Taking the load off the RX-A3040 - Small Class D 4-channel Amp for Height Speakers Recommendation

[Fried Chicken]

The amplifier does not, the input signal does and that goes back to the sound engineer's mix desk. An amp will put out the dynamic of the signal fed to it. So the average volume on the surround channels is way lower than the front three over time. Now a fall of just 3 db. halves the power requirement to any channel. The power to the surrounds is of the order of at least 20db. lower than the fronts over time. So the power provided by the surround amps is miniscule compared to the fronts.

So reducing the load on an AVR requires providing amps for the front three channels.

Hmm;

this is true. They don't really need much for the heights.

I already have the load off the two fronts, but that's still maxing the amps capabilities driving 9 channels

You seem to have you heart set on a used fosi v3. So why ask here for advice?

Not at all. Anything cheap that won't heat the room and won't sound noticeably problematic. This was just the cheapest that came up on Amazon.

I think I saw his review. I think the bottleneck for all the cheap class D amps is the power supply, so it's literally a matter of sourcing a good one

 

[TLS Guy]

Hmm;

this is true. They don't really need much for the heights.

I already have the load off the two fronts, but that's still maxing the amps capabilities driving 9 channels


Not at all. Anything cheap that won't heat the room and won't sound noticeably problematic. This was just the cheapest that came up on Amazon.

I think I saw his review. I think the bottleneck for all the cheap class D amps is the power supply, so it's literally a matter of sourcing a good one

I think that is likely beyond your budget. If you listen at a lower volume, that will solve your issue and cost nothing. Every time you advance your volume 3db. your are doubling the power required of your receiver.

 

[Fried Chicken]

I could also just remove the height speakers entirely; I'm not sure they do anything, and I can't help but think it's a waste of time/money/effort

 

[3db]

@Fried Chicken Please answer the questions I asked you. I feel like you’re rushing in to get additional amps for the sole reason that you want, not need more amps. I have a RX-A3060 driving 8 PSB speakers and I’m barely tapping into the power of the AVR. While exercising, all 8 channels are driven in 9 channel stereo and the AVR is barely breaking a sweat.

 

[Fried Chicken]

@Fried Chicken Please answer the questions I asked you.

Oh easy; I was watching a blu-ray (hans zimmer live in prague) and the rx-a3040 was cooking.

I also believe in more power headroom: the only consequence to more power is the burden on your wallet.

I opened up the RX-A3040 and only saw 2 x 33000µF filter capacitors. My front amp for only 2 channels has 4 x 33000µF. The RX-A3040 can drive 4.5x as many channels with only half the filter capacitance.

That constant drain on the filter caps also leads me to believe I'm more exposed to powerline voltage fluctuations and so I've even considered a power conditioner.

Also when playing that blu-ray (where the receiver was cooking), I thought the sound quality was ass and not the glorious that I expected. I actually have a separate 5-channel receiver I can use as an amplifier, but it's AB and that's just another room heater I don't want in my system.

 

[3db]

Oh easy; I was watching a blu-ray (hans zimmer live in prague) and the rx-a3040 was cooking.

I also believe in more power headroom: the only consequence to more power is the burden on your wallet.

I opened up the RX-A3040 and only saw 2 x 33000µF filter capacitors. My front amp for only 2 channels has 4 x 33000µF. The RX-A3040 can drive 4.5x as many channels with only half the filter capacitance.

That constant drain on the filter caps also leads me to believe I'm more exposed to powerline voltage fluctuations and so I've even considered a power conditioner.

Also when playing that blu-ray (where the receiver was cooking), I thought the sound quality was ass and not the glorious that I expected. I actually have a separate 5-channel receiver I can use as an amplifier, but it's AB and that's just another room heater I don't want in my system.

How big is your room, how loud were you playing, and what type of speakers are you driving? Did you have and DSP settings turned on inadvertently? Was YPAO engaged? Do you have the impedance selector set to 4 ohms or 8 ohms?

 

[Fried Chicken]

I am not new to this.

I'm looking for recommendations on inexpensive Class D amplifiers, not anything else. Ideally 4-channels b/c I don't like having little boxes floating around, I have enough already.

 

[TLS Guy]

Oh easy; I was watching a blu-ray (hans zimmer live in prague) and the rx-a3040 was cooking.

I also believe in more power headroom: the only consequence to more power is the burden on your wallet.

I opened up the RX-A3040 and only saw 2 x 33000µF filter capacitors. My front amp for only 2 channels has 4 x 33000µF. The RX-A3040 can drive 4.5x as many channels with only half the filter capacitance.

That constant drain on the filter caps also leads me to believe I'm more exposed to powerline voltage fluctuations and so I've even considered a power conditioner.

Also when playing that blu-ray (where the receiver was cooking), I thought the sound quality was ass and not the glorious that I expected. I actually have a separate 5-channel receiver I can use as an amplifier, but it's AB and that's just another room heater I don't want in my system.

If you are really heating that Yamaha up like you say, then you are playing it very loud. I would suggest using a cooling fan.

Now I am going to have one more attempt at explaining this, as I don't think your receiver is all that may be 'fried' here.

Now you have an older receiver, 12 years, and for a receiver that is getting old, and therefore likely towards the end of its useful life, so you do need to be cautious and NOT heat it up unduly.

Now that receiver is rated at 150 watts into 8 ohm 2 channels driven. The one channel rating is 230 watts. So I think we can say that the power supply can provide at probably something like 400 watts spread between 9 channels. They don't have an all channels driven rating, but I'm going to make an educated guess that if you drove all 9 channels you would get something like 45 watts per channel plus minus a small insignificant amount.

However, program is not like a test bench, and unless you drive it hard in all channels driven mode, which you should not, the speakers other than the fronts will be taking little power. If the unit is on but with no sound, then the power consumption is 45 watts, so 5 watts to each of the nine power amps.

It will make no difference if you disconnect the speakers as the unused channels will still consume 5 watts each.

Now loudness is log and not linear. 3db. increase in apparent volume is about the minimum you can easily detect. However that doubles the power output from the device. That is why loudness kills.

If you think you need more power, then you need powerful external amps, if your speakers can handle it. Small Fosi amps will add nothing significant.

Achieving concert hall dynamics is a formidable and costly undertaking.

That is what it takes to get significantly louder then 300 watts, the 3000 watts you see there. However, that is only 3db louder than 300 watts, but gives decent headroom.

 

[Fried Chicken]

Listen.

I understand fully. I understand the relationship between dB and power. I understand the relationship between the stated 2-channel output, and true output with the all-channels-driven. I understand that mixing does not load 4 height channels strongly, and where the center or some surround channel might face 90 watts, the heights will maybe get 10 watts.

If I were gravely concerned about power, I would get a separate multi-channel power amplifier. I am not that concerned. All I'm seeking is a middle ground between getting a separate multichannel power amplifier and simply leaving it all to the 9 output channels of the RX-A3040. $200 for four channels of shitty class-d amplification is a small price to pay, for a small expected yield.

You say the 5 watts idle is insignificant, but over 4 channels that's already 20 watts. Add 10 watts to drive each channel, and it's already 60 watts from my precious 400 watts. (BTW I think you're vastly oversimplifying how an amplifier divides power between channels, but it's also not my area of expertise, so I'll run with your assumptions).

So I ask again: recommendations for inexpensive not-too-shitty 4-channels of class D amplification, please.

 

[TLS Guy]

Listen.

I understand fully. I understand the relationship between dB and power. I understand the relationship between the stated 2-channel output, and true output with the all-channels-driven. I understand that mixing does not load 4 height channels strongly, and where the center or some surround channel might face 90 watts, the heights will maybe get 10 watts.

If I were gravely concerned about power, I would get a separate multi-channel power amplifier. I am not that concerned. All I'm seeking is a middle ground between getting a separate multichannel power amplifier and simply leaving it all to the 9 output channels of the RX-A3040. $200 for four channels of shitty class-d amplification is a small price to pay, for a small expected yield.

You say the 5 watts idle is insignificant, but over 4 channels that's already 20 watts. Add 10 watts to drive each channel, and it's already 60 watts from my precious 400 watts. (BTW I think you're vastly oversimplifying how an amplifier divides power between channels, but it's also not my area of expertise, so I'll run with your assumptions).

So I ask again: recommendations for inexpensive not-too-shitty 4-channels of class D amplification, please.

I have it right. Even if you add those amps, it won't change the Quiescent current. Each amp with no speaker connection will still draw 40 watts.

My point is that spending money on those amps will achieve nothing, absolutely nothing significant. If you really want to make a difference then you need a two or three channel power amplifier and power either the left or right speakers, or the front three. Anything else is a pointless financial outlay.

Your receiver seems to be doing what you want, and eventually it will need replacement most likely on the next five to six years. I would be putting money away to cover that event and not wasting money on an endeavor that will achieve absolutely nothing of any consequance.

 

[Fried Chicken]

Your receiver seems to be doing what you want, and eventually it will need replacement most likely on the next five to six years. I would be putting money away to cover that event and not wasting money on an endeavor that will achieve absolutely nothing of any consequance.

It's doing what I want and won't need replacement anytime soon

 

[TLS Guy]

It's doing what I want and won't need replacement anytime soon

Hard to predict. One day you will be enjoying it and the next day it will be a brick. These units are not repairable as a rule.

 

[lovinthehd]

Seems adding a center channel amp or replacing the M65 with a more powerful 3ch amp might be a thought, and/or just a cooling fan for the avr if indeed runs hot to the touch. Can't imagine adding amps for the surrounds over the mains, but there are many ways of going about that depending what you want to spend and how much power you want from them.

 

[Fried Chicken]

Hard to predict. One day you will be enjoying it and the next day it will be a brick. These units are not repairable as a rule.

Say that to my Hakko

 

[TLS Guy]

Say that to my Hakko

I doubt you will get very far with even that, as the boards are all surface mount by robot. The problem is that they are generally out of parts and boards in less than five years, which they should not be. The other issue is they don't publish service manuals which is a disgrace.

 

[3db]

For someone not new to this, your making all the rooky mistakes. Based on my system loads and it being only 2 years yonger than yours, it sounds like you have inadequate ventilation space around your AVR. My RX-A3060 has never cooked even when driving all 8 channels in to the mid 90 dbs. All my speakers are nominal 6 ohms dipping down to 4 ohms.

 

[Fried Chicken]

For someone not new to this, your making all the rooky mistakes. Based on my system loads and it being only 2 years yonger than yours, it sounds like you have inadequate ventilation space around your AVR. My RX-A3060 has never cooked even when driving all 8 channels in to the mid 90 dbs. All my speakers are nominal 6 ohms dipping down to 4 ohms.

Try the "Hans Zimmer Live in Prague" blu-ray, and crank it.

 

[AcuDefTechGuy]

Strange days, indeed. I just want to make sure you're okay. You didn't get concussed in a car accident or something, did you? Should we send help? A wellness check?

Haha. We can always agree on facts.

But we don’t have to agree on opinions.

Although by the end of yesterday, I almost felt like I was concussed because I had to do so many things nonstop for a family party. Then I went into my HT room before bed and watched for 2 hours and felt much better.

 

[AcuDefTechGuy]

I want numbers. I also want a technical understanding of how an amplifier can discriminate between channels.

I sold a Yamaha A4A and KEF R9 tower 5CH HT system to a client who had planned on buying a real powerful ATI 200x5 amp in the following year because of budget. He doesn’t use any subwoofers. So he sets the front L/R R9 towers as “Large”, which requires a lot more power than “Small”. But after 5 years, he realized that he didn’t even need any external amps. @TLS Guy said my client is a fool for not adding 200WPC power amps for his AVR and system.

Audioholics has a few articles on the subject of ACD.

If you still believe ACD and need more power for your speakers after reading the Audioholics articles, then get some real big powerful 200-300 WPC amps. Only problem is, the brand new real powerful amps cost a lot, not a few hundred. So maybe save up some money and buy a real powerful amp

I use ATI AT2005 200WPC and Bryston 9b3 200WPC (that retail $14,000 each) for all my speakers (including the 4 ATMOS ceiling speakers) for my dedicated 26’ x 22’ x 14’ HT. I don’t think my system needs all the power, but I just want it anyway.

It’s perfectly okay to want to add external amps. Just make sure the amps are real powerful amps.

 

[3db]

Try the "Hans Zimmer Live in Prague" blu-ray, and crank it.

It will still sound good. What speakers are you using, make and model?