Listening impressions
I am happy builder of CFA 100W version.
I decided to build two monoblocks since I had suitable boxes and power supply parts that fitted. My listening tests are for about 20 years the same. I build power amp or preamp and then I compare the new one with the older ones. The preferred one or two amps I use then for quite long time - untill some other construction beat the previous one. If I don't like the sound of the new one I obviously dismout it. If it is excellent sound but still on the third/fourth place I use it as a gift to some of my friends.
My list of power amps with my preferences for the soud before CFA was:
1. TubSuMo from Valery
2. Hypa from Mr. Stranka - unfortunately schematics not present at diyaudio forum
3. JLH - generaly available
4. DPA 222 - Pavel Dudek construction available quite easily
5. Supersymetry Pass monoblocks - my own experiment schematics
6. Pass A75
7. others = dismounted quite quickly
At this moment exist only numbers 1., 2., 4. (= in my daughter house) and 6. (= my friend house). Box from JLH is now home for TubSuMo and boxes from Pass Supersymetry are homes for CFA. JLH was so high in my ranking for many years because of the quality of reproducing piano music. For other kind of music it could go lower.
Initial listenings for CFA were clearly very pleaasant without any objections from my side. I would describe sound as neutral maybe a bit analytical. Especially high part of spectrum was a bit brighter then I am used to.
The lowest octave in organ music was deeper then expected. I would say that it was the deepest bass in my household.
Then I started direct comparison among Hypa, TubSuMo and CFA. After long hours of listening I concluded as follows:
If the recording is top quality then CFA beat the other ones. Clarity, deepest bass and relaxed listening is characteristic feature. Otherwise when recording is not so perfect CFA is without mercy to anything. It is quite funny that from my point of view the sound that is really relaxed and enjoyable in one recording start to be not so pleasant in other recording. TubSuMo produces more musical sound and it does not care so much for the lower quality of recordings. HYPA is somwhere in between these two. It is not so musical as TubSuMo and also not so detailed as CFA.
My English vocabulary does not allow me exactly describe the sound in a way that is obvious in HiFi magazines and even I don't feel competent to do that. My conclusion is that CFA is perfect power amp for those who prefere more detailed sound and also for those who asks for deeper bass. I can imagine that this amp connected to even bigger loadspeaker then my could produce really excellent bass.
In my listing of power amps CFA is now on the second place. The reason is that I mostly listen to piano music from the previous century and the quality of recordings is sometimes questionable. Then TubSuMo is the winner. IF music producers will start to do their business more seriously from the quality of recording point of view then CFA could become real star.
Testing equipment in my case: battery supplied Notebook, USB cable, Audiolab CD900 DAC, passive LS silonex preamp or Kuartlotron buffer, chord speaker cable and Elam Flex 3w speakers (cca 60 litres) from Troels Gravesen.
Thank you Damir for beautiful design and really respectable piece of work. I wish you lots of succesess in other designs and joy from listening experience.
Ladislav
I am happy builder of CFA 100W version.
I decided to build two monoblocks since I had suitable boxes and power supply parts that fitted. My listening tests are for about 20 years the same. I build power amp or preamp and then I compare the new one with the older ones. The preferred one or two amps I use then for quite long time - untill some other construction beat the previous one. If I don't like the sound of the new one I obviously dismout it. If it is excellent sound but still on the third/fourth place I use it as a gift to some of my friends.
My list of power amps with my preferences for the soud before CFA was:
1. TubSuMo from Valery
2. Hypa from Mr. Stranka - unfortunately schematics not present at diyaudio forum
3. JLH - generaly available
4. DPA 222 - Pavel Dudek construction available quite easily
5. Supersymetry Pass monoblocks - my own experiment schematics
6. Pass A75
7. others = dismounted quite quickly
At this moment exist only numbers 1., 2., 4. (= in my daughter house) and 6. (= my friend house). Box from JLH is now home for TubSuMo and boxes from Pass Supersymetry are homes for CFA. JLH was so high in my ranking for many years because of the quality of reproducing piano music. For other kind of music it could go lower.
Initial listenings for CFA were clearly very pleaasant without any objections from my side. I would describe sound as neutral maybe a bit analytical. Especially high part of spectrum was a bit brighter then I am used to.
The lowest octave in organ music was deeper then expected. I would say that it was the deepest bass in my household.
Then I started direct comparison among Hypa, TubSuMo and CFA. After long hours of listening I concluded as follows:
If the recording is top quality then CFA beat the other ones. Clarity, deepest bass and relaxed listening is characteristic feature. Otherwise when recording is not so perfect CFA is without mercy to anything. It is quite funny that from my point of view the sound that is really relaxed and enjoyable in one recording start to be not so pleasant in other recording. TubSuMo produces more musical sound and it does not care so much for the lower quality of recordings. HYPA is somwhere in between these two. It is not so musical as TubSuMo and also not so detailed as CFA.
My English vocabulary does not allow me exactly describe the sound in a way that is obvious in HiFi magazines and even I don't feel competent to do that. My conclusion is that CFA is perfect power amp for those who prefere more detailed sound and also for those who asks for deeper bass. I can imagine that this amp connected to even bigger loadspeaker then my could produce really excellent bass.
In my listing of power amps CFA is now on the second place. The reason is that I mostly listen to piano music from the previous century and the quality of recordings is sometimes questionable. Then TubSuMo is the winner. IF music producers will start to do their business more seriously from the quality of recording point of view then CFA could become real star.
Testing equipment in my case: battery supplied Notebook, USB cable, Audiolab CD900 DAC, passive LS silonex preamp or Kuartlotron buffer, chord speaker cable and Elam Flex 3w speakers (cca 60 litres) from Troels Gravesen.
Thank you Damir for beautiful design and really respectable piece of work. I wish you lots of succesess in other designs and joy from listening experience.
Ladislav
More accurate amplifier will be more pleasure if the quality of recordings is better. Garbage in garbage out.
Some type of distortion can make bad recording sound good. It may second harmonic distortion dominant or third harmonic distortion dominant.
I suggest you try high-resolution recording. Some of high-resolution recording is really good. I think the imaging is easiest to be notice.
Yes, exactly. The best performance of CFA was with high resolution recordings, especially those one that are recommended for testing purposes.
But still I wonder, why some other recordings that are relaxed with TubSuMo are a bit "nervous" with CFA (sorry, I could not find more suitable english term)
BR, Ladislav
I would not know to answer that. I designed this amp to be as transparent as possible, with quite high negative feedback up to high frequencies.
This is the point at which one needs to voice the amplifier. Deliberately increase H2 by a small amount, till it sounds more pleasant with mediocre recordings. H3 may also increase, but as long as it is lesser than H2, it does not matter.
OStripper, tried a few methods in the Honey Badger thread, if I remember.
Hugh Dean and Nelson Pass use different approaches to achieve this effect. Nelson Pass' BA3 used as a preamp, is an example, through which, one can dial in the amount of H2/H3 via a pot.
Alternately, use a musical tube preamp.
OStripper, tried a few methods in the Honey Badger thread, if I remember.
Hugh Dean and Nelson Pass use different approaches to achieve this effect. Nelson Pass' BA3 used as a preamp, is an example, through which, one can dial in the amount of H2/H3 via a pot.
Alternately, use a musical tube preamp.
I don't agree with this, amplifier is not musical instrument and should influence the reproduction as less as possible.
For a guitar amplifier this is a wanted effect.
For a monitor amplifier which should represent the whole audio range as neutral as possible this is nonsense.
If you have an idea of adding "warmth" to sound, as studio and live sound engineers do in their mix, you wouldn't be reacting. Check legendary amplifiers, their specs and harmonic distortion profile. Read Jean Hiraga, perhaps. Maybe you can knock up something like Nelson Pass' ACA to appreciate the point. Any way, to each his own.
I agree. But some people think differently.
As amplifier designer, I must learn why some kind of distortion sound pleased.
So, I hope I can design any kind of amplifiers.
What you mean by reacting, I just stated my opinion. As astx said a guitar amp is different. I played electric guitar in my youth and built some guitar amps, mostly tubes and used distortion to voice it. If you want simple but good amps as the ones from Hiraga or Nelson then some harmonics are the result of that simplicity not deliberately added.
I was a bit taken aback by the term "nonsense". Every one is free to express one's opinion, but allowing space for counter opinions. Further discussions ought not to be scuttled by any tinge of aggressiveness. Let us also bear in mind that opinions change with time and experience, unless one wants to hold on even in the face of better or/and counter knowledge.
Well, to say that simpler circuits produce distortion is being naive. The simplicity in design with reference to Pass and Hiraga is a design choice with definitive objectives.
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All circuits produce distortion, more or less, and who is naive now and aggressive too.
Sam, at least you will have my empathy, unfortunately this thread happens to be the "ultra low distortion" camp which also attracts people of certain discipline who rather treats amplifier as a "laboratory instrument" and gets a massive boner satisfaction from 0,0000000000000..............n% measured distortion figures, then there are others like you and I who would prefer to treat an amplifier as a "music instrument" with warmth and soul whose satisfaction in opposition to distortion figures comes from the music played.
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I met several people like you who never tried to used accurate amplifier with good recording. When they hear my amplifier than they change their mind
When they hear my amplifier than they change their mind
Ok bimo you got me sold, I am immediately ordering the flights tickets to Indonesia!
But seriously, don't read too much into what I previously wrote, the thing is I can enjoy amps from both camps, I have an old little tube amp that I truly love, but let say for a more complex large orchestra classic music a more precise low disting SS amp is often better, all the amp variants are for me emotional instruments and art each with its purpose beyond secluded minds imaginary.
If you have presented your design somewhere on the net I would be happy to have a look at it, any link?
Edit: ok maybe I found your amp, if it is on the Anistardi Wordpress page?
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