My first OPA549 chipamp

[Igla]

Hi !
Here is my first OPA549 chipamp (non-inverted).It's stil a prototype until I decide what next.
PS is in separate housing - 200W toroid trafo and double MUR860 bridge.
On the picture:
Alphastat 10k log pot; OPA549 with 220u Epcos caps on the pins, LM338 regulators and 4700u+2x2200u caps.Everything rests on a cooper bar (an electrode for electro erosion).
Regulated supply is by Pedja schematic and gives +- 18.5V.
The feedback resistor on OPA549 is 18k and the resistor to ground is 1k.This gives the gain of 19.
I was testing regulated power supply with LM3875 and replaced them with OPA549 just to hear them.
I must say that I like what I hear.....

or in Carlos words....

After some
bas is so deep and defined
mids are silk to for
the hights are so clean

Regards;
Igla

[Igla]

Sorry guys.I just couldn't resist.Those icons can be really annoying,would you agree.
Never mind the rats nest on the photo but these OPA549 sounds pretty good.They are more smooth with better bas comparing to LM3875.I still like to listen to LM3875 but for my ears they can sound fuzzy on top from time to time and somehow thin.
Regards;
Igla

[Buhl]

I have the same experiences with the 3875, wich lead me into the arms of the 3886 - and this is the chip I use daily in parallel.
Then recently I tried the 3875 again, but now with only two Elna cerafine 1000uF pr. channel, normally I would use panasonic FC, or what ever lies around. Have tried generec elnas also - all with the same result a little harsh and "Fsssiiich" on the top. with the cerafines, all this disserpered - it now plays highs with a darkness behind them and no tendency of emphasing the highs. The bass is still no match for two 3886 with 88.000uF behind them - but everything from 100Hz and up is simply wonderfull - its like theres missing an wolly curtain compared to the 3886.

Cheers
Hans

[Igla]

I never tried some exsotic caps.All I can get at the local shops are Nippon , SME and Jamicon.Recently I've got some 220u Epcos caps from Conrad and they sure souns lot better;little darker but without lost of details.I use the same caps for my NON OS TDA1543 DAC.
The Alphastat pot is also from Conrad and for my ears sounds better than Alps blue.
I was really surprised when I changed LM3875 for OPA549.The sound is so smooth; I could say silky and the bottom is just great.And this is with the same parts.Still can hear all the details but without forwardness of LM3875.The forwardness of LM3875 partially dissapeared when changed to regulated PS (check Pedja's site for comments).Hard to describe the sound, especially when I must describe it in English but OPA549 are a little more laid back and smooth without hiding details.
Cheers;
Igla

[Upupa Epops]

Look at : " Bivoj " - new chip amp

[Igla]

Yes...I so the Bivoj thread.
I wouldn't know about the distortions, I am just listening and in the same configuration and with the same parts I like OPA549 more.LM3875 just sounds thin to me.Well, not thin like there is not enough low end but more like some upper mids are missing and too much treble.This is strange because my speakers are 20cm 8ohm fullrange units with sensitivity of 92dB and they are easy to drive.
Regards;
Igla