Service manual PDF for the Audio Pro TA150 receiver, matching the rec and sm tags in the name.

Service manual for the Audio Pro B1.35 MK2 subwoofer, read from the B1_35MK2, sub and sm tokens in the name.

Power-supply service schematic for the Audio Pro AP3000, based on the pwr and sm tags in the name.

Audio Pro Ace Bass B4-200 subwoofer service manual, going by the AceBassB4_200, sub and sm tokens.

Schematic, per the sch suffix, for the Audio Pro Ace Bass B2-70 subwoofer. The 546 KB PDF covers the built-in amplifier, likely including the ACE-Bass circuitry, Audio…

Service manual PDF for the Audio Pro Ace Bass B2-50 subwoofer, named with the sub and sm tags.

Audio Pro Ace Bass B2-40 subwoofer service manual in PDF form, about 1.96 MB, as indicated by the sub and sm tags.

Service documentation for the Audio Pro Ace Bass B1-45 subwoofer, going by the sub and sm tags.

Service manual for the Audio Pro Ace Bass B1-39 subwoofer, a compact 272 KB PDF that likely holds the core amplifier schematic and perhaps a parts list.

Audio Pro Ace Bass A101 service manual, with the int tag suggesting an integrated amplifier, though the name does not state this firmly.

Second part of the service manual for the Audio Pro A4-14 speaker, going by the spk and sm2 tokens.

First part of the service manual for the Audio Pro A4-14 speaker, a 6.15 MB PDF identified by the spk and sm1 tokens and paired with a second volume.

Service schematic for the Audio Pro A2, supplied as a 542 KB PDF; the int-sm suffix most likely marks an international service manual edition.

Audio Pro A101 service documentation in PDF form, about 3 MB, with the int-sm tag pointing to an international service manual version.

Copper-side PCB artwork for the Apex AX 20 amplifier project, a 208 KB PDF showing the track pattern rather than a circuit diagram.

Mirrored version of the Apex AX 20 copper-side layout, a small 62.3 KB PDF. The reversed image is meant for toner-transfer or photoresist methods, where the pattern must…

Component placement drawing for the Apex AX 20 amplifier board, a 61 KB PDF. It shows where each resistor, capacitor, transistor and connector sits on the PCB, which…

Top silkscreen layer for the Apex AA9 board, marked as MD revision 2, in a 58.7 KB PDF.

Component layout for the Apex Class A shunt design; raspored elemenata is Serbo-Croatian for parts placement.

Copper pattern of the Apex Class A shunt board, viewed through the PCB from the component side, according to the Serbo-Croatian title.

Spanish-language schematic for a stereo amplifier titled Zener, rated at 1000 W, in a 1.15 MB PDF.

Reference design document for an adjustable-output 200 W SEPIC power supply, a 3.26 MB PDF.

Michaels International diode equivalents guide, a large 8.42 MB PDF catalogued here as a schematic but actually a cross-reference book.

Schematic for the 60 W NDFL amplifier published by ETI in 1983, combined with a regulated power supply, in a 6.74 MB PDF.

Tone control circuit intended for a 2.1 channel audio system, in a 159 KB PDF. It shows the bass and treble adjustment network that sits between the source or preamp and…

Speaker protection circuit for a 2.1 audio setup, a user-drawn design in a 139 KB PDF. Such boards normally delay relay engagement at power-up to stop thumps and…

Diagram of a 2.1 preamplifier joined to an audio power amplifier, taken from a YouTube project; the doubled pdf extension is just a naming slip.

Hi-fi 2.1 amplifier schematic credited to SeahorseDIY, in a 688 KB PDF. It covers a stereo-plus-subwoofer layout, likely with the crossover or filter stage feeding the…

Schematic of a 2.1 channel amplifier based on the TDA2030A, from Technical Mriganka, in a 416 KB PDF.

2.1 channel hi-fi audio amplifier circuit by Technical Mriganka, a 164 KB PDF. The title does not name the amplifier ICs or output devices, so identify them from the…

2.1 amplifier schematic attributed to Amiru, a compact 98.7 KB PDF. The name gives no details about the ICs or power level, so the diagram itself must be read for…

Technical Mriganka 2.1 amplifier design using the TDA7379 and TDA7377 power amplifier ICs, a 206 KB PDF.

2.1 amplifier schematic built around the TDA7294, by Technical Mriganka, in a 219 KB PDF.

2.1 amplifier schematic using the 2SC5200 and 2SA1943 complementary power transistor pair, in a 184 KB PDF.

Class H power supply schematic, version 0.2, fuse type, marked final, in a 1.39 MB PDF.

Schematic of a 1000 W audio power amplifier rated into 2 ohms, marked R2, RLVA SE1, 2012 revision 1, in a 110 KB PDF.

Modified 2.1 channel amplifier schematic, a 90.6 KB PDF; the title does not say which original design was altered or which ICs are used.

Circuit diagram for a two-way active audio crossover, supplied as a 134 KB PDF. The name gives no designer, part numbers or crossover frequency, so expect a generic…

Plain-text document of 12.3 KB whose name suggests a single unit with a 15x15 layout in a golden format.

Schematic of a 5-band graphic equalizer in a small 16 KB PDF, with a YMYA tag in the name that may refer to the source or the designer.