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Author Topic: SymAsym - A superb Audio Amplifier  (Read 2437 times)
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Hi Folks!

I recently finished building my own 5-Channel Audio-Amplifier, its not so much Arduino(yet) but I wanted to share this great project with you. Search for "SymAsym" if you want to rebuild it yourself.

Each PCB is for one channel, so I used 5 to have a 5.(1) System. Its an A/B Amplifier with incredible sound!

For those of the english persuasion:
http://www.lf-pro.net/mbittner/Sym5_Webpage/symasym5_3.html

And the German version:
http://www.symasym.holgerbarske.com/doku.php?id=symasym

The versions from the links are a little bit different from each other, but nothing severe, mostly a question of design.
You might also want to look for "toner transfer" to etch your own PCBs.

Anyway, I highly recommend you to try to build one PCB and comare this to your current Amplifier, and imagine the possibilities an arduino could open up combined with this thing^^

Cheers!

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Great Effort! The circuit  is quite compact for such impressive statistics! I used to like transistor amps, but now i am exclusively using the National secmicondictors overture series (Lm1875) based gainclones. They are small and sound better than transistorised variants.
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Thanks!

Since discussion about Audio-quality is nearly impossible, I'd be great if you could post some tests for this chip-amp, since as far as I've done research there aren't many amplifiers that can keep up with the SymAsym. (But I'm open to suggestions, since our Kitchen could use a decent sound-system ;-) )

Cheers!

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I'd be great if you could post some tests for this chip-amp, since as far as I've done research there aren't many amplifiers that can keep up with the SymAsym. (But I'm open to suggestions, since our Kitchen could use a decent sound-system ;-) )

Cheers!


Actually chip amp's were frowned on until 47 lab's gaincard which is based on lm3875 gained rave reviews http://www.sakurasystems.com/reviews/reviews6.html and http://www.6moons.com/audioreviews/47labs5/gaincard.html
You may have come across this design http://dogbreath.de/GainCard/GainCard.html  . The gaincard only used a 1000uf power decoupling capacitor(!) and the length of the signal path is just a few centimetres, and the feedback resistor is mounted so close to the IC that the length of this path is less than 1cm!  

A guy has benchmarked the circuits based on the gaincard (gainclones) here http://www.adx.co.nz/techinfo/audio/gainclone1.htm and comments "The harmonic distortion that matters never exceeds 0.001%, which equates to a power level ten billion times lower than the fundamental (0.001%^2 = 1E-10). This is better than the performance of most CD players, including many high end models."

I use the LM4780 stereo 60watt amp whose THD at  2x30w from 20Hz - 20kHz is only  0.03% THD.  http://www.national.com/mpf/LM/LM4780.html

There is no doubt that the symAsym is a excellent transistor amp with impressive statistics and if you are into transitorised amps then thats the way to go.

The reason i like chipamps is that they are so convienent to build, have excellent power supply ripple rejection ratios, and have so many safety measures like safe operating area and  over-voltage, under-voltage, overloads, shorts to the supplies or GND, thermal runaway, and there THD is so low that it rivals that of transistor designs.


If you havent tried the national secmiconductor Overture series of chip amps, then i would strongly recommend you try it...they are fun and the audiophille in you wont be disappointed smiley Here is a link on how one guy created a clone of the original, http://dogbreath.de/Chipamps/GainCardCopy/GainCardCopy.html
« Last Edit: June 07, 2011, 01:45:38 am by kalum » Logged

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Thanks for the links! This looks great, and since its on the cheap side I will try it and compare afterwards, and give a feedback of the two amplifiers in comparison!

Cheers!
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In the meantime I have developed a PCB for the lm3886 Chip-amplifier.
You might want to check this thread if you intend to build one yourself :-)

cheers!

It's essentially a hifi amplifier at low cost, providing excellent value for money!
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In the meantime I have developed a PCB for the lm3886 Chip-amplifier.
You might want to check this thread if you intend to build one yourself :-)

cheers!

It's essentially a hifi amplifier at low cost, providing excellent value for money!

How did it sound for you? In my experience they sound excellent. I indeed heard about the gainclones and their superb sound quality but i was skeptical until i built one myself based on the lm3886 and tried it. The first time i powered it i did not leave the room for 2 hours, such was the sound quality smiley Sometimes a burn in period of a few days might be needed.
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