Posted some pictures of my amp + pre.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=53220
http://www.diyaudio.com/forums/showthread.php?s=&threadid=53220
I built one too
I built this amp in one weekend.
But it's not cased yet...that may take 3 or 4 weekends for me
I used Alcaid's OPA549 schematic, 330uf caps. The board for each channel is 1 3/4 inches square, point-to-point wired.
I made sure to "double up" on the wire thickness in the power input lines to the chip, as well as the ground, and the signal Out.
But for the buffer, I tested it with this circuit, as I had it built already for another project :
Page 22,
fig. 6-53
http://waltjung.org/PDFs/ADI_2002_Seminar_Ch6_Audio_Drivers_I.pdf
---------------
For this amp, I might build a similiar driver/buffer earlier in that PDF,
page 20,
fig. 6-51
where for a gain of 3, changes would be:
R1=3k
R2=1k
R3=1k
R4=1k
using a dual 50k audio taper pot in the front.
=RR=
I built this amp in one weekend.
But it's not cased yet...that may take 3 or 4 weekends for me
I used Alcaid's OPA549 schematic, 330uf caps. The board for each channel is 1 3/4 inches square, point-to-point wired.
I made sure to "double up" on the wire thickness in the power input lines to the chip, as well as the ground, and the signal Out.
But for the buffer, I tested it with this circuit, as I had it built already for another project :
Page 22,
fig. 6-53
http://waltjung.org/PDFs/ADI_2002_Seminar_Ch6_Audio_Drivers_I.pdf
---------------
For this amp, I might build a similiar driver/buffer earlier in that PDF,
page 20,
fig. 6-51
where for a gain of 3, changes would be:
R1=3k
R2=1k
R3=1k
R4=1k
using a dual 50k audio taper pot in the front.
=RR=
Pics of finished opa549 integrated amp..
(Thanks for the amp schemo, Alcaid !!)
Inside overview (minus Xformer, for grounding test)
Chip amp view:
http://i5.photobucket.com/albums/y177/Midiot/DSCN2056.jpg
Preamp view:
http://i5.photobucket.com/albums/y177/Midiot/DSCN2060.jpg
PSU (cap multiplier for the Chipamps + pre-regulator (esp website) and 78/7915 regulated for the Preamps....showing voltages - loaded.)
http://i5.photobucket.com/albums/y177/Midiot/DSCN1927.jpg
Exterior:
http://i5.photobucket.com/albums/y177/Midiot/DSCN2064.jpg
Sounds real good for a small secondary system. It drives those NHT bookshelf's to their limit. 4 inputs + a pair Out (off the switch) for a headphone amp. No offset cap between pre and amp...maybe I should have those
??
I have not calculated the Watts RMS yet....(I've got that formula somewhere..
)
=RR=
(Thanks for the amp schemo, Alcaid !!)
Inside overview (minus Xformer, for grounding test)
An externally hosted image should be here but it was not working when we last tested it.
Chip amp view:
http://i5.photobucket.com/albums/y177/Midiot/DSCN2056.jpg
Preamp view:
http://i5.photobucket.com/albums/y177/Midiot/DSCN2060.jpg
PSU (cap multiplier for the Chipamps + pre-regulator (esp website) and 78/7915 regulated for the Preamps....showing voltages - loaded.)
http://i5.photobucket.com/albums/y177/Midiot/DSCN1927.jpg
Exterior:
http://i5.photobucket.com/albums/y177/Midiot/DSCN2064.jpg
Sounds real good for a small secondary system. It drives those NHT bookshelf's to their limit. 4 inputs + a pair Out (off the switch) for a headphone amp. No offset cap between pre and amp...maybe I should have those
??I have not calculated the Watts RMS yet....(I've got that formula somewhere..
)=RR=
Yesterday finished quick and dirty versiom of my OPA549 "gainclone" based on Alcaid's schematic and PCB. Although I'm using cheap components, comparing to amplifier I was using before it sounds great. I hope to finish it properly so I could show everyone my idea of low power HiFi amplifier
Thanks to Alcaid for such a nice version of this amp
Thanks to Alcaid for such a nice version of this amp
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