no Stefanoo
we can't be good
I'm just envy of your knowledge , overall brilliance , good manners ....... and wallet
so , do not worry , I'll be hiding in corner ....... drooling ......... and just writing here and there , to remind all participants how Great are all your Qualities
we can't be good
I'm just envy of your knowledge , overall brilliance , good manners ....... and wallet
so , do not worry , I'll be hiding in corner ....... drooling ......... and just writing here and there , to remind all participants how Great are all your Qualities
Attachments
checkin out
Okay, now we're getting somewhere, output power has nothing to do with the sound quality of an amplifier. Often though things get more complicated and you have issues to deal with as output power increases and this can reduce the absolute quality (measurements) if things are not handled correctly. But on the whole the quality of an amplifier isn't determined by the size of its output stage.
Well it isn't a case of a preference for one or the other, all systems should have the dynamic range required for reproducing the music you want to listen to, at the levels you want to listen at, it's all about system matching, which is what everyone has been saying when it comes down to measuring what your requirements are. No one is saying there's anything wrong with going high power, just that it's pointless to build something more powerful then you have the use for. It's one thing to over build an amplifier if it's a standard optimally biased class B, but it's another entirely to up the output power of a class A amplifier from 100 to 200 watts.
Just because the B&Ws are expensive and have a team of good engineers behind them, that doesn't automatically mean their stuff is going to be well designed. If the lead designer has a misguided idea about keeping things simple, even if it means ignoring obvious issues, then the end result will be worse then it could potentially be. Keeping it simple has been the crossover philosophy of a great deal of manufactures and their products generally perform worse off then they should. Besides that though, this is a forum for encouraging people to question the design choices made by engineers/designers, so that they can learn and better understand how their equipment works, either as a way of modding or redesigning out the flaws. Also I most certainly do not have to accept that they might be right, if they do such things as to leave large peaks, slap bang in the ears most sensitive range, un-attentuated.
This isn't an opinion it's a fact based on the loudspeakers impedance. The 800s are hard to drive, there's no arguing that. Some loudspeakers are more of a pain to drive, but the B&Ws are not an easy load.
Well if that's the case then a 30wpc class A amp should be perfectly adequate for your normal listening levels. If you want to build a 200 wpc class A amp then that's up to you, but by the looks of things 100 watts would be more then enough to give you what you want.
There's nothing wrong with asking questions, but you've been making statements and comments that simply are not right and have then seemingly got defensive even though you've been incorrect. Of course this is going to bring out the argumentative side in people.
One thing that you could do is design the class A amp so that you can alter the bias setting, one for 200 watts of class A and one for say 50 watts. This would let you select the 50 watt setting for your current loudspeakers and most of your listening, but then you can swap over to the 200 setting if you want to listen at louder levels or if you want to use an even harder to drive pair of loudspeakers.
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Some people think different
Fm the Leaving Class A Paper "Higher bias doesn’t just move the Class A transition to higher ground – it has a
profound influence on the amplifier at all power levels. It lowers the distortion at low levels as well as high levels, as seen in the distortion vs power curves for an amplifier with the bias set at different levels."
Again
"It is not simply that the distortion numbers are lower, but the characteristic of the distortion is improved in terms of the ratio of lower order harmonics (2nd and 3rd) to higher order harmonics (4th, 5th, 6th and so on)..."Yep...
Again
This is getting old...Havent some of us been here before? Some just think and hear different If I were to drive this point home the only ending would be the same 'ol argument and...
5th element,
listen you are making these huge, mega statements that are just assumptions about things you don't even own have tried never compared never had experience nor any first hand.
You are assuming you don't like B&W without any experience.
You are still free of not liking them, but I am sure that if you are a prepared listener and after having listened to them my guess is that you will end up appreciating the work B&W has done.
The funny thing is that your judges are not even toward the low end such as 705s or other cheaper series but the 800Signature which has been choosen by important recording studios as reference for mastering, awarded by Magazines, won several and several rewards in the past many years as the one of the most technological and best sounding speakers on the planet and yet you are ripping at them
It looks like you came out of the blue and know all the answers are ready to make a better speaker!!
....then why don't you just do your own design, commercialize it and see how it will go and especially at what pticetag you end up?!?!
I am really looking forward to seing your products reviewed by one of the audio magazines.
Ultimetly I like the quote on the signature of flg:
“Be who you are and say what you feel because those who mind don't matter and those who matter don't mind.”
I think this tells everything!!!
listen you are making these huge, mega statements that are just assumptions about things you don't even own have tried never compared never had experience nor any first hand.
You are assuming you don't like B&W without any experience.
You are still free of not liking them, but I am sure that if you are a prepared listener and after having listened to them my guess is that you will end up appreciating the work B&W has done.
The funny thing is that your judges are not even toward the low end such as 705s or other cheaper series but the 800Signature which has been choosen by important recording studios as reference for mastering, awarded by Magazines, won several and several rewards in the past many years as the one of the most technological and best sounding speakers on the planet and yet you are ripping at them
It looks like you came out of the blue and know all the answers are ready to make a better speaker!!
....then why don't you just do your own design, commercialize it and see how it will go and especially at what pticetag you end up?!?!
I am really looking forward to seing your products reviewed by one of the audio magazines.
Ultimetly I like the quote on the signature of flg:
“Be who you are and say what you feel because those who mind don't matter and those who matter don't mind.”
I think this tells everything!!!
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Some people think different
Fm the Leaving Class A Paper "Higher bias doesn’t just move the Class A transition to higher ground – it has a
profound influence on the amplifier at all power levels. It lowers the distortion at low levels as well as high levels, as seen in the distortion vs power curves for an amplifier with the bias set at different levels."
Again
If the amplifier is already in class A then any crossover and higher order artifacts should be completely gone from the spectrum. An output stage is capable of producing very low levels of harmonics and in the pass designs low distortion isn't even particularly sought after. In designs that are simpler, but still follow standard configurations the output stage is not the dominant factor when it comes to the distortion produced, the limitations here are imposed by the stages before the output stage. The bias level shouldn't affect the lower order and a lot of the higher orders, unless of course the amplifier is brought out of class A where you then get GM doubling going on which no one wants.
By most definitions though, you are either in class A, and hence are completely free from crossover artifacts, or out of class A, in a high bias design, where you're getting GM doubling artifacts crapping up the show. Increase the bias again so that you're back into class A and the higher level harmonics will disappear again. If something magical happens in the Pass amps with the way Nelson has his output stages configured, where ever increasing the bias will continue to lower the distortion even further, even if you've been in class A all the time, then this is something I am not familiar with. But really I wasn't arguing to the contrary where I pointed out that if you want to increase the bias per device then you need to go for a lower power amplifier that runs off of lower power rails. I don't really see why what you said was contraditory to what I was saying anyway?
Stefanoo, I know what putting a 5dB peak in the frequency response of an otherwise flat loudspeaker at 3.5kHz sounds like, it isn't particularly nice compared to flat, not with my ears.
No Stefanoo, I know that I don't like loudspeakers where the mid range is run so high that you get its breakup smeared all over the lower treble, not to mention that 3.5k peak once again that will make my ears hurt. I don't need to listen to the loudspeaker, just because it's a B&W to prove myself right.
Look it's simple, the number 1 design parameter, the first thing that you need to prioritise when designing a loudspeaker is getting a flat frequency response, that is without any sudden peaks anywhere and especially not peaks in the 1-4kHz range, this is a big no-no. It doesn't matter who designs them or what their name or brand is, if you've designed a loudspeaker that has a frequency response that is all over the place then no, it is NOT good design work and no, I will not like listening to it as my sensitive ears don't appreciate bumps in the presence region.
Yes, Stefanoo, I would do a better design of the crossover in the B&W 800. With my design you'd end up with a flatter overall frequency response, without any sudden peaks, I would also lower the xover frequency between the mid/tweeter as low as the tweeter would cope with, probably something like 2-2.5kHz, with steeper slopes to give you a much improved off axis response too. This are all highly desireable things to have, but it's a completely different approach to the one B&W have taken. Would it sound different? Yes, very different I'd bet. Would it sound better, to my ears, yes, to yours, maybe not, I don't know what you like. If you dig a peak in the presence band then you'd find my design too laid back for your liking.
I have done plenty of my own designs and they all sound very nice. What does commercialising any of them have to do with anything?
And that's exactly what I do, speak my mind.
You are probably right in general, but the mosfets Nelson uses need all the help in the world to sound decent.
The basic reasoning is that at higher bias the devices become more linear. Other functions such as gain of the devices goes up, +/- compression/expansion (still basically linearity) become less, even the funky P channel behaviour starts to go away at high temp/more bias.
But of coarse the same 'ol functions like good clean headroom for transients also improves. I'm only talking output stage here.
But of coarse the same 'ol functions like good clean headroom for transients also improves. I'm only talking output stage here.
5th,
If you are not familiar with the correlation between bias and harmonic distortion on MosFET you use on your FXX and other projects then I would safely assume all you do is blindly copy things posted on the forum.
I don't care whether you copy or whether you actually have the skill to make one on your own.
The fact you made speakers that sound nice is very debatable and it is only your own opinion.
There are little boxes (read speakers) from the 80's that have frequency response stamped on the front of the shoe box and it is as flat as a 45dB FB power amp.
Does this make them good sounding???
NOT AT ALL!!!
This should tell you something all alone!!
Commercialize a product means carrying on a responsability.
As you go public you have to be willing to accept very deep critics by users and by magazines.
This can easily send you out of business -if your products suck-
If you are telling me that B&W just BY CHANCE gained the reputation and the business they have today, then you are just fooling yourself!
They have what they have because their products are great and they have been admired since the first version of the matrix structure and continued up till nowdays.
I own 805s and 800Signature.
They are both beautiful speakers that can easily give a run to other products on the same price range.
Regarding running the tweeter lower, well the 805 runs the tweeter lower, but I can assure you from a A/B test that there is a TOOONNN of difference on the midrange and highs...more air around...more oxygen....more detail.....by doing the way they do on the 800S.
You know what? You should present your resume to B&W they are in your country if I am not wrong.
If you are so skilled it will show on your interview and maybe you can redesign the crossover and share your knowledge with them and see what they think!!!
Sounds fair?
If you are not familiar with the correlation between bias and harmonic distortion on MosFET you use on your FXX and other projects then I would safely assume all you do is blindly copy things posted on the forum.
I don't care whether you copy or whether you actually have the skill to make one on your own.
The fact you made speakers that sound nice is very debatable and it is only your own opinion.
There are little boxes (read speakers) from the 80's that have frequency response stamped on the front of the shoe box and it is as flat as a 45dB FB power amp.
Does this make them good sounding???
NOT AT ALL!!!
This should tell you something all alone!!
Commercialize a product means carrying on a responsability.
As you go public you have to be willing to accept very deep critics by users and by magazines.
This can easily send you out of business -if your products suck-
If you are telling me that B&W just BY CHANCE gained the reputation and the business they have today, then you are just fooling yourself!
They have what they have because their products are great and they have been admired since the first version of the matrix structure and continued up till nowdays.
I own 805s and 800Signature.
They are both beautiful speakers that can easily give a run to other products on the same price range.
Regarding running the tweeter lower, well the 805 runs the tweeter lower, but I can assure you from a A/B test that there is a TOOONNN of difference on the midrange and highs...more air around...more oxygen....more detail.....by doing the way they do on the 800S.
You know what? You should present your resume to B&W they are in your country if I am not wrong.
If you are so skilled it will show on your interview and maybe you can redesign the crossover and share your knowledge with them and see what they think!!!
Sounds fair?
No, I was familiar with FETs needing a higher standing bias then BJTs to work correctly but I didn't assume that if the output stage was already running in class A, that running the bias any higher, for a given amount of output power, would result in better linearity. In other words, you have an amplifier biased to give 10 watts into class A, and you're looking at its performance when delivering 5 watts. You then increase the bias so that it can give 20 watts class A, this I would not expect to give you even lower distortion because the output stage is already running in class A.
Maybe there wouldn't be a linearity increase, maybe the linearity of the FETs goes up exponentially as current increases, but only up to say 300mA or so, then it plateaus out. Does anyone have a link to the curves for the FETs Nelson uses? I think I've seen them before, but it'd be nice to see exactly what's going on. Or links to a paper discussing this. I tried searching for 'leaving class A' but that didn't easily come up with a paper to read.
Then why make the comment? You know perfectly well that I don't just copy stuff, as we discussed earlier on with my DSP. Yes I do copy in some places, but that's just common sense, why redesign the wheel, when someone else has already done it for you? But when this isn't possible, which is most of the time, I design it myself.
If all you can do is resort to personal attacks then it would be better if you don't comment at all. It isn't just my opinion its the opinion of anyone else who hears them. To quote yourself from earlier on
Whether that's enough to convince you is another story, but it was plenty enough proof that your B&Ws are amazing earlier on.
The frequency response in and of itself doesn't tell the whole story, but it's a good start. There's no point in having a flat frequency response if you've had to push the tweeter far too low and it's distorting madly and screeching all over the place. But there are other factors that you need to keep acceptable otherwise you will not get good results.
If a loudspeaker has...
1) A flat frequency response.
2) A smooth set of off axis curves.
3) Well integrated drivers
4) Low harmonic distortion without any peaks that would indicate a driver is struggling, or that a driver has been used inappropriately.
Then yes, it will sound good. You can decide to compromise on some of these if you like, but then you really do need to listen to see if it sounds good. B&W for example use the mid range up too high and with a very simple crossover, on both the tweeter and the mid. This means that they compromise 1 and 2. If they crossed over the mid and the tweeter much lower, but still kept the xover simple then they'd dramatically improve 1 and 2, but would compromise 4 as the tweeter would struggle with only a very shallow xover. So you'd have a flat frequency response and much improved power response, but the speaker would likely sound worse as a result.
It tells me that the reviewer either liked a coloured sound or that the loudspeakers had other problems, like in the example above, that made them sound bad. However, I don't think I have ever seen a bad subjective review of a pair of loudspeakers in stereophile when the loudspeakers are properly designed with all design criteria boxes ticked. Ie when a loudspeaker measures flat, has a smooth off axis set of curves, has well integrated drivers and low harmonic distortion, the reviews are excellent. On the other hand, there are plenty of loudspeakers with poor measurements that review poorly.
Yes, but going commercial doesn't tell you anything about the things I am speaking of. There are plenty of commercial products out there that do SUCK, but the companies are still in business. There are plenty of Chinese things on ebay that do suck, but they are still in business too.
Even if your products are excellent though, you can still go out of business.
I would have no problem inviting a hifi magazine into my house to let them review my system, though.
Whenever have I said this? I don't think anyone in this thread has ever said that the B&Ws that you own suck, or that their engineers or designers are rubbish and that their products are on the whole crap. Of course they aren't, it's just that B&W design their loudspeakers to sound a specific way. If this suits you, then good for you. It's that you started this by making claims that the B&Ws are a very neutral pair of speakers, which I had a problem with because they aren't neutral.
Mmm, because the FST mid range driver is one of the best in the world when it comes to specifications alone, having better mids does often translate into better highs too. Just like subjectively having excellent highs can translate into a speaker sounding as if it has better bass.
No, it sounds ridiculous, like someone cannot accept that their B&Ws might not be the be all and end all and is coming up with cheap ways to snipe back.
Well now you see how it feels to receive personal attacks, don't you?
Anyhow, the fact you compare your design to the 800 is just a little arrogant in my opinion.
Also you say: no-one is saying that my 800 sound bad or whatever.
However you are actually debating on frequency response, phase response, dips response and so on...which in turns is the same thing as say this is rubbish.
What you still haven't explained to me is why audiophile and important studio recordings choose that speaker as a standard and still haven't explained why the speaker received important awards and still haven't explained to me why the speaker received outstanding reviews ALL over the WORLD NOT only stereophile.
It is considered one of the most neutral speakers on the planet within their price-range.
Accordingly to what your findings are, the speaker shouldn't be on the ballpark of a 25K speaker thus you would understand that if that was the truth the turn around of reviews and everything else would have been very different especially in light of the possibility that a 5K whatever speaker could easily perform much better than a 25K.
This just wouldn't make sense.
Why chinese are in business? it is because there are still people like you and others who look inside and think they are using the same things and pricewise are good and cheap enough and they buy them.
That's why!!
Afterall they don't sound as bad as they used to....they learned how to copy afterall but I mean they are far, far away from good sounding stuff!!
Oh but I forgot they measure pretty good so now go figure!!
This is going back to the debate of speakers and it is not really the core of this thread.
Please let's not talk about something you haven't listened nor had deep experience on it and made many A/B tests on it!
I think this is fair.
Regarding your resume you should try and tell us about your success on it!
Anyhow, the fact you compare your design to the 800 is just a little arrogant in my opinion.
Also you say: no-one is saying that my 800 sound bad or whatever.
However you are actually debating on frequency response, phase response, dips response and so on...which in turns is the same thing as say this is rubbish.
What you still haven't explained to me is why audiophile and important studio recordings choose that speaker as a standard and still haven't explained why the speaker received important awards and still haven't explained to me why the speaker received outstanding reviews ALL over the WORLD NOT only stereophile.
It is considered one of the most neutral speakers on the planet within their price-range.
Accordingly to what your findings are, the speaker shouldn't be on the ballpark of a 25K speaker thus you would understand that if that was the truth the turn around of reviews and everything else would have been very different especially in light of the possibility that a 5K whatever speaker could easily perform much better than a 25K.
This just wouldn't make sense.
Why chinese are in business? it is because there are still people like you and others who look inside and think they are using the same things and pricewise are good and cheap enough and they buy them.
That's why!!
Afterall they don't sound as bad as they used to....they learned how to copy afterall but I mean they are far, far away from good sounding stuff!!
Oh but I forgot they measure pretty good so now go figure!!
This is going back to the debate of speakers and it is not really the core of this thread.
Please let's not talk about something you haven't listened nor had deep experience on it and made many A/B tests on it!
I think this is fair.
Regarding your resume you should try and tell us about your success on it!
I already read it several time and funny enough I had that opened on my computer just yesterday
!!!
Jacco,
this is a honest question if you feel like answering please just replace the numbers on the formulas if there is something wrong.
Please don't start from scratch.
I want to understand how come the 400W MAX ClassA ends up dissipating ONLY 700W including SE (not included in the calculation below).
Here it is:
200W @8ohm -> VPK=56.56 -> VSwing_HALF=28.28V -> VRAILS=+/-35V -> IPK=7.07A
if Amp has to handle up to 400W of Class A (obviously @4ohm) it has to draw double that so
-> IpK=14.14A
For a PP topology each quadrant draws half that
-> IQuadrant=7.07A @35V -> PQuadrant=250W -> PIDLE =1KW
If Amp uses 80 Output Devices per channel -> 20/per quadrant
-> PBIAS/Device=12.5W -> IBIAS/Device=350mA
this is a honest question if you feel like answering please just replace the numbers on the formulas if there is something wrong.
Please don't start from scratch.
I want to understand how come the 400W MAX ClassA ends up dissipating ONLY 700W including SE (not included in the calculation below).
Here it is:
200W @8ohm -> VPK=56.56 -> VSwing_HALF=28.28V -> VRAILS=+/-35V -> IPK=7.07A
if Amp has to handle up to 400W of Class A (obviously @4ohm) it has to draw double that so
-> IpK=14.14A
For a PP topology each quadrant draws half that
-> IQuadrant=7.07A @35V -> PQuadrant=250W -> PIDLE =1KW
If Amp uses 80 Output Devices per channel -> 20/per quadrant
-> PBIAS/Device=12.5W -> IBIAS/Device=350mA
To answer to another detail at 5th several posts, the FET are also happier thus sound better as the DS voltage goes up.
So it is kind of a trade off there as well. Thus very low power amp (80W under) carry on too little of a output voltage to put these Fets on the hot spot unless you decide not to go balance in which case the voltage doubles and you are then back to the ballpark.
So it is kind of a trade off there as well. Thus very low power amp (80W under) carry on too little of a output voltage to put these Fets on the hot spot unless you decide not to go balance in which case the voltage doubles and you are then back to the ballpark.
MOSFETs have a capacitance curve with Vds and Vgs that is crazy non-linear at low voltage. Generally the type N.P. uses start with an extreme upward slope down below 20Vds. This tends to flatten out somewhat above 20V but it is a real concearn depending on the cicuit and the input and FB resisances. Without good drive current this create distorton especially at lower voltages and higher frequencies.
MOSFETs have a capacitance curve with Vds and Vgs that is crazy non-linear at low voltage. Generally the type N.P. uses start with an extreme upward slope down below 20Vds. This tends to flatten out somewhat above 20V but it is a real concearn depending on the cicuit and the input and FB resisances. Without good drive current this create distorton especially at lower voltages and higher frequencies.
That is completely correct! Thanks for sharing the thought.
Except I've not attacked anyone here so I don't understand your comment.
Where did I compare my design to the 800? I didn't.
No Stefanoo, not rubbish, just coloured. The fact the speaker is slightly coloured is obvious from looking at the frequency response. If it isn't perfectly flat, then it's coloured.
ok...to begin with I have the 800Signature and not the 800D you should probably pay more attention to my disclaimers before jumping to the conclusion.
This means that I don't have the diamond tweeter nor have a flexible cone for the midrange, so I can't speak for the 800D as I haven't audiotioned that one.
I am sure it is wonderful speaker, but like I say I can't speak so strongly for that!!
You should look at the frequency response for the 800Signature from the anecoic room made by B&W!!
I don't think we are talking about the same thing.
Frequency response is impressively flat!!
You are definitely assuming you can do better which is what I am arguing!
You have no proven experience of any sort and definitely cannot measure up to a fully equipped structure and with professionals at work.
If you were working as a professional on the field for the last 10-20years and created products that were worldwidely acknolewdged (like NP here) then it would be really different.
Ultimetly you DO need to listen to the speakesr if you have NEVER listened to any of those before judjing just by a graph made by a guy at Stereophile who migh have not even taken the measurement correctly!!!
Also you look at graphs on anecoical room which is not what is going to happen on YOUR room!! How can't you understand that?
That is why speaker would in theory have to be matched to your room and personal tastes.
Beside you are criticizing me becuase I wouldn't need to listen to the XA200.5 to say that it is a wonderful amp, but you forgot a good detail, I already own one of his products thus I have a good feeling for what the higher end could possibly do better!!!
This means that I don't have the diamond tweeter nor have a flexible cone for the midrange, so I can't speak for the 800D as I haven't audiotioned that one.
I am sure it is wonderful speaker, but like I say I can't speak so strongly for that!!
You should look at the frequency response for the 800Signature from the anecoic room made by B&W!!
I don't think we are talking about the same thing.
Frequency response is impressively flat!!
You are definitely assuming you can do better which is what I am arguing!
You have no proven experience of any sort and definitely cannot measure up to a fully equipped structure and with professionals at work.
If you were working as a professional on the field for the last 10-20years and created products that were worldwidely acknolewdged (like NP here) then it would be really different.
Ultimetly you DO need to listen to the speakesr if you have NEVER listened to any of those before judjing just by a graph made by a guy at Stereophile who migh have not even taken the measurement correctly!!!
Also you look at graphs on anecoical room which is not what is going to happen on YOUR room!! How can't you understand that?
That is why speaker would in theory have to be matched to your room and personal tastes.
Beside you are criticizing me becuase I wouldn't need to listen to the XA200.5 to say that it is a wonderful amp, but you forgot a good detail, I already own one of his products thus I have a good feeling for what the higher end could possibly do better!!!
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