How to figure out amplifier class in my integrated amp?

R

rnaeye

Audioholic Intern
I have Yamaha RX-777 integrated stereo amplifier. How do I figure out what class amplifier it uses (Class A, A/B, etc)? Manual does not say anyhthing explicitly? Any pointers thanks.
 
Swerd

Swerd

Audioholic Warlord
rnaeye – welcome to Audioholics.

I'd be surprised if your Yamaha's amplifier sections were not class A/B. Most solid state audio amplifiers that are built into receivers are class A/B. Some more recent models have class D or G amps, but you can tell by their lighter weight and smaller size.

I don't know of any solid state amplifiers or receivers that are class A. I might be wrong about that, but it would be a rare bird. Is there a specific reason why you want to know? Or are you just curious?

By the way, your Yamaha RX-777 is a multi-channel Audio/Video receiver – a pretty decent one. Like all AVRs, it has built-in digital multi-channel processing (such as Dolby or DTX in movies), digital to analog conversion, AM/FM reception, and multiple amplifier channels (7 in this model). In audio, the term 'integrated stereo amplifier' means a 2-channel only device that lacks multi-channel digital processing and has no AM/FM radio reception.
 
Pogre

Pogre

Audioholic Overlord
rnaeye – welcome to Audioholics.

I'd be surprised if your Yamaha's amplifier sections were not class A/B. Most solid state audio amplifiers that are built into receivers are class A/B. Some more recent models have class D or G amps, but you can tell by their lighter weight and smaller size.

I don't know of any solid state amplifiers or receivers that are class A. I might be wrong about that, but it would be a rare bird. Is there a specific reason why you want to know? Or are you just curious?

By the way, your Yamaha RX-777 is a multi-channel Audio/Video receiver – a pretty decent one. Like all AVRs, it has built-in digital multi-channel processing (such as Dolby or DTX in movies), digital to analog conversion, AM/FM reception, and multiple amplifier channels (7 in this model). In audio, the term 'integrated stereo amplifier' means a 2-channel only device that lacks multi-channel digital processing and has no AM/FM radio reception.
I see it actually has a 2 ohm rating? That's pretty rare for a receiver. Is that right?
 
Swerd

Swerd

Audioholic Warlord
I see it actually has a 2 ohm rating? That's pretty rare for a receiver. Is that right?
Are you talking about the Dynamic Power ratings?
1618691699929.png

I usually don't pay any attention to those Dynamic power ratings, so I wouldn't know if that's rare or standard for Yamaha.

I only pay attention to the FTC power ratings, like this
1618691906131.png
 
Pogre

Pogre

Audioholic Overlord
Are you talking about the Dynamic Power ratings?
View attachment 46776
I usually don't pay any attention to those Dynamic power ratings, so I wouldn't know if that's rare or standard for Yamaha.

I only pay attention to the FTC power ratings, like this
View attachment 46777
Yes, the dynamic power rating was what I was talking about. I kinda caught the "dynamic" part after I asked you. Still tho, it implies 2 ohm capability, which is really pushing it for a receiver. Just another example of the confusing numbers games these guys like to play with specs. Like their 1 channel, 1 kHz rating also...
 
R

rnaeye

Audioholic Intern
rnaeye – welcome to Audioholics.

I'd be surprised if your Yamaha's amplifier sections were not class A/B. Most solid state audio amplifiers that are built into receivers are class A/B. Some more recent models have class D or G amps, but you can tell by their lighter weight and smaller size.

I don't know of any solid state amplifiers or receivers that are class A. I might be wrong about that, but it would be a rare bird. Is there a specific reason why you want to know? Or are you just curious?

By the way, your Yamaha RX-777 is a multi-channel Audio/Video receiver – a pretty decent one. Like all AVRs, it has built-in digital multi-channel processing (such as Dolby or DTX in movies), digital to analog conversion, AM/FM reception, and multiple amplifier channels (7 in this model). In audio, the term 'integrated stereo amplifier' means a 2-channel only device that lacks multi-channel digital processing and has no AM/FM radio reception.
I am mostly curious about it. I have purchased it several months ago on Ebay for $100 (I thought it’s better than paying for a new one for a first stereo amp). To my surprise, it’s fully functional, and I am very happy with it considering the price I paid. I use it to listen to stereo music.

One thing I do not like about is that if I forget it on, it does not go into standby automatically. I guess they did not bother with that reature ~15-20 years ago. There is 1h sleep function but inconvenient to use it. If I forget it on, it stays on forever. And I consider myself environmentally friendly (or at least trying to be). Its power consumption is rated as 260W. What does it mean? Does this mean that if the amplifier is idling i.e. I am not playing a music but it’s on, does it still consume 260W per hour or does the power consumption changes by the type of music I am playing etc. This might be very basic question for most, but I would like to know. Could you offer any information? Standby power is rated as 0.9W.
Thanks.
 
R

rnaeye

Audioholic Intern
I am mostly curious about it. I have purchased it several months ago on Ebay for $100 (I thought it’s better than paying for a new one for a first stereo amp). To my surprise, it’s fully functional, and I am very happy with it considering the price I paid. I use it to listen to stereo music.

One thing I do not like about is that if I forget it on, it does not go into standby automatically. I guess they did not bother with that reature ~15-20 years ago. There is 1h sleep function but inconvenient to use it. If I forget it on, it stays on forever. And I consider myself environmentally friendly (or at least trying to be). Its power consumption is rated as 260W. What does it mean? Does this mean that if the amplifier is idling i.e. I am not playing a music but it’s on, does it still consume 260W per hour or does the power consumption changes by the type of music I am playing etc. This might be very basic question for most, but I would like to know. Could you offer any information? Standby power is rated as 0.9W.
Thanks.
To be clear. This is RX-777. It is different than RX-V777.
rnaeye – welcome to Audioholics.

I'd be surprised if your Yamaha's amplifier sections were not class A/B. Most solid state audio amplifiers that are built into receivers are class A/B. Some more recent models have class D or G amps, but you can tell by their lighter weight and smaller size.

I don't know of any solid state amplifiers or receivers that are class A. I might be wrong about that, but it would be a rare bird. Is there a specific reason why you want to know? Or are you just curious?

By the way, your Yamaha RX-777 is a multi-channel Audio/Video receiver – a pretty decent one. Like all AVRs, it has built-in digital multi-channel processing (such as Dolby or DTX in movies), digital to analog conversion, AM/FM reception, and multiple amplifier channels (7 in this model). In audio, the term 'integrated stereo amplifier' means a 2-channel only device that lacks multi-channel digital processing and has no AM/FM radio reception.
 
Kvn_Walker

Kvn_Walker

Audioholic General
rnaeye – welcome to Audioholics.

I'd be surprised if your Yamaha's amplifier sections were not class A/B. Most solid state audio amplifiers that are built into receivers are class A/B. Some more recent models have class D or G amps, but you can tell by their lighter weight and smaller size.

I don't know of any solid state amplifiers or receivers that are class A. I might be wrong about that, but it would be a rare bird. Is there a specific reason why you want to know? Or are you just curious?

By the way, your Yamaha RX-777 is a multi-channel Audio/Video receiver – a pretty decent one. Like all AVRs, it has built-in digital multi-channel processing (such as Dolby or DTX in movies), digital to analog conversion, AM/FM reception, and multiple amplifier channels (7 in this model). In audio, the term 'integrated stereo amplifier' means a 2-channel only device that lacks multi-channel digital processing and has no AM/FM radio reception.
The RX-777 (no “V”) is a turn-of-the-century stereo integrated amp.


I have one sitting upstairs collecting dust. If I can ever find a remote control for it, I’ll sell it.

Pretty sure it’s a Class AB, because I don’t think Yamaha was selling any home AV gear in Class D back then, and it sure isn’t Class A because you can’t boil a pot of water on its top surface.
 
R

rnaeye

Audioholic Intern
I have one sitting upstairs collecting dust. If I can ever find a remote control for it, I’ll sell it.
If you sell it, someone else can enjoy it! Did you like it while you were using it?
 
lovinthehd

lovinthehd

Audioholic Jedi
Yeah I'd think your receiver is A/B....

As to your power consumption thing, hard to know what even the 260 represents (general, max, or what?). If you did have the newer avr, it probably spells out the various standby power consumption figures, new units use little (my newest avr only uses 5.1 W even with both hdmi-cec and network standby enabled, but only .1W in the disabled mode I use). I have seen specs on some older avrs that had a pretty high idle wattage when enabling hdmi/network standby...something like 45W on one unit I considered....can't remember which one that was, tho.
 
lovinthehd

lovinthehd

Audioholic Jedi
Thanks for the correction. I was looking at the V777. Yours has a 2 ohm dynamic rating too tho, lol.
Think it's fairly normal for Yamaha to do the dynamic ratings, don't know how they define it tho....
 
Pogre

Pogre

Audioholic Overlord
Think it's fairly normal for Yamaha to do the dynamic ratings, don't know how they define it tho....
Yeah, same BS they all do. It's definitely not out of the ordinary.

Does look like a decent integrated stereo amp tho. Good power. It's almost certainly A/B, which is not a bad thing. I see a trend toward more efficient designs lately, but by and large most consumer integrated and AV receivers are A/B from that era.
 
j_garcia

j_garcia

Audioholic Jedi
If it does not specify then you can expect it is AB because if it were class A then they would want to make sure you knew it.
 
P

PENG

Audioholic Slumlord
Yeah, same BS they all do. It's definitely not out of the ordinary.

Does look like a decent integrated stereo amp tho. Good power. It's almost certainly A/B, which is not a bad thing. I see a trend toward more efficient designs lately, but by and large most consumer integrated and AV receivers are A/B from that era.
The funny thing about just BS spec is that if you complain to their customer support, elevate your complaint to their engineering team and tell them you blew up the 2 Ohm rated RX-V385 after hooking it up to your 4 Ohm big tower speakers with dips to 2.5 Ohm, they might scream at you and might even call you stupid %^$%^#$)! etc.:D:D

RX-V385, for $280 from Crutchield, dynamic rating, 180 W, 2 Ohms!!

Jokes aside, surely they don't mean to mislead, but wording could have been clearer. Oops, sound like I am joking..:p
 
Eppie

Eppie

Senior Audioholic
The 260W consumption rating will be power usage at the rated 100W per channel into 8 ohms, so consider it a max rating. Any equipment that can be turned on and off with a remote control needs to have constant power, so there is a standby rating of 0.9W when the unit is 'off' (technically in standby mode). If you forget to turn the receiver off, I would guess the idle power consumption to be only 20 or 30W. No more than leaving a light bulb on. Most of the current draw will be from the amplifier section when driving speakers.
 
P

PENG

Audioholic Slumlord
I have Yamaha RX-777 integrated stereo amplifier. How do I figure out what class amplifier it uses (Class A, A/B, etc)? Manual does not say anyhthing explicitly? Any pointers thanks.
First, the verdict: It is a stereo receiver, not an integrated amp. The amps are of the class AB type based on what I could see in the manuals.

As to how you can figure out, without the manuals:

1) Consider the power to weight ratio. The RX-777 is rated 100 WPC, weighs only 21 pounds soaked and wet. So not class A. If class A, that thing would weigh at least 50 lbs, more likely 70 lbs or more.

To quote Nelson Pass:
PassDiy
"One pound of weight for every 2 watts is a good litmus test for evaluating Class A amplifiers. An amplifier weighing less might not be pure Class A. It might be almost Class A, or it might be one of the many products which achieve a Class A designation through trick circuitry."

2) The efficiency: this depends on how they specify the "Power consumption".
In this case, the power consumption is 200 (|Australia) to 260 W (US) but that's not always useful unless the specifications include the condition under which the consumption is based on, such as at rated output, or whatever. If it is say 260 W at rated output then that's another evidence that it is not class A, because the theoretical maximum efficiency would be 50%, much less in practice.

3) The heat:
Without external cooling, leave it on for an hour with the volume at minimum, if it doesn't get very warm (say >40 deg C) to the touch it is not class A.

If you combine 1) through 3), you can bet whether it is class A or not.
 
M Code

M Code

Audioholic General
The 8/6/4/2 Ohm Dynamic power spec is widely used in Europe and other international markets...
Since the audio market is now global the respective brands still mention this spec on their websites..

Just my $0.02... ;)
 
lovinthehd

lovinthehd

Audioholic Jedi
The 8/6/4/2 Ohm Dynamic power spec is widely used in Europe and other international markets...
Since the audio market is now global the respective brands still mention this spec on their websites..

Just my $0.02... ;)
Do you know what the parameters are, tho?
 
lovinthehd

lovinthehd

Audioholic Jedi
The 260W consumption rating will be power usage at the rated 100W per channel into 8 ohms, so consider it a max rating. Any equipment that can be turned on and off with a remote control needs to have constant power, so there is a standby rating of 0.9W when the unit is 'off' (technically in standby mode). If you forget to turn the receiver off, I would guess the idle power consumption to be only 20 or 30W. No more than leaving a light bulb on. Most of the current draw will be from the amplifier section when driving speakers.
At two ch spec?
 

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