Improved Vacuum Tube Models for SPICE Simulations An update of the article originally published Glass Audio, Vol. 8, No. 5, 1996, p. 18.
Tubemods.zip Shift-click to download the tube models as a compressed file which must be “unzipped” with Pkunzip, Winzip or a similar program. 87 kB.
PSpice shareware package instructions Instructions for the models and circuits in Tubemods.zip.
Finding SPICE tube model parameters A Matlab program for automatically determining tube model parameters from data sheets.
Feedback and Fidelity Submitted to Stereophile in 1998 and landed in a black hole on the editor’s desk, probably because it was too technical. Deals with the effects of negative feedback (NFB) on sound quality. Although NFB has bad rap among audiophiles, it has great benefits when done properly (it’s often done badly), but it has some limitations in power amplifiers. It also explains why total harmonic distortion (THD) is a misleading indicator of audio quality, i.e., THD is an unsuitable measurement. Part 2 contains basic plans for the Local Hero amplifier, a modification of the Dynaco Mark 3.
SPICE and the art of preamplifier design An update of an article originally published Glass Audio, Vol. 9, No. 2, p. 1 and No. 4, p. 38, 1997. Discusses preamplifier design using the Dynaco PAS as an example. Contains designs with outstanding sound quality, some suitable for PAS modification projects, some for new projects.
The Emperor’s New AmplifierTM My ultimate dream amplifier. 80 watts of class AB2 triode power with low feedback (none global) using a wide bandwidth toroidal output transformer with a servo to maintain dc-balance. Designed with extensive PSpice simulation. Arguably the most sophisticated vacuum tube amplifier design ever.
AmericanRadioHistory.com (a fantastic resource; a real treasure trove for geeks, discovered 2019) Contains complete scans of magazine issues on radio, broadcasting, and electronics technology. Of particular interest is a complete archive of Audio Engineering/Audio magazine from 1947 through 2000. I found several RCA Tube Manuals here. Worth digging into.
Dr. Craig Hollabaugh has put a page on Pentode Modeling on Github. He also has a page on Tube modeling on Youtube, with lots of utstanding information. Recommended! (Added May 2017)
Duncan’s Amp Pages The best source of vacuum tube data sheets and links. A Brit who never uses the word “valve.” American cultural imperialism strikes again. Frank’s Electron tube Pages Another amazing tube data resource.
Art Ludwig’s Sound Page Lots of great stuff on the physics of sound, human hearing, and audio design. From a passionate physicist, passionate about the art of music.
The Art of Electronics by Paul Horowitz and Winfield Hill. Their book is a must for anyone who wants to really know electronics. Beautifully written.
WinSpice A free Spice3F4 Port for Windows 95, 98, 2000 & NT. Very intriguing. Will simulate much larger circuits than evaluation PSpice.
PSspice student version (version 9.1 at last look) has limited capabilities by standards of solid-state circuit design, but it can be amazingly useful in simulating vacuum tube amplifiers, which tend to have fewer components. Hard to find on the OrCAD website. I had to go to the CadencePCB home page and click on All Downloads. The full versions are expensive.
LTSPICE/SwitcherCADIII A free and unlimited SPICE simulation program from Linear Technology with support through its user group, (http://groups.yahoo.com/group/LTspice). LTSPICE is highly compatible to PSPICE on a netlist level for analog components and models. Of course, the schematic editor and symbol editor are different. Recommended by Helmut Sennewald, who is one of the two moderators of the LTSPICE Yahoo-group. Sounds excellent; I haven’t tried it.
BeigeBag Spice B2 is a promising low-cost ($189) alternative to PSpice. The evaluation “lite” version is more severely limited than the PSpice student version. I haven’t tried it out.
One Electron offers design services and manufactures audio transformers. But what really makes their page interesting is links to service manuals and schematics for electronic equipment , and especially for audio equipment (classic amplifiers, tuners, etc.). Also has some entertaining and edifying links.
A reader informed me that Alex Cavalli had some excellent PSpice tube models. His article, A Fender-Tone Tube Headphone Amplifier, on Headwize.com, looks like a good place to start. Interesting site!
REG on Audio (Robert E. Green) Extremely interesting audio and music commentary. Many previously published in The Absolute Sound. I wish I had the time to go through them all…
James E. Lanier’s PSPICE Triode Calculator is a promising program for finding tube model parameters. It’s still under development; he plans to expand it to include tetrodes and pentodes.
Jeroen’s Technical Center: Motega (Modeling Of Tubes Employing Genetic Algorithms). Written in Matlab.
Plitron Manufacturer of superb toroidal output transformers. Includes a treasure trove of technical publications.
Ariel Loudspeaker, designed by Lynn Olson. After hearing Chris Brady’s Ariel I purchased a kit from North Creek Music Systems. I haven’t had time to build it.
Accel Thermal makes heat sinks.
Valutronics Swedish maker of kit loudspeaker and stereo power amplifier.
Welborne Labs has some excellent technical information and schematics.
Antique Electronic Supply
The Parts Connection
Parts express has interesting stuff including Hammond transformers for tube amplifiers.
ExpressPCB offers free software for PCB design and low cost board manufacturing in small quantities. I would give them careful consideration if I were currently involved with audio.
Vacuum Tube Valley Strong on projects and history. Audioxpress Incorporating Glass Audio. Tube CAD Journal Excellent online magazine for DIY tube enthusiasts. The tube collector, published by a group of passionate amateur collector-historians.
Audiophiles with interesting projects (strong technical content) and links:
Chris’s tube haven Fascinating projects and images of audiophiles in the Denver metro area (my neighborhood) | One Electron— John Atwood has nice technical articles and amplifier designs.
Boston Audio Society has excellent events, articles, and links.
Radiomuseum.org is developing a resource for antique ratios— descriptions, schematics, etc.
Record collecting: I have about 7,000 LP’s, two-thirds classical, and I’m trying to reduce my collection by eliminating duplicates and music I’m not in love with. I’m starting to compile links about collecting, labels and pressings for my own education. Labels in the UK are mostly different from the USA. UK pressings are regarded as having higher quality, but they’re rare here. Some sites I’ve found: Harry Pearson’s famous super LP list | Princeton Record Exchange has buying lists.
Reviews (mostly CD) Classical Net has some nice links. | Classics Today