This is a location for papers, magazine articles, and data not directly related to any Tavish Design product, for fellow audiophiles and DIYers. Product brochures and owner's manuals for Tavish Design products are located with the detailed product descriptions in our catalog. Enjoy!
Audio Tube Noise Measurements
Here is a list of measured noise data on a selection of current production audio tubes (and a few NOS tubes). So far, it includes vacuum tube types 12AX7 / ECC83, 5751, 12AT7 / ECC81, 6DJ8 / 6922 / E88CC, EF86, ECC99, and 6SL7GT. It includes the brands JJ, Shuguang, Sovtek, Tung Sol Reissue, and Electro-Harmonix. New measurements are being added regularly, so please let us know if there are other types or brands we should include. We recently added measurements on the D3a, RU-6C45PI, RU-6H9C (6SL7GT), RU-6H16, and RU-6H6, as well as additional samples of 5751, 6922, E88CC, and 6SL7GT. Most recently we added measurements on the new JJ 12AY7 and 6SL7 (last update 27 April 2017). We've also added measurements on the Toshiba 2SK209 low-noise audio JFET, as an interesting comparison to the tubes. Download the summary (tube_noise_summary.pdf) or visit the project webpage.
The RIAA Replay Characteristic for Phono Stages, and Inverse RIAA Networks
Tavish Design phono stages are designed to implement the traditional RIAA replay curve. We do not implement the 1976 IEC Amendment which rolls off the replay response at 6dB/octave below 20Hz, and we do not implement the occasionally discussed “Neumann pole” at 50 kHz. Tavish Design calibrates its phono stages against an inverse RIAA network as described in Lipshitz and Jung. Read more on our RIAA webpage.
Direct-Coupled Tube (or Tube-MOSFET) Headphone Amplifier
Here is a design in progress at Tavish Design. You can visit the project webpage to see detailed schematics and a discussion of the idea, which will be updated with measurements, photos, and revisions as the project goes on. The same basic circuit topology could be used to build a direct-coupled hybrid power amplifier as well. There's a thread on diyaudio, if you have comments or questions.
Noise Measurement Amplifier and Filter
Here is a simple circuit that makes it easy to measure weighted noise levels or signal-to-noise ratios with a PC-based oscilloscope. The circuit is quite versatile and also works well with a conventional analog scope. It consists of a 100X amplifier and a variety of filters, including A-weighting and C-weighting filters. I developed a PC board to make it easy to duplicate, and I thought some fellow DIYers might also find it useful. The white paper describing it (noise_meas_amp_filter.pdf) and an Eagle board file (noise_meas_amp_filter.brd) are free downloads.
LED Bias Monitor for Tube Amps
Here is an article describing an LED Bias Monitor for Tube Amps, published in audioXpress in November 2008. I recently reordered a few boards which are available here.
- Here are two articles on a DIY planar magnetic loudspeaker, written by Daniel Patten and published in Speaker Builder in 1995 and 1996. Posted with permission of Elektor.
Patten_SpkrBldr_895.pdf and Patten_SpkrBldr_496.pdf
- Here is an article that I wrote back in 1999, on a very low distortion tube amp, and published in Glass Audio. The prototype appearance is a bit rough, but the performance is exceptional for an all-tube amp, and I'm still proud of the circuit design. This circuit topology may become the basis for some future product. 70W_6L6GC_GlassAudio_No5_99