DOA riddle solved

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jensenmann

Well-known member
Joined
Oct 10, 2004
Messages
2,850
Location
Karlsruhe, Germany
Here´s some pictures about a mystery DOA riddle which I have solved:

https://ibb.co/4VXXfZG
https://ibb.co/0FPdnf6
https://ibb.co/KKb1Gjv
https://ibb.co/cbbs0C1
https://ibb.co/nB0pZLq

Guess what that is....
8)
 
wlinart said:

Exactly. That was fast...

Since I repair Sontecs quite often I ran into the problem to repair defective DOAs at some point. Thanks to Corona lockdown early this year I had enough time to reverseengineer a HS2030 DOA. I made a PCB layout and finished my first DIY HS2030  last night. It´s working. Happy camper here :)
 
Have you seen Joe Malone's (JLM Audio) work on these?

https://www.jlmaudio.com/shop/hs3030-opamp.html

He's done quite a bit of work on Sontec opamps, including the HS2030, an adaptor for the HS10** opamps, HS2000, and the HS6000, among others.

 
Yes, I did. I´m using his DOAs in my Don Classics 250. They are spot on. That combination is as close as you can get to a real 250c. I had them side by side. Joe´s DOAs are available with 2520 pinout, so he´s doing us DIYers a big favor.

Joe´s DOA came out when I was in the middle of reversing the HS2030. I don´t know if I´d done all that work if they were available earlier. Anyway, his DOAs are SMD and my version is all original THT with all those obsolete unobtainum transistors. As I said before I repair Sontec, mostly for mastering studios here in EU, and most clients want it to be as original as possible. That´s what I was trying to accomplish with my PCB. From a commercial POV it doesn´t make sense to do it other than SMD. But paranoid mastering guys love that minute detail ;-)
 
jensenmann,

Sorry to revive an old thread, but is there any chance you'd have docs/prints on those? Info on what sort of unobtanium transistors they are? I just put one up on the bench, and the darned things have the numbers filed off. Lovely. While doing a deep dive on it might be fun, I doubt the owner wants to fund that many hours.

Any help would be appreciated. Thanks.
 

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