Audio DIY Projects and other wanderings

PP 300B amplifier I have several DIY projects on the go: some complete, some still at the planning stage, and some still in bits after years of tinkering. The list here includes projects long vanished into the parts recycling bin, items that make up my current listening system, right up to fantasy projects that are unlikely to ever get built. There are discussions of hardware designed and built by other people, as well as some of my various assorted opinions on related topics. I have included some links to the pages of a few people whose views on audio matters I find challenging (in a positive sense!).

Disclaimer - please note that any project details posted on this site are supplied for general interest only, rather than as contructional guidelines, and I cannot guarantee their correctness or reliability. Anyone trying to build from them is responsible for their own safety and for any possible resulting damage to property or to persons.

Another word of warning - I am by training a physicist, not an engineer, so I maintain that the square root of minus one is i. This may or may not confuse some engineering types...

Loudspeaker projects

  • My three-way Neptune speaker project
  • Converting my speakers to fully passive operation
  • Some vague ideas for a pair of closed-box subwoofers
  • Some even more vague thoughts on copying the Sonus Faber Amati Homage
  • Some similarly inchoate plans for active speakers for a home theatre system
  • Allen Wright's preamplifiers
  • What's so special about the Realtime Preamplifier?
  • Building my own RTP3
  • Comparing my RTP3 with the Audio Research SP-11
  • Building my Six-Valve preamplifier
  • My remote-controlled solid-state preamplifier project
  • Ideas and design notes
  • Plans and circuits
  • The implementation
  • The relay-switched attenuator volume control
  • Other phono stages and preamplifiers
  • Croft valve preamplifiers
  • My Audio Synthesis ADEQ phono stage
  • The Audio Research SP-11 preamplifier: my understanding of how it works
  • Power amplifiers
  • Kevin Kennedy's push-pull 300B amplifier
  • Giovanni Stochino's 100W high-speed amplifier design
  • My own Stochino amplifier project
  • Croft Series 5 - a classic hairshirt valve amplifier
  • The Audio Research Classic 30: a little gem
  • The Maplin 50W amplifier kit
  • Active crossovers
  • My universal active crossover
  • Active compensation for the baffle step
  • Ideas for a fully differential active crossover without using negative feedback
  • My valve-based differential crossover project
  • Various DIY projects
  • Velleman K4500 FM tuner
  • Adding a dedicated mains spur to the system
  • Building a shelving system for my electronics
  • Housing my LP collection
  • Odd articles (by me)
  • Wire and connectors - some rambling thoughts
  • The Golden Ratio in loudspeaker enclosure design
  • The "Signal Path" - Some thoughts
  • Ever wondered how big a DC offset you can get away with on an amplifier output? Here are some guidelines.
  • Linear phase crossovers with filler drivers
  • My Audio Asylum review of the Funk Firm modifications to my Pink Triangle PT TOO turntable
  • Some thought-provoking links
  • Troels Gravesen's astonishing speaker project pages. Troels has built, tested - and most helpful of all - fully documented dozens of DIY speaker projects.
  • Lynn Olsen's Ariel project: high-quality, high-efficiency transission line speakers designed for relatively low-powered valve amplifiers. Mike McColl has posted a coupled of YouTube videos here and here as at least the start of a construction guide for the project
  • Comparison by Contrast - how a better system makes music more varied
  • A little note on real-world digital audio
  • An interesting article on Audioholics on measurements of vinyl LP and CD
  • A nice semi-technical article about why valves might sound different from transistors
  • John Atkinson on Blind Listening
  • Arthur Salvatore's site: some occasionally contentious but interesting and strongly-held opinions about high-end audio in general. His criteria for reference components is worth a read: his priorities, particularly low listening fatigue, "immediacy" and the audibility of low-level musical information, overlap with mine quite substatially.
  • Lynn Olsen's excellent articles on his Nutshell Hifi site. Here are some particular personal recommendations: the nature of distortion in simple and complex amplifier circuitsi; his ultra-purist Amity amplifier project, starting from the premise of the lowest possible open-loop distortion and no feedback; and on issues in film-and-foil capacitor construction. His Ariel speaker design, designed specially for low-powered valve amps, also draws me in.
  • Siegfried Linkwitz' article on the audibility of crossover phase distortion
  • Rod Elliott's excellent tutorial on heatsink choice and implementation - a must for anyone building their own amplifier.
  • Steve Bench's survey of valve-based shunt voltage regulators.
  • Some worthy manufacturers' sites
  • The Funk Firm: innovative turntable manufacturers, of Pink Triangle lineage.
  • Vacuum State Electronics: producing some very special valve circuits. It appears that VSE are still selling kits and complete products, despite the untimely loss of its founder, Allen Wright.
  • Croft Acoustics - Solid and intelligent valve designs at low prices.
  • Online magazines and discussion groups
  • The Vinyl Asylum - my favourite audio forum on the 'Net. The atmosphere is always civilised and the passion of the participants for this medium is obvious.
  • The Vinyl Engine Pink Triangle and Funk Firm forum. A great resource for these classic and underrated turntables.
  • The Tube DIY Asylum. Some occasional bad-tempered exchanges, but still a good source of knowledge.
  • The Tube DIY Forum: as above, but a superior level of discussion.
  • The Multi-way speaker DIY Forum. This has some fascinating and wide-ranging discussions, and - unlike a lot of other forums - still has some top-flight and original designers making active contributions.
  • Positive Feedback online magazine. PFO has published some very interesting and informative articles in the past, although the frequency of these has decreased recently, and the site (perhaps unavoidably) has an increasing prominence of advertising.
  • TNT online review site. A nice friendly hangout, although the quality of reviews has dropped recently.
  • The often fractious and childish (but occasionally illuminating) Pink Fish Media audio forum.
  • Stereophile magazine. This has a terrific archive of subjective and technical reviews.
  • Mail me