I always taught (and read everywhere) Gain your source to about 3/4 maximum volume, then gain each device as it runs down the signal path. This way you less likely to be in the clipping zone of each unit. Also the signal to noise will be lower. Keep everything down and turn up the amp. I’ve experienced 90% of the time, it will raise the noise floor.
Maybe you should clarify that some class AB amplifiers can operate at class A at low output but not all of them. People will start listening to their amps at low volume, thinking it's operating in class A. The ones that can operate at class A in low volumes have to be designed to do so. They need a large enough DC offset and quiescent current to operate in class A at low levels. They also need a way to remove the DC offset from the signal e.g. using a capacitor or DC servo circuit so that it does not damage speakers. Only a few high-end amplifiers are designed that way. For the majority of class AB amplifiers, it remains in class AB at all volume levels. The output devices emitters are usually connected directly to the speakers or via the network of parallel inductor and a resistor (the reason why some amplifiers have no problem driving Planar speakers).
Q: Does volume and loudness impact bias levels ? A: Only if it's a really badly designed Class-AB circuit or the thermal sensing bias diode(s) are broken or loose on the heat-sink. Proper biasing is an internal design issue and has NOTHING to do with the end users "gain" and/or volume setting anywhere in the signal chain.
This all reminded me of one of those math questions in school; "If an orchestra of 10 takes 5 minutes to play a piece, how many would it take to play it in 4 minutes?" 🤨😂
Class AB amplifiers were invented to prevent crossover distortion as the current swing passed from positive to negative ... Class B amplifiers were widely used in early transistor radios where battery economy was of the main concern . There are several classes of AB amplifiers depending on the output devices that are employed.
I would say, that you are spot on 🙂 One thing I'm not so certain of, is the typical class used in preamplifiers. I own a Musical Fidelity The Preamp 2A, and the main PCB says "Pure Class A". Due to the low power demands from a preamplifier, this makes sense; it should be quite normal - but maybe isn't?
@@MC-bg7ro It is important to remember that "Class A" wasn't named that because it's *better*, even when it is, or claimed in flowing gold script. It is the most fundamental and the ordering is purely technical. There is some reason to use AB in a preamp if you want to drive any load or super long cables, but that would rarely be necessary, more likely in "pro" audio.
@@spentron1 Agreed: The naming is not important; the function however is. A sine wave is fully represented by one transistor in Class A (high set bias point). This is not the case in Class (A)B. A preamp is not a power amp, so demands for output power should be very low - in this concidered the input impedance of power amplifiers, which is high. Ok, "any" load. I seem to recall, that the mentioned Musical Fidelity preamp actually could drive speakers directly - at low volume of course. What is normal for (other) preamps, I do not know - that is why I asked.
If the volume control is before the DAC, information will be lost. Beyond that, the location of the volume control in the signal chain will affect S/N ratio, dynamic range, and distortion.
Just a thought: Inaccurate adjustment of output stage bias control (class AB) can cause severe low volume listening distortion (buzzing sound) - adjustment is critical!
Should it even matter when there are no standards in the recording industry for how loud a particular album sounds? It amazes me how much I have to correct the volume every time I change a recording.
Most engineers these days mix to 14-9ish LUFS and streaming services compress to 14 or 16 LUFS depending on the service. If a song is not that loud then it is unaffected by the streaming service's compression. That is the "standard" as far as I know. Direct download digital masters will preserve whatever LUFS the engineer mastered to assuming whoever provides the masters actually provides the original masters and not a different render (which is another issue when big labels provide the "masters.") Older stuff like MJ's Thriller on Tidal are so close to the masters I can't tell a difference in dynamics or fidelity when directly comparing to the master DSD. But I, like Paul, prefer having the amp turned up and use the streamer as a volume control (unless at my desktop then I use my rme interface out of habit with studio monitors amp turned up).
Is the NAD C 356B amp an AB? Cos mine gets hotter than my Audiolab 6000A amp (which I know is an AB). And aproximately what wattage is the changeover point, does it switch over just on power output (and changes over really quickly to keep up with the variation of output satisfactorily)? Or does it only change over after more constant loud passages, and not so much on sudden mometary higher wattage moments, when vastly most of it is soft? And is it true that I can listen to a class AB amp (under the changeover wattage) and it's like a pure class A amp in sound? Didn't realise how much I don't know! 😂
Not sure if I'm doing it correctly My streamer doesn't have a volume control Everything else is controlled from its phone amp I bypass its internal DAC with my external DAC that has a volume control I set that to almost 100% then I control the volume I want on my tube pre amp
An alternative method can work very well. First turn your pre-amp (Dac, streamer, etc) all the way up. Now put on some music Adjust your power amp gains to the loudest level you're likely to listen at. From there use the pre-amp volume control to manage your actual listening levels on a day to day basis. The advantage of this method is that you are far less likely to accidentally drive your power amp into severe clipping which can and does damage speakers. Then there is the secondary effect of not having the cops at your door about noise complaints.
For severel volume-adjusting steps, then go for the best low noise/low distortian setting. Normally it is pretty obvious when an amplifier starts clipping - your tweeters shout "help, save us". One just need to be a bit careful about this. If the cop should arrive at your door step, you could go "Nice uniforms. It wasn't me - I was annoyed as well. Have a great evening".
@@MC-bg7ro By the time you notice clipping it's severe, you probably have a hard time detecting minor clipping, it's would just be like a poorer quality recording. This is for class AB, class D is sharper clipping like falling off a cliff.
@@dwaynepiper3261 I agree; it can be subtle - at least for class A or AB. Thank you for the information with regards to class D, I did not know that. Back in the days, say the 80s, I recall that VU metre/LED metre, were quite commen - also clipping indicators. This is not typical anymore, or am I mistaken?
@@MC-bg7ro Clipping is seldom obvious until you are overdriving so wildly as to clip the main content of your music (i.e. about 20% distortion) Your tweeters will give up the ghost long before you hear clipping.
Isn't the various Classes (A, AB, B, D) best explained from an output transistor view? I would suggest that the amount of drawn power at the 115V/230V inlet is a result, rather than an explanation.
@dwaynepiper3261 Clipping has all to do with the amps power surge. Since class D demands a lot less, it doesn't take a very large power supply to meet it's demands
@dwaynepiper3261 My Hypex Nilai modules draws a maximum of 525W at 4 ohms, and the power supply delivers a maximum of 800 watts (both per channel, monoblock design) Absolutely no issues with clipping!!
What if the input signal suggests "Hey, lets provoke this Class D amp to go over its capacity"? The tweeters will cry as the Class D amp gets familiar with Fourier series. Going into distortion, you would have a energy shift upwards in frequency - I can't really see why Class D should be superior in this area.
this is really weird beliefs. like I don't get it, people would spend thousands on audio, never looking at how the products differ? like this whole thing could be shown with a diagram of a class ab amp and the ac+dc levels pretty easily? that it doesn't matter to the amplifier stage where the levels change prior to it? instead of trying to act like that yeah a k&n filter is kind of like a supercharger and you need the hydrogen generator for the oxygen breakdown and that's like a turbo... like there's a sort of a faraway connection to reality, but it's just sort of and doesn't really make sense and thinking about it would be something like you'd want to avoid? even if you had ab amp with such a huge crossover region that you could hear music staying within it.
I always taught (and read everywhere) Gain your source to about 3/4 maximum volume, then gain each device as it runs down the signal path. This way you less likely to be in the clipping zone of each unit. Also the signal to noise will be lower. Keep everything down and turn up the amp. I’ve experienced 90% of the time, it will raise the noise floor.
Clipping typically occurs in the power amp section of the chain.
Learning audio is like watching a soap opera. You miss a day or two you have no clue what's going on.
In a way. The main thing is however that the only one that know what is best for you, is yourself.
We all have different preferences.
Maybe you should clarify that some class AB amplifiers can operate at class A at low output but not all of them. People will start listening to their amps at low volume, thinking it's operating in class A. The ones that can operate at class A in low volumes have to be designed to do so. They need a large enough DC offset and quiescent current to operate in class A at low levels. They also need a way to remove the DC offset from the signal e.g. using a capacitor or DC servo circuit so that it does not damage speakers. Only a few high-end amplifiers are designed that way.
For the majority of class AB amplifiers, it remains in class AB at all volume levels. The output devices emitters are usually connected directly to the speakers or via the network of parallel inductor and a resistor (the reason why some amplifiers have no problem driving Planar speakers).
One of those was Musical Fidelity P270, as I recall.
Q: Does volume and loudness impact bias levels ?
A: Only if it's a really badly designed Class-AB circuit or the thermal sensing bias diode(s) are broken or loose on the heat-sink.
Proper biasing is an internal design issue and has NOTHING to do with the end users "gain" and/or volume setting
anywhere in the signal chain.
Agreed - I found this very strange.
This all reminded me of one of those math questions in school; "If an orchestra of 10 takes 5 minutes to play a piece, how many would it take to play it in 4 minutes?" 🤨😂
@@PSA78 Perfect, impossible mix, haha.
Class AB amplifiers were invented to prevent crossover distortion as the current swing passed from positive to negative ... Class B amplifiers were widely used in early transistor radios where battery economy was of the main concern . There are several classes of AB amplifiers depending on the output devices that are employed.
I would say, that you are spot on 🙂
One thing I'm not so certain of, is the typical class used in preamplifiers. I own a Musical Fidelity The Preamp 2A, and the main PCB says "Pure Class A". Due to the low power demands from a preamplifier, this makes sense; it should be quite normal - but maybe isn't?
There is no crossover in class A to distort that is the difference between A & B with AB a compromise between both
@@dwaynepiper3261 Yes, a single transistor (Class A) vs two transistors (Class B/AB).
@@MC-bg7ro It is important to remember that "Class A" wasn't named that because it's *better*, even when it is, or claimed in flowing gold script. It is the most fundamental and the ordering is purely technical. There is some reason to use AB in a preamp if you want to drive any load or super long cables, but that would rarely be necessary, more likely in "pro" audio.
@@spentron1 Agreed: The naming is not important; the function however is. A sine wave is fully represented by one transistor in Class A (high set bias point). This is not the case in Class (A)B.
A preamp is not a power amp, so demands for output power should be very low - in this concidered the input impedance of power amplifiers, which is high.
Ok, "any" load. I seem to recall, that the mentioned Musical Fidelity preamp actually could drive speakers directly - at low volume of course.
What is normal for (other) preamps, I do not know - that is why I asked.
If the volume control is before the DAC, information will be lost. Beyond that, the location of the volume control in the signal chain will affect S/N ratio, dynamic range, and distortion.
How will information be lost?
Just a thought: Inaccurate adjustment of output stage bias control (class AB) can cause severe low volume listening distortion (buzzing sound) - adjustment is critical!
@2:50 -- Our host answers Per's question.
Should it even matter when there are no standards in the recording industry for how loud a particular album sounds? It amazes me how much I have to correct the volume every time I change a recording.
A window.
Most engineers these days mix to 14-9ish LUFS and streaming services compress to 14 or 16 LUFS depending on the service. If a song is not that loud then it is unaffected by the streaming service's compression. That is the "standard" as far as I know. Direct download digital masters will preserve whatever LUFS the engineer mastered to assuming whoever provides the masters actually provides the original masters and not a different render (which is another issue when big labels provide the "masters.") Older stuff like MJ's Thriller on Tidal are so close to the masters I can't tell a difference in dynamics or fidelity when directly comparing to the master DSD. But I, like Paul, prefer having the amp turned up and use the streamer as a volume control (unless at my desktop then I use my rme interface out of habit with studio monitors amp turned up).
Great explanation. Thanks Paul!
Is the NAD C 356B amp an AB? Cos mine gets hotter than my Audiolab 6000A amp (which I know is an AB). And aproximately what wattage is the changeover point, does it switch over just on power output (and changes over really quickly to keep up with the variation of output satisfactorily)? Or does it only change over after more constant loud passages, and not so much on sudden mometary higher wattage moments, when vastly most of it is soft? And is it true that I can listen to a class AB amp (under the changeover wattage) and it's like a pure class A amp in sound? Didn't realise how much I don't know! 😂
Not sure if I'm doing it correctly My streamer doesn't have a volume control Everything else is controlled from its phone amp I bypass its internal DAC with my external DAC that has a volume control I set that to almost 100% then I control the volume I want on my tube pre amp
An alternative method can work very well.
First turn your pre-amp (Dac, streamer, etc) all the way up.
Now put on some music
Adjust your power amp gains to the loudest level you're likely to listen at.
From there use the pre-amp volume control to manage your actual listening levels on a day to day basis.
The advantage of this method is that you are far less likely to accidentally drive your power amp into severe clipping which can and does damage speakers. Then there is the secondary effect of not having the cops at your door about noise complaints.
For severel volume-adjusting steps, then go for the best low noise/low distortian setting.
Normally it is pretty obvious when an amplifier starts clipping - your tweeters shout "help, save us". One just need to be a bit careful about this.
If the cop should arrive at your door step, you could go "Nice uniforms. It wasn't me - I was annoyed as well. Have a great evening".
@@MC-bg7ro By the time you notice clipping it's severe, you probably have a hard time detecting minor clipping, it's would just be like a poorer quality recording. This is for class AB, class D is sharper clipping like falling off a cliff.
@@dwaynepiper3261 I agree; it can be subtle - at least for class A or AB. Thank you for the information with regards to class D, I did not know that.
Back in the days, say the 80s, I recall that VU metre/LED metre, were quite commen - also clipping indicators. This is not typical anymore, or am I mistaken?
@@MC-bg7ro Yes just keep in mind VU meters are RMS not peak signal. I prefer amps with sensitivity input adjustment and/or clipping indicator.
@@MC-bg7ro
Clipping is seldom obvious until you are overdriving so wildly as to clip the main content of your music (i.e. about 20% distortion) Your tweeters will give up the ghost long before you hear clipping.
Isn't the various Classes (A, AB, B, D) best explained from an output transistor view?
I would suggest that the amount of drawn power at the 115V/230V inlet is a result, rather than an explanation.
th-cam.com/video/d8ug0NbaIds/w-d-xo.htmlsi=DUolt4Kn7nNmS7Oy
Per. Pronounced like the fruit, Pear.
Im-Per-ative 😂
Terri’s Class A, very hot! 😂
Close, if you get really short on the "r". It's quite abruptly pronounced. Best regards from Denmark.
I had to give this video the 👍!
All preamplifiers are made for a reason 💯👍 R. I. P. Sam Moore 🙏 Stax Legend 🎤🎶
The best preamp is a piece of wire. Passive preamp?
Thank God for class D, no clipping whatsoever and no heat issues + the best signal amplification = Win Win WINNING (the last to phrase Charlie Sheen)
How is there no clipping for class D? It clips much harder/sharper than class AB when exceeding its maximum capacity.
@dwaynepiper3261 Clipping has all to do with the amps power surge. Since class D demands a lot less, it doesn't take a very large power supply to meet it's demands
@@5starmaniac Look at any class D amp specs for power continuous and peak. There is no headroom. Now compare to a class AB.
@dwaynepiper3261 My Hypex Nilai modules draws a maximum of 525W at 4 ohms, and the power supply delivers a maximum of 800 watts (both per channel, monoblock design)
Absolutely no issues with clipping!!
What if the input signal suggests "Hey, lets provoke this Class D amp to go over its capacity"? The tweeters will cry as the Class D amp gets familiar with Fourier series. Going into distortion, you would have a energy shift upwards in frequency - I can't really see why Class D should be superior in this area.
Dam & Dave
@3:54 The direct answer to Per's question.
I hope Paul does not subscribe to his own advise when recording music at Octive Records.
x↦Bx +A.......
I believe he is speaking Class G. Arcam is big on Class G heard on an SA20 through some Sonus Faber's it was like eargasmic.
Class A is the best (according to audiophools) so keep the level so, that it doesnt go into AB mode.
😂😂Hilarious.
this is really weird beliefs. like I don't get it, people would spend thousands on audio, never looking at how the products differ?
like this whole thing could be shown with a diagram of a class ab amp and the ac+dc levels pretty easily? that it doesn't matter to the amplifier stage where the levels change prior to it? instead of trying to act like that yeah a k&n filter is kind of like a supercharger and you need the hydrogen generator for the oxygen breakdown and that's like a turbo... like there's a sort of a faraway connection to reality, but it's just sort of and doesn't really make sense and thinking about it would be something like you'd want to avoid? even if you had ab amp with such a huge crossover region that you could hear music staying within it.
@lasskinn474 Audiophools reasoning is a peculiar thing. But who needs hindrance by science, right ? Audiophoodoo is were it's at, apparantly... 😂
Debatable.. I'm a class D audiophool 😅
@@5starmaniac LOL! Same here.But when I start blasting it, it will turn into class Z. 😄
@@5starmaniac Great, haha 🙂
Class A is superior to Class AB.
Class A vs Class D is way more interesting.