiple channels are driven. Whats more important than simply impedance of a speaker is its efficiency and how uniform the impedance/phase of the speaker is over the audio bandwidth.

I will tell you that I ran the RX-V2400 for almost 3 months on all 4ohm 89dB SPL efficient speakers without any issues. Occassionally the fan did come on during high output levels when listening to movies or DVD-A/SACD, but it ran fine for me. My advice here is to ensure you have plenty of ventilation for the receiver. Try it on 8ohms first. If you find it becomes overly hot and the fan is always on, switch to the 6ohm setting.

Note, I don't take responsibility for blown receivers

 

[surveyor]

Impedence Switch @ 8

I own a RX-V2200 and use speakers between 4 and 6 0hm. I use the 8 ohm switch as Gene reccomends. I've yet to experience any problems, or loss of audio quality in two years. I agree with audioholics fully! I wouldn't think that you should have any thing to worry about at the 8 ohm setting. If your speakers are very inefficient, you might supply Gene with the make and model. I'm sure he will advise you to do the right thing.

Cheers

 

[av_phile]

Yamaha is quite adament that the 6 ohm setting should be used in this case to avoid over heating. Audioholics staff member suggested that dynamics would be limited with the 6 ohm setting. Anyone have any thoughts on this? I don't want to buy the yammie if I am forced to use the 6 ohm setting and it limits the quality of sound in any way. Yammie says it does not; Gene says it does. Who is right?

Thanks for your help

If you are still considering this model for your purchase, I would recommend you look elsewhere. When it comes to brute power, dynamic headroom, and driving difficult loads, Yamaha is not at the top of my list. I have been in this hobby long enough to distinguish between amps that use a current or voltage dividing circuit at the back to allow the use of low impedance speakers so they can claim their products can handle low impedance loads when the sad fact is, they really cannot. At least not if they ever want to pass UL certification limits for safe heat dissipating operation. This is exactly my argument in favor of so called "high-current" circuit designs that make it a breeze for amps to handle even 2 ohm loads continuously at high volumes without ever overheating or tripping their protection relays.

Look for a NAD, Harman Kardon or Rotel. Most of their models have no problems driving 4 ohms loads continuously at high volumes. There are no speaker load impedance selector switches behind their units. Only a caution that says: Miiumum Speaker Load: 4 ohms. But if you are enamoured by the digital processing of a Yamaha which admittedly is indeed superior in many respects, then get one with Pre-outs and use a more "high-current" external multi-channel amp. THis will cost $$$, but it's your call.

 

[Unregistered]

Agreed AV_Phile; if you want higher noise, less processing power go with the Nad, Rotel or HK. Its funny how when I read power measurement reports in all of the magazines, the Denon's and Yamahas are right up there if not higher than the brands you mention. Don't know why you are such an pusher of these other brands. All have their pros and cons, but generally speaking the best processing sections are found in the Yamaha,Denon, Integra pieces with comparible amp sections to those in the same price class as the Nad,HK and Rotels.

 

[theguy]

clarification

My speakers are all Axiom. MT60 in the front (8 ohmns), VP150 centre (6 ohmns) and QS8 in the rear (6 ohmns). Should the 8 ohm setting be OK for Axiom? Are they efficient enough?

Thanks

 

[av_phile]

Speaker efficiency and impedance are two entirely different things. If your receiver specifically says at the back or in the manual: MINIMUM 8 Ohms, I'd strongly recommend you stick to it. If it has selectable 4 or 8 ohms, then I'd consider it a safe choice to use the 4 ohm setting. In a solid state amp, when in doubt, its safer etter to use higher impedance speakers. So a setting of 4 ohms mated to speakers that are a mix of 6 and 8 would make your receiver run cooler.

 

[hopjohn]

Agreed AV_Phile; if you want higher noise, less processing power go with the Nad, Rotel or HK. Its funny how when I read power measurement reports in all of the magazines, the Denon's and Yamahas are right up there if not higher than the brands you mention. Don't know why you are such an pusher of these other brands. All have their pros and cons, but generally speaking the best processing sections are found in the Yamaha,Denon, Integra pieces with comparible amp sections to those in the same price class as the Nad,HK and Rotels.

Hey I'm no huge proponent for avV Phile here and his lofty attitude at times, but this particular post seems pretty accurate. How about signing in and revealing your identity before you start slinging dirt?. I wish unregistered posts wouldn't even be allowed here. Besides what's this have to do with the original post anyway?

 

[zipper]

I semi-concur with AVphile.I have Axiom mt60's driven by a Yammy 3300 &,while I have found the combo to be pleasing,think it's the minimum power I would want driving these. The 3300 is only rated 10wpc higher than the 2400 but has a heftier power supply. Unfortunately,as far as I know,the next step up in the Yammy line from the 2400 is the ZX-9,which is a lot more cash.What I would do is get the 2400 & add an amp to it.It will end up costing less than a ZX-9. You can get the 2400,try it out,then decide if you're happy with that setup.If not,add an amp.
Maybe you're not after the "ultimate" at this point.But if you are, I doubt any midline receiver by itself will serve the purpose.Just my opinion & there are sure to be others who would not agree with me,but it is a viable option.

 

[gene]

Speaker efficiency and impedance are two entirely different things.

Yes they are two different things, however they are inter-related in determining how beefy an amp needs to be to drive the speaker. Nominal impedance tells very little about how an amplifier and speaker react. For example, there are many 8 ohm speakers out there that have +-45 degree electrical phase shifts in the audio band making them a more difficult load to drive than a 4 ohm speaker with a more benign phase response, much like my RBH T-2 system (for example) which to the amplifier looks very much like a resistive load impedance (see my review). In addition, my 4 ohm RBH speakers are over 90dB SPL efficient at 1 watt/meter, which again is why a quality receiver can drive them well. Add in the fact that a speaker system like this is crossed over at 80Hz or so, since the system has powered dedicated subs, and you will soon realize how easy of a load it is for a receiver to drive. This is just one example of many speaker systems out there. When determining just how much of a robust amplifier one needs, consider the following:
1) Room Size
2) Room liveliness
3) Speaker Impedance
4) Speaker Electrical Phase
*5) Speaker Efficiency (very important and often overlooked!)
6) Listening level preferences

*A note about efficiency, as many of you know, for every 3dB difference in efficiency there is between two loudspeakers, required an amplifier of double the power for the lower efficient speakers to produce equal loudness of the higher efficient speaker.

However, more power should not be chosen over amplifier quality and signal to noise ratio, etc. In fact, if you really want to increase dynamic range of your system, first focus on room background noise. You will see over the course of the next few months articles on acoustics here to help educate the masses on the importance of getting the room right. If you can't get the room right, then your precious equipment will never live up to its potential. I have seen too many cases where folks invest big dollars into mega separates systems only to integrate them into a poor room where more of their budget should have been spent.

Bottom Line: Bad room with great electronics = not so great sound
Great room with decent electronics = very good sound

I just got my new Sencore scope and I will be taking power measurements for all of you power freaks to demonstrate how much power is actually being consumed in steady state conditions for most home theater system environments.