Apple iPhone 11 Pro diagram excerpt describing the earpiece receiver and its audio amplifier circuit, stored in a 314 KB RAR archive.

Circuit extract for the Apple iPhone 11 Pro covering the power amplifier supply circuit, packed as a 246 KB RAR archive.

Apple iPhone 11 Pro circuit material for the high-frequency power amplifier section, packed in a 430 KB RAR archive with no format details given in the name.

iPhone 11 Pro circuit excerpt for the low frequency power amplifier circuit, packed into a 369 KB RAR archive.

Archive for the Blaupunkt GTA 250 amplifier, part number 7607792037, packed as a 649 KB RAR file.

ZIP archive of 7.03 MB named PA 6.0 CIRCUIT, apparently a set of circuit drawings for a unit called PA 6.0, possibly a public address amplifier, though no maker is…

Compact archive referring to the NE5558 / SA4558 family part numbering, most likely a datasheet for a 4558-type dual operational amplifier.

Documentation for the Apple 820-2299 audio board, a separate small board for the audio circuit, packed into a 140 KB RAR.

Archive named RC4559, 343 KB, with no brand listed. RC4559 is the part number of a dual operational amplifier, so the contents are most likely the datasheet for that IC…

Documentation for the Apple iMac A1150 M9 LIO audio board at PVT stage, drawing number 051-7066, packed into a 410 KB RAR.

Repair guide archive for the Oppo A9 2020 covering no network or weak signal faults, 352 KB in RAR format.

Archive for the Apple audio board 820-2136, a 137 KB RAR file covering the daughterboard that handles audio connections.