Question re power output of these Onkyo Receiver

[Jaap74]

I recently upgraded from B&W bookshelf to floor-standing B&W 703 S2 speakers. They are in a 5.1 system with a REL sub. I currently have this Onkyo receiver which is about 13 years old:

Onkyo TX-SR805

manual : https://www.intl.onkyo.com/downloads/manuals/pdf/tx-sr875_805_manual_e.pdf

I feel that the receiver is lacking a bit of oomph with the new floor-standers, I mainly listen to stereo and 5.1 music, I don't watch very many movies. How does this new receiver compare in terms of power ?

Onkyo TX-RZ1100

manual : file:///C:/Users/cdudeck/Downloads/Manual-TX-RZ1100-BAS-ADV-En.pdf

I know power ratings can be fudged in terms of terminology used so any insight is appreciated.

Thanks

 

[lucid]

It's not that different that you'd notice.

AFAIK, the 805 used (uses) conventional transistor amplification whereas the 1100Z uses what amounts to switch-mode power supply amps. Onkyo refers to it as their "High-Current Digital Amplification", but it's not really digital.

Switch-mode amps are a way to get more speaker power from less mains power consumption. This is because the amplification is more efficient, but it is so at the expense of fidelity and high frequency noise.

The bottom line though is that they're still measuring the amp by driving just one channel at a frequency, Ohm rating and with a distortion figure that will give them a seemingly plausible power output, and then multiplying that up as if the transformer can supply the same power to all the channels driven simultaneously. The problem is there's no free lunch.


I'm a bit curious why you think that the sound lacks oomph as you put it. It's true that larger B&Ws like a bit of power to drive them, but still, they are fairly sensitive, and while the 805 isn't a Krell or Bryston, it's not bad for a 7-channel AV receiver. You're not trying to bi-amp the B&Ws from the receiver by any chance, are you?

 

[james.miller]

in to 8 ohm loads, the numbers from both amps are actually pretty similar. ON the bench, both will output around 170w RMS in to 2 channels and 110w RMS in to 7 channels. What i don't really know is what the z1100 can with 4 ohm loads - it's a THX select plus amp whilst the 805 was ultra2 certified which means either the z1100 cant drive difficult loads as well as the 805 can (ultra2 certified amps must be rated to output a minimum current at 3.2ohms) OR onkyo didnt want to pony up for ultra2 certification. Not sure. At any rate, without hearing them side-by-side id say the 805 would have the edge in amplification at least but it's going to be really close.

fun fact, the tx-rz1100 and the pioneer sc-lx801 are virtually identical. In fact, large parts of the pioneer lx801 & lx805, onkyo rz100,rz3100 & pr-z5100 and Integra DRX-7, DRX-R1 & DRC-R1 are all covered by the same service manuals

 

[Jaap74]

You're not trying to bi-amp the B&Ws from the receiver by any chance, are you?

Yes they are bi-amp'd or bi-wired or whatever it is called.......

 

[sHo0sH]

I had some older b&w 603 floorstanders and initially ran them through an av receiver. Whilst they sounded ok for movies they just sounded lifeless for music.
I moved to a stereo amp for them (rotel ra1062) instead and the difference was remarkable. I

I were to get another reciever I'd make sure I could bypass the amp for the fronts and keep the floorstanders powered by the stereo amplifier. It looks like you've got the pre outs on your AV reciever that would allow you to do this.

 

[Jaap74]

Good suggestion however I have a very large 5.1 music collection so play about 75% stereo to 25% 5.1 so would forever be switching between the receiver / stereo amplifier

I use Roon so like the fact that I can play anything from that via the receiver

 

[lucid]

Yes they are bi-amp'd or bi-wired or whatever it is called.......

These are two different things, but IMO both are a waste of time with a single amp upfront, especially bi-amping.

Bi-wiring is where one set of speaker terminals on the amp then connects to two sets of cables to the speakers. It changes the sound of the speakers, but in my book it's not a change for the better. My experience is that the HF and LF lose cohesion with each other.

Bi-amping with a single amplifier is where the two sets of speaker terminals connect via two cable to each speaker. The amp has a software setting to change it to bi-amping mode.

The problem here is two-fold. First, all the power is still coming from the single transformer in one amplifier; so it's not really bi-amping in the true sense because there's no additional power. All that has happened is the cake has been cut in to smaller pieces.

Second, even though the HF/LF links are removed, the speaker crossovers are still in place.

In order for bi-amping to be a real benefit, there should be two independent amplifiers for a start. Also, the speaker crossover should sit between the pre-amp and the power amps so that the LF channel gets the lion's share of the power.

Bi-wiring and bi-amping from a single amp is good for your dealer's bottom line because they sold you two sets of speaker wire. I'm not convinced it helps your sound though.


Running either a stereo power amp for the fronts, or going for a stereo amp to drive the 703s is your way forward unless you're going to buy an AV pre-amp with a multichannel power amp.

As @sHo0sH suggested, you can run the pre-outs from the AVR in to a stereo amp. In this way, the power requirement of driving the fronts is lifted away from the AVR. You get a cleaner path for pure stereo source direct through the stereo amp, and a better power reserve for those speakers, but you still retain all the benefits on multichannel processing via the AVR. There's no speaker cabling swapping involved in daily use. The only change to your listening routine is that both amps need to be on for multichannel mode, and the stereo amp needs to be set to a specific volume level each time if it doesn't have an AV Bypass mode. That's hardly the most difficult thing to do; setting the volume dial to say 10 o'clock.

 

[hornetstinger]

Mines similar to that but instead of a av amp, have av pre. With a ATI amp below the hifi amp (stereo pre amp) then another ATI amp for side/surrounds

 

[Jaap74]

I should have mentioned that my current receiver is on it's last legs. Only 2 HDMI inputs work and sometimes the surrounds don't produce any sound until I turn it off from the power point for a few minutes. Therefore getting a new receiver and separate amp for the floor-standers is not an option.

 

[lucid]

Well then, since you're arguing so much against any solution that isn't the TX-RZ1100, it seems like you've made up your mind that it's the only solution for you, despite lots of advice here to the contrary.

You've now just added that the 805 is on its last legs, so I predict that you'll be picking up one of the last RZ1100s fairly soon then.

I wonder, did you bother to go and actually listen to the speakers before you purchased?

The 805 has serviced your needs up to this point, so I'm guessing that you haven't got ATMOS speakers and you don't need eARC and 4K pass-thru etc etc. However, they would be useful upgrades. A more sensible option then would be to buy a lower-range AVR with pre-outs and buy a new or even used 2ch stereo amp to drive those B&Ws properly. My guess is that there's a big discount on offer somewhere on an end-of-line RZ1100, so it's your wallet driving this desire rather than your ears.

I hope you'll remember to be happy with your purchase after the sweetness of the discount has faded from memory.

 

[Jaap74]

Wow Lucid, so many assumptions in your post above. I did appreciate your detailed reply, it was full of good information however I must say that in over 10 years on OCUK I've never received such a condescending reply to anything I've posted.

Thanks to the other posters who gave an opinion in a humble and friendly manner, much appreciated.

 

[lucid]

Touched a raw nerve, did I? I guess it was a bit too close to the home truth?