Let's place an end in this nonsense....
Hey, Glen don't spend your time in this confused - caused from me as well and from you - topic.
I am sure that you have the expertise so you can understand very well that i am not a novice in audio electronics. The same i believe for you.
But i become nervous many times, when unskilled persons ask from me - when i publish a project with documents such curves from scope and not only by writing hypothetical numbers - data without meaning such slewing. Many people they impressed from big numbers and they can't understand the bandwidth from the curves of rise time. They confused between speed and bandwidth, while slewing limit or rise time related only with the bandwidth limit in the upper region of spectrum under stability.
I have seen many times in manuals of comercial amplifiers, the simple numerical reference of a slew rate of 130V/ìs, while in curves quoted a rise time of 1,9ìs. And i wondered, where is the curve represents this amazing slewing?
The answeer is that, this slewing it is measured without the existence of in-out, global-nested feedback filters in their place. Thus - i have tried also me many times to make such measurement without success - we can obtain a lot of spikes, overshoots, harmonics etc etc in output. What is usefull of them?
To cause impression in people?
Instead there are many comercial amplifiers which sincerelly they report the slew rate as 40V/ìs (obviously measured from a curve such mine). Also there are many other constructors which don't reffer the slew rate.
To make the thing short, there are two slew rates. The one without the restrictive filters in the circuit, and the second with these filters in place. I am suspicious that the reference in the first it is for causing impressions, because i can't understand in what it is usefull. Also i am curious to see at least one time this curve of 120 or 300!!! V/ìs. Have you in your stock a such curve of the named extrinsic slew rate to solve my query?
Fotios
Hey, Glen don't spend your time in this confused - caused from me as well and from you - topic.
I am sure that you have the expertise so you can understand very well that i am not a novice in audio electronics. The same i believe for you.
But i become nervous many times, when unskilled persons ask from me - when i publish a project with documents such curves from scope and not only by writing hypothetical numbers - data without meaning such slewing. Many people they impressed from big numbers and they can't understand the bandwidth from the curves of rise time. They confused between speed and bandwidth, while slewing limit or rise time related only with the bandwidth limit in the upper region of spectrum under stability.
I have seen many times in manuals of comercial amplifiers, the simple numerical reference of a slew rate of 130V/ìs, while in curves quoted a rise time of 1,9ìs. And i wondered, where is the curve represents this amazing slewing?
The answeer is that, this slewing it is measured without the existence of in-out, global-nested feedback filters in their place. Thus - i have tried also me many times to make such measurement without success - we can obtain a lot of spikes, overshoots, harmonics etc etc in output. What is usefull of them?
To cause impression in people?
Instead there are many comercial amplifiers which sincerelly they report the slew rate as 40V/ìs (obviously measured from a curve such mine). Also there are many other constructors which don't reffer the slew rate.
To make the thing short, there are two slew rates. The one without the restrictive filters in the circuit, and the second with these filters in place. I am suspicious that the reference in the first it is for causing impressions, because i can't understand in what it is usefull. Also i am curious to see at least one time this curve of 120 or 300!!! V/ìs. Have you in your stock a such curve of the named extrinsic slew rate to solve my query?
Fotios
Mooly said:
I built this amp and have been using it for about 7 years, driving a pair of Dynaudio Finale speakers and Ellis 1801b. I am very impressed with the sound - very detailed. Pic of one of the monoblocks is attached. Never had any problems with stability, output devices (a lot of people don't think they are robust enough) and anyone who has heard the amps are very impressed.
Attachments
smithy666 said:
Hi smithy
Very impresive construction, my compliments sir!
If you have a scope and a square wave generator - there is not the need of a dummy load so much - can you please inject a 20KHz square wave in the input of this beauty, so its output swings at 50% of full level for safety? And if you can do this, can you post a photo from the screen of scope?
A such document can resolve all this senseless discussion about slew rate (EXTRINSIC and INTRINSIC!!! Wow! What about a scientific expression!!!).
If this amplifier has a 300V/ìs s.r. as refered by my friend Mooly, then the curve at 20KHz must be presents almost a perfect angle of 90deg at the rising edge corner.
If the amplifier has zobel in output, don't forget to desolder the resistor for its safety.
Thanks
Fotios
suzyj said:
Hi suzyj
Your link does not redirect. Anyway, i made by typing the address in browser.
This amplifier it is unrelated with audio. It is for boosting coaxial (aerial or cable?) signals in the region of GHz.
Are you make joke?
Also in the curves there is not at least one indicating slew rate.
Regards
Fotios
This is the reason why i am grumbling
In the following 3 docs, you can see the refered slew rate of 125V/ìs in the first, and in the two next the curves indicating the rise time curves. Your conclusions Clen?
Fotios
In the following 3 docs, you can see the refered slew rate of 125V/ìs in the first, and in the two next the curves indicating the rise time curves. Your conclusions Clen?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Fotios
Hi Smithy666
Excellent construction congrats. I have also built this fine amp and can say that it is at the top of my favourite Class B AB amps so far for sound quality on this forum and strangely enough not much has been said about it, a lot of flak though. Ive built most of the designs on this forum but two that i find interesting, as prototypes on veroboard and have no complaints but high praise for this one. I built it with high quality japanese transistors and use a 17 000$ amp | eletrocompaniet nemo | as reference, compares very very well.
Warning This amp doesnt sound tube like, it sounds lifelike. There is only one correct way for a musical signal being amplified by a amplifier to sound and that is accurate to the source. Use high end sources and youll smile, for anything less rather build one of the less accurate but warmer, tubey, ear pleasing, sweet sounding amps which flatter cold harsh metallic cd sources.
Maybe the high slew rate does have something to do with it......
Excellent construction congrats. I have also built this fine amp and can say that it is at the top of my favourite Class B AB amps so far for sound quality on this forum and strangely enough not much has been said about it, a lot of flak though. Ive built most of the designs on this forum but two that i find interesting, as prototypes on veroboard and have no complaints but high praise for this one. I built it with high quality japanese transistors and use a 17 000$ amp | eletrocompaniet nemo | as reference, compares very very well.
Warning This amp doesnt sound tube like, it sounds lifelike. There is only one correct way for a musical signal being amplified by a amplifier to sound and that is accurate to the source. Use high end sources and youll smile, for anything less rather build one of the less accurate but warmer, tubey, ear pleasing, sweet sounding amps which flatter cold harsh metallic cd sources.
Maybe the high slew rate does have something to do with it......
fotios said:
Hi Fotios
Unfortunately it's not a simple task for me to run such a test, as they are cabled up and have other audio equipment sitting on top of them (which I don't really want to move, recable etc). If I have to reorganise the setup, then I will take them out and run the test. Stochino did produce detail about testing and measured results etc in his first article from Electronics World April 97. I have a copy of this if you are interested.
Mooly said:
I am surprised as well. I think EW sold a lot of boards for this, but very people people on this forum ever built it. Maybe there are a lot of half finished Stochinos lying around.....
homemodder said:
My source is a Gryphon Tabu CD player, which I think matches well with the amp. Prior to building this amp I was using a pair of Cherry NDFL that I built in the 80s from an ETI article. These amps sunded good, but the Stochinos were a very dramatic change...they certainly had the "wow" factor when I first fired them up years ago.
smithy666 said:
Thanks smithy for your reply
I hope that you not misunderstand me; I realy asked your help, and only this, according to my post; was not an occasion for criticism, by no way. Fortunatelly - because i am no good in english - your reply it is in accordance. Sorry friend - friends i call only the obviously good mens - if i was confused you.
My best greetings
Fotios
fotios said:
Hi Fotios
No confusion or problem. Your post was perfectly fine. I would be happy to help with such a test if I could do it easily, but (linking to another post here), my wife would not be happy with me disassembling the living room again!! I would also be interested in the results of such a test - pity I didn't do it at the time.
All the best.
smithy
Figure 27 it is probably fake!
By looking it, with my falcon eye- expertised for 25 years by looking in screens of scopres as well in docs - i believe that the nr.27 figure in 3rd photo it is fake. It is not possible the increase of supply by 31V to offer a such reduction in rise time as it is presented. A good reason is that; it is not reffered the vertical scale graduation.
To not missunderstand me, i know very well that the symetrical input stage - or the double LTP pair - it offers a better rise time by 20% at least from the single LTP input.
You can obtain the whole project by typing in your browser "AN1308". Then, select what is refer "motorola".
Fotios
By looking it, with my falcon eye
- expertised for 25 years by looking in screens of scopres as well in docs - i believe that the nr.27 figure in 3rd photo it is fake. It is not possible the increase of supply by 31V to offer a such reduction in rise time as it is presented. A good reason is that; it is not reffered the vertical scale graduation. To not missunderstand me, i know very well that the symetrical input stage - or the double LTP pair - it offers a better rise time by 20% at least from the single LTP input.
You can obtain the whole project by typing in your browser "AN1308". Then, select what is refer "motorola".
Fotios
smithy666 said:
I was relieved!
My best greetings also to your familly (you are married as i see, and by chance given i wish in your wife and in you a life strewn with flowers)
Hey, i have seen in news on TV, that in Australia it hailed yesterday (in Sidney region) and you supposed that it snows
Also we in Greece we have to see a good snow about 10 years ago.
Ah, these climatic changes!
From a small corner of north Greece where is my home.
Fotios
Hello Smithy and Homemodder,
Interesting comments on sound quality. As you both will know having built it, me saying "No gate resistors to the FET's" was incorrect. Actually there are - I was thinking of Giovanni's previous articles which were a " build up " to the final published design and PCB's.
This was one design I was always interested in building someday, but have grown to like the sound of my present amp.
Which does seem to flatter most material, but it is just so involving to listen to. You lose yourself in the music. You forget all thought of "slew rates and rise times" and start thinking about the music itself. Maybe I am just a "Tube Guy" in denial
Audio is certainly strange, but that's what keeps us all interested I suppose.
Anyway a very nice job indeed.
Interesting comments on sound quality. As you both will know having built it, me saying "No gate resistors to the FET's" was incorrect. Actually there are - I was thinking of Giovanni's previous articles which were a " build up " to the final published design and PCB's.
This was one design I was always interested in building someday, but have grown to like the sound of my present amp.
Which does seem to flatter most material, but it is just so involving to listen to. You lose yourself in the music. You forget all thought of "slew rates and rise times" and start thinking about the music itself. Maybe I am just a "Tube Guy" in denial
Audio is certainly strange, but that's what keeps us all interested I suppose.
Anyway a very nice job indeed.
Mooly said:Hello Smithy and Homemodder,
Interesting comments on sound quality. As you both will know having built it, me saying "No gate resistors to the FET's" was incorrect. Actually there are - I was thinking of Giovanni's previous articles which were a " build up " to the final published design and PCB's.
This was one design I was always interested in building someday, but have grown to like the sound of my present amp.
Which does seem to flatter most material, but it is just so involving to listen to. You lose yourself in the music. You forget all thought of "slew rates and rise times" and start thinking about the music itself. Maybe I am just a "Tube Guy" in denial
Audio is certainly strange, but that's what keeps us all interested I suppose.
Anyway a very nice job indeed.
Obviously, it is a nice project yet if it is many complex and i consider this number of SR=300V/ìs some excessive to be real. But this not means, by no way, that this circuit it is very faster from anything i have seen untill now, from my expertise and by looking only the plans that have posted to me my friend Mooly.
I will make an effort to simplify and to join this circuit with mine (with bjt in output) in an effort to make something special and easilly implemented, such a monoblock amplifier with higher supply at +/-60Vdc so we get also the dynamics offered by this supply level.
Any comment and any help for a colaboration it is well accepted.
Fotios
I couldnt care less if the Stochino design had a tenth of the slew rate it is claimed to have, what I do care is that it will not smear, make music involving or make me lose myself in the music and ohh and ahh and more ahh but to be as accurate sounding as possible to the source which in turn should be as accurate sounding as possible to music as produced in a concert hall or stage by the instruments and voices of the musicians themselves. The only differences I like to hear is the percieved distances from soundstage in which very good setups differ and in which the music is still lifelike and as close as possible as if I were to stand or sit among those attending the music event.
The Stochino does a very good job of producing music as produced by your source. Now if your source is upto the job of producing lifelike music you may be a little bit closer to having musicians making music in your living room.
There are some tube amps that protray lifelike music too, in some respects some of them even better than any solid state amplifier could.
Now just maybe the good specs, be it the slew rate or low distortion figures of the Stochino amp help out making the stochino amp a gem of a lifelike sounding amp.
Smithy your choice seems a good one, I mostly use a Marantz Sa11 although I have some others but I loved using my Linn Sondek turntable which unfortunetly is now damaged and my missing JLH preamp from a move to europe.
Fotios Ive looked at your design in another thread, looks good, congrats.
The Stochino does a very good job of producing music as produced by your source. Now if your source is upto the job of producing lifelike music you may be a little bit closer to having musicians making music in your living room.
There are some tube amps that protray lifelike music too, in some respects some of them even better than any solid state amplifier could.
Now just maybe the good specs, be it the slew rate or low distortion figures of the Stochino amp help out making the stochino amp a gem of a lifelike sounding amp.
Smithy your choice seems a good one, I mostly use a Marantz Sa11 although I have some others but I loved using my Linn Sondek turntable which unfortunetly is now damaged and my missing JLH preamp from a move to europe.
Fotios Ive looked at your design in another thread, looks good, congrats.
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