The punch line is that the MFB filter is a better active filter, which explains why it is often used in demanding audio applications, such as high-dynamic-range ADC input stages. It is slightly more complicated than the equivalent non-inverting Salen-Key filter, so it is largely unknown to most audiophiles.
I ran out of my own supply of hookup wire, so I bought a huge spool of CAT-6 600 MHz cable. The cable holds four sets of twisted pairs of 23 gauge copper solid-core wire coated with Teflon-FEP. This hookup wire is great for wiring up electronic projects, as the Teflon-FEP high-temp sheathing melts at 500F. In addition, the 23 gauge wire holds its tight twisting and stays in place, unlike the 24 and 26 gauge alternatives.
With electrostatic headphones, you simply hear things that you never hear with any loudspeaker and with few other headphones; for example, classical musicians turning their sheet music over, floorboards creaking under the bass player and his fingerprints rubbing against the strings.
Electrostatic-headphone amplifiers and power supply kits.
Aikido LV, ACF, CCDA, BCF, Unbalancer, and SRPP+ PCBs and kits. Buy just the PCB or add the items that you need to finish your project.
Tube-based buffers provide no gain, but do offer a low output impedance and can deliver the current needed to drive capacitance-laden cables.
New New LV-Regulator: an audio-grade low-voltage regulator that uses a simple RC filter (1 ohm & 10kµF) as a pre-filter before the LDO regulator and holds bypass capacitors for all the electrolytic capacitors and a 4.7µF/400V polypropylene shunting capacitor at the output. Perfect replacing the cheap switcher wallwart that came with your external DAC or Squeezebox Duet or Touch.
Ah, headphones: either you love them or you hate them. I love them. I like not hearing noise from refrigerators, air conditioners, barking dogs, the subwoofers of rude neighbors, cars, trucks, and especially loud minibikes and motorcycles. Moreover, I like hearing normally unfamiliar and uncharted musical events: the floorboards creaking beneath the 300-pound jazz bass player, the hall’s reverberation, the guitarist’s fingerprints across the strings, the vocalist’s gasps for air, the recording engineer’s clumsy edits, the sheet music’s repeated turnings during every classical performance, George Harrison’s thick-fingered flubs, the mechanical articulation on a saxophone, the pianist’s humming—well, strike that last one item—in other words, the hundred diminutive sonic artifacts harbored by recordings but seldom heard. Some are annoying, others are embarrassing, others still are transporting, but all reveal a hidden world unmapped by even the finest loudspeakers.
Tubes are famous for their musical sound, which soothes the soul. Bringing the tube's magic to headphone listening is the goal.
Aikido & Tetra Phono Stages are stereo tube phono preamps that uses two gain stages per channel and passive equalization in between.
Stepped attenuator kits and audio signal switches. Staggered AC power switch.
Coupling capacitors and tube sockets for your tube audio projects.
Transformers for GlassWare Power-Supply Kits