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Onkyo Tx-RZ70

All the new AVRs seem to have a high drop from 5 to 7 channels. But that's really not that important for anyone who has a sub.

I ran full range bi-amped fronts (7ch) for 13+ years so I was doubling my LR consumption and pushing low-end frequencies and it never complained or felt compressed.

The moment I got a sub even with my lower crossovers, it barely heats up. It's those 2 octaves at the bottom that seem to demand the most power.

In fact, given the fact that people will run at least 1 sub with these, I'd rather see smaller transformers capable of higher 3 channel wattage (3x150 watts or 4x120), more capacitance (60k-100k), smaller toroidals, copper chassis for better isolation and other things to improve sound. Put the money where it matters most.

If someone needs more power, they can always get a small external amp for a few channels but they can't increase the quality of the main unit although these do seem really well built but it's sad to see the omission of a toroidal even if it cost $100 more.
The main culprit for all AVRS is, that all built-in amps are using a single unstabelized power supply (transformer), which hamper the available current the more channels are used at the same time. From the physical size and weight there are limits to this, so this seems to be an invisible wall they are running against. Class D might push this somwhat upwards, but the "solution" would be a preprocessor + external amps, which increases the space constraints again unfortunatelly...
 
The main culprit for all AVRS is, that all built-in amps are using a single unstabelized power supply (transformer), which hamper the available current the more channels are used at the same time. From the physical size and weight there are limits to this, so this seems to be an invisible wall they are running against. Class D might push this somwhat upwards, but the "solution" would be a preprocessor + external amps, which increases the space constraints again unfortunatelly...
Although I am making some assumptions - the RZ70, seems a close relative to previous generations like the SR876 and Integra DTR 70.4, both of which I owned - and both of which had no trouble handling all the channels simultaneously along with my 4 ohm (with minimum at 1.6 ohm) mains.

The flagship models from Onkyo (& brethren) or from Denon (AV1H) have very substantial power supplies, and can typically cope well with pretty much anything.

This however is not true of the models further down the range - the processing is just as good (or sufficiently close that it doesn't matter) - but the much smaller power supplies, can become a limiting factor.

The key there is, do you need substantial current... the ability to handle low impedances.

If all the speakers are "standard" 8 ohm without dramatic dips in impedance (so say dips no lower than 4 ohm) - then the RZ50 or NR7100 will cope just fine.

But if the speakers are 4ohm with dips down to 2 ohm or below (not that unusual for a 4 ohm speaker) - then they can get into trouble and are best run with an external power amp. - this does not mean you need an external amp for ALL the channels - typically the surrounds and heights are an easier load, as well as needing less power - which means most of the lower end AVR's can run perfectly fine, even with difficult speakers, as long as you power the mains with an external power amp (suited to them obviously! - no point getting a power amp with the same limitation!).

Hence I run my Integra DRX3.4 (equivalent to NR7100, but with full pre-outs) - with a Crown XLS2500 powering the front L&R - and the DRX3.4 handles everything else in a 5.1.4 setup...

Once Dirac ART becomes available for the flagship models, I will consider whether to trade my 3.4 for an 8.4 or RZ70... and perhaps trade my power amp too... based on my experiences with previous generation Onkyo flagships, I probably won't need the power amp.
 
The main culprit for all AVRS is, that all built-in amps are using a single unstabelized power supply (transformer), which hamper the available current the more channels are used at the same time. From the physical size and weight there are limits to this, so this seems to be an invisible wall they are running against. Class D might push this somwhat upwards, but the "solution" would be a preprocessor + external amps, which increases the space constraints again unfortunatelly...
The root cause limit is a 15 amp 115 volt power outlet.
The second, and typically more important in AVRs, is cooling.
Most gaming computers use liquid cooling with low noise fans and huge heat sinks.
But stuffing 11x that in an AVR would make it too big.
One thing to remember, particularly if you use the bi-amp feature, is that the power requirements to achieve a given volume have a largely inverse exponential curve with frequency.
So you can largely discount the "high" channels in terms of overall power.
Using one or more active subwoofers will also greatly reduce stress on the AVR power supply. Particularly if you set the crossover to the THX recommended 80hz.
But you are going to have to hire a good electrician to rewire your listening room because most homes don't have multiple 15 or, better, 20 amp branch circuits in the same room.
So plugging your AVR and sub(s) into the same branch circuit will not help much.
The superior solution remains a good processor and one or two good multichannel amps designed to handle nominal 4 ohm loads. Along with two good powered subs properly located.
You still need to have the room wired to provide 15 amps to each sub, 15 or 20 amps to the AVR and another 15 for peripherals.
And don't crowd ventilation by using small or closed cabinets.
 
Class D might eliviate the cooling question somewhat, but it will not solve the question of space needed for this. Higher End class D amps produce quite some heat, especially the power supplies needed for them.
 
Class D might eliviate the cooling question somewhat, but it will not solve the question of space needed for this. Higher End class D amps produce quite some heat, especially the power supplies needed for them.
Class D becomes more efficient at high loads...

At Idle and low loads, Class D and Class AB are pretty much the same in terms of power load/heat.

In actual use, at normal listening levels in my large open plan living space - peak power never gets past 4W.... (according to the LED's on my power amp)

According to the status on the Integra DRX3.4 AVR, the temperature internally never rises (it only drives surround and height as my power amp handles fronts).

So yeah in theory class d might alleviate some cooling issues under extreme loads - in practice, it is a complete non-event.

The issues with heat in previous generation AVR's were not associated with the power amp circuits (which were always well built, heatsinked and fanned) - but were associated with the DSP and HDMI chips which ran seriously hot.

The current generation run much cooler - and from sad experience, the Onkyo engineers have also fitted heatsinks to them...
 
The problem: "good" class D amps are (usually) quite expensive (Ncore, Purify etc.) and they all need a (switching ?) power supplies, which also generates heat (some quite a lot)
I do have 3 channels of Ncore amps, but they are getting quite hot and need additional (forced) ventilation, athough built into the manufacturer suggested casings.
Linear power supplies are out of the way most of the time for poor efficiency. One migth get a class D multichannel amp with as many channels as needed (and a post filter PFBB design) with a large (powerful) switching power supply, but at a price...
 
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The problem: "good" class D amps are (usually) quite expensive (Ncore, Purify etc.) and they all need a (switching ?) power supplies, which also generates heat (some quite a lot)
I do have 3 channels of Ncore amps, but they are getting quite hot and need additional (forced) ventilation, athough built into the manufacturer suggested casings.
Linear power supplies are out of the way most of the time for poor efficiency. One migth get a class D multichannel amp with as many channels as needed (and a post filter PFBB design) with a large (powerful) switching power supply, but at a price...
dlaloum (post#45 above) explained some of the reasons, I would add that those class D amps, being much smaller and the heat would therefore be more easily felt by touching the small enclosure. The total heat, in say Joules, or BTUs would still be less (relatively speaking, vs class AB), but it would be much more focus to be felt, again I am just adding to points dlaloum already made.

As to multichannel amp, I always think that a lot of users don't actually need all channels to have equal output, some AVR manufacturers actually use less powerful amps for the surround/height channels, same idea as some use lower dac chip models for those channels. The need of the so called all channel driven without the measured output driven is really a myth, for lots of, probably most home theater applications, but many people would continue to believe what they believed in the beginning...:D
 
The problem seems to be, that external class D amps need space to be installed externally.
Many users also prefer class A/B amps, although new class D amps have proven to be superior as amps...
 
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The problem: "good" class D amps are (usually) quite expensive (Ncore, Purify etc.) and they all need a (switching ?) power supplies, which also generates heat (some quite a lot)
I do have 3 channels of Ncore amps, but they are getting quite hot and need additional (forced) ventilation, athough built into the manufacturer suggested casings.
Linear power supplies are out of the way most of the time for poor efficiency. One migth get a class D multichannel amp with as many channels as needed (and a post filter PFBB design) with a large (powerful) switching power supply, but at a price...
Class D amps just requite a power supply, some deliver it with transformer based old style power others with switching - it just needs V & A... just like a class AB!

Pioneer's AVR's had class D for a few generations... and it was priced competitively with Class AB AVR's

Pioneer chief designer has stated that he would like to further differentiate Pioneer from its Onkyo/Integra siblings... potentially bringing back Class D - but right now Voxx is in financial difficulty, so I doubt there will be funding for that effort... for now.

However it is clear that Class D can be used in AVR's and that cost is not necessarily an issue (given it has already been successfully done by several brands).

Onkyo/Integra have a reputation in amps based on Class AB ... and they may be trying to leverage that.

Personally I believe that one of the biggest steps forward in AVR's would be changing to switch mode power supplies... which can be done in less space, than transformers, and deliver more power - that alone would provide many AVR's with improved power sections without in any way altering the power amp circuits!
 
new class D amps have proven to be superior as amps...
Not true - look at the Benchmark AHB2... a state of the art Class AB power amp.

There are SOTA amps in Class D, as well as Class AB... the amp class doesn't tell you anything about its performance...
 
Does anyone know how many write cycles the chip inside the RZ70 that stores the Dirac config (measurements and filters) can handle?
The thing is, when you change the speaker config after measuring the Dirac config gets deleted.
That would suck when I want to listen to music in 4.0 with Auro-2D Surround and the only option is to disable the center which requires to upload the Dirac config again.
 
Not true - look at the Benchmark AHB2... a state of the art Class AB power amp.

There are SOTA amps in Class D, as well as Class AB... the amp class doesn't tell you anything about its performance...
But this seems to change currently, because most released and/or newly tested "high end" amps are now class D, if my observations are to be trusted. That doesn't mean, that older class A/B or class A amps are of lesser quality but they are at least less efficient :) or take up more space...
 
@Robert-Hifi
If I rember correctly, most flash memory chips have been setup for a lifetime of at least 100 straight write cycles, whilst originally this has been about 1000 (with much less memory). Memory managment might have changed that in the meantime...
But this is not "certified" as my memory might betray me :)

I hope others will chime in to correct me...

But: Usually the speaker configuration does not change after the initial setup + some correction runs.
Your repeated rather "unusual" change in speaker configuration depending on the use situation is not taken into account. Thus the flash chip should "normally" rarely reach its "normal" end of life settings during normals use.
 
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@Robert-Hifi
If I rember correctly, most flash memory chips have been setup for a lifetime of at least 100 straight write cycles, whilst originally this has been about 1000 (with much less memory). Memory managment might have changed that in the meantime...
But this is not "certified" as my memory might betray me :)

I hope others will chime in to correct me...

But: Usually the speaker configuration does not change after the initial setup + some correction runs.
Your repeated rather "unusual" change in speaker configuration depending on the use situation is not taken into account. Thus the flash chip should "normally" rarely reach its "normal" end of life settings during normals use.

I was afraid the write cycles wouldn't be sufficient for my unusual user case, but there is no other way.
It's either that or try to live with just 2.0 instead of 4.0.

Audyssey doesn't have this limitation, you can disable the center without issues, but Audyssey isn't available anymore on Onkyo gear.
The Onkyo TX-NR906 had a nice option to leave the speaker config alone and set the center to "Use: No" while it was still enabled, but that option is no longer available on the RZ70.
 
But this seems to change currently, because most released and/or newly tested "high end" amps are now class D, if my observations are to be trusted. That doesn't mean, that older class A/B or class A amps are of lesser quality but they are at least less efficient :) or take up more space...
The claim of efficiency is pretty much true... but only when running at rated power levels.

But if you look at actual power draw at idle and at normal levels (my open plan space, and inefficient 86db/wm speakers has my class D amp peaking at a grand total of 4W...) - the efficiency is on a par, with many AB's bettering their D peers... and vice versa.
 
Audioholics TX-RZ70 test results.
It looks like the nannies issue has been fixed. Furthermore, there is now a different procedure when forced into protection whereby the receiver restarts and does a channel by channel test instead of silently throttling. This is highly preferable to the old behavior.

Also, very impressive results: 266 WPC 2ch @ 4R and 118 WPC 7ch @ 8R. I expect the Pioneer and Integra siblings deliver the same results, just with slightly different heatsinks.

It's also good to see the Pre-Amp disconnect mode is effective.
 
It looks like the nannies issue has been fixed. Furthermore, there is now a different procedure when forced into protection whereby the receiver restarts and does a channel by channel test instead of silently throttling. This is highly preferable to the old behavior.

Also, very impressive results: 266 WPC 2ch @ 4R and 118 WPC 7ch @ 8R. I expect the Pioneer and Integra siblings deliver the same results, just with slightly different heatsinks.

It's also good to see the Pre-Amp disconnect mode is effective.

Yes, pretty much all I could ask for. This is going on top of my AVR shortlist.
 
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