I am renewing my HT system, with plans for a new Mits DLP and also Axiom M80ti, QS8(3), VP150, SVS 20-39pci sub. I am going to get a new receiver in the future when more DVI switchers are available but right now I have to use the Onkyo TX-DS797 I have had for a few years. According to the manual if even one of your speakers is 4ohms set them all at 4ohms! But there is some debate as to this being done with the 797 without over heating, shutting down or invoking current limiting. Does anyone have this set up and will it work? Thanks

radtek2,

Sorry, don't mean to ignore you. I have a 797, but I'm running 8 ohm M60s with 6 ohm VP150 and 6 ohm QS8s. So I can't be much help. However, If you would send a private message, or an email to our resident Axiom expert, Alan, and ask him your question, I'm sure he'd be able to help you.

Sorry I'm not more help.

I used to have an Onkyo 797 and checked its manual - you can set the receiver to 4 ohm for 4 ohm speakers. The amp is rated at 135 wpc into 6 ohms. I'd guess your 797 can handle M80s' 4 ohm load.

Ajax,
I did indeed talk with Alan and he was not sure on my particular Onkyo model so said to ask on the message board if any one else had used the M80's with it. He suggested the M60's but ...Man! I love the looks of the 80's
Thanks

radtek,

My GUESS is that the 797 will handle the M80s, but since I have no concrete evidence, I was reluctant to say so. As 2x6 pointed out, just go into the hardware setup menu, and set the speaker impedence to 4 ohms (page 28 in the manual).

How old of a model is the 797? I just thought I'd ask cause I know the 601 handles the M80's fine.

Now I think the 797 came out a few years before the 601 did, but I was thinking since it's a higher model then the 601, just a little older, I can't help but think it would handle the M80's just fine. I can't say for sure though, cause I really don't know.

Try calling onkyo dude. Ask them about it, tell them what your wanting to buy and ask them if the 797 can handle a 4 ohm load. That's what I'd I do bud.



Sutter Cane

The 797 is about 2 and a half years old. I bought mine in March 2002, and it was very new at that time.

the real question here jack is, which of you has aged better??

the 797 or you!!!

bigjohn

No contest....................................................................................................................the 797.

radtek2,

Ask Onkyo if the 797 will deliver its FULL POWER OUTPUT into a 4-ohm load with the switch at the 4-ohm setting. I'm fairly sure that Onkyos of the 797 vintage inserted a current-limiting circuit at the 4-ohm setting to prevent the output stage from overheating. But it does that by limiting the power output to about 30 watts per channel. And if you get the M80s, you are going to want a lot more power. If Onkyo says, "Sure it will drive 4 ohms." You should say, "Yes, but what is the maximum power output into 4 ohms with the switch at the 4-ohm setting?"

Regards,

Alan, I have emailed Onkyo for a response on this question. Have been busy with WORK! so have not had the time to call them but will soon if no answer from them. I have a gut feeling you are correct. But, in the manual's specification page it lists dynamic power output (stereo)at 2 x 210 watts at 4 ohms. If indeed it won't carry the load so to speak, I guess then I will have to renegotiate with the wife the need for a new receiver in-lieu of new HT room furniture! Doesn't bother me to sit in my somewhat tattered and abused Lazy Boy a while longer. >-

radtek:

Ignore all "dynamic power" ratings (at 4 ohms, 2 ohms, etc.) for A/V receivers not just from Onkyo but other brands as well. It's a very misleading and useless spec because the dynamic power rating is measured in milliseconds (that's a few thousandths of a second). So, sure, it may deliver 210 watts per channel into 4 ohms for a couple of hundred milliseconds (1/5 second), or perhaps even a second, then it will overheat and the thermal or current-limiting sensor will shut it down.

Look for a continuous power-output rating into a 4-ohm load, perhaps just at 1 kHz with one or two channels driven.

Regards,

Alan, In that case, Continuous Power output (DIN) is rated at 135 watts at 6 ohms. Maximum Power output 160 watts at 6 ohms. No 4 ohm ratings other then what I mentioned before. I will go with M80's and if the Onkyo has an effort problem with them will get a Denon 3805 or since I really like the Onkyo maybe a Onkyo 901.
And, thanks for all the help with this

Dewayne, one suggestion I'd have is to only set the 797 to 4 ohms as a last resort, i.e. if it keeps shutting down. As Alan pointed out, receivers which have a 4 ohm switch or menu setting have reduced maximum power at that setting, since what it does is to reduce the maximum voltage, and therefore power, available. The 797 is a pretty sturdy unit and I suspect that there won't be a problem, but I don't have any specific info on the matter.