Pioneer VSX-LX505 AVR Review

[MbphotoX]

thanks.. kinda underwhelming..

I was really hoping for a comprehensive thread about those systems.

"I measured once for each and on different days. Look, it's better." doesn't quite convince me.

 

[Audio Science Pal]

Hopefully these screenshots are enough to satisfy that with DLBM, you can choose XO for each group (fronts, center, surround pairs, height pairs, etc.).

Front Left/Right
View attachment 357734

Center
View attachment 357735

Surrounds
View attachment 357736

Front Heights
View attachment 357737

That is interesting.

 

[Kachda]

Does anyone know why I am unable to change the delays on the AVR ? I used to be able to set the distance in feet manually, but after I ran Dirac Live, it seems to have switched the delay to msec, and I am unable to move the sliders or change the delay through web interface or the AVR menu. The problem is that these delays aren't correct, and I can definitely hear echoes instead of a seamless music now.

 

[Johnp]

Does anyone know why I am unable to change the delays on the AVR ? I used to be able to set the distance in feet manually, but after I ran Dirac Live, it seems to have switched the delay to msec, and I am unable to move the sliders or change the delay through web interface or the AVR menu. The problem is that these delays aren't correct, and I can definitely hear echoes instead of a seamless music now.

View attachment 359106

That is just how it is once Dirac is loaded on this unit. You cannot adjust distances.

 

[pras1011]

Is the 805 any better?

 

[MisterT3]

As an electrical Engineer, can you take the thing apart and tell us what relay this is and why it is switching? (cannot find the service manual, either)
What happens to the power drawn by the Receiver?

I have experienced/heard the switching after several dozen or so minutes of just playing background music.. sounds to me like the amp just switching off certain things, cranking down the internal stuff because it's not needed.

But what you describe appears to be something different entirely. As if the amp tried to protect itself.
Did you drive output past 0dB setting (Volume control), too?
How did you measure the signal with 8 Ohms loads? (I'm no electrical engineer, just trying to understand the implications of this for real people)

Now, 25 Watts for me is 96dB from a single speaker.. that's basically the peak SPL I would expect when playing a movie on the -10dB setting (105dB is reference level)
never for 30 seconds straight, though..
But I really want to understand how these things come to be, because the amplifier has more than enough power from the psu (700+ Watts) and it was rated at 100+ Watts per channel and actually measured by acclaimed audio magazines to put out the rated amount of power into 5/7 channels respectively.
View attachment 358426

This relay activates ("the click") from thermal or detection of large signal, dont know.. My bet is that the relay switches a different set of secondary windings on the main power transformer that lowers the bipolar supply rails to the class AB amps, limiting power. If I could find a service manual I would see if a simple circuit board hack could disable current through that relay coil.. In that case I would purchase this AV in a heartbeat, as the price/performance is very good..

 

[MbphotoX]

This relay activates ("the click") from thermal or detection of large signal, dont know.. My bet is that the relay switches a different set of secondary windings on the main power transformer that lowers the bipolar supply rails to the class AB amps, limiting power. If I could find a service manual I would see if a simple circuit board hack could disable current through that relay coil.. In that case I would purchase this AV in a heartbeat, as the price/performance is very good..

according to @popej this might be the reason:
"Looking at service manual for older models, we can find a switch for power amps supply. High supply voltage is +-64V, low is +-26V. This low voltage is consistent with Amir's measurement in protected mode, where output power drops to about 20W/8Ohm and 35W/4Ohm. It should be the same for low volume mode."

Now, the question that remains, at least to me, would be:
does this at all matter?!

It normally happens when you don't actually NEED any power from the AVR, so it basically goes into eco mode.
As soon as you draw more power by increasing the volume, the relay switches back to high power mode.

 

[dlaloum]

This relay activates ("the click") from thermal or detection of large signal, dont know.. My bet is that the relay switches a different set of secondary windings on the main power transformer that lowers the bipolar supply rails to the class AB amps, limiting power. If I could find a service manual I would see if a simple circuit board hack could disable current through that relay coil.. In that case I would purchase this AV in a heartbeat, as the price/performance is very good..

Lots of use have been hoping to see service manuals for the current generation - so far they are unobtainium