Class A headphone amplifier

popiol667 wrote:

My title mate, give me some convincing arguments

What do you mean, buddy?
You're picking on because I found out that:

tytka wrote:

In my opinion, class D for headphones is more of a joke (unless on the phone).

tytka wrote:

On a preliminary comparison, yes, yes. However, to choose an amplifier that suits me sonically; however, I prefer it additionally
your listening experience. Unfortunately, the parameters alone do not say everything about the sound.

So I answer:
- Yes, for me it makes no sense to build a class D headphone amplifier. The headphone amplifier generates low output power, so you can go ahead and make it in a less efficient class. The more that in such an "uneconomical" class it is quite a simple device.
In general, I personally see class D in battery-powered equipment and in loudspeakers in large rooms and stages.

- This is how I can hear the difference in the sound of amplifiers and I think a lot of people can do it (though probably not in the way you think).
I sometimes repair an amplifier. After I fix it, I like to listen to one or two albums with it. I would like to point out that in a room whose acoustics I know well from everyday listening, and on speakers that I listen to on a daily basis, During such listening sessions, I often hear a certain difference in the sound between this amplifier and my private one, which I use every day. I just listen to an album that I know, which I have listened to many times on my own equipment, and during such listening (not listening too forcefully) I hear some differences in the exposure of certain sounds.
That's the way it is, and I feel good about it. What do you think about it is your business.

I share the opinion of the previous speaker. Little acoustic nuances in a well-known listening room ... are very much audible. A class "d" headphone amplifier ... a joke like my friend's ashes. But I will tell you that more than once I have wanted to somehow standardize these "blind" tests of audio equipment ... they would expose unfair treatments bought for a "T-shirt" or "cup" of advisors ... amplifying "better equipment in the listening rooms ...

To find out that "I can hear the differences" you should perform the A / B / X test. Otherwise, you could write that "I think I hear".

tytka wrote:

I would like to point out that in a room whose acoustics I know well from everyday listening, and on speakers that I listen to on a daily basis, During such listening sessions, I often hear a certain difference in the sound between this amplifier and my private one, which I use every day. I just listen to an album that I know, which I have listened to many times on my own equipment, and during such listening (not listening too forcefully) I hear some differences in the exposure of certain sounds.

As long as you know which amplifier is playing, you can only write: "I think I hear some differences many times".

tytka wrote:

That's the way it is, and I feel good about it. What do you think about it is your business.

No, it is not. Either poor hardware parameters, different conditions in which the compared hardware plays, or self-suggestion. Your statements contradict serious scientific research of human hearing. You make comparisons in a way that gives the possibility of self-suggestion and on the basis of them you draw erroneous conclusions "I hear differences".

tata30 wrote:

I share the opinion of the previous speaker. Little acoustic nuances in a well-known listening room ... are very much audible.

First of all, you need to check if they exist - with a blind test.

A lot also depends on the headphones themselves .. So what if someone will buy or make a very good quality amplifier and also buy some low-shelf earpieces. Then neither golden resistors, nor tubes, nor class A will help these ear muffs .. the amplifier will get hit by the owner.

And this is a fact that most studio projects, in "Studio" quotation marks, insult all dignity. I even encountered one performance of classical music recorded as if it was mean hip-hop from a garage studio in the basement of a huge block of concrete slabs. In addition, distortions wheezing on the vocals.

Piotrek608 wrote:

And this is a fact that most studio projects, in "Studio" quotation marks, insult all dignity.

Well, such times, care for the brand and quality does not count so much as profit and cost cutting.

ramrusazer wrote:

Piotrek608 wrote:
A lot also depends on the headphones themselves (...).

And here I fully agree.

I also subscribe to it.
My two pairs of fairly good on-ear headphones from different manufacturers provide a slightly different listening experience. (Although probably, someone will say that it is impossible, that it only seems to me and that it is a self-suggestion )

tytka wrote:

My two pairs of fairly good on-ear headphones from different manufacturers provide a slightly different listening experience. (Although probably, someone will say that it is impossible, that it only seems to me and that it is a self-suggestion )

The differences in the frequency characteristics of the headphones are quite large, so you should catch them, for example:

https://reference-audio-analyzer.pro/en/report/hp/beyerdynamic-dt-990-pro-250.php#gsc.tab=0
https://reference-audio-analyzer.pro/en/report/hp/grado-sr-80e.php#gsc.tab=0

PS. I do not know if these headphones are quite good, I chose those in the PLN 500-1000 range.

If someone has a pair of sk170 / sj74, I recommend this system: https://www.audiostereo.pl/topic/99587-wzmlif...e-sprzężeniem-prądowym-knutt-h-nygaard-hdp01/

ramrusazer wrote:

the 880s are the most fun to listen to

I think so too, I have DT990 600 Ohm version, I had Sennheiser HD600, "they went to the people". I cannot create audiophile, flowery sound descriptions, but for me, subjectively, the Sennheisers sounded "dry" (of course, they reproduced the sound incredibly faithfully), and the Beyerdynamic DT990 sound "juicy", the sound is pleasant, not tiring.

ramrusazer wrote:

As for the amplifier, I have a 2JK construction from EDW waiting in the queue

Now I don't listen to much on headphones, so I don't plan to build an amplifier, but once I wanted to build a headphone version of the iconic JLH 1969 (https://sound-au.com/tcaas/index-1.htm), there are a few threads on diyaudio. com, they write well about him. Class A amplifier, so simple that it can be folded into a "spider". On Aliexpress, a plate for a very "fancy" version is about PLN 36.

ramrusazer wrote:

Thanks because I'm looking for something easy to run. I don't feel like carving with some advanced designs or buying expensive amplifiers.

intentionally I didn't provide the address from this headphone project website (https://sound-au.com/tcaas/jlhphones.htm) because I don't like them. They differ from the original JLH design, with a +/- power supply and no output capacitor, and I have reservations about plugging expensive headphones directly into the amp. In the event of a failure, when a shorted transistor gives a constant voltage to the converter, then the headphones. I prefer the connection through the output capacitor, the more that with a load of 32 Ohm, 470 uF - fg 10Hz is enough, "stubborn" can be made of polypropylene, if someone does not like electrolytes.

romarcin wrote:

In the event of a failure, when a shorted transistor gives a constant voltage to the converter, then the headphones.

The problem to be bypassed with the security system of the headphones.

bb84 wrote:

The problem to be bypassed with the security system of the headphones.

of course you are right but i like the simplicity of the layout. The original JLH design runs on a single voltage, so even this "nasty" output electrolyte has "comfortable" working conditions because it is DC biased properly.
I love subjectively perceived good sound of music, but I'm not a "golden-eared audiophile", I don't "hear" capacitors (unless they are damaged).

romarcin wrote:

I am not a "golden-eared audiophile", I do not "hear" capacitors

Symmetrical layouts are made for a reason. For safety, I suggest you insert polypropylene capacitors.

Fimek wrote:

Eh there, it seems to me that the D class can also sound well with headphones.

As the name suggests, in the segment of headphone amplifiers, class D is up to ...

I made a similar construction over 10 years ago (I even put it on Elka), I was based on the schematics from SoundWest ESome something ... This is a good, classic design, warm sound, good dynamics and detail. Of course, the question about the model of the headphones used. By the way, these BD139 / 140 pairs give a lot of power (for headphones), the Australian author even wrote about driving 3W speakers. No heat sinks are needed for 32? headphones. And it's worth knowing where to reduce the gain level. The best point is the op-amp feedback resistor. Any advice on increasing the value of the output resistor can be put in your shoes. I remember that in the original system I could unscrew a maximum of 15% on the potentiometer, then it broke off.

yogi009 wrote:

This is a good, classic design, warm sound, good dynamics and detail.

I believe that this amplifier is characterized by a withdrawal of the stage, a summer sound but without a "glass" in the upper sonic range and compression of micro-details, which can be perceived as a so-called "detail".

popiol667 wrote:

I believe that this amplifier is characterized by a withdrawal of the stage, a summer sound but without a "glass" in the upper sonic range and compression of micro-details, which can be perceived as a so-called "detail".

Oh, watch out, purebred electronics are about to challenge you to audio-voodoo

ramrusazer wrote:

I will not describe the differences in the amplifiers, so as not to be accused of audiovoodo

After describing the difference in headphones, you qualify in excess

ramrusazer wrote:

As for the headphone amplifier, there are some headphones that require more power at the output of the amplifier.

Exactly, not every amplifier is able to "feed" headphones with a greater "appetite". There is an abundance of power here, I wrote only about its regulation, this element just came out in practice right after building the prototype.

At the same time, I do not agree with the statement about the stage being withdrawn, for me it was just the opposite, everything is nicely arranged in the panorama, the vocal in the front. The first album "Dżem" suddenly showed sounds that you would normally not listen to.

popiol667 wrote:

I believe that this amplifier is characterized by a withdrawal of the stage, a summer sound but without a "glass" in the upper sonic range and compression of micro-details, which can be perceived as a so-called "detail".

Yeah ??? Or maybe only, it seems to you, because after all:

popiol667 wrote:

On the other hand, the fact that you hear the difference in the sound of the two amplifiers shows that either of them (or both) are kicked. The parameters of amplifiers have long since exceeded the human perception capacity.

popiol667 wrote:

As long as you know which amplifier is playing, you can only write: "I think I hear some differences many times".

Sorry, I do not understand these contradictions in my friend.

tytka wrote:

Sorry, I do not understand these contradictions in my friend.

Why contradictions? Maybe I did a blind test?

I wrote some smashed dubs between my morning coffee and the shower, not even fully considering the point. If it weren't for you, there would probably have been some learned discussion on the page or more ...

If someone believes that one amplifier puts the vocal into the lead in relation to the other, or narrows the stage, then I suggest you read the materials describing the mechanisms of spatial hearing (e.g. Department of Multimedia Systems, Gdańsk University of Technology) and then draw appropriate conclusions. There are also very good materials on YouTube regarding the production of recordings.

In order for the differences in the sound stage to be heard, the amplifier would have to, for example:
a) introduce cross-channel crosstalk in an entire band or fragment
b) introduced a phase shift between the channels
c) introduced a delay in one channel
d) has an unequal frequency response
e) have different gains between the channels
f) have a built-in DSP processor

ramrusazer wrote:

I will not describe the differences in the amplifiers, so as not to be accused of audiovoodo ...

A colleague described the differences between the headphones in a visual way, translating this into the characteristics, one could probably justify that the increase of low frequencies in closed headphones "spoils" the impression of holography.

It is said that the system has very good dynamics, and in fact no one has tried to measure / calculate the dynamics of this system, SNR. Maybe it is at a lower level than a good signal source?

popiol667 wrote:

If someone believes that one amplifier in relation to the other puts the vocal in the lead, or narrows the stage ...

It is not a question of faith. If this were not the case, the development of new amplifier designs would have been pointless for a long time. Since everyone plays the same. I emphasize once again, there is no algorithm that would describe, for example, the timbre of the instrument. And not only an acoustic instrument such as a wooden cello, guitar or transverse flute. There isn't even an algorithm that accurately reflects the timbre of ... the Hammond organ. Currently, the greatest approximation to the natural acoustic color is achieved by recording and sampling. I had this American guitar in my hand, it emulated 16 sounds, from several types of guitars, through mandolin, banjo, to sitar. I think that at most 2-3 colors were similar to the original on stage. None of them in the studio.

yogi009 wrote:

It is not a question of faith.

Until you have done reliable research to prove the hypothesis, it is a matter of faith. This applies to every field of science. Otherwise there is only gibberish with withdrawn macro-details.

yogi009 wrote:

If this were not the case, the development of new amplifier designs would have been pointless for a long time.

In fact, everything has already been invented in the last century. The purpose of developing "new" amplifier designs is to make money. The casing is changed, marketing voo-doo is added to the same, reheated cutlet, for example: "10% better hologram effect, etc.".

yogi009 wrote:

I emphasize once again, there is no algorithm that would describe, for example, the timbre of the instrument. And not only an acoustic instrument such as a wooden cello, guitar or transverse flute. There isn't even an algorithm that accurately reflects the timbre of ... the Hammond organ.

Great and so what? Why do I need an algorithm? We recreate the waveforms of these instruments. They are relatively simple and undemanding (compared to other signals found in electronics). Does an amplifier make a difference whether it recreates the waveforms of a Hammond organ or an acoustic guitar? This and this is a signal that every well-designed amplifier will cope with faithfully reproduction.

BTW. Of course they are - e.g. devices from Kemper, Line6 Helix faithfully imitate effects, amplifiers, guitar speakers, so they probably have some algorithm.

The human hearing has been thoroughly examined thanks to reliable research methods. If you draw conclusions that contradict this research, it must be proved (by reliable scientific methods), otherwise someone else has the full right to say that you are telling a basket-opałki.

The presented system has been known for at least 40 years. If you reject romantic-mysterious-para-scientific advice such as: increase the R3 resistor by 157 ohms and the stage increases or transistor replacement gives better detail, then we are familiar with the book layout, which fulfills the purpose for which it was designed.

Blind tests often reveal the difference between the listener's expectations about the audio equipment and the theoretical advantage of one device over another. The oscilloscope and the measurement of the harmonic content in the output signal are only paper and soulless data, which in no way translate into our impressions during the listening session. As the saying goes, there are tastes and tastes - one likes the mother, the other likes a little girl. A similar situation occurs with regard to colors - each of us has our own preferences. For this reason, I believe that the statement that something is better because it has better quality parameters is wrong.

pawel83 wrote:

The oscilloscope and the measurement of the harmonic content in the output signal are only paper and soulless data, which in no way translate into our impressions during the listening session.

That's right, among other things, knowing which amplifier is currently playing has a much greater impact on our experience. Blind tests reveal that these devices cannot be distinguished from each other.

pawel83 wrote:

A similar situation occurs with regard to colors - each of us has our own preferences.

You're right, the only thing is that by increasing the depth of colors, you come to the point where the human eye is no longer able to distinguish between two adjacent colors, because the changes are too small. Information that the color depth is 40 bits is also soulless data, but from this information we know that manipulations on e.g. the least significant bit are imperceptible to the human eye.

popiol667 wrote:

You're right, the only thing is that by increasing the depth of colors, you come to the point where the human eye is no longer able to distinguish between two adjacent colors, because the changes are too small. Information that the color depth is 40 bits is also soulless data, but from this information we know that manipulations on e.g. the least significant bit are imperceptible to the human eye.

And what does that prove? That forty years ago a perfect amplifier was created and there is no point in improving anything? It's like with the Russian Lada, they created a perfect car right away and didn't fix anything for decades.