About Pupcom, Inc
Home of mc_PuP

Mission

Create small high-fidelity preamps, mixers, and effects generators, and have fun doing it.

What Does mc_PuP Mean?

The meaning of mc_PuP:

mc=master of ceremonies, plus PuP=Performance under Pressure.

Background

A few years ago, this old dog retired from 35 years working as an electronics engineer. The dog has always enjoyed making things work. Through the years, I have watched as audio program material, notably music, was compressed in both dynamic range and response, digitized through phase-distorting filters, and tone-masked to hide noise. Many ingenious methods for cramming audio into low voltage signal paths and tight digital streams have been introduced over the years. The vinyl record and the phonograph cartridge were left in the shadows, only revered by audiophiles and folks with large record collections.

With the resurgence in vinyl records over the past 20 years, audio consumers are looking for a tangible improvement in their listening and sonic creation experiences.

mc_PuP products are simple and self-powered, designed with uncompressed linear audio channels with the option for loads of headroom. It is easy to cascade multiple units with no degradation in audio quality. With future mc_PuP effects products, analog audio channels will be digitized to 24 bit samples at a variety of rates, from 32 to 44.1 to 192kHz. Higher sampling rates allow for more relaxed anti-alias filtering (and less group delay distortion). Digitized audio inputs and outputs will be SPDIF streams (the consumer cousin of AES3) on coax cable or optical link connections. Wireless communication will be employed only for cellphone or laptop control of audio volume and effects.

For the audio enthusiast, backyard DJ, practicing musician, or Friday night chanteu(se)(r), mc_PuP is the quick and easy hookup.

Ken Buttle, pupcom Inc.

Folsom, CA

The Science of Sound: Preserving the Full Audio Experience

If you have ever been to a live symphonic performance, you may have experienced the whole body effect of great music played well. It makes the hairs on the back of your neck stand up. It can make you feel things that are indescribable. These feelings are the result of real instruments played by real people making air pressure waves that directly reach your ears, with nothing else in between.

Vinyl records are not in general the pinnacle of sound reproduction, but there are amazing pressings out there that can tax the limits of the best phonographic cartridges. The phono cartridge has electromechanical limitations of its own, such as the combined elements of mass, compliance, and damping, all working together to faithfully follow the undulations of the groove. (Think of a motorcycle wheel trying to stay in contact with a bumpy road.) Then, how much noise does the phono preamplifier let in? How much noise does the preamplifier create on its own? What is its dynamic range? How much noise comes from the record itself?

Reports have put the dynamic range requirement of input amplifiers at 20dB (10x) above the rms voltage of the audio signal, regardless of the source level (line-level, magnetic tape, microphone, or phono cartridge. So a 500mV rms line-level signal would need +/-5V of dynamic range to avoid clipping.

Once a signal is digitized, a decision is made as to how much analog signal range to commit to the linear digital sample range, typically a 16-bit or 24-bit word. Does one compress the range with a non-linear transfer function, or "soft-clipping" of the peaks? Does one add all-pass filtering to phase-skew frequency components to reduce simultaneous peaking? Phase distortion is hard for the human ear to detect, but the sonic peaks that are eliminated will be missed. Many down-mixes to the final recording do these things, but there are also many media that preserve as much information from the live performance as possible. These media, however, are becoming less popular for mainstream consumption of music, in exchange for content from streaming services. One does not always know the quality of the source material that they are paying for from these services.

mc_PuP will strive to follow the 20dB rms-to-peak-to-peak guideline when handling audio signals. Good sound, and great sound effects, demand linearity, wide dynamic range, flat frequency response, and minimal extraneous phase distortion.