My dear..dear Hifidaddy
'well, at 1mAmp collector current the voltage amplification in 22k resistor is about 500, and the miller cap is 500 times 3pF (assuming this is the reverse capacitance) equals 1500pF. Having these 1500pF or not (in the case you remove the resistor) will affect the high frequency behaviour and might affect stability. Now you say that doesn't matter, and try to teach things. '
Your profound misunderstanding of the operation of this amplifier leaves me breathless.......
The input diff. pair is a transadmittance stage , i.e, current out for differential voltage in. This is the case by default, because the second, (common emmiter), stage is converted into a transimpedance stage by the shunt-derived, shunt-applied, frequency dependant negative feedback, courtesy of the miller compensation capacitor.
The input impedance at the input of the second stage is near zero at audio frequencies as a consequence.....
I trust it should be obvious now why the voltage at the relevant collector of the diff. pair is of near-blinding irrelevance.
To determine the linearity of the input stage therefore, you would have to measure distortion in its output current , with respect to its differential input voltage.
'Mr Perrot measured distortion by output voltage, which is the only right way. '
I think its should be pretty clear now why monseiur perrot is wrong.....!?
please look: 4k7 plus 22k for the (+)input bias is 26k7, which is 1% difference from 27k for the (-)input bias, so where is the mismatch ?
So i am the proverbial engineering perfectionist! Surely that is part of the pleasure of DIY? There is'nt much point in charging people an horrendous of money for a product unless and untill attention to detail can be demonstrated. Thats my view anyway.
Cheers!
Fear not 'Hifidaddy', i am not trying to steal your daddy crown.....
'well, at 1mAmp collector current the voltage amplification in 22k resistor is about 500, and the miller cap is 500 times 3pF (assuming this is the reverse capacitance) equals 1500pF. Having these 1500pF or not (in the case you remove the resistor) will affect the high frequency behaviour and might affect stability. Now you say that doesn't matter, and try to teach things. '
Your profound misunderstanding of the operation of this amplifier leaves me breathless.......
The input diff. pair is a transadmittance stage , i.e, current out for differential voltage in. This is the case by default, because the second, (common emmiter), stage is converted into a transimpedance stage by the shunt-derived, shunt-applied, frequency dependant negative feedback, courtesy of the miller compensation capacitor.
The input impedance at the input of the second stage is near zero at audio frequencies as a consequence.....
I trust it should be obvious now why the voltage at the relevant collector of the diff. pair is of near-blinding irrelevance.
To determine the linearity of the input stage therefore, you would have to measure distortion in its output current , with respect to its differential input voltage.
'Mr Perrot measured distortion by output voltage, which is the only right way. '
I think its should be pretty clear now why monseiur perrot is wrong.....!?
please look: 4k7 plus 22k for the (+)input bias is 26k7, which is 1% difference from 27k for the (-)input bias, so where is the mismatch ?
So i am the proverbial engineering perfectionist! Surely that is part of the pleasure of DIY? There is'nt much point in charging people an horrendous of money for a product unless and untill attention to detail can be demonstrated. Thats my view anyway.
Cheers!
Fear not 'Hifidaddy', i am not trying to steal your daddy crown.....
Re: My dear..dear Hifidaddy
you even cannot make a difference between Miller cap of the (-)input of first stage and the input of the second stage. This is a poor statement for an EW writer ... Well, I admit, that your articles are the first EW audio articles I didn't file in my library. But according to your art of argumenting I suppose you are young and able to learn a lot.
You are talking Naim down, and you showed all of us, that you don't understand the Naim power amps, further it seem that you never built a series of Naim clones and tested them, and maybe never listened to one.
You are no help at all for the DIYers around here.
regards,
Hartmut
BTW, for noise calculations - I got the impression that you miss them in your books - I recommend reading Motchenbacher: Low Noise Electronics
mikek said:
you even cannot make a difference between Miller cap of the (-)input of first stage and the input of the second stage. This is a poor statement for an EW writer ... Well, I admit, that your articles are the first EW audio articles I didn't file in my library. But according to your art of argumenting I suppose you are young and able to learn a lot.
You are talking Naim down, and you showed all of us, that you don't understand the Naim power amps, further it seem that you never built a series of Naim clones and tested them, and maybe never listened to one.
You are no help at all for the DIYers around here.
regards,
Hartmut
BTW, for noise calculations - I got the impression that you miss them in your books - I recommend reading Motchenbacher: Low Noise Electronics
phew!
Hifigranddaddy,
All that is required is an objective analysis of the technical facts on their own merits without getting emotional.....
I think your failure to address the points i have raised speaks for itself....
As for noise calculations.....where have i mentioned these in the context of this thread?.....dear...dear....
Input stage degeneration does add noise, but this in a power amplifier, remains insignificant if the degeneration is not overdone....linear electronic design is about trade-offs....you know?
A more significant source of noise is the effective magnitude of the resistance to ground at the feedback and input nodes of the diff. stage.......use 10K max for input and feedback resistor.....
For diff. stage degeneration, an effective rule of thumb is quiescent voltage drop across each resistor should not exceed Vbe/2...the noise produced by these should then be insignificant...
I rest my case
Cheers.
Hifigranddaddy,
All that is required is an objective analysis of the technical facts on their own merits without getting emotional.....
I think your failure to address the points i have raised speaks for itself....
As for noise calculations.....where have i mentioned these in the context of this thread?.....dear...dear....
Input stage degeneration does add noise, but this in a power amplifier, remains insignificant if the degeneration is not overdone....linear electronic design is about trade-offs....you know?
A more significant source of noise is the effective magnitude of the resistance to ground at the feedback and input nodes of the diff. stage.......use 10K max for input and feedback resistor.....
For diff. stage degeneration, an effective rule of thumb is quiescent voltage drop across each resistor should not exceed Vbe/2...the noise produced by these should then be insignificant...
I rest my case
Cheers.
Mikeh,
You seem very sure you can (in theory) improve upon the Naim design. In audio, your ears are the most important measure you can use. These instruments are your guiding light for getting beyond the rudimentary electronics taught at college and published in textbooks. In audio, if a circuit sounds very good then it is very good, regardless of how idiosyncratic or seemingly unrefined the circuit may appear. The design choices in the Naim amp are deliberate. The 22k collector resistor is not just there because Naim like wasting resistors; this would be silly for a manufacturing business. Your scorn is misplaced; you are using circuit theory that is overly simplistic for this application. That's why I feel the Naim design is quite a challenging one for new designers to take on and get sounding good.
BAM
You seem very sure you can (in theory) improve upon the Naim design. In audio, your ears are the most important measure you can use. These instruments are your guiding light for getting beyond the rudimentary electronics taught at college and published in textbooks. In audio, if a circuit sounds very good then it is very good, regardless of how idiosyncratic or seemingly unrefined the circuit may appear. The design choices in the Naim amp are deliberate. The 22k collector resistor is not just there because Naim like wasting resistors; this would be silly for a manufacturing business. Your scorn is misplaced; you are using circuit theory that is overly simplistic for this application. That's why I feel the Naim design is quite a challenging one for new designers to take on and get sounding good.
BAM
Hi traderbum
On the contrary, i have no scorn, as you put it, for Naim or its products......they are a succesfull business and that, one has to respect...and yes they are BRITISH
Rather, i feel that every design decision must have a RATIONAL explanation...there is no magic whatever anyone says....and no, i hardly read textbooks anymore......
I find it interesting however, that you should think my views simplistic, the unbridled ravings of a mere schoolboy.........This i find rather difficult to accept, as i humbly suggest my objections, (neither of which you have addressed), are perfectly legitimate.
Of course there are a great many audibly inferior amplifiers out there.....i believe however, that these flaws can infact be diagnosed with current test and measurement procedures...
Needless to say, one has to know what to look for in the first place....
I happen to think that if the humble transistor had been subjectively designed there would be no DIY audio, or indeed much else electronic today....
I respect the views of everyone on this forum...and i hope the converse is true also....Have a nice weekend...whats left of it...
cheers!
mikek , chigwell, essex, uk.
On the contrary, i have no scorn, as you put it, for Naim or its products......they are a succesfull business and that, one has to respect...and yes they are BRITISH
Rather, i feel that every design decision must have a RATIONAL explanation...there is no magic whatever anyone says....and no, i hardly read textbooks anymore......
I find it interesting however, that you should think my views simplistic, the unbridled ravings of a mere schoolboy.........This i find rather difficult to accept, as i humbly suggest my objections, (neither of which you have addressed), are perfectly legitimate.
Of course there are a great many audibly inferior amplifiers out there.....i believe however, that these flaws can infact be diagnosed with current test and measurement procedures...
Needless to say, one has to know what to look for in the first place....
I happen to think that if the humble transistor had been subjectively designed there would be no DIY audio, or indeed much else electronic today....
I respect the views of everyone on this forum...and i hope the converse is true also....Have a nice weekend...whats left of it...
cheers!
mikek , chigwell, essex, uk.
Re: naim
Hi Nickgreek,
this looks original to me, the leads of the power transistors indicate it is not a TO-3 case and not a TO-220 case, so it is not a Naim 160/250/135 and not a Naim 110. The Naim 140 first series of chrome bumper production years had Sanken 2SC2922 inside, I guess it is that what you have. Great little amp, BTW, this is the one I like best sonically from Naim. Much more neutral than e.g. the NAP160.
I guess the Sanken power transistors as well as the AKSA power transistors (Toshiba) are a lot more linear than Naim's proprietory power transistors. I am using a lot of Toshibas in my own designs, and they are excellent.
regards,
Hartmut
nickgreek said:
Hi Nickgreek,
this looks original to me, the leads of the power transistors indicate it is not a TO-3 case and not a TO-220 case, so it is not a Naim 160/250/135 and not a Naim 110. The Naim 140 first series of chrome bumper production years had Sanken 2SC2922 inside, I guess it is that what you have. Great little amp, BTW, this is the one I like best sonically from Naim. Much more neutral than e.g. the NAP160.
I guess the Sanken power transistors as well as the AKSA power transistors (Toshiba) are a lot more linear than Naim's proprietory power transistors. I am using a lot of Toshibas in my own designs, and they are excellent.
regards,
Hartmut
Mike
You've just missed an excellent opportunity to learn something here.
Some people actually know stuff based on actual experience, not theory.
I've spent far too long trying to emulate, for example, Naims apparently very simple preamp PSU's. They're only an LM317 + conventional raw supply, so my LM317 sheet and any text book on PSU's will tell me all I need to know, based on your previous posts.
I defy anyone though to be able to produce a supply that sounds as good as the Naim one using off-the-shelf technology - I will tell you now it cannot be done.
I eventually decided to solve the problem the proper engineering way by building a circuit to give the best performance possible in all of the parameters I could think of, then understanding what was important in a PSU, by changing parameters individaully and correllating measured results against sonic ones.
I learnt an awful lot, yet I suspect if I posted a schematic of the Naim supply you would no doubt tell us all how poor it is, and what's wrong with it. But I guarantee you could not do better using the same technology.
Swallow your pride, open your mind and learn something, I'm sure you, as much as anyone else have useful information and ideas to disseminate, just don't automatically assume you're always right.
In the end it matters not one jot how the final circuit looks or measures, it's how it sounds, and on that criteria you are evidently on shaky ground. It's a spot of ground that's well inhabited though, by the likes of Self et al - designers who listen with their spectrum analysers, and IMVHO know diddly squat about sound quality...
Andy.
You've just missed an excellent opportunity to learn something here.
Some people actually know stuff based on actual experience, not theory.
I've spent far too long trying to emulate, for example, Naims apparently very simple preamp PSU's. They're only an LM317 + conventional raw supply, so my LM317 sheet and any text book on PSU's will tell me all I need to know, based on your previous posts.
I defy anyone though to be able to produce a supply that sounds as good as the Naim one using off-the-shelf technology - I will tell you now it cannot be done.
I eventually decided to solve the problem the proper engineering way by building a circuit to give the best performance possible in all of the parameters I could think of, then understanding what was important in a PSU, by changing parameters individaully and correllating measured results against sonic ones.
I learnt an awful lot, yet I suspect if I posted a schematic of the Naim supply you would no doubt tell us all how poor it is, and what's wrong with it. But I guarantee you could not do better using the same technology.
Swallow your pride, open your mind and learn something, I'm sure you, as much as anyone else have useful information and ideas to disseminate, just don't automatically assume you're always right.
In the end it matters not one jot how the final circuit looks or measures, it's how it sounds, and on that criteria you are evidently on shaky ground. It's a spot of ground that's well inhabited though, by the likes of Self et al - designers who listen with their spectrum analysers, and IMVHO know diddly squat about sound quality...
Andy.
I defy anyone though to be able to produce a supply that sounds as good as the Naim o
http://www.users.zetnet.co.uk/avondale/
http://www.diyaudio.com/forums/showthread.php?s=&threadid=1437
"Finnesse regulator noise
Hi everyone,
I built this circuit some time back, and it does work, although emitter resistor value, in the transistor circuits, is critical for best performance.
I have some SPICE plots somewhere if anyone is interested.
I didn't like it's sound though, powering various bits of a Naim 42 preamp, but that could have been due to inadequate transistor performance (fT). Bit if a 'bun-fight' between filter and circuit ipossibly.
I've just built a 4 transistor discrete regulator, based on the Walt Jung POOGE series that appeared in 'The Audio Amateur'.
I've made a simple mod that offers stunning noise performance when compared with any monolithic regulator, whilst lowering output impedance and improving line rejection dramatically.
Again, if interested I'll post circuit / results.
Andy."
I have great respect for your post and opinions but what exactly is off-the-shelf-technology?
http://www.users.zetnet.co.uk/avondale/
http://www.diyaudio.com/forums/showthread.php?s=&threadid=1437
"Finnesse regulator noise
Hi everyone,
I built this circuit some time back, and it does work, although emitter resistor value, in the transistor circuits, is critical for best performance.
I have some SPICE plots somewhere if anyone is interested.
I didn't like it's sound though, powering various bits of a Naim 42 preamp, but that could have been due to inadequate transistor performance (fT). Bit if a 'bun-fight' between filter and circuit ipossibly.
I've just built a 4 transistor discrete regulator, based on the Walt Jung POOGE series that appeared in 'The Audio Amateur'.
I've made a simple mod that offers stunning noise performance when compared with any monolithic regulator, whilst lowering output impedance and improving line rejection dramatically.
Again, if interested I'll post circuit / results.
Andy."
I have great respect for your post and opinions but what exactly is off-the-shelf-technology?
Hi ALW,
Speaking of ultimate psus, have you studied Avondale's website which claims their APX pre-amp psu module is "...both technically and sonically superior to anything on sale at present"? The photo seems to show off-the-shelf parts. Thought I'd point this out in case Les decides to claim on your guarantee.
BAM
Speaking of ultimate psus, have you studied Avondale's website which claims their APX pre-amp psu module is "...both technically and sonically superior to anything on sale at present"? The photo seems to show off-the-shelf parts. Thought I'd point this out in case Les decides to claim on your guarantee.
BAM
Yes, Nickgreek, it is a photo image of a part of the 140 main amp channel. I suppose you did not scan it yourself, did you ?
I compared images, and I think it is a section of the image which is on the net for some time now (do not ask me where). When you look at the complete image you will see the Sanken 2SC2922 output devices, as Hartmut already correctly mentioned.
You can look at the full images here (short time only):
http://webplanet.lion.cc/uranus/380072/blue/140_02.jpg
http://webplanet.lion.cc/uranus/380072/blue/140_03.jpg
I too found the 140 a very good amp, significantly better than the 110, but it is a long time that I heard one of it...
Thank you, Andy, for interfering here, and making your statement, which I will fully support. I actually was about to never open this thread anymore again, getting very much annoyed by the quite aim- and useless discussion started, so it is good to focuse a bit and get back to the point, which we are all interested in.
What makes a seemingly simple and/or wellknown circuit sound good ( oh not just good, that is not so difficult, but VERY GOOD)?
Klaus
I compared images, and I think it is a section of the image which is on the net for some time now (do not ask me where). When you look at the complete image you will see the Sanken 2SC2922 output devices, as Hartmut already correctly mentioned.
You can look at the full images here (short time only):
http://webplanet.lion.cc/uranus/380072/blue/140_02.jpg
http://webplanet.lion.cc/uranus/380072/blue/140_03.jpg
I too found the 140 a very good amp, significantly better than the 110, but it is a long time that I heard one of it...
Thank you, Andy, for interfering here, and making your statement, which I will fully support. I actually was about to never open this thread anymore again, getting very much annoyed by the quite aim- and useless discussion started, so it is good to focuse a bit and get back to the point, which we are all interested in.
What makes a seemingly simple and/or wellknown circuit sound good ( oh not just good, that is not so difficult, but VERY GOOD)?
Klaus
Off-the-shelf
Bam / Harry,
What I meant, but maybe was not clear about, is that using LM317's available to the general public, and any transformer / capacitor combination they should choose, they will never beat a standard Naim PSU of Hicap status, or greater.
It is possible to build something better, but it takes a different approach.
Andy.
Bam / Harry,
What I meant, but maybe was not clear about, is that using LM317's available to the general public, and any transformer / capacitor combination they should choose, they will never beat a standard Naim PSU of Hicap status, or greater.
It is possible to build something better, but it takes a different approach.
Andy.
ALW said:
Andy,
this is exactly what I feel about Naim. I went into circles for some time when I made Naim clone amps, and only managed to make better ones, when I dropped the Naim theme and went into Mark Levinson/Kaneda style schematics, which are more rewarding.
Mathematically, Naim has found something like a local extreme value for its not-so-state-of-the-art circuits.
regards,
Hartmut
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