Chris Groppi

Denon AH-D7000 Headphones and Headroom Ultra Desktop Headphone Amplifier

Chris Groppi

My first "high end" system consisted of Sennheiser HD-580 headphones, an original HeadRoom headphone amplifier, an Audio Alchemy DAC in the Box, and a Sony Discman with an optical digital out. I was a college student at the time, and there was no way of having a real, properly set up hifi system in my dorm room. It was clear to me at the time, listening to both my system and uber high end Hifi in shops, that my little headphone setup blew away many high dollar loudspeaker based systems.

Headphone and Earphone Reviews

THIEL CS3.7 Floor-Standing Speakers

Chris Groppi

THIEL is one of the most well known and long lived high end loudspeaker companies. Jim Thiel founded Thiel Audio in 1976, building his company's reputation on speakers that are time and phase coherent. All of THIEL's full range loudspeakers have followed this recipe, including the new CS3.7. Where the CS3.7 differs is in its level of execution. The CS3.7 is almost double the price of the older CS3.6 model, and approaches or exceeds the price points of the larger CS5 and CS7 speakers of the past. While the speaker follows the same recipe as past THIEL models, it is reinvented in almost every way. For some (at least those who haven't heard it), the increased price was a big disappointment. I call this sour grapes for people who thought they could afford the CS3.7 but then had to realize they couldn't. The CS3.7 is worth every cent, and is a strong contender versus pretty much any full-range loudspeaker in the under-$20k price category.

Floor Standing Speakers

Emotiva XPA-1 Monoblock Power Amplifier

Chris Groppi

ADDENDUM - 4/1/09 I (JEJ) was so impressed with Chris' review of the XPA-1 (published in January, 2009), I asked Emotiva to send me one so I could run some of my own tests. I borrowed a different power amplifier from a friend that cost more than 6 times the price of the XPA-1, which I will call Amplifier "X" here. I ran the same tests on both amplifiers. Click on the photo to see the results (go to Page 4: Emotiva XPA-1 On the Bench, and my results are down near the bottom of the page).

Power Amplifiers

Rocky Mountain Audio Festival Show Report

Chris Groppi and Rick Schmidt

This year was the first time at the Rocky Mountain Audio Festival for secrets writers Chris Groppi and Rick Schmidt. Unlike many of the other trade focused shows, the RMAF is open to the public. Both manufacturers and retailers show products here, and displays are focused on listening demonstrations. This year, there were more than 160 display rooms each usually showing equipment from several manufacturers. Rooms were from both retailers as well as manufacturers and distributors, with a wide range of equipment from around the world. All the big hitters were here, plus many companies we had never heard of.

In addtion to the rooms, seminars on topics ranging from turntable setup to digital recording technologies are offered. This is an intimate show, focused on 2 channel audio, and everyone has a chance to see every room. The show was great fun for both of us!

Show Reports, Film Festivals and Concerts

Zu Audio Druid Mk 4/08 Speakers

Chris Groppi

High sensitivity speakers have had a following amongst the proponents of low power single ended tube amplifiers for a long time. Many of these speakers work well with these low power amps, but not necessarily with more typical amplification. Not so with these Zu audio Druids. While I am sure they still are wonderful with low power tube amps, they also deliver with more typical solid-state amplification. The Druid, made by cable and speaker manufacturer Zu Audio in Ogden, Utah, has had a cult following among many audiophiles. I was able to test the latest Mk. 4/08 version, released earlier this year.

Bookshelf Speakers

A New Way to Plot Speaker Impedance: the Smith Chart

Chris Groppi

Impedance is the extension of the idea of electrical resistance to AC signals (like music). In high school, we all likely learned Ohm's law at some time or another. Whether we remember it or not is another story! Luckily, the refresher course is easy. Resistance is a way of relating voltage and current in a simple DC circuit.

Technical Reviews