Hi, constructive critisism is welcome. Confirmation of a problem or a solution again expected. But importantly be positive.
If someone states an idea and or design that you disagree with then by all means offer the alternative as opinion or quote a source. Reasoned argument will never be rejected, but please don't be negative for the sake of it.
Many of us are here to learn from our peers and our experts give of their time willingly. Do not chase them away!
regards Andrew T.
If someone states an idea and or design that you disagree with then by all means offer the alternative as opinion or quote a source. Reasoned argument will never be rejected, but please don't be negative for the sake of it.
Many of us are here to learn from our peers and our experts give of their time willingly. Do not chase them away!
regards Andrew T.
Re: Re: Re: Confirmation on Affirmation
Notice also that Lars does a great job here and you amp_man haven't contributed so much despite the fact that you are a professional. I also want to point out that you contribute as much as you want.
I only said that you haven't offered so many solutions of the problems you claim this design has and which Lars not at this moment can confirm. I think we shall stay positive unless we have signs of the opposite.amp_man_1 said:
Notice also that Lars does a great job here and you amp_man haven't contributed so much despite the fact that you are a professional. I also want to point out that you contribute as much as you want.
Di Quan,
You finally sorted out the problem in your Zeta project , what was the problem due to ???
You finally sorted out the problem in your Zeta project , what was the problem due to ???
Hi! All,
Can any one give a link to even one of these so called best designs???.
Considering component availibility all over the world including lesser developed countries. As a DIYer I find Zeta to be an outstanding design in its class.
Regards
Rahul
Some Serious Comments
Hi Every Body,
I havent Criticise anyone so far [no never]in this forum rather than I have only pointed some Short Comings in some designs which must not be considered as criticism.
Secondly I havent said that our designs are the best, the reality is that there are very good designs indeed in this forum then ours and ofcourse in the world and nor I want to state the we design bad circuits.
As far as contribution is concerned I want to state that the Zeta must be desined Symmetrically which will improve its slew rate and dynamism for a pro lander.
Solution is as follows An additional N-channel Driver stage must be used for positive Rail mosfets to cope the symmetry with negative rail mosfets as they are already driven by P-channel mosfet.
This addition will Definitly boost its performance in every aspect. regarding professional standards are concerened by Diyers.
Zeta is a very good design By Lars Clausen.
One more thing Lars has Stated that its slew rate is about 50V/us , but according to me it must be somewhere near 100V/us
because Mosfets are driven very efficiently with their drives inturns they are also driven commonly from a single node which will provide a good dominant pole for high frequency operation.
Hope this will help to all of u in a better understanding with us
Hi Every Body,
I havent Criticise anyone so far [no never]in this forum rather than I have only pointed some Short Comings in some designs which must not be considered as criticism.
Secondly I havent said that our designs are the best, the reality is that there are very good designs indeed in this forum then ours and ofcourse in the world and nor I want to state the we design bad circuits.
As far as contribution is concerned I want to state that the Zeta must be desined Symmetrically which will improve its slew rate and dynamism for a pro lander.
Solution is as follows An additional N-channel Driver stage must be used for positive Rail mosfets to cope the symmetry with negative rail mosfets as they are already driven by P-channel mosfet.
This addition will Definitly boost its performance in every aspect. regarding professional standards are concerened by Diyers.
Zeta is a very good design By Lars Clausen.
One more thing Lars has Stated that its slew rate is about 50V/us , but according to me it must be somewhere near 100V/us
because Mosfets are driven very efficiently with their drives inturns they are also driven commonly from a single node which will provide a good dominant pole for high frequency operation.
Hope this will help to all of u in a better understanding with us
amp_man, if the slew rate is far beyond what you need at 20 kHz, why is it so important to have symmetrical slew rate according to you?
Lars, all your files linked from lcaudio.dk don't work. Have you changed URL's or have you removed the files?
Lars, all your files linked from lcaudio.dk don't work. Have you changed URL's or have you removed the files?
peranders: We have changed the server alltogether, and gone to an external server with lcaudio.dk. However lcaudio.com is not moved yet, because it takes a bit of time to update .com servers.
Until then some functions will not work.
The pictures you mention i will try to find, and upload to the new server asap.
Thanks !
amp_man: Thanks for your comments, you may be right about the 100 V/us because now i am using IRFP260 (not N) it has about 4 times higher capacitance than IRFP250N. 🙂
Lars
Until then some functions will not work.
The pictures you mention i will try to find, and upload to the new server asap.
Thanks !
amp_man: Thanks for your comments, you may be right about the 100 V/us because now i am using IRFP260 (not N) it has about 4 times higher capacitance than IRFP250N. 🙂
Lars
Lars, isn't better to use a mosfet as temp sensing element? I used BS170 together with my IRFD120/9120 in my monster headphone amp. I got very good stability
Schematic here .
How good temp stability do you get now? Is it over, under or perfect compensated?
You could also use any other mosfet I should think. It's more practical with a T0220 if you want to attach it on the heatsink. It's pretty to glue a TO92 also.
BS170 example
Have you tested cheap BC847BS, monolithic pair, dirt cheap and pretty good.
BC847BS
BC847BS in a pcb
BC847BS example 2
Schematic here .
How good temp stability do you get now? Is it over, under or perfect compensated?
You could also use any other mosfet I should think. It's more practical with a T0220 if you want to attach it on the heatsink. It's pretty to glue a TO92 also.
BS170 example
Have you tested cheap BC847BS, monolithic pair, dirt cheap and pretty good.
BC847BS
BC847BS in a pcb
BC847BS example 2
Some Serious Comments
P-E-R-A-N-D-E-R-S The Moderator ,
The answer is simple The music signal swings both positively and negatively therefore to reproduce exact music signal at output of the amp ,the must the slew rate must be symmetrical in both positive and negative drives especially at high frequencis or there may arise distortion products at output which effects the overall timbre of sound. Secondly Music is directly related to TIME DOMAIN Function therefore to produce an exact replica one must attain a symmetrical slew rate drive which improves the DYNAMISM.
High Slew rate increases Damping Factor therefore Produces Tight Bass and it also doesnt cause smearing effects.But our Modern DJ's are somewhat more funky towards Scratch effecs and Pitch control , therefore it is necessary to have high Slew Rate in order to have full dynamic transient attack at the ouput.
Meyer Sound Have their Monitors Fitted with Mosfet amps with Slew rate of 300V/us and when u listen to them u feel different about the Synergetic impulsive transient attack they are Exhibiting out of it.
Hi Lars,
Yeah ur now on rite track , carry on improving the Zeta and u will definately achieve ur goal.
Regards,
ampman
peranders said:
P-E-R-A-N-D-E-R-S The Moderator ,
The answer is simple The music signal swings both positively and negatively therefore to reproduce exact music signal at output of the amp ,the must the slew rate must be symmetrical in both positive and negative drives especially at high frequencis or there may arise distortion products at output which effects the overall timbre of sound. Secondly Music is directly related to TIME DOMAIN Function therefore to produce an exact replica one must attain a symmetrical slew rate drive which improves the DYNAMISM.
High Slew rate increases Damping Factor therefore Produces Tight Bass and it also doesnt cause smearing effects.But our Modern DJ's are somewhat more funky towards Scratch effecs and Pitch control , therefore it is necessary to have high Slew Rate in order to have full dynamic transient attack at the ouput.
Meyer Sound Have their Monitors Fitted with Mosfet amps with Slew rate of 300V/us and when u listen to them u feel different about the Synergetic impulsive transient attack they are Exhibiting out of it.
Hi Lars,
Yeah ur now on rite track , carry on improving the Zeta and u will definately achieve ur goal.
Regards,
ampman
hmm does high slew rate also account for all the good weather in India? 😀
amp_man Sorry to be the one to tell you but some of this claim above is really far fetched! Slew rate is - IMO of course - a product of Hitachi in the early 1980's they were looking for an alternative parameter to compete against Technics who were and have always been the kings of low THD. So Hitachi were the ones who tried to make people look for high slew rate instead of low THD. Those were the days where everybody read technical data of new amplifiers, instead of the newspaper. ;-)
Now times have changed and most people realize that the tech data is mostly useless, as it will not tell you anything useful about how the amplifier sounds.
Soundwise slew rate is really insignificant, except for one angle. To get a good natural sound you need low feedback delay and low open loop gain (if you are dealing with a feedback system of course) These two parameters sometimes (but not always) go hand in hand with high slew rate, especially in IC opamps. So the high slew rate is really an (uncertain) spin off from what you really want in your amplifier.
Some Serious Comments
Hi Lars,
I think u r not following a wiser criteria towards slew rate or u just dont want ur design to be associated with it.
Lars,
In a domestic environment people are not that much hectic towards technical specs.,
Our's is a pro Arena in which People are going to buy only that stuff which performs excellent both in terms of Technical specs and ofcourse the performance in terms of sound quality, reliability, and maintenance issues.
A pro amp without mentioning its slewrate is like a Formula I Ferrari without any specs regarding its Acceleration or top speed.
The People who buy pro-Gear r now more intelligent and technically sound and have some brains to see the technical specs and perform the judgements accordingly.
Simply Saying Slewrate is not an important factor for determining the amp's performance isnot a good thing.
Every high end Pro amp such as Peavey, Crown, Crest, etc Quote the slewrate of their amps so that the customer feels a better possession of technical specs.
I know that u r not related with pro-environment and the other guys here on forum are also not much into pro-environment thats why u people dont want to be associated with the standards of Something That is PROFESSIONAL IN ITS TRUE NATURE.
Regards,
Kanwar Abhishek Singh
Lars Clausen said:
Hi Lars,
I think u r not following a wiser criteria towards slew rate or u just dont want ur design to be associated with it.
Lars,
In a domestic environment people are not that much hectic towards technical specs.,
Our's is a pro Arena in which People are going to buy only that stuff which performs excellent both in terms of Technical specs and ofcourse the performance in terms of sound quality, reliability, and maintenance issues.
A pro amp without mentioning its slewrate is like a Formula I Ferrari without any specs regarding its Acceleration or top speed.
The People who buy pro-Gear r now more intelligent and technically sound and have some brains to see the technical specs and perform the judgements accordingly.
Simply Saying Slewrate is not an important factor for determining the amp's performance isnot a good thing.
Every high end Pro amp such as Peavey, Crown, Crest, etc Quote the slewrate of their amps so that the customer feels a better possession of technical specs.
I know that u r not related with pro-environment and the other guys here on forum are also not much into pro-environment thats why u people dont want to be associated with the standards of Something That is PROFESSIONAL IN ITS TRUE NATURE.
Regards,
Kanwar Abhishek Singh
Some Serious Comments
Lars,
Have u ever tested ur manufactured gear with Professional Speakers Such as 18" Low Frequency drivers, they need a high Damping factor and high Slew rate amp to Kick the helll of them to produce High SPL.
A low slewrate amp will definately fail to drive the punching power hungry low frequency drives at high SPL.
For example- Meyer Sound is the only company which claims to produce SPL of 140dB i.e is because of the high slew rate amps.
Regards
Kanwar Abhishek Singh
Lars Clausen said:
Lars,
Have u ever tested ur manufactured gear with Professional Speakers Such as 18" Low Frequency drivers, they need a high Damping factor and high Slew rate amp to Kick the helll of them to produce High SPL.
A low slewrate amp will definately fail to drive the punching power hungry low frequency drives at high SPL.
For example- Meyer Sound is the only company which claims to produce SPL of 140dB i.e is because of the high slew rate amps.
Regards
Kanwar Abhishek Singh
So, mr. amp_man, how do you calculate the slew rate you will need?
Let's say, 500 watts out, 4 ohms, 50 kHz bandwidth at least. ( I know how to calculate slew rate)
SR= 2*pi*f*SQR(2*P*R) = 2*3.14*50000*SQR(2*4*500) = 19 V/us = aboslute minimum. Some overhead is wanted, let's say 25-50 V/us is what you need.
Here is good link for this:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/a741p3.html
If you want fast slew rate you can also choose to have a current feedback amp.....
Let's say, 500 watts out, 4 ohms, 50 kHz bandwidth at least. ( I know how to calculate slew rate)
SR= 2*pi*f*SQR(2*P*R) = 2*3.14*50000*SQR(2*4*500) = 19 V/us = aboslute minimum. Some overhead is wanted, let's say 25-50 V/us is what you need.
Here is good link for this:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/a741p3.html
If you want fast slew rate you can also choose to have a current feedback amp.....
Some Serious Comments
Hi Moderator Senor,
Your Calculation regarding the slew rate is right but it only hold good for sine waves, whereas in the case of mixed musical transients this doesn't hold good.
As we know that music comprises various transient Attacks which are akready produced at very high Attack rates i.e. very fast rising signals which made the use of a high slew rate amp very much essential.
Lets Consider an Example ,
U stated that with 50KHZ bandwidth there is sufficient margin and slewrate as u stated at 25 to 50V/us hold good for casual music. This is alright but Things are different when u want to reproduce Techno-Trance Effects + Scratch effects which are very high speed fast transient attack signals then the headroom margin required is increased to 3 to 4 times than an average signal. And also there are now music signals with fast attack bass transient require fast reproduction equipment which necessitates the use of high speed amps.
The normal Signal transient require a slew rate of no more than 50V/us.
But to Produce fast transient Signal at high Accuracy at especially High Voltage and Current level that is I mean to say that For High Sound Pressure level the high slew rate requirement is evident to produce high voltage transients. Therefore a clear Factor is to increase the normal slew rate to about 3 to 4 times in order to create a signal transient of high speed at high Voltage thereby producing High SPL which is requirement of Large PA's and are catered by Professional equipment only.
At normal signal 50V/us of Slew rate is enough , but to produce fast signal at high voltage , the amp has to be more fast than its signal speed in order to reproduce the desired signal. A slew rate of 50 X K is required for good response , where K is a factor determining the number of times the margin is required acc to the application environment.
If we choose K= 3 than ur slew rate required is 50 * 3 = 150 and so on.
Current feedback amps are best suited to these application, I have already tested a prototype earlier , and also ur Headphone amps are a great source of inspiration for us to develop a current feedback amp of power level at 1200WRMS per channel.
Dont u still understand why ur Headphone amps are extremely high in detailing the sound, that due to the fact that they are are high slew rate amps by the virtue of current feedback.
Regards & Compliments to the moderator for his headphone amps.
peranders said:
Hi Moderator Senor,
Your Calculation regarding the slew rate is right but it only hold good for sine waves, whereas in the case of mixed musical transients this doesn't hold good.
As we know that music comprises various transient Attacks which are akready produced at very high Attack rates i.e. very fast rising signals which made the use of a high slew rate amp very much essential.
Lets Consider an Example ,
U stated that with 50KHZ bandwidth there is sufficient margin and slewrate as u stated at 25 to 50V/us hold good for casual music. This is alright but Things are different when u want to reproduce Techno-Trance Effects + Scratch effects which are very high speed fast transient attack signals then the headroom margin required is increased to 3 to 4 times than an average signal. And also there are now music signals with fast attack bass transient require fast reproduction equipment which necessitates the use of high speed amps.
The normal Signal transient require a slew rate of no more than 50V/us.
But to Produce fast transient Signal at high Accuracy at especially High Voltage and Current level that is I mean to say that For High Sound Pressure level the high slew rate requirement is evident to produce high voltage transients. Therefore a clear Factor is to increase the normal slew rate to about 3 to 4 times in order to create a signal transient of high speed at high Voltage thereby producing High SPL which is requirement of Large PA's and are catered by Professional equipment only.
At normal signal 50V/us of Slew rate is enough , but to produce fast signal at high voltage , the amp has to be more fast than its signal speed in order to reproduce the desired signal. A slew rate of 50 X K is required for good response , where K is a factor determining the number of times the margin is required acc to the application environment.
If we choose K= 3 than ur slew rate required is 50 * 3 = 150 and so on.
Current feedback amps are best suited to these application, I have already tested a prototype earlier , and also ur Headphone amps are a great source of inspiration for us to develop a current feedback amp of power level at 1200WRMS per channel.
Dont u still understand why ur Headphone amps are extremely high in detailing the sound, that due to the fact that they are are high slew rate amps by the virtue of current feedback.
Regards & Compliments to the moderator for his headphone amps.
I think we have an another debate here becasue from a CD nothing more than 22 kHz can come out so a fast transient can never be faster than corresponding 20 kHz bandwidth.
I'll believe 50-100 V/us more than sufficient in Lars' design here and for non-professional use.
Regarding my headphone amps I don't think it's a very big difference between my 1200 V/us amp and my 60 V/us amp. Sorry.... but I like the fast one more.
I'll believe 50-100 V/us more than sufficient in Lars' design here and for non-professional use.
Regarding my headphone amps I don't think it's a very big difference between my 1200 V/us amp and my 60 V/us amp. Sorry.... but I like the fast one more.
Confirmation on Affirmation
Hi Moderator
Pro world Demands High Slew rate amps, whereas Zeta is non pro design.
But U like the Fast amp with 1200V/us slew rate[U said it]😀
regards
peranders said:
Hi Moderator
Pro world Demands High Slew rate amps, whereas Zeta is non pro design.
But U like the Fast amp with 1200V/us slew rate[U said it]😀
regards
Amp_man, this thread is about a powerful amp, with decent performance (not necessarily high-end performance) and for amatuer use. Could you please angle your inputs towards this product area.
I also want to point out (since some wonders) that I support Lars' efforts only becasue I think it's a good idea and noone of you which (thinks you) know much more than Lars hasn't done anything as much as he has done here. This is about sharing and sharing theory is good but sometimes not so useful for an unequipt amatuer. They want a ready and tested design and also in many cases a good pcb.. dirt cheap of course
It seems that Lars is more of a doer than a talker. Good work so far, Lars
I also want to point out (since some wonders) that I support Lars' efforts only becasue I think it's a good idea and noone of you which (thinks you) know much more than Lars hasn't done anything as much as he has done here. This is about sharing and sharing theory is good but sometimes not so useful for an unequipt amatuer. They want a ready and tested design and also in many cases a good pcb.. dirt cheap of course
It seems that Lars is more of a doer than a talker. Good work so far, Lars
rajeev luthra said:
I didn't.
I just used a lower supply voltage since this is where the amp runs fine. 😀Rahul said:
unfortunately, it was something just off the top of my head. I couldn't find the threads, it was a bit while ago.
Some Serious Comments
Hi Moderator u r rite in ur statement in ur own way but i am rite in my own way thats it.
Hi Moderator u r rite in ur statement in ur own way but i am rite in my own way thats it.
Hi, Ampman,
LC mentioned the more important thing, low NFB delay and low OL gain. I think this area makes the difference more than THD or slewrate or damping factor.
It is true, home amps and pro amps quite different in deciding amount of feedback and OLgain. High feedback usually results in high slewrate, damping, low THD etc. But they are designed by the same calculations, the same equations, but with different parameters.
Those who knows "why" and mastered "how" to obtain "what" can make whatever kind of amp they want. Are you sure LC knows nothing about pro-amps?
Thats what I tought at first. But unfortunately, the bass quality is not related to damping factor at all. It is the "folklore told generation to generation". So, like the Meyer you said have good bass control, it is produced by other factor, but not the damping factor figure.
LC mentioned the more important thing, low NFB delay and low OL gain. I think this area makes the difference more than THD or slewrate or damping factor.
Technical figures like slewrate and damping factor usually are not tailored by the maker. It comes from nature. The bigger you built, usually bigger slewrate and damping factor comes automaticly.
You wouldn't know who as "just a name" participated here 😀
It is true, home amps and pro amps quite different in deciding amount of feedback and OLgain. High feedback usually results in high slewrate, damping, low THD etc. But they are designed by the same calculations, the same equations, but with different parameters.
Those who knows "why" and mastered "how" to obtain "what" can make whatever kind of amp they want. Are you sure LC knows nothing about pro-amps?
Could you share the method of measuring slewrate not by using sinewave, but using real music? I'm really interested.
I like discotheque sound system and dance music too😀 Especially that fast bass that shake my heart and crispy clear synthesizer sound. Synthesizer effect and turntable scratch effect are fast, but I can still hear them. That means it is definitely below 20khz, where the calculation will hold true. Or you can hear above 20khz?
I wouldn't argue about current feedback with Peranders😀