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Message: [QUOTE="Menno1000, post: 1019870, member: 56080"] Thanks a lot for all your replies! I put work in it and found the fault. First I got back and tested components. Q1 and Q2 tested ok. Transformer was the same as on the good boards. Put everything back. I missed that with replaced c21 and c22 the trace was on the component side of the pcb and did no connection between -15V supply and Q2 . I reinforced all traces with hard wire and now it works fine again. I ordered new BD517/518, pretty hard to find. So best i replace these even if it now works now? I replaced C21/22 1000uF with Panasonic FC. While I am at it, is it a good idea to add a film cap parallel? Yes gonna do this. Yes, i will. Funny the Frako EP J 1000uf created a short. I never knew a lytic could create a short circuit. But this one did. I really like these mic pre's and i am on the lookout for more. I modded two boards by replacing the 5534 for an opa627 en shorted tantalum C5 en and C8 to make it dc coupled. C15 I kept in place to have at least one dc block in the chain. Maybe it can go? These boards sound a lot faster. In the unmodded boards i could replace the tantalum decoupling caps with Panasonic FC or FM. Or leave this in for the sound reasons? Any. Thanks again and have a good day. [/QUOTE]