Thanks guys. Looking forward to more on that subject. The most memorable part was the whoosing sound the feedback discussion made as it flew over my head! But seriously, I learn a lot from your videos and eventually they will sink in! Cheers!
He actually explained it r e a s o n a b l y well considering that I for one would rather correct frequency response than "increase" it but I think it was just a choice of words for him. There are lots of discussions around the internet explaining NFB, it's quirks, hazards and benefits. To my ears if you like a silky smooth, friendly presentation pile it on but if you want to hear the inherent harshness of a cymbal crash or the true grit from a snare, I could go on, then play it raw dog with no NFB.
So funny, 25 years ago I was an electronics engineer. And now I''m listening to this and realizing, wait I know all of this :-) Completely forgot about it because I don't work with electronics anymore for years. It's all coming back now.
I can agree, feedback can be a concern. But, lots of great sounding audio products use feedback to get the output signal closer to the input signal for the best audio fidelity. Decades ago it became obvious that feedback can cause serious audio issues when poorly engineered yielding especially TIM distortion usually due to the feedback mechanism being with some latency. Then amplifier companies started focusing on slew rate. One test that can show horrible feedback issues is a simple square wave test. Rapidly rising/dropping signals can reveal poor feedback. I've seen some bad case in a brand new class D amplifier recently. BTW, the talk about pros and cons regarding servo subwoofers (they rely on feedback) sort of has quite a similar flavor to it.
Does anybody here remember the eighties and nineties when they had speakers that had a built-in microphone dangling in front of the speaker. I don't know if that was a form of feedback so the audio system could correct itself.
Looking forward to when you've got that studio set up to make real audiophile recordings. I have no idea how it will sound, but I'm sure it'll be great. Plus, it means there will finally be a PS Audio product I can afford!!
Nice video. But regarding the positive feedback comment : Look at what is the feedback in a ring oscillator. Secondly try reversing plus and minus of an opamp to see if it's oscillating.
You guys are on a role lately. I have been reading up about aplifiers and designs and was curious if you have a taken on positive current feedback in amplifier designs? It's something Nelson pass uses in some of his amplifiers such as the first watt f7. Or using big power fets in a class a amplifier with no degeneration resistors at the source that is common with bipolar transistor amplifiers? Thanks guys!
1:24 Are you saying "error signal" ? I'm not able to discern it. Thanks. And does an error signal behave as a noise cancelling wave form? I'm trying my best to understand stuff that is out of my depth. I understand that it's probably engineering 101 day one stuff but I'm an artist and never grasped higher math. Thanks. -✌🏼
Assume that you're the manager of a bar. You have a reference checklist of how much and what liquids to mix for a drink. Then you have a subordinate who makes the exact mistakes of pouring 20ml instead of 10ml or reverse etc predictably. Like say adding water or alcohol to the drinks. Now you are a super high sensitive manager who checks every drop the subordinate adds, I mean every microlitre. In spite of your subordinate being so crappy and uncontrolled, your drink is going to be perfect because of your constant feedback correcting his mistakes. Like you say pour 5ml instead of an actual 10ml when you know he will pour double. Now the high sensitivity of the manager is the gain of the amplifier and the crappiness of the subordinate is the non-linearity. Any deviation of the output from the reference voltage which is the error is now the amplifier input which would keep driving the output till the error goes to zero. An otherwise open loop output that an amplifier would have generated would be like a destroyed drink, would be now crystal clear audio because of your close monitoring. Hope this helps.
You compare the signal on the output with the signal on the input. Any difference is an error. In this way the error can be corrected by thr amplifiers
Hang on we in the valve /tube world have been saying this for years.. Feedback is a plaster to cover the faults.. When a amp can do incredible things without feedback then something has been done correctly.
I usually like to hear what was intended from the master recording. If added distortion was a thing for me, I would like a "distortion on/off" switch so I can turn it off for the music where it hurts more than it helps. But I agree with your point, it's true that for some music, adding even harmonic distortion makes it sound more live-like and musical. So give us the distortion button and you can keep it on all the time if you want and I'll probably mostly have it off.
@@ThinkingBetter - if you want to listen to what was recorded as intended, then you need the same speakers & amp that were used in mastering that recording. And the same room too.
@@Enemji Yes, true. Also, I can agree that for some music, adding distortion on top of the intended experience can make music sound better. Still, I pursue the cleanest signal as that works best for the music I like.
@@ThinkingBetter Let's keep in mind that he's talking about levels of distortion below your ability to hear, but still measurable. 0.1% distortion would be considered a terrible spec for an amp, but you can't even hear it that. Loudspeakers have more than 0.1% all day long. Saying that an amp with 0.02% THD is better than an amp with 0.04% THD is nonsense.
@@michaelturner4457 I'd say it's two purposes: get casuals more interested in high end, and promote the ps audio brand, with promoting their actual products I guess being a third but not quite as high priority. The smart thing about promoting higher end stuff to casual audiophiles is that ps audio is basically positioned at the entry level to high end, so it seems like very effective marketing. And it's the kind of marketing I like cuz it also hinges on educating the consumer.
Maybe he doesn't want to force those annoying midroll ads on his viewers. In the end, these videos themselves are the advertisement lol No need to do dual layer advertisement.
Paul understands _presentation_ ....there are things needing to mentioned for the lay man which these geniuses blow by. Paul is interjecting on our behalf. Making the message more palatable for the mortals.
@John Cunningham , I completely disagree. Chris & Darren are v e r y intelligent men. but public speech is not their strong suit. their solo videos were informative...but dry. i was asleep in 3 minutes. Paul helps keep them 'inbounds' .
Thanks guys.
Looking forward to more on that subject.
The most memorable part was the whoosing sound the feedback discussion made as it flew over my head!
But seriously, I learn a lot from your videos and eventually they will sink in!
Cheers!
He actually explained it r e a s o n a b l y well considering that I for one would rather correct frequency response than "increase" it but I think it was just a choice of words for him. There are lots of discussions around the internet explaining NFB, it's quirks, hazards and benefits. To my ears if you like a silky smooth, friendly presentation pile it on but if you want to hear the inherent harshness of a cymbal crash or the true grit from a snare, I could go on, then play it raw dog with no NFB.
So funny, 25 years ago I was an electronics engineer. And now I''m listening to this and realizing, wait I know all of this :-) Completely forgot about it because I don't work with electronics anymore for years. It's all coming back now.
Simply excellent explanation!
I can agree, feedback can be a concern. But, lots of great sounding audio products use feedback to get the output signal closer to the input signal for the best audio fidelity. Decades ago it became obvious that feedback can cause serious audio issues when poorly engineered yielding especially TIM distortion usually due to the feedback mechanism being with some latency. Then amplifier companies started focusing on slew rate. One test that can show horrible feedback issues is a simple square wave test. Rapidly rising/dropping signals can reveal poor feedback. I've seen some bad case in a brand new class D amplifier recently. BTW, the talk about pros and cons regarding servo subwoofers (they rely on feedback) sort of has quite a similar flavor to it.
Many of the most enjoyable and musical sounding amps I've ever heard have zero feedback. Audio Note Ongaku, First Watt SIT3, etc.
Does anybody here remember the eighties and nineties when they had speakers that had a built-in microphone dangling in front of the speaker. I don't know if that was a form of feedback so the audio system could correct itself.
Should I introduce negative feedback (to what ever degree) on my dscrt 741 in my LM388 20amp PSU? hmm, maybe I should find an oscilloscope
great guys
Sansui had claimed in their 70-80's amplifiers, "super feed forward" technology which claimed to eliminate distortion "before" it happens.
@Fat Rat I read it in the brochure for the 9090DB. Quite the beast.
Looking forward to when you've got that studio set up to make real audiophile recordings. I have no idea how it will sound, but I'm sure it'll be great. Plus, it means there will finally be a PS Audio product I can afford!!
There are already available some on their homepage
Can you explain feed-forward technology please?
Nice video. But regarding the positive feedback comment : Look at what is the feedback in a ring oscillator. Secondly try reversing plus and minus of an opamp to see if it's oscillating.
You guys are on a role lately. I have been reading up about aplifiers and designs and was curious if you have a taken on positive current feedback in amplifier designs? It's something Nelson pass uses in some of his amplifiers such as the first watt f7. Or using big power fets in a class a amplifier with no degeneration resistors at the source that is common with bipolar transistor amplifiers? Thanks guys!
You mean.... "on a roll". A role is a part in a play.
@@TheMirolab thanks. I wasn't aware grammar school teachers were present.
1:24
Are you saying "error signal" ?
I'm not able to discern it. Thanks. And does an error signal behave as a noise cancelling wave form?
I'm trying my best to understand stuff that is out of my depth. I understand that it's probably engineering 101 day one stuff but I'm an artist and never grasped higher math. Thanks.
-✌🏼
Assume that you're the manager of a bar. You have a reference checklist of how much and what liquids to mix for a drink. Then you have a subordinate who makes the exact mistakes of pouring 20ml instead of 10ml or reverse etc predictably. Like say adding water or alcohol to the drinks. Now you are a super high sensitive manager who checks every drop the subordinate adds, I mean every microlitre. In spite of your subordinate being so crappy and uncontrolled, your drink is going to be perfect because of your constant feedback correcting his mistakes. Like you say pour 5ml instead of an actual 10ml when you know he will pour double.
Now the high sensitivity of the manager is the gain of the amplifier and the crappiness of the subordinate is the non-linearity. Any deviation of the output from the reference voltage which is the error is now the amplifier input which would keep driving the output till the error goes to zero. An otherwise open loop output that an amplifier would have generated would be like a destroyed drink, would be now crystal clear audio because of your close monitoring. Hope this helps.
You compare the signal on the output with the signal on the input. Any difference is an error. In this way the error can be corrected by thr amplifiers
This dude reminds me of Spinal Tap. The scene where his amps went upto 11.
DONT TOUCH IT. No don’t even look at it
He also looks like the band member who was a "cucumber enthusiast."
Hang on we in the valve /tube world have been saying this for years.. Feedback is a plaster to cover the faults.. When a amp can do incredible things without feedback then something has been done correctly.
I don't want to listen to a piece of medical equipment....
2nd and 3rd harmonics in small proportional amounts sounds pleasant.
I usually like to hear what was intended from the master recording. If added distortion was a thing for me, I would like a "distortion on/off" switch so I can turn it off for the music where it hurts more than it helps. But I agree with your point, it's true that for some music, adding even harmonic distortion makes it sound more live-like and musical. So give us the distortion button and you can keep it on all the time if you want and I'll probably mostly have it off.
@@ThinkingBetter - if you want to listen to what was recorded as intended, then you need the same speakers & amp that were used in mastering that recording. And the same room too.
@@Enemji Yes, true. Also, I can agree that for some music, adding distortion on top of the intended experience can make music sound better. Still, I pursue the cleanest signal as that works best for the music I like.
@@ThinkingBetter Let's keep in mind that he's talking about levels of distortion below your ability to hear, but still measurable. 0.1% distortion would be considered a terrible spec for an amp, but you can't even hear it that. Loudspeakers have more than 0.1% all day long. Saying that an amp with 0.02% THD is better than an amp with 0.04% THD is nonsense.
Good for you
“Dude, it’s July!” .... If you know, you know!
With the proliferation of speakers with bizarre impedance curves feedback can save the day making an un-playable system work.
Videos must be at least 10 minutes long to maximize your RUclips Advertising revenue so please let him, and yourself talk a little longer, cheers.
Maybe he’s not in it for the money
i mean. thats not true anymore lol, but also yeah this channel doesnt make its money from advertising. hell, this channel *is* advertising
This channel is basically an ad for their products, isn't it.
@@michaelturner4457 I'd say it's two purposes: get casuals more interested in high end, and promote the ps audio brand, with promoting their actual products I guess being a third but not quite as high priority. The smart thing about promoting higher end stuff to casual audiophiles is that ps audio is basically positioned at the entry level to high end, so it seems like very effective marketing. And it's the kind of marketing I like cuz it also hinges on educating the consumer.
Maybe he doesn't want to force those annoying midroll ads on his viewers.
In the end, these videos themselves are the advertisement lol
No need to do dual layer advertisement.
my kind of nerds
Come on man. Let the man talk....
Paul understands _presentation_ ....there are things needing to mentioned for the lay man which these geniuses blow by. Paul is interjecting on our behalf. Making the message more palatable for the mortals.
@@googoo-gjoob they compliment eachother. They do a great job.
@John Cunningham , I completely disagree. Chris & Darren are v e r y intelligent men. but public speech is not their strong suit. their solo videos were informative...but dry. i was asleep in 3 minutes.
Paul helps keep them 'inbounds' .
@@googoo-gjoob where are those videos?
@@thunderpooch , above, in the description, click on *PS AUDIO*
then click on VIDEOS......scroll thru the past vids.....
People having a talk at the camera while wearing sunglasses still annoys me, especially when the glasses reflect the surroundings.
YMMV.
Get over yourself and your personal pet peeves.
@@thunderpooch
Get over yourself and your personal pet peeves.
@@QoraxAudio Uh, no. You being pedantic isn't a pet peeve.
@@thunderpooch Uh, no. You being pedantic isn't a pet peeve.
@@QoraxAudio You copy me because I'm a God to you. 🤷