Those are the input transistors. Part numbers on the schematics are still good to find datasheets. Of course they are obsolete.
It is possible to find adequate transistors. Recently I have made measurements and pairing of A970/C2240. Initially I wanted to use KSA992/KSC1845 instead but I have desoldered ON Semi transistors and used CDIL because measurements with curve tracer were overwhelming. THD-N measurements have confirmed that in the particular case CDIL transistors were better choice. There are also other adequate generic products that can be used in this cloning project.
This amplifier has very wide bandwidth and excellent bass. I have a similar amplifier that sounds great.
Note, that there is an error in the schematics: a line connecting D9 and R21 should not be connected with the line connecting R20 and the bases of Q6 and Q7. These lines should just cross eachother, without a dot indicating junction.
This amplifier has very wide bandwidth and excellent bass. I have a similar amplifier that sounds great.
Note, that there is an error in the schematics: a line connecting D9 and R21 should not be connected with the line connecting R20 and the bases of Q6 and Q7. These lines should just cross eachother, without a dot indicating junction.
Old thread, but another error in that in post #1 schematic is that the Q14 emitter should be facing the positive DC rail. Hopefully helps someone in the future.