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Stereo Amplifiers >$500 (Not Integrated)

amirm

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#61
I have not found any use for perception of loudness from sensitivity+power computations. Sensitivity ratings are not standardized and are mostly marketing specs. My rule remains: get as much power as you can. Don't convince yourself of needing less.
 

andreasmaaan

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#62
My last post about this. We're getting a little too deep into the weeds about acoustics on an amplifier thread.
Fair point. I’ll make this my last too :)

1/4 wavelength placement will result in boundary reinforcement, but this is only 94Hz for a 3' placement. So you get pretty much nothing about that.
Well, most speakers have a woofer placed less than 3’ from the floor. There’s your first 6dB, and for a floorstander with woofers closer to the floor that will typically be up to around 200Hz. Then you have an additional 12dB from front and side walls. This is likely to give 12-18dB below 100Hz in most situations.

re: critical distance, right at the critical distance you gain only 3dB. Closer than critical distance, you don't get even that.
I don’t have any idea what you mean here but we’ve already agreed to drop the discussion so I guess I’ll never know. The critical distance is the distance at which the SPL of the room’s reflections eclipses the SPL of the direct sound. In typical rooms it is very close to the speakers. Beyond the critical distance, it doesn’t matter much how far back one moves from the speakers - there is little reduction in SPL.

To put this in overly general terms: in typical rooms, the level at any point in the room is going to be barely lower than the level 1m from the speakers. No need for the inverse square rule here.

The limited vertical dispersion of many direct radiating speakers (such as an MTM) can and does push the critical distance much farther from the speaker than it would be for something with controlled dispersion, even in a small room. In my room, which has a 56 square foot opening into a hallway that extends teh effective length of over 50 feet, the critical distance is somewhere out past the back wall of the room, for better or worse.
This seems extremely unlikely and I’m not sure how you’ve reached this conclusion, but let’s agree to disagree.

It's probably fair to simply say that all rooms and situations will be different where acoustics are concerned.
Agreed :)

EDIT: I just tested my reasoning regarding critical distance in the room of my parents’ house in which i happen to be sitting right now. It’s a large open plan living/dining room leading to an open hallway on one side and a kitchen on the other.

At 1m from my mother’s portable Bluetooth speaker (placed 1m from the front wall, 70cm from the floor, and 1.5m from the sidewall), the average SPL of a highly compressed piece of electronic music at 1m was not significantly different from the average SPL on the other side of the room, around 4m away: 81dB to 83dB in both cases.

This is just using my iPhone and a Bluetooth speaker but I’ve always noted similar results in other rooms in the past using a calibrated measurement mic and test signals, ie the critical distance is not that great, and the SPL doesn’t decrease much beyond it.
 
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#63
Fair point. I’ll make this my last too :)
I don’t have any idea what you mean here but we’ve already agreed to drop the discussion so I guess I’ll never know. The critical distance is the distance at which the SPL of the room’s reflections eclipses the SPL of the direct sound. In typical rooms it is very close to the speakers. Beyond the critical distance, it doesn’t matter much how far back one moves from the speakers - there is little reduction in SPL.
Since this is at least arguably closely related across a significant number of frequencies, I'll make an exception from my "off topic" rule for this one point. :) Since the direct sound and the reflected sound are equal at the critical distance, you pick up 3dB from the additive effect. Closer in, though, you do not pick up 3dB over the direct sound. Farther out, you pick up more than 3dB since the reflected sound does not continue to decay, whereas the direct sound does. For example, 80dB(direct)+80dB(reflected)=83dB, but 83db(direct)+80dB=85.8dB. Thus, if you sit closer to the speaker than the critical distance, you do not get what amounts to a free doubling of amplifier power. In this example, you would get 1.8dB.

On the bright side, my amplifier tips are now so happily buried beneath the noise that there should be plenty of stock out there to be had before rabid audiophiles drive the prices to $1500 apiece... ;)
 

andreasmaaan

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#64
Since this is at least arguably closely related across a significant number of frequencies, I'll make an exception from my "off topic" rule for this one point. :) Since the direct sound and the reflected sound are equal at the critical distance, you pick up 3dB from the additive effect. Closer in, though, you do not pick up 3dB over the direct sound. Farther out, you pick up more than 3dB since the reflected sound does not continue to decay, whereas the direct sound does. For example, 80dB(direct)+80dB(reflected)=83dB, but 83db(direct)+80dB=85.8dB.
83+80=84.8dB, but otherwise ok, I catch your drift.

Thus, if you sit closer to the speaker than the critical distance, you do not get what amounts to a free doubling of amplifier power. In this example, you would get 1.8dB.
As the critical distance in a small room tends to be 1m or less, nobody in reality sits anywhere near it. The important calculations in small room acoustics are not about what's happening inside the critical distance or even near it, but about what's happening outside of it. And outside it, not much (in terms of SPL reduction with distance) is happening ;)
 
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#65
I’m boggled at the power requirements people are looking for. For me anything above 95db is alarmingly loud. For average listening I’m between 78-83 dB, my amp is hovering under 1 watt.

At levels above 100db hearing damage is a matter of minutes, not hours.
 
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#66
I’m boggled at the power requirements people are looking for. For me anything above 95db is alarmingly loud. For average listening I’m between 78-83 dB, my amp is hovering under 1 watt.

At levels above 100db hearing damage is a matter of minutes, not hours.
You're looking at average levels, which is a mistake. 80dB is as loud as a telephone dial tone. So if that's the AVERAGE level, and say it takes around 1 watt, then hitting symphonic peaks will still take over 300 watts to do it without clipping. Most people just clip off the transients and never realize it unless the amplifier has poor clipping behavior. Here's a good video of Alan Shaw of Harbeth being rather surprised by how much power his own speakers are using with a pair of (extremely expensive) CH Precision amplifiers that have a digital readout peak sample power meter.

There's a reason most high end amps don't have a simple $.50 circuit for a clip light. There are potentially many audiophiles who, somewhat sadly, have never heard their rather expensive systems reproduce music at realistic levels without clipping.

Given that the measured performance of most expensive amplifiers isn't anything better than many less expensive products, I think it makes more sense to just spend less and get more watts. For a brand new amplifier, the Monolith 2x200 is a great value, or some of the used PA gear I mentioned earlier. You need to go used to get under $500 unless you're happy with low power.
 
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andreasmaaan

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#67
You're looking at average levels, which is a mistake. 80dB is as loud as a telephone dial tone. So if that's the AVERAGE level, and say it takes around 1 watt, then hitting symphonic peaks will still take over 300 watts to do it without clipping. Most people just clip off the transients and never realize it unless the amplifier has poor clipping behavior. Here's a good video of Alan Shaw of Harbeth being rather surprised by how much power his own speakers are using with a pair of (extremely expensive) CH Precision amplifiers that have a digital readout peak sample power meter.

There's a reason most high end amps don't have a simple $.50 circuit for a clip light. There are potentially many audiophiles who, somewhat sadly, have never heard their rather expensive systems reproduce music at realistic levels without clipping.

Given that the measured performance of most expensive amplifiers isn't anything better than many less expensive products, I think it makes more sense to just spend less and get more watts. For a brand new amplifier, the Monolith 2x200 is a great value, or some of the used PA gear I mentioned earlier. You need to go used to get under $500 unless you're happy with low power.
Superb Pan Sonic track :)
 
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#68
I’ve some tunes to about the loudest I ever listen to, checking in a spl meter I have on a multimeter and also an iPhone app it says peak level about 86db A weighted. About 10 ft from speakers.

Maybe it’s not really doing a peak reading.

I pretty much only listen to music in the rock/pop category (broadly speaking). These recordings are all essentially peak limited, so play close to full volume all the way through.

I’ve often wondered if there is a benefit to having more power in a situation where the amp is operating on the lower side of its power rating.

On a classical record with full dynamic range represented I can see a full on section with a lot of bass needing the exponential power if you wanted a loud average level, but it seems like that would be scary loud.

An actual orchestra at full volume approaches loud rock concert levels, but I’ve found that level to be physically painful and can only attend concerts with earplugs. The levels found at the average amplified concert are irresponsible, hearing damage pretty much guaranteed without hearing protection.

I think there must be some genetic component to how loud of sound people can tolerate.

Exposure to sound over 120 dB is rolling the dice for immediate hearing damage.
 
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#69
I’ve some tunes to about the loudest I ever listen to, checking in a spl meter I have on a multimeter and also an iPhone app it says peak level about 86db A weighted. About 10 ft from speakers.

Maybe it’s not really doing a peak reading.

I pretty much only listen to music in the rock/pop category (broadly speaking). These recordings are all essentially peak limited, so play close to full volume all the way through.

Exposure to sound over 120 dB is rolling the dice for immediate hearing damage.
The meter is showing averages only. The average dynamic range is lower on some rock. However, on recording before the late 80s the average dynamic range of rock recordings exceeds classical music. And remember that say, DR10 is just an average. That does not deal with the loudest peaks. 120dB is not achieved by most systems, and would require over 1000W on most systems unless horns or other highly efficient speakers were in the equation. 115dB peaks are quite tolerable.
 

andreasmaaan

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#70
The meter is showing averages only. The average dynamic range is lower on some rock. However, on recording before the late 80s the average dynamic range of rock recordings exceeds classical music. And remember that say, DR10 is just an average. That does not deal with the loudest peaks. 120dB is not achieved by most systems, and would require over 1000W on most systems unless horns or other highly efficient speakers were in the equation. 115dB peaks are quite tolerable.
The vast majority of home audio speakers are passive 2-ways with 5" or 6" woofers and a port tuned to 40-50Hz.

These speakers are completely incapable of achieving peaks anywhere near 115dB @ 1m. Typically, such speakers hit Xmax at under 100dB. However, due to most domestic rooms having a critical distance of 1m or less as discussed above, this will result in SPLs close to 100dB at the listening position anyway.

No way these speakers will be hitting 115-120dB though.
 

RayDunzl

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#71
I’ve often wondered if there is a benefit to having more power in a situation where the amp is operating on the lower side of its power rating.
Nobody* knows.

<---- *has bigger than average amplifiers
 

RayDunzl

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#72
115dB peaks are quite tolerable.
I measured 116.9dB peak here with a "calibrated" drum solo (only a couple of seconds).

It was as if someone was smacking my speakers with a baseball bat, though it sounded like a kit in the room (loud). The baseball bat part I found intoleralble, since they aren't really made for it..

Whatever you read as "average", in my day to day experience here with a UMIK-1 and REW, add 15 to 20dB for a reasonable estimation of peak levels.

Listening to the HDRadio right now. Volume turned up a little.

Female vocal, acoustic guitar, harmonica, at the listening position:

75.7dB average over time, 92.8dB peak

1552350206256.png


Female vocal, electric guitar, electric bass, drums, slow bluesy stuff, same volume setting:

79.7 average, 95.6dB peak

1552350336333.png
 
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andreasmaaan

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#73
In general, 4 times the power required to driver the woofer to Xmax is a more than reasonable absolute maximum.

To illustrate, if 100W can drive a woofer to Xmax, 400W will drive it to 2 times Xmax. This is usually about the point at which the woofer will be permanently damaged (although it depends on the woofer of course - many midwoofers will risk permanent damage sooner).

So in such a case, it would be very safe to say that no more than 400W would be necessary (or indeed desirable).
 
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JW001

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#74
Yamaha A-S2000/A-S2100 Integrated Amplifier:
- http://i.nextmedia.com.au/avhub/pdf_yamahaas2000hfnov08.pdf?128701600396577735
Probably above your desired budget, but it's 100% balanced inside and with floating ground (amp's ground is not tied up to case's ground, so lower background noise, no ground-loops possible and less distortions at full power vs. similar amps with similar power specs).
A-S1x00/S2x00/S3x00 measures the same way and is also sharing the same internal schematic, only the no. of output transistors differ and, of course, output power and PSU/transformer are more powerfull as well.
A-S1x00/S2x00/S3x0 are using Circlotron technology and are using MOSFET in output buffer (overheating cause auto-decreasing the output power, so less worry about overheating defects); also, using several linear PSUs inside and lot of reservoir caps. Also, there's included a dedicated high-quality headphone amplifier around transistors and with 10uF input cap; separate PSU for the headamp as well. Several protections inside: DC-output for speakers, thermal protection for most power bridges, transformer, output transistors for each heatsink, over-current etc. Also, firmware upgradable not only for the inside DAC (on A-Sx100 models), but also for the microcontroller that takes care of the protection circuits and the relays inside.

Yamaha A-S700/A-S701/A-S800/A-S801 Integrated Amplifier:
- http://i.nextmedia.com.au/Assets/Yamaha_AS-700_Amplifier_Review_LoRes.pdf
- https://audio.com.pl/testy/stereo/wzmacniacze-stereo/2786-yamaha-a-s801
- https://audio.com.pl/testy/stereo/odtwarzacz-cd-wzmacniacz/2676-yamaha-cd-n301-a-s701
- https://audio.com.pl/testy/stereo/odtwarzacz-cd-wzmacniacz/1510-yamaha-cd-s2100-a-s2100
A-S70x/A-S80x measure the same way and is also sharing the same internal schematic. Also https://www.audioholics.com/amplifi...1-amplifier-review/yamaha-a-s801-measurements worth a read. These amps are using BJE/bipolar transistors in output buffer and dual PSU for entire amplifier, but separate smaller PSUs for DAC, preamp etc. Like most amp in this price-range, there's no dedicated headamp inside, just couple or resistors that creates a resistive divider, connected to the 6.3mm output jack. Several protections inside: DC-output for speakers, thermal protection for most power bridges, transformer, output transistors for each heatsink, over-current etc. Also, firmware upgradable not only for the inside DAC, but also for the microcontroller that takes care of the protection circuits and the relays inside.

BTW, if you like a bit of DIY, then you could have a look over https://www.neurochrome.com/lm3886-done-right/ and how well it measures (almost 100dB between fundamental and its 2nd harmonic!). Also, https://www.neurochrome.com/product/modulus-286-2-2/ and recommended PSUs, plugs wires and case might be even better.

P.S.: I do own A-S701 and I'm enjoying it. It can push over 2x130W RMS with less than 0.1% distortions on my 4-16 Ohms speakers, that would be over 100dB in my living room, so quite powerful.
Warm greetings to everybody at ASR!

How these two charts THD+N vs power can be reconciled?
https://www.audioholics.com/amplifi...amplifier-review/AS801Psweep2CH8ohm.jpg/image
and
https://audio.com.pl/images/9/3/5/45935-laboratorium-yamaha-a-s801-laboratorium3-audiocompl.jpg

Thanks!
 

JW001

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#75
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