15lyl

Thank you Dr.Kevin.

Hope Kevin will explain the circuit detail.

So complicated !

https://drive.google.com/drive/folders/1r3g2TAtBUaBdiMorTWX7yYgeJ7maQbYW https://drive.google.com/drive/folders/0B7egryukiT7_TFlEQlBRejdVdDQ?resourcekey=0-nGWwBYQ_Uivj-ciBLYMeaA

https://www.richardsonrfpd.com/Products/Product/C2M1000170D

They are in China. 86 is China, Hong Kong is 852.

We cannot get these 2SK109 and 2SK389 anymore, they are obsolete for a long time, all of them are fake from AliExpress.

Hi Kevin, Thank you for your message about the bias of the cfa3 amp, I am running the ZF, by disconnecting the 4 600p, I could adjust the bias smoothly to 200mA, no squeak or oscillation any more. What are those 600P for?

I etched the board myself, am running the ZF. I can only stop the oscillation by connecting a 500P to the B, C of the output transistors, smaller than 500P can’t stop the oscillation. I may try to run the SS later to see the negative feedback will help the oscillation.

Thanks, I did so.

Hi Kevin, the 4 transistors around THAT340 are in different orientation, the THAT340 pnp C is to the following Tr E, while the npn is to C. which one is correct? All ON brand MJE15030, 15031 that I used in the power output had oscillation, some Motorola were stable. Is the fT30 too high?

I use this schematic for KGSS +-15V 15V.pdf