WhitakerAudio
 
Audio Projects – Downloads and Resources

The book includes three major projects—a stereo preamplifier, a 25 watt stereo amplifier, and a 50 watt stereo power amplifier. Pictures of the completed projects are shown below along with links to various available documents and resources.

Note that the parts lists provided below contained valid stock numbers as of the date of publication (2012). Component availability changes over time, and so some substitutions may be needed based on current availability.

Note also that the application files provided below are from programs in use at the time of publication. Most newer versions of computer applications are backward-compatible, in that older file versions can usually read by current version software. However, this may not always be the case.

Printed circuit board

Stereo Preamplifier

This project is described in Chapters 9 and 12 of the book. The stereo preamp serves as a perfect companion to the 25 W and 50 W power amplifiers.

Stereo preamplifier

The preamplifier provides four available inputs:
• Phonograph
• Microphone
• Auxiliary
• Tuner

An input switch selects the desired source, which is fed to a tone-control stage and finally to an output buffer amplifier. The final design includes a pair of printed wiring boards (PWBs) and stylized cabinet.

The starting point for the stereo preamp is a collection of preamp circuits described in the classic RCA Receiving Tube Manual (1975), with some new ideas and tweaks along the way.

One challenge in building a tube amplifier today is finding the right parts for the project. The bill of materials download below is intended to help make that effort easier.

The following documents are available for the stereo preamplifier, as a single ZIP file:
• Schematic diagram of the final design preamplifier (Figure 9.7 in the book).
• Bill of materials (BOM) for one channel in Word format (double the quantities for stereo).
• Bill of materials for one channel as an Excel spreadsheet (double the quantities for stereo).
• Printed wiring board (PWB) layout as a ".pcb" (ExpressPCB) file for one channel (two boards are needed for stereo).
• Front panel layout design as a "fdp" (Front Panel Designer) file.
• Back panel layout design as an "ai" (Adobe Illustrator) file.

For those interested in using the PWB file, please remember that this file can be used only with the vendor ExpressPCB. The front panel layout file can be used only with the vendor Front Panel Express. See Chapter 9 and Chapter 12 for details on this project.

Note that the files above are provided as-is. Every effort has been made to make sure they are complete and accurate, but no warranties are expressed or implied. Builders are encouraged to double-check the information contained in the above files prior to proceeding. All files are provided for personal use only. No further distribution is allowed.


25 W Stereo Amplifier

This project is described in Chapters 10 and 12 of the book. This medium-power amplifier is well suited to listening in a home environment.

25 W stereo amplifier

This high-quality amplifier provides approximately 12.5 W per channel. The input stage uses as 7199 pentode/triode and a pair of 6973 beam power tubes for the output section. This design is built around a pair of PWBs, one for each channel. A stylized cabinet is used, featuring exposed tubes.

The starting point for this amplifier is a circuit described in the classic RCA Receiving Tube Manual (1975), with some new ideas and changes along the way.

One challenge in building a tube amplifier today is finding the right parts for the project. The bill of materials download below is intended to help make that effort easier.

This project is a good starting point for a a tube-based audio system. While not easy to build, it is not a huge project either. As with most tube-based amplifiers, the major costs are the transformers used in the project. The author has used Hammond transformers in this project and the 50 W amp described below with good results.

The following documents are available for the 25 watt stereo amplifier, provided as a single ZIP file:
• Schematic diagram of the final design 12.5 W amplifier block (Figure 10.4 in the book).
• Bill of materials (BOM) for one channel of the amplifier in Word format (double the quantities for stereo).
• Bill of materials for one channel of the amplifier as an Excel spreadsheet (double the quantities for stereo).
• Printed wiring board (PWB) layout as a ".pcb" (ExpressPCB) file for one channel (two boards are needed for stereo).
• Front panel layout design as a "fdp" (Front Panel Express) file.
• Back panel layout design as an "ai" (Adobe Illustrator) file.

For those interested in using the PWB file, please remember that this file can be used only with the vendor ExpressPCB. The front panel layout file can be used only with the vendor Front Panel Express. See Chapter 10 and Chapter 12 for details on this project.

Note that the files above are provided as-is. Every effort has been made to make sure they are complete and accurate, but no warranties are expressed or implied. Builders are encouraged to double-check the information contained in the above files prior to proceeding. All files are provided for personal use only. No further distribution is allowed.


50 Watt Stereo Power Amplifier

This project is described in Chapter 8 (the power supply), Chapter 11 (the amplifier board), and Chapter 12 (complete system).

50 W stereo amplifier

This amplifier builds on the 25 W stereo amplifier, using a high-capacity power supply and 7868 beam power tubes in a push-pull configuration. Exceptional performance is achieved through attention to detail and oversized output transformers. A great-sounding amp.

As with the other projects described in the book, the starting point for this amplifier is a circuit described in the classic RCA Receiving Tube Manual (1975), with some updates and modifications.

One challenge in building a tube amplifier today is finding the right parts for the project. The bill of materials download below is intended to help make that effort easier.

This is a relatively big project. Quality transformers are expensive, and the ones used in this design are no exception. Chapter 12 in the book describes construction of this amplifier as a hand-wired chassis. A PWB version has also been produced by the author, with good results.

The following documents are available for the 50 watt stereo power amplifier, provided as a single ZIP file:
• Schematic diagram of the final design power supply (Figure 8.6 in the book).
• Schematic diagram of the final design amplifier block (Figure 11.3 in the book).
• Bill of materials (BOM) for one amplifier channel in Word format (double the quantities for stereo).
• Bill of materials for one amplifier channel as an Excel spreadsheet (double the quantities for stereo).
• Bill of materials for the regulated power supply in Word format.
• Bill of materials for the regulated power supply as an Excel spreadsheet.
• Printed wiring board (PWB) layouts as a ".pcb" (ExpressPCB) file: amplifier board, power supply board with regulator circuit, power supply rectifier, power supply regulator.
• Front panel layout design as a "fdp" (Front Panel Express) file.
• Back panel layout design as an "ai" (Adobe Illustrator) file.

For those interested in using the PWB files, please remember that these files can be used only with the vendor ExpressPCB. The front panel layout file can be used only with the vendor Front Panel Express. See Chapter 8, Chapter 11, and Chapter 12 for details on this project.

Note that the files above are provided as-is. Every effort has been made to make sure they are complete and accurate, but no warranties are expressed or implied. Builders are encouraged to double-check the information contained in the above files prior to proceeding.. All files are provided for personal use only. No further distribution is allowed.