My 6 monoblocks are finally finished 
They are DC coupled LM3886 inverted amps with gain of 17,4 and feedback servo.
Supply for each of this amps is made of one 200VA 2x28V toroid transformer and 2 LM338T regulators. Before each regulator there is 3x2200uF + 470nF of capacitance, and after regulators 47nF near the regulator and 1000uF + 100nF by the LM3886 on each rail.
On regulator boards I left space for the snubber network, but tweaking will have to wait until I get to know the sound of this amps a little better.
I will use them for triamping my unfinished diy speakers.
I haven't had too much time for listening this amps yet, but in this little time I noticed that bass is phenomenal. It is deep and strong, but in the same time very well controlled with great dynamics. The highs are very detailed. Sound of this amps is little more opened than the of the last ones I had which were based on TDA7293.
More serious listening will have to wait until I finish speakers and preamp with active crossovers for them.
They are DC coupled LM3886 inverted amps with gain of 17,4 and feedback servo.
Supply for each of this amps is made of one 200VA 2x28V toroid transformer and 2 LM338T regulators. Before each regulator there is 3x2200uF + 470nF of capacitance, and after regulators 47nF near the regulator and 1000uF + 100nF by the LM3886 on each rail.
On regulator boards I left space for the snubber network, but tweaking will have to wait until I get to know the sound of this amps a little better.
I will use them for triamping my unfinished diy speakers.
I haven't had too much time for listening this amps yet, but in this little time I noticed that bass is phenomenal. It is deep and strong, but in the same time very well controlled with great dynamics. The highs are very detailed. Sound of this amps is little more opened than the of the last ones I had which were based on TDA7293.
More serious listening will have to wait until I finish speakers and preamp with active crossovers for them.
Attachments
At first I intended to triamp my new 2-way loudspeakers with them, but now I think I will go biamp because they drive 4 ohms with such ease, and they get just slightly warm even after long time full power listening. So now I have to think of a way to use the 2 spare amps I will have.
Speakers in the picture are closed box Q=0,7 2-way system with Westra XW165-1368 midbasses
http://www.elektro-akustik-labor.de/uploads/media/XW-165-1368.pdf
and Seas 25TFFC (H519) tweeter.
http://www.seas.no/seas_line/tweeters/H519.PDF
The first step now that amplifiers are finished is to finish this loudspeakers so I can finally start to listen some music because I gave my old speakers to my dad few days ago for his resthouse in hills so I now have nothing I can connect to outputs of this amps
Speakers in the picture are closed box Q=0,7 2-way system with Westra XW165-1368 midbasses
http://www.elektro-akustik-labor.de/uploads/media/XW-165-1368.pdf
and Seas 25TFFC (H519) tweeter.
http://www.seas.no/seas_line/tweeters/H519.PDF
The first step now that amplifiers are finished is to finish this loudspeakers so I can finally start to listen some music because I gave my old speakers to my dad few days ago for his resthouse in hills so I now have nothing I can connect to outputs of this amps
Attachments
One more pic of the inside:
The box of the amp is made from 10mm MDF painted in black, except the front panel which is 22mm MDF veneered in padouk and the sides which are made of pear tree.
The amp is completely silent with no input signal present, and I can't hear any hum by putting my ear near the speakers.
The regulated supply works so fine that I can't measure any deviation in output voltage of regulators even at full power bass attacks.
The box of the amp is made from 10mm MDF painted in black, except the front panel which is 22mm MDF veneered in padouk and the sides which are made of pear tree.
The amp is completely silent with no input signal present, and I can't hear any hum by putting my ear near the speakers.
The regulated supply works so fine that I can't measure any deviation in output voltage of regulators even at full power bass attacks.
Attachments
Thanks, Netlist !
It all went very smoothly until I made 5 amps, and started to build the last one. Then I got nervous asking myself: When will this all be over ? I can't take it any more ! I thought I'll never finish them. Making so many amplifiers at once was a big bite and a great test for my nerves.
But now, just looking at that array of amps makes me forget all my troubles.
It all went very smoothly until I made 5 amps, and started to build the last one. Then I got nervous asking myself: When will this all be over ? I can't take it any more ! I thought I'll never finish them. Making so many amplifiers at once was a big bite and a great test for my nerves.
But now, just looking at that array of amps makes me forget all my troubles.
On the last amp I worked on I somehow managed to connect the positive rail regulator wrong (+ to gnd and gnd to +) to the amplifier when testing. Thanks to God nothing happened, and that regulator got just slightly warm. Even the fuse didn't blow. On the output I got 2V of offset and just a little 100Hz hum. I wonder how that amplifier survived inverse polarity on one rail ? I did similar thing once to TDA7293 and it cracked in half.
Schematic
This chips don't like big supply capacitors because they ruin the sound of this chip in higher frequencies. If you put only small supply capacitors, the bass will be weak. By adding regulators you can add as much capacitance as you wish before regulators and leave just small caps near the chip, so you get the best of both worlds without any sacrifice in sound.
Except providing small supply impedance for amplifiers, regulators ensure that the voltage provided to amplifiers is stable as a rock, so the dynamics is also greatly improved.
karma,
cute horns you got there. I didn't know that they sell Westra drivers in Canada. I thought they can be bought only in some east and central European countries. They give great value in sound for the money they cost. How much did you pay Westra drivers there ?
In the file attached are the sch and pcb files. They are compressed to .ace because .zip file would be too large. I can't upload .ace file to diyaudio so i renamed it to .zip.Please rename the file after downloading to .ace. Winrar should open it.
This chips don't like big supply capacitors because they ruin the sound of this chip in higher frequencies. If you put only small supply capacitors, the bass will be weak. By adding regulators you can add as much capacitance as you wish before regulators and leave just small caps near the chip, so you get the best of both worlds without any sacrifice in sound.
Except providing small supply impedance for amplifiers, regulators ensure that the voltage provided to amplifiers is stable as a rock, so the dynamics is also greatly improved.
karma,
cute horns you got there. I didn't know that they sell Westra drivers in Canada. I thought they can be bought only in some east and central European countries. They give great value in sound for the money they cost. How much did you pay Westra drivers there ?
In the file attached are the sch and pcb files. They are compressed to .ace because .zip file would be too large. I can't upload .ace file to diyaudio so i renamed it to .zip.Please rename the file after downloading to .ace. Winrar should open it.
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