Thanks Jenssenmann. I apreciate this replies. It´s my first DIY, and even I have basic electronics knowledge, I´m still lost about preamp desings, and all this infinite world of reading and reading. At this learning point have to ask sometimes things that I know are very basic for the guys on the forum, and even it sounds absurd, I´m still trying to find out, what really I´m building. I mean, what are the advantages and limits of this preamp.
As you tell, this design allow a very neutral-pre at affordable cost.
This suggest me more doubts.
Well, this is a trafo-less design. What limit the performance of this designs, the thing that have no trafo? Seems that Trafo based preamps, look for a specific color, but seems that also some designs using trafo try to use it to get things up, or I´m wrong?
For the Supergreen, I could finally get the original 2SC3329 transistors, the big Wimas, etc.
I guess what more can get, moreover the neutral sound, what is very fine. I mean, low distorsion, low noise... I´m still not sure if this parameters give better sound, because have reading several times about pres with higher dist, and noise sounding better then other with better specs... so get me more confused.
The DOA seems atractive, although complicate things, if can open a new door for the preamp sound, if really can clear things up.
I have read some suggestion from Jim Williams from Audio Upgrades, recomended trying the LT1357 opamp, what is designed for video. This one is a 8 pin compatible, so no problem to try it, and found about.
The 990 is an atractive thing to try, but I think would need some help for the isolation issue.
Do you think the 990 would worth the try on this preamp, or do you think would need other design to get the best of the DOA?