Audio Projects for Home Entertainment
For more years than I care to remember I've been tinkering with audio amplifiers to listen to vinyl records, tape decks, FM receivers or to provide music for an event. My first unit was a pair of 6L6G tubes with big transformers providing some 40W into open frame speakers built in 1960 for a school event... This project was followed by a classical 2x EL84 full amplifier - later converted to stereo - and the 6L6G unit upgraded to a full amplifier. All the while tinkering with preamps, tone control, single ended amplifiers etc. slowly converting from tubes to transistors and ICs.
As there has been quite a revival of tube amplifiers and - quite apart from the "audiophile" group - many people are interested in building such units, there follows some information on projects being done here using sometimes recently available nice PCBs from China combined with quality components and transformers obtained from the EU or sometimes from my stock. Where available the sources of these materials are listed. There are several projects and I try to describe them as they are completed:
The refurbished Philips EL6400 MkII.
- 20W PP Mono PA Amplifier Philips EL6400 MkII, made in 1954 and now fully restored using 50ies technology. For description, pictures and diagrams go to → A Journey into the Audio Technology of the 50ies. The text itself is in German.
- PP Stereo Power Amplifier using two pairs of EL84 tubes, 10W output transformers (from Germany), magic eye display and a fully regulated HV supply with DC heaters for all tubes.
- PP Stereo Power Amplifier using two pairs of 6L6GC, 20W output transformers (ex-Pioneer) and regulated HV power supply and DC heaters.
- My "crazy project": PP Stereo Power Amplifier using two pairs of GU50 tubes, 40W transformers (from Germany), preamp, phono preamp, tone control, magic eye display and regulated HV power supplies and DC heaters. A big unit in a 19" frame. It's about 60% complete...
Other audio projects
- PLL type high stability Tape Speed Control for the Studer-ReVox B77 MkII tape deck.