Right, I forgot the Onkyo's don't have preamp mode like the D+M avrs have and that would disconnect the power amp inputs. If the amps are not switched off, then it won't be in quiescent state either.
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Pioneer VSX-LX505 AVR Review
- Thread starter amirm
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ivo.f.doma
Active Member
In that case, it is not even usable as a PRE PRO for LCR (even if SINAD will be good there), because after 30 seconds it starts limiting the other channels connected to the internal power amplifiers.
I GUESS NO!!!
This doesn't make any sense. If the amplifiers are not drawing current, how are they amplifying anything? It strikes me as a logical impossibility that the signal from the pre-amps could be amplified with no load on the speaker terminals. If there are no speakers attached (or something else, like test equipment), then it is an open circuit. Onkyo told me specifically that if there is no load on the speaker terminals, the amplifiers are inactive and merely draw minimal current from the power supply.
In a review of an Emotiva power amp, Amir stated (correctly I am sure) "In use the A-500 never complained, shut down or go into thermal protection. This is nice benefit over the delicate amplifiers in AVRs which if you look at them wrong, they go into protection/shut down. Clearly this is much more robust solution."
I took the quoted comment as an article of faith, and it is consistent with my experience, consequently, other than for an experiment or convenience, I've always used external power amps. It seems like there is a lot of confusion and lack of clarity in the analysis in this thread. My only question has been whether this aggressive protection (or nanny circuit) has any impact on the pre-outs. Beyond that question, I don't care one bit about the internal amplifiers. My conclusion is that it does not affect the pre-outs (hope I'm right) so I'll just get on with enjoying the music.
The amplifier section is mainly comprised of the voltage gain stage and the current/unity gain stage. If voltage is applied to the input the amplifier will amplify the voltage and then right before the speakers the current gets amp'd up and that occurs whether speakers are connected or not. The operation of this circuity is not 100% efficient and there are losses.
But will this negatively affect the signal from the pre outs if one is using outboard amps?
The pre-out should clip where it usually clips at and not be affected by the amp operation.
Usually yes, pre out's distortions will increase quickly when the power amp output voltage clips, with or without speakers connected.
antcollinet
Grand Contributor
Thats not what happens - in fact the pre outs might even be performing better as a result of the amp outputs being limited.
antcollinet
Grand Contributor
OP
- Thread Starter
- #350
Some do in my testing, and some don't. The Yamaha RX-A3080 is an example of one that did: https://www.audiosciencereview.com/forum/index.php?threads/yamaha-rx-a3080-review-avr.29520/
The issues I experienced with the sound from the power amp output, were not present when running as Pre into my external amps.
Of course I have no evidence that the issues were related to the Nanny State being triggered - and my suspicion is that the amps couldn't drive the low impedance load presented by my speakers - and that the nanny state/protection power down, was never triggered.
But as stated before - no one out there is reporting this issue in actual use... and my personal use as a prepro is not showing this issue either.
Further in depth measurement, reverse engineering, and analysis would be required to determine what exactly is happening and what the parameters around it are....
Right now these AVR's are subjectively excellent, with the exception being low impedance speakers, and used as prepro's driving external amps they are showing excellent performance.
There is a strong cognitive dissonance between the experience of Pioneer/Onkyo/Integra owners, and some of the assumed ramifications of AmirM's measurements.... I say assumed ramifications, because right now, we don't know what the actual ramifications are outside the limits of the specific tests amirm has done... a lot of the rest is a bunch of speculation.
So the current situation preditcs next logical step would be to find out not only if but also find exact conditions when and how the protection kicks. As it stands rigjt now, there is just a buch of guessing. At the end, @amirm isconly a human, allowing him to make mistakes. Intentional or not. I am hapoy owner of lx305 model, it did not happen yet for me to see the limiter would engage. And I have impedance demading speakers also, dropping below 2ohms. Maybe @amirm used EU version for 220V in USA? 
I am sure he did not, but who knows...
I am sure he did not, but who knows...
OP
- Thread Starter
- #354
I know. I measured the thing. And no, it doesn't turn on if it is set for the wrong voltage. Why would an EU model land here anyway?So the current situation preditcs next logical step would be to find out not only if but also find exact conditions when and how the protection kicks. As it stands rigjt now, there is just a buch of guessing. At the end, @amirm isconly a human, allowing him to make mistakes. Intentional or not. I am hapoy owner of lx305 model, it did not happen yet for me to see the limiter would engage. And I have impedance demading speakers also, dropping below 2ohms. Maybe @amirm used EU version for 220V in USA?
In reverse, you don't know if you have or have not hit the issue. There is no indicator. Even if you want to defend this "feature," you need to contact the company and complain about it taking such drastic action on performance without letting the owner know. That is what I did. Sadly they ignored my message but if more people do this, maybe things will improve in the future.
The indicator is in the web GUI menu, so this is kind of clear situation. And you are probably reading it wrong, as I am not defending the situation as is, for me at least, just a prove that price cuts are reflecting in worse user experience instead of going for better and it is happening just all around us. For me it is still more a question of finding a perfect AVR (amplifier, speakers, etc replace with your own object) and even if a such thing would exists, it will probably not meet other factors, like most obviously price, then maybe design, size etc.. with size being the most notable factor for me thinking of such an advances in electronics and computers and we still have huge ugly boxes..
DavidMcRoy
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To reiterate what I wrote waaay up the thread, I only use my "similar" VSX-LX503 as a processor and it has only ever gone into Nanny Mode when passing pink noise or sine waves through any or all channel(s). It's never done that on program audio signals. I suspect there may be a circuit involved that is able to detect the presence of steady-state signals, and if such are detected, the countdown starts. I always hear a telltale series of relay clicks when auto-shutdown is imminent.
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Aerith Gainsborough
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²Buying AVRs really seems to be a friggin minefield, when it doesn't have to be.
I'll definitely steer clear of that brand, should I ever need to replace my lil' Yammy.
Yeah, it really depends on how the power amp output's limiting scheme is designed/work, may be someone can find out from Onkyo.
That makes sense to me. Since you mentioned "..a bunch of speculation..", I would say that one good thing about such test results is that because of such tests, we don't have to speculate as much. As you pointed out, a lot of the owners are not experiencing the "ramifications", and that's not surprising because it could simply be that in their usage, the "pull back" behavior Amir found, might not have been triggered, or triggered but not noticed by the owner (as Amir found, there was no indicators). Just like your specific speakers did not do well with your Integra and you noticed it, yet other owners may not (unless the unit actually shutdown).
Having seen the test results, potential owners can make a more informed decision. For example, if I had the kind of uncommon impedance/phase angle characteristics speakers like yours, the RZ50, and its Pioneer, Integra cousins would not be my choice. Since I don't have such speakers and have no plan to acquire anything like them, the RZ50 would be on my short list if I needed an AVR.
In my opinion, ASR is a good place for people who prefer objective measurements to help them make their choices. Those who don't like the results and/or questioned their values would still benefit from the information, that again, should help them in making more informed decisions such as to avoid the DUT (the LX505 in this case), or not, based on their needs.
Quite....
However my analysis of AVR's and Prepros around this price level, did not indicate any that would provide confidence with their ability to handle my speakers - ultimately all contenders were suspect in terms of very low impedance handling.... so then it became an issue of their suitability to run surround/height channels, and effectiveness as pre-amps / processors. (ie: after my initial analysis, I was fairly sure that I would need to use my power amps regardless which AVR I went with... unless I was willing to go up to a much higher price category - and even then...)
Shortlist ended up with Anthem, Denon and Onkyo/Integra.... I wanted to move away from Audyssey.... and then decided I preferred to try out Dirac based on the many positive reviews I was reading (and a couple of impressive listening sessions at audio shows a few years back).
So, not overly concerned about the power amp weaknesses - and the processing and sound quality strengths are excellent.
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