See, this world (just as many other ones) is not always just as it seems.
I guess that in this world, especially when you are somehow considered a guest, you need to have a certain propensity for public relations and awareness of what you do and where you do it.
It's a bit utopian to think that a sort of merit that we recognize in someone's work is automatically worthy of so much attention as to be equally interesting for anyone else, especially when in some cases you behave like a sort of sidekick for someone who has completely different interests.
For these reasons, which are not at all cynical, but simply realistic in my view, I believe it will not happen.
Much less a sub-forum.
And this regardless of the objective value of the thing or the intellectual honesty of the our guests, which I do not doubt in the slightest.
It's just that, that's how the world goes, even if not always...
By the way, obviously you're not stupid at all.
I have not been able to find reasonably priced equipment (for me) to accomplish this task. However, even if the equipment is able to capture every detail of how the device works, which may or may not be true, there's a big difference when all of that data is plugged right into your nervous system and analyzed there vs having to pick it up conceptually and analyze it in your conscious mind.
What you're doing when you're listening is translating the qualities of that electrical device into a stream of information that is high bandwidth enough to carry enough data to the nervous system to have something to chomp on and in a way that it's used to making sense out of - the hearing.
I'm not in favor of either, but for now, I think the hearing will be more useful. When we have ai to analyze the absolute gargantuan amount of data in the Sonic stream or the electrical stream of data, then we'll make REAL gains. But it's just my opinion. I'm really not too familiar with all the devices that are available nor do I have the budget to buy them all or the know how to interpret all the data. I just know for example that none of them have been able to prove the utterly obvious Sonic differences that are indeed huge between different cables (whether they pick them up or not is a moot point thusly when you can't interpret the data), from interconnects to speaker cables and yet the ear picks them up without any trouble.
Not to mention, the data received by the ears is much more intuitively interpreted, it's not a big science, you just listen and compare your experience. It's hard to put into words, but it's not so hard to hear the differences. Unless they are subtle, but at that point the electrical equipment often offers limited insight too. Great for something like harmonic distortion though. Actually I really don't know, maybe the equipment is actually more useful in audio at the end of the day, it's just that I haven't been using it very much in my journey so far except for FR curves. I have heard a lot of things though!
AI will change everything, mark my words.
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I wish it was easy for me to digest what you are saying, but I'll do my best. I'm not up to speed with everything you wrote cumbb. 10s of posts behind. The diagrams are especially interesting. I will study and do my best to understand. I read it all, but certainly not understood or applied it all yet. In this case I don't understand why the bias should be positive voltage instead of 0 and moreover - different for 1 stage or 2 stage followers, but I'll try to figure it out. There's a lot for me to figure out ITT.
Anyway, I'm listening with driver transistors (BD441 BD442) on both channels now. One (right) has the original output transistors and the other (left) has BD441 BD442 as output transistors. The clarity and magic is mostly preserved in the left channel despite adding the driver transistors I believe (compared to single stage EF). The bass is much improved I believe especially while playing on the louder side. The break ups and distortions on max volume are almost gone but still present on the last maybe 9dB of my DAC/preamp. Still - it's flatter and less powerful than original transistors in terms of bass, but clarity, detail and nuance, especially in voices is greater. Meanwhile the right channel's bass (with driver BD441/442 and original output transistors) finally sees benefit from the large 20mF caps and it experiences no break-up on max volume except occasionally, rare busy tracks of synth bass on the last 3dB. The bass improvement is quite addictive since I listen to a lot of bass and electronic music.
Unless I play this amplifier very silently at night (which seems not to suffer the bad compression of the bass or only play the tweeter / headphones, I believe I will keep the driver transistors as this is more fun for me it seems, but I'll go back to single stage Emitter follower again most likely to make sure. With drivers the performance has less artifacts at max output, but most of the resolution and purity is there perhaps, although the comparison in this case is a bit rushed.
22mF(actually 20mF) PEH200 vs 2.8mF PEG227 (all 8 measured more or less exactly 2.8mF). Big ones are blacker, more silent (not talking about noise floor here but about music presentation), more analytical and the noise floor is so low I couldn't hear it with my speakers last I remember. The small ones have clearly hearable noise floor, but more emotion, warmer, I don't know about ultimate detail, but voices are more realistic and enjoyable, everything's smoother, but what I mean is not smothered rather more liquid, I don't think I'm loosing any detail, maybe even the opposite - the detail that was there before is still here, now more engaging and grabs your attention more. As I said - everything is quite a bit warmer. Surprisingly, the bass is actually better defined and more incisive and textured at least on the moderate/low levels I usually listen at (this seems to carry on on higher volume too - the bass seems better) which is very welcome! Overall preferred are the smaller ones in most if not all aspects. Well except of course in terms of having higher noise floor, which can be very significant with headphones.
I also replaced the C415 C416 with 2.8mF and found a significant (not as significant as PSU caps) sound improvement. How much more can this amplifier keep improving?
Attachments
Step by step;-)
The NAD still has a lot going for it. But it is a 5-stage amplifier, which has a two-stage complementary transistor push-pull, and I have described its problems often. And then there is the thesis, new to me as well, that silicon pnp sound terribly colorless, black and carbonized. Perhaps this also explains the early limitations with regard to the cleanliness and harmony of complementary push-pulls - not only the demonstrably different sound of equal components, the different sound of npn and pnp, but the enormous difference in sound between npn and pnp. So the NAD has early limits.
But it continues with sophisticated digital or real pp: https://www.diyaudio.com/community/threads/zero-feedback-impedance-amplifiers.42259/ or even final se - due to the choice of components. And not forget: tubes;-)
The 2 x 1.2 volts are also shown on the circuit diagram. These are the added base voltages of the two follower stages. Strictly speaking, you can measure the breakdown voltage at the transistor with a diode tester. The B-E voltage. You adjust this and your transistor runs;-) And the easiest way is to remove the entire bias network and replace it with just one trimmer. And then simply measure the voltage between its two legs, between the bases (see NAD circuit diagram) of the "positive" npn transistor (Q411) and "negative" pnp transistor (Q413). And if it is only one follower stage, then only 2 x 0.6 volts.
I now have the npn follower to run. The pnp only made me nauseous, sick. It may be good, as a "grandpa" and without teeth I can no longer tolerate any overtones and frequencies and material resonances (I never used to experience this stress) - teeth act like clocks in the entire organism, stabilizing it immensely. Without them, I am much more sensitive to frequencies and vibrations and moods. We are part of a frequency and electro-verse;-) I just have to test any pnp on the spot;-)
The NAD still has a lot going for it. But it is a 5-stage amplifier, which has a two-stage complementary transistor push-pull, and I have described its problems often. And then there is the thesis, new to me as well, that silicon pnp sound terribly colorless, black and carbonized. Perhaps this also explains the early limitations with regard to the cleanliness and harmony of complementary push-pulls - not only the demonstrably different sound of equal components, the different sound of npn and pnp, but the enormous difference in sound between npn and pnp. So the NAD has early limits.
But it continues with sophisticated digital or real pp: https://www.diyaudio.com/community/threads/zero-feedback-impedance-amplifiers.42259/ or even final se - due to the choice of components. And not forget: tubes;-)
The 2 x 1.2 volts are also shown on the circuit diagram. These are the added base voltages of the two follower stages. Strictly speaking, you can measure the breakdown voltage at the transistor with a diode tester. The B-E voltage. You adjust this and your transistor runs;-) And the easiest way is to remove the entire bias network and replace it with just one trimmer. And then simply measure the voltage between its two legs, between the bases (see NAD circuit diagram) of the "positive" npn transistor (Q411) and "negative" pnp transistor (Q413). And if it is only one follower stage, then only 2 x 0.6 volts.
I now have the npn follower to run. The pnp only made me nauseous, sick. It may be good, as a "grandpa" and without teeth I can no longer tolerate any overtones and frequencies and material resonances (I never used to experience this stress) - teeth act like clocks in the entire organism, stabilizing it immensely. Without them, I am much more sensitive to frequencies and vibrations and moods. We are part of a frequency and electro-verse;-) I just have to test any pnp on the spot;-)
Symmetry. The fewer teeth, the more important. Right-left and also top-bottom. More than 80 % of the upper teeth and less than 20 % of the lower teeth have an effect on the body - can also be tested with a tuning fork;-) Without teeth there is no more hunger - I would starve to death if I didn't eat according to habit. And much many more influences;-) Dentists don't know that. I almost died because of asymmetry of teeths;-)
They are vibrations and moods that also serve as carrier frequencies. Without teeth, communication in the body is much quieter.
It's like the difference between an amplifier and a follower too. With teeth a loud stable vibration, without teeth everything is quiet and has its own aura.
And different combinations of teeth sound and act different. I occasionally had a tuning that sounded like a Hiraga Classe A. And I was immediately transported 30 years back in time: I couldn't do anything with internet, for example, I was really in the mood and with the images and feelings of the 90s;-)
All is swinging, frequencies, waves...-)
They are vibrations and moods that also serve as carrier frequencies. Without teeth, communication in the body is much quieter.
It's like the difference between an amplifier and a follower too. With teeth a loud stable vibration, without teeth everything is quiet and has its own aura.
And different combinations of teeth sound and act different. I occasionally had a tuning that sounded like a Hiraga Classe A. And I was immediately transported 30 years back in time: I couldn't do anything with internet, for example, I was really in the mood and with the images and feelings of the 90s;-)
All is swinging, frequencies, waves...-)
Fascinating. I did a 11 day dry fast once. I did not feel hunger anymore after a few days, but I did start craving moisture after around 6. I'm lucky I still have all my teeth, but they're damaged after years of craziness that I went through and the jaws are pretty out of shape too - like most people's jaws and faces :> The Japanese are cooking up something to sprout new teeth, we'll see where this goes.
Enjoying the amplifier currently too much to do anything to it, but if I don't get too sleepy too early, I will try doing some studying and physical work on the amplifier.
Yes I noticed it too - everything is vibrating, cycling. I'm ok with it though. Quite fascinating.
Enjoying the amplifier currently too much to do anything to it, but if I don't get too sleepy too early, I will try doing some studying and physical work on the amplifier.
Yes I noticed it too - everything is vibrating, cycling. I'm ok with it though. Quite fascinating.
That sounds like a comparison of 1 piece 22 mF and 1 piece 2.8 mF.
Try putting a few 2.8 mF in parallel. And since we don't just have a basic education in electrical engineering, here's a selection that defines current differently. See if they sound different, and feel free to write about the differences, if there are any;-)
Attachments
![DSCN0605[1].JPG](/community/data/attachments/1266/1266315-1202a12d2795281c2a51f476075fd64d.jpg?hash=EgKhLSeVKB)
I can't get to grips with the esoteric scam and approach - this thread is absolutely weird.
You two seem to be true believers in your own doctrine, knowers without real knowledge - or you want to take other people for fools?
It's entertaining for a short while, but in the end it's just meant to spread stupidity, a belief.
This is really unfortunate, because the NAD amplifiers are actually all great.
#
If it is not possible to generate a separate subforum for cumbb, then at least a subforum with the heading esotericism.
Maybe cumbb can present its own audio amplifier design there - and doesn't have to run permanently on the same track, but can show something really serious.
I feel really sorry for the currently mistreated NAD amp, I feel sorry for it.
Regards,
HBt.
😢
You two seem to be true believers in your own doctrine, knowers without real knowledge - or you want to take other people for fools?
It's entertaining for a short while, but in the end it's just meant to spread stupidity, a belief.
This is really unfortunate, because the NAD amplifiers are actually all great.
#
If it is not possible to generate a separate subforum for cumbb, then at least a subforum with the heading esotericism.
Maybe cumbb can present its own audio amplifier design there - and doesn't have to run permanently on the same track, but can show something really serious.
I feel really sorry for the currently mistreated NAD amp, I feel sorry for it.
Regards,
HBt.
😢
The main problem is the mixture of half-truths and complete nonsense; at the same time, some of the attempts at explanation are not even given or are based on sheer ignorance.
There is a great lack of knowledge of physics and electrical engineering.
Nevertheless, I wish you both lots of fun with your handicrafts.
Let's call it by its name:
alternative electrical fiddling!
Tschüß,
HBt.
There is a great lack of knowledge of physics and electrical engineering.
Nevertheless, I wish you both lots of fun with your handicrafts.
Let's call it by its name:
alternative electrical fiddling!
Tschüß,
HBt.
Not sure if trolling or for real, but just in case, I will say this - my NAD sounded terrible relative to what I have now. Truly an amp of no interest in it's original form.
All the other audio related stuff I said I think was pretty reasonable. And if anything I think I'm probably the most open minded and eager to learn in this thread (if it's cables sounding different that you thought was controversial I don't think we have anything more to discuss audio related between us two - we are worlds apart). Maybe this thread just isn't for you, sir. Begs the question - why follow, read and post here if you do not resonate or find it useful...
Respectfully, for now let's just keep this clear - the original amp was a really poor quality amplifier in terms of sound. I have one and listened to it. My 2 cents.
All the other audio related stuff I said I think was pretty reasonable. And if anything I think I'm probably the most open minded and eager to learn in this thread (if it's cables sounding different that you thought was controversial I don't think we have anything more to discuss audio related between us two - we are worlds apart). Maybe this thread just isn't for you, sir. Begs the question - why follow, read and post here if you do not resonate or find it useful...
Respectfully, for now let's just keep this clear - the original amp was a really poor quality amplifier in terms of sound. I have one and listened to it. My 2 cents.
A
- comparison with the original state is no longer possible
- metrological before and after is also not available or correctly documented!
The question of why I'm paying attention to this thread is purely professional - and also because I'm both a NAD fan (that's what the 1980s student years bring) and a German, like cumbb.
So it's more or less a coincidence - but from a methodological (and of course didactic) point of view, this thread is really not recommended for teaching.
To be completely honest, I'm interested in cumbb's education and professional career - out of sheer curiosity.
But the nice thing about a forum is that everyone should be able and allowed to express themselves as they wish.
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As I said:
Please summarize clearly and with correct drawings what you have done to improve the sound of this NAD. Please also provide the necessary and usual measurements, i.e. a protocol. At the same time, a double blind test, a comparison with a non-abused, original NAD is necessary.
kindly,
HBt.
Sound is representable, i.e. measurable - only the associated subjective or medical perception lies outside my profession as an engineer.
I am interested in measurable facts.
The subjective experience of the sound, the pleasure or the disturbance, is another matter.
If the NAD sounds better to you now - Then I ask about the technical why!
Crafting is a great activity for boys and girls
For you, it's as much about fiddling as it is about improving the subjectively perceived sound. The amplifier is a popular victim. In other words, you must have noticed a shortcoming or believe there is one.
The wiring, the charging capacitors, the trimming potentiometers, the semiconductors ... you explicitly state the most absurd things, but the BDxxx BJT gizmo can be used as a direct hook again:
I'm just interested in why the BDxxx sounds better than the BDxxx from the other bag - in the correct technical and physical sense.
HBt.
For you, it's as much about fiddling as it is about improving the subjectively perceived sound. The amplifier is a popular victim. In other words, you must have noticed a shortcoming or believe there is one.
The wiring, the charging capacitors, the trimming potentiometers, the semiconductors ... you explicitly state the most absurd things, but the BDxxx BJT gizmo can be used as a direct hook again:
- Why is the BDxxx better sounding than the original type selected by NAD and why is the BDxxx with the same number from a different bag (manufacturer and batch) even better sounding than its BDxxx which has already been pronounced the ultimate
- How do you determine all this, just with your ears, fingers and eyes - or with measurable evidence
I'm just interested in why the BDxxx sounds better than the BDxxx from the other bag - in the correct technical and physical sense.
HBt.
Without proof, one can only take note of your statements.
At the very least, an attempt should be made to provide an understandable explanation.
Thats all,
bye
HBt.
😉
At the very least, an attempt should be made to provide an understandable explanation.
Thats all,
bye
HBt.
😉
If I understand what he’s done here correctly, he’s bypassed the original drivers and run BD441/2 as an EF1 output pair. On the positive half cycle, the beta-enhanced VAS will likely drive it just fine. More distortion, but nothing gross will happen. But on the negative side, you get beta times the VAS idle current and not one micro amp more. It should be current clipping long before you reach the -29V rail. Maybe that’s what’s saving it - put the drivers back in, rebias, turn it up and poof. In any case, like it is there will be a LOT of 2 HD. Maybe subjectively it sounds good, but not being able to get anywhere near full power ought to be noticeable.
As far as survivability, the 40w outputs might actually tolerate this. I’ve seen and repaired MANY low end Jap recievers claiming 30-ish wpc, that run a single output pair of 30W/4A Jap TO-220’s in EF2. They will run forever if the output is not shorted, into a single-driver 8 ohm speaker. Do anything more than just crack the volume control up to 8 o’clock with 4 ohm speakers (or dual drivers, or two pair) and you get POP - HUMMMMM, and are buying a new set of outputs and drivers. When they say “8 ohms minimum” they MEAN it. But for “normal” operation, it IS enough SOA.
I would expect that the same output mods on +/-50V (the other PA-940 thread) to go over like a LED Zeppelin.
As far as survivability, the 40w outputs might actually tolerate this. I’ve seen and repaired MANY low end Jap recievers claiming 30-ish wpc, that run a single output pair of 30W/4A Jap TO-220’s in EF2. They will run forever if the output is not shorted, into a single-driver 8 ohm speaker. Do anything more than just crack the volume control up to 8 o’clock with 4 ohm speakers (or dual drivers, or two pair) and you get POP - HUMMMMM, and are buying a new set of outputs and drivers. When they say “8 ohms minimum” they MEAN it. But for “normal” operation, it IS enough SOA.
I would expect that the same output mods on +/-50V (the other PA-940 thread) to go over like a LED Zeppelin.
👍
Perhaps @cumbb will draw a correct and complete circuit diagram, with paper and pencil if he like, as long as it is correct.