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Discussion Starter · #1 ·
Hey guys, I'm new here, and new to home theaters.

I'm looking to upgrade my Onkyo receiver (HT-R550) from my old HTIB (http://www.onkyousa.com/Products/model.php?m=HT-SR800&class=Systems)

Looking at the specs, and comparing them against newer models (Onkyo TX-NR636 - http://www.onkyousa.com/Products/model.php?m=TX-NR636&class=Receiver&source=RelatedModels), the power ratings confuse me. Are the newer receivers less powerful? Other than updated HDMI audio, is it worth upgrading?

Thanks for the help!

OLD RECEIVER:
Rated Output Power (FTC)
All channels: 110 watts minimum continuous power
per channel, 8 ohm loads, 2 channels
driven at 1 kHz, with a maximum total
harmonic distortion of 0.9%
Rated Output Power (IEC)
7 ch × 130 W at 8 ohms, 1 kHz, 1 ch
driven
Maximum Output Power (JEITA)
7 ch × 160 W at 8 ohms, 1 kHz, 1 ch
driven
Dynamic Power 210 W (3Ω, 1 ch driven)
190 W (4Ω, 1 ch driven)
130 W (8Ω, 1 ch driven)
THD (Total Harmonic
Distortion) 0.08% (Power Rated)
Damping Factor 60 (Front, 1kHz, 8Ω)
Input Sensitivity and
Impedance 200 mV/ 47 kΩ (LINE)
Output Level and
Impedance 200 mV/ 470 Ω (REC OUT)
Frequency Response 5 Hz–100 kHz/ +1 dB–3 dB
(Direct mode)
Tone Control ±10 dB, 50 Hz (BASS)
±10 dB, 20 kHz (TREBLE)
Signal to Noise Ratio 100 dB (LINE, IHF-A)
Speaker Impedance 8Ω–16Ω

NEW RECEIVER:
All Channels 95 W (8 Ohms, 20 Hz-20 kHz, 0.08%, 2 channels driven, FTC)
115 W (6 Ohms, 1 kHz, 0.7%, 2 channels driven, FTC)
Dynamic Power 240 W (3 ohms, Front)
210 W (4 ohms, Front)
120 W (8 ohms, Front)
THD+N (Total Harmonic Distortion + Noise) 0.08% (20 Hz-20 kHz, Half power)
Damping Factor 60 (Front, 1 kHz, 8 ohms)
Input Sensitivity and Impedance 200 mV/47 k-ohms (Line)
2.5 mV/47 k-ohms (Phono MM)
Rated RCA Output Level and Impedance 200 mV/2.2 k-ohms (Rec out)
Maximum RCA Output Level and Impedance 2.0 V/2.2 k-ohms (Line Out)
Phono Overload 70 mV (MM, 1 kHz, 0.5%)
Frequency Response 5 Hz-100 kHz/+1 dB, -3 dB (Direct Mode)
Tone Control ±10 dB, 20 Hz (Bass)
±10 dB, 20 kHz (Treble)
Signal-to-Noise Ratio 106 dB (Line, IHF-A)
80 dB (Phono MM, IHF-A)
Speaker Impedance 6 ohms–16 ohms
 

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Not clear which ratings confuse you. You can ignore most of that stuff. Probably all of it. But I can attempt to clarify.

I always look at the power spec that shows from 20hz to 20khz into 8 ohms, two channels driven when it's there. I don't see that spec for either model. So we are stuck with their 1khz rating.

Older receiver
---
per channel, 8 ohm loads, 2 channels
driven at 1 kHz, with a maximum total
harmonic distortion of 0.9%

So it's at 1khz, which means the 20hz to 20khz figure will be lower. It's at .9% distortion, where 1% is often considered to be the point of audible clipping


Newer receiver
---
115 W (6 Ohms, 1 kHz, 0.7%, 2 channels driven, FTC)

There's an important difference here compared to the older receiver. It's rated into 6 ohms. That gives it a significant power advantage. THD is about the same, but the ohm rating indicates it has similar or maybe less power than the other one. The difference in actual SPL is probably slight.

Note that a 200 watt receiver vs a 100 watt receiver makes a difference of 3 dB SPL which is not much. So small differences in power are not that big of a deal. For example take Yamaha's cheapest receiver vs. most expensive. Maybe the most expensive has twice the power so a difference of 3 dB is expected. There might be other factors such as low impedance capability, but was trying to put this power thing into perspective.
 

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These are the sort of fun specs thrown in which don't mean much IMO

"Dynamic Power 240 W (3 ohms, Front)"

If you don't read the fine print of 3 ohms, you might think wow, this is a 240 watt receiver for miliseconds thinking of 8 ohms. But it's not 8 ohms, it's 3 ohms. It's more like a 240 watt receiver for miliseconds, into one channel ( until the caps drain and the voltage drops possibly to the point of clipping.)

I should note that I assume it's one channel dynamic, but because they say front it "could" be three channels driven. But again only for a brief time as dictated by however they measure dynamic power.
 

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Discussion Starter · #4 ·
So, I guess the better question is: is it worth the money to upgrade? Am I going to get a better sound out of the same speakers?

It is interesting to me that a HTIB from 2007, retailing for around $450 can have a receiver just as good as a $599 stand-alone receiver in 2014. I know video processing is upgraded (more HDMI inputs, cary audio instead of just passthrough), but what am I missing here?
 

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The new receiver has a way better feature set. I don't see those two receivers being in the same class at all. I don't see your older receiver being "just as good".

The 636 adds:

Analog to HDMI video conversion
Marvell QDEO video scaler
HDMI audio
networking/internet radio
dual HDMI outputs
Zone 2 capability
Wireless and Bluetooth
USB input
Larger power supply
 

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Discussion Starter · #6 ·
The new receiver has a way better feature set. I don't see those two receivers being in the same class at all. I don't see your older receiver being "just as good"

Point taken. If I narrowed it down just to audio output vs. audio output, looking at that alone, is it safer to say they are still comparable?

Thanks everyone for all the good input!
 

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FWIW I a long time ago far far away I was involved in
servo system amplifiers. These were military monsters
but basically the same design as Audio Class A/B
amplifiers. "What's the frequency response" was just
as much of an issue there. But, per the dictation of
my Boss ( General Electric Mil Division ), the first
thing you measured was the frequency response of the
power supply of the amplifier. With a little
calculation you replaced the power supply reference,
lets call it a zener diode, with a sweep frequency
generator. You'd then put the power supply under the
anticipated max load and sweep it from say 10Hz to
20Khz. How the power supply held up under that was
the basic frequency response of the amplifier.
Another thing you looked at was the ripple on the
power supply rails when the thing was put back into
normal operation. If I remember right if the power
supply had more then 1% ripple sweeping through
10hz -> 20Khz at full load it was back to the
design table.
 

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With most power supplies in AVRs, it seems they are unregulated so I presume the designers have to over voltage them to some extent to cope with losses and perhaps the fact the power supply is not regulated.
 

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So, I guess the better question is: is it worth the money to upgrade? Am I going to get a better sound out of the same speakers?

It is interesting to me that a HTIB from 2007, retailing for around $450 can have a receiver just as good as a $599 stand-alone receiver in 2014. I know video processing is upgraded (more HDMI inputs, cary audio instead of just passthrough), but what am I missing here?
The old receiver has a power consumption of 5.9A vs. 6.3A for the new one. Since the old one was from a receiver/speaker package and would probably be compared by the consumer with the typical htib which often had "1000 Watts of Total Power!!" plastered all over the front (more like 100 watts of total power) Onkyo must have fudged the numbers of the HT-800 as much as they could to at least sound competetive. The 60x series receiver of the same period as the HT-800 (which the 550 was very closely related to) was normally listed as 90 wpc. That's the number you should use to compare to the 636's 95 wpc.

5.9A----90 wpc

6.3A----95 wpc

The 550 was rated at the flywheel (130 wpc)

The 636 at the rear wheels (95 wpc)

Basically the same engine.
 

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I agree with Michael here yet again with regard to these specs that don't add up to much; unfortunately, Onkyo is infamous for doing this, especially with their HTiB products...once you see specs that are rated in "one channel driven" or at some other specified ohm rating much lower than 8, you can begin to get suspicious about any power claims the manufacturer is making. Onkyo for the longest time was rating their standalone receivers as "two channels driven at 8 ohms" (for most North American market products) but with their AVRs that come with the HTiB packages, these specs got really foggy -- suddenly, wattage ratings that would seem to make a flagship receiver blush were slapped on cheap packaged systems and that's suspect right there...the thing is, Onkyo was rating these as ONE channel driven at a ridiculous frequency and ohm spec, all of which inflates these power ratings due to current demand (don't wanna get too technical here)...


Take these power ratings -- is the bottom line -- with a grain of salt; the best thing you can do is hook a receiver up to given speakers and LISTEN to them, seeing if you can achieve your SPL numbers in YOUR room without distortion or strain...
 

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Just for yuks I pulled out an old Crown D-60 AMP
and once it got going ( bridged mode ) I pulled
the AC power cord. It takes 4 or 5 seconds before
it actually stops working. Tell you something
about the power supply?
 

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Just for yuks I pulled out an old Crown D-60 AMP
and once it got going ( bridged mode ) I pulled
the AC power cord. It takes 4 or 5 seconds before
it actually stops working. Tell you something
about the power supply?
My dual mono B&K EX 442 Sonata amp does the same thing. Of course it has 4 soup can sized power supply capacitors in it.
 

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I was looking at the schematic for my Z7 the other day. The power supply for the amps was using two 1800 uf caps.

But they are not designed to be batteries. They are designed to smooth the voltage from the secondary. Presumably they manage at that role
 

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Just for yuks I pulled out an old Crown D-60 AMP
and once it got going ( bridged mode ) I pulled
the AC power cord. It takes 4 or 5 seconds before
it actually stops working. Tell you something
about the power supply?
Tells me it has one. How fast the rails collapse depends upon many things like bias current, drop-out voltage, supply capacitance, if there are bleeders to discharge the caps (and what value), etc. Some amps mute the inputs and kill the output bias immediately so there is no correlation between supply capacitance and how long it takes to "stop working".
 

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Interesting points, Don. So the discharge time could be totally due to the RC time constant due to the bleeder resistor?
 

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I was looking at the schematic for my Z7 the other day. The power supply for the amps was using two 1800 uf caps.

But they are not designed to be batteries. They are designed to smooth the voltage from the secondary. Presumably they manage at that role
Ever look at the complex circuit equiv for a tant capacitor?
It don't do so well at high frequencies. If my memory
still works for me I remember having to drop additional
caps across the tants to smooth the high frequency
delivery from the power supply. Note: it's been awhile
since I did this stuff so I'm not up to speed on what's
being done in the latest gear. Batteries also don't
do well at high freq. It least they didn't used to.
 

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I guess what I poke'n at here are the newer amplifiers
( Class D ) less susceptible to power supply perturbations
then the old Class A/B designs? Thanks
 

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Interesting points, Don. So the discharge time could be totally due to the RC time constant due to the bleeder resistor?
Well, anything's possible, but usually bleeders are very high in value so probably not. What usually sets the discharge is the bias current and capacitor values. The main point was that there are many variables. A class-A amp might discharge much faster than a class D amp, for instance, but that doesn't really say anything about the power supply's relative merit. Or much of anything else.
 

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Ever look at the complex circuit equiv for a tant capacitor?
It don't do so well at high frequencies. If my memory
still works for me I remember having to drop additional
caps across the tants to smooth the high frequency
delivery from the power supply. Note: it's been awhile
since I did this stuff so I'm not up to speed on what's
being done in the latest gear. Batteries also don't
do well at high freq. It least they didn't used to.
Yes. For audio power bypass they are decent enough though have other drawbacks and do not make good coupling capacitors. Of course, designing a power supply that deals with multi-GHz signals is a little different than designing an audio power supply, but the concepts are the same.
 

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I guess what I poke'n at here are the newer amplifiers
( Class D ) less susceptible to power supply perturbations
then the old Class A/B designs? Thanks
Class D amplifiers are usually more sensitive to the power rails than conventional designs. You are switching between the power rails so any perturbations on the rails is sent on to the output.
 
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