r 21?
i have made mistake when i post the old schematic and here is the corrected schematic. r21 is connected to power gnd same as apex schematic.input gnd can be connected to power gnd.but in apex schematic he used r36 as an option if hum is present.i have connected pin 3 of ic1 to input gnd same also in apex schematic.
foil pattern had been corrected in last post.
i have made mistake when i post the old schematic and here is the corrected schematic. r21 is connected to power gnd same as apex schematic.input gnd can be connected to power gnd.but in apex schematic he used r36 as an option if hum is present.i have connected pin 3 of ic1 to input gnd same also in apex schematic.
foil pattern had been corrected in last post.
Attachments
i finish build this amp. Result is sound very excellent. Low noise. Vocal is clear and i like this amp. i use 2 pair power output. Drive on +-50V. Not use any buffer or pre amp. Use car heatsink. Thanks to apex and alex. More picture for my sr200 here.
Nice PCB 🙂
Edit:
😕
Q11 (BD139, bias regulator), Q13 (2SC4793) and Q12 (2SA1837) should be located at the same heatsink with 2SA1943/2SC5200
Just great amplifier,judging by the posts of the people that built it! That will be the third one from you APEX. The first one will be the AX12(or a B80),the second NX16 and the third studio reference 200. Now i know what i will build in a next year,two or even more-depends of my money/time sources. It is nice to have such a great people that are willing to share schematics and pcb-s of devices that are tested and risk-to-built-free! Greetings to all of you!
What kind of noise? Deep bass or a sound of a wind through the trees? They are caused by a different things. First one could be from magnetic field of a transformer (if it is too close to an amplifier pcb-s),not enough filtering in a PSU(too small or old capacitors),damaged bridge rectifier...those are all reasons for a deep bass noise. I once had a noise ("wind in a tree"kind) in one other amplifier and it was caused by leaking capacitor 68nF,when I replaced it the noise was gone.
Ultimate Fidelity use current source and current mirror at differential stage, but I can't see inte Studio Reference. Why? Best regards
15V zener and 15k resistor give 1mA CCS. Current mirror give beter offset, Studio Reference use DC servo.
Regards
OK thank you. LF411 difficult to be found in my country, can't I use single op-amp (eg. TL071) and trim offset null to get minimum DC offset? Regards..
Hi APEX I need your help with psu, I can't use 2 psu because I dont have space but I need to suply 4 sr50, what changes do I need to do to psu rail volt 40-45 dc. Thanks
D
Deleted member 148505
Hi, anyone here that has a latest compilation of SR200? like bill of materials, notes for building.. etc
Would greatly appreciate it.
I just backread and I got confused of many versions. I got the pcb layout and picture of sr200 v2.3. I think that's sufficient to build sr200 but I don't know the value of diameter and number of turns of the inductor. I also need tips on how to get it right the first time.
Thanks
Would greatly appreciate it.
I just backread and I got confused of many versions. I got the pcb layout and picture of sr200 v2.3. I think that's sufficient to build sr200 but I don't know the value of diameter and number of turns of the inductor. I also need tips on how to get it right the first time.
Thanks