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Old 12th November 2011, 11:30 AM   #81
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Quote:
Originally Posted by homemodder View Post
Nico, thats an interesting design, have you tried dispencing with the input LTP section, its really not needed. A couple of Jfets in parallel on second LTP to get high enough transconductance and you good to go.
No homemodder, I have not. When something is working, I tend to leave it alone.
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Old 12th November 2011, 11:41 AM   #82
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Originally Posted by Lazy Cat View Post
I am sorry but I don't want to have a tube amp in my system. Thanks for the tip anyway.
I hate tube amps, too coloured.
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Old 14th November 2011, 04:08 AM   #83
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Originally Posted by Nico Ras View Post
This is the amplifier I tested your input configuration with.
Hi Nico,

Yes this is a relative of SYMEF, however.....
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Old 14th November 2011, 04:15 AM   #84
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Originally Posted by drowranger View Post
this is what i have in my mind.may i know what is the characteristic of the output transistor that is suitable for your amplifier?
Hi Joel,
I see you sorted out your thermal compensation. I hope you have enjoyed the Slone amp. You can use devices from any respectable manufacturer. Hows the progress?

Thanks.
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Old 14th November 2011, 04:20 AM   #85
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Quote:
Originally Posted by Nico Ras View Post
And its square wave response. However the front end filter cap I have changed to 220p instead of 470p
Quote:
Originally Posted by Nico Ras View Post
Hi Andrej,

when the specification differences become negligible, forget it, to make any choices based on subjectivity, these systems sound identical.

There is no way that anyone can say with that the SSA and RAS44 will sound different even if SAA reveals that the 3rd harmonic being dominant or that in RAS44 2nd harmonic is dominant.

Practically neither distortions exists. Both amps have bandwidth extending beyond 1MHz, both amps has slew rates of several 100V/uS, both amps phase deviation is less than 1 degree at 100kHz.

Besides, if you listen at normal volume levels both amps added or subtracted artifacts will be below the noise-floor anyway - what is the point?

When your product reaches a certain level of sophistication going beyond this is pointless, they will perform identically. It is only placebo that could cause a subjective difference to be detected.
Quote:
Originally Posted by Nico Ras View Post
Andrej, when you get to the point where the technical performance of your amp exceeds a criteria, then I believe that there is no difference in the sound between these products, whomever designed them.

If a designer chooses to introduce some artifacts by means of feedback, filtering, etc. that he believes improves the sonic characteristic, this is most probably what people hear and either like or dislike about a specific product and it may not be as subjective as we think.

I think that most of us on DIY audio have the objective to produce technically perfect amplifiers, however we still see the subjective nature of the designers come into play when speaking of 2nd and 3rd harmonics being dominant and whether bootstraps or CCS improves the sound, etc.

When you reach a point where artifacts are several orders of magnitude below the detection threshold of the human ear, then I believe that it is placebo unless the designer intentionally modifies the signal to produce such an effect.

So Andrej, your amp is as good as it gets. When we are fooling around with numbers beyond the third or fourth decimal point is probably more egotistic than realistic.
For sale,

Clinical ham amplifiers for sale. Do not operate near class D amplifier equipment
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Old 14th November 2011, 04:36 AM   #86
AKSA is offline AKSA  Australia
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Cheap shot OnAudio.

If you knew Nico's background and achievements I doubt you would be so cavalier.

Hugh
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Old 14th November 2011, 04:39 AM   #87
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Thumbs up good work

Quote:
Originally Posted by Nico Ras View Post
And the harmonic distribution, each harmonics contribution as % and THD as %. Of course these are all simulations. My amps are transparent subjectively speaking. Simulating with your front end configuration did change the harmonic distribution as well as THD marginally in the simulation but the ear would not detect it as it is virtually non existent.

I have listened again and again switching between the two configurations on headphones after I have adjusted each config to output the exact same amplitude. Now I must admit that I am convinced that in my first testing claiming a different sound that it was placebo. I can hear absolutely no difference at all.
Quote:
Originally Posted by Nico Ras View Post
I have simulated the input circuit in my L-MOSFET version of Andrej's SSA (with input circuit & without input circuit) as well as listened intensely to any change of character of instruments, voices. etc.

The speakers I use are bookshelf size and incorporates the classic Scanspeak 2010 tweeter and Peerless 6.5 inch Aluminium cone woofer in a 27 litre enclosure and Andrej's SSA has been my choice for my office amp for the past 7 or 8 weeks.

I spend most of my time in my office (around 8 - 10 hours per day) and always have music playing so I am very familiar with this amp/speaker combination and have enjoyed it immensely since I built it.

I am not doing blind test because I have to physically switch the input by inserting the front end circuit or removing it, so time passes between listening and re-listening.

The THD curves are plotted on the same graph and the green markers is used to display the harmonics and THD with Onaudio's circuit in place and the red markers without the additional input conditioning.

Honestly, and as much as I would like to report otherwise, I cannot hear any difference at all.

I have for the past two hours irritated my wife to the extent that if I would go and do the same tests on my main system in my lounge, she would shoot me and I would have to do this when she goes out on her own because I played the same song over and over at pretty loud levels for about an hour listening to different things and making notes what I hear that I thought was different.

I am sorry I cannot be of more help Onaudio, you may get better responses from the other 29999 people who might be testing your idea. The problem is the responses are subjective and not of much use really.

I will be following this thread, but I feel my limited contribution to it is now exhausted.
Hi Nico,

Thumbs up for the level of work and sacrifice you have taken. However
1. You did not actually listen to the SYMEF, what have you overlooked ?
2.The human body compensates for persistent stimulus by numbing the senses
For example were you to set the temperature of the shower, it will be warm and pleasant at first, after a while you will feel that the water is not hot enough and increase the temperature. Were you to eat chocolate, you would be unable to distinguish some tastes for some time
3. When you finally have the SYMEF connected to your speakers and you crank up the volume, you will be asked for a dance
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Old 14th November 2011, 04:59 AM   #88
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Quote:
Originally Posted by OnAudio View Post
Hi Joel,
I see you sorted out your thermal compensation. I hope you have enjoyed the Slone amp. You can use devices from any respectable manufacturer. Hows the progress?

Thanks.
onaudio Im still in middle east country and im going vacation and will be there on first week of december in philippines.I will build your amp. as soon as i get there.and also I have finished sloan class A pcb and will compare both of them.but right now all I can do is prepare the board.anyway whats best of your amp.is its free and we have your guarantee its working.
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Old 14th November 2011, 12:45 PM   #89
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Hi Onaudio,
I do not argue the subjective nature of seeing, hearing, feeling, tasting, smelling.

I merely showed a schematic and simulated performance characteristics of the amp I used to test the input circuit with.

I did not present component values because I do not want anyone to build it, I demonstrated the curves simply to say that it is technically no worse than yours, and there was no intention of ridiculing your design, but if you understood it in that way then I apologize profusely.

What I would like to understand simply is your methodology to categorizing subjective experiences into meaningful data that would create the formula for a universally accepted design. I see it as some like blue and some red, making it purple may not appeal to either. I have tasted salty chocolates made in Holland, I nearly puked when I put it in my mouth - but many Dutch people love it.
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Old 14th November 2011, 04:06 PM   #90
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Quote:
Originally Posted by Nico Ras View Post
Hi Onaudio,
I do not argue the subjective nature of seeing, hearing, feeling, tasting, smelling.

I merely showed a schematic and simulated performance characteristics of the amp I used to test the input circuit with.

I did not present component values because I do not want anyone to build it, I demonstrated the curves simply to say that it is technically no worse than yours, and there was no intention of ridiculing your design, but if you understood it in that way then I apologize profusely.

What I would like to understand simply is your methodology to categorizing subjective experiences into meaningful data that would create the formula for a universally accepted design. I see it as some like blue and some red, making it purple may not appeal to either. I have tasted salty chocolates made in Holland, I nearly puked when I put it in my mouth - but many Dutch people love it.
Hi Nico,

This is going to be an interesting one. Responses will be dealt with by creating a model that can be used to categorize user experience as either very good, good, acceptable,poor and very poor.

I haven't applied a parser and a lexer to your responses yet but they look promising .

You have done some beautiful work and am only waiting for you to take the final step

many thanks
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