SonyClone(pre)AMP by viktor1986,Dragan100 and APEX

SonyClone(pre)AMP by viktor1986,Dragan100 and APEXaudio

my friend viktor1986 was interested in this Sony preamplifier,so by few instructions of Dragan100 he redesigned original schematic and draw a pcb on it's own and have it done. most of attention he got when he uploaded measurements that he made,specially with 150kHz square input/output. than APEXaudio added an idea to build a headphone amplifier based on this schematics,than a few schematics of a power amplifier and that "triggered" Dragan100 to do a simulation of schematic that was a product of various ideas of his own combined with APEXaudio's and viktor1986's ideas.

basic files and measurement of preamp made by viktor1986(i can not upload files for a pcb,i haven't asked him if i could do that):


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schematic of Dragan100 wil be posted under this post. i have started drawing a PCB for it and i have got to some point,from wich i must now first check everything out before i do a pcb and begin to fill a pcb with parts. i had some place on a pcb so i added APEX controle (power,clip and signal) and APEX PROTECT (DC protect,overload protection,"Mute" function and power-on delay). protect part is adjusted to work in a negative voltage,just as controle part is(inverted related to schematics). VAS part of an amplifier will work at higher voltage to achive maximum out of output stage,and that part will also be done by one of APEX schematic,wich files i will add soon.

i would add a sprint file but in this computer i do not have rar/zip program working, i will try to do something about that...


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i really do not have any particular question about this amplifier,i just assumed that it is very interesting to share. naturally,if anyone would see a mistake done in a pcb,i would appreacheate to point me to correct it. i have high hopes on this one,and will share all my experiences on it. progress will be slow,but i would not be sad if anyone would have done this one before i would,just not before i double and tripple check everything on documents,and than one should check it too before starting doing it.

simulation is very very promising in all ranges,and output stage is designet pretty "bulletproof" consitering current demands of possibly problematic loads/loudspeakers. we'll se...
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Regarding schematic in the first post (headphone amp)...few questions and ideas...
- what would happened if bias pot looses wiper contact - solution is to connect wiper to Q12 emitter
- for better thermal tracking - stable bias, use the same device as output stage uses. So, use another IRF710 to form Vgs multiplier and recalculate R21, R22 and RT1, wiper connection rule still aply (instead of BJT Q12, judging by the image of the real thing it should be easy swap...e-c-b vs g-d-s
- if you split R5 in two equal resistors, midpoint could be used as DC servo injection point from IC1 output, also DC servo amp in this case should be you have a DC servo control (almost) completely outside the signal loop