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A full set of measurements was made on the Sonic Frontiers Power 3 in its balanced mode, with selected measurements repeated in unbalanced (single-ended) mode. Unless noted otherwise, all measurements are for balanced configuration.

Following its one-hour warmup, the Power 3 was typically hot for a tube amplifier. Its input impedance measured a high 198k ohms (99.3k ohms unbalanced), its output impedance a maximum of 0.17 ohm at 20Hz and 1kHz, increasing to a maximum of 0.22 ohm at 20kHz. These are very low—and very good—values for a tube amplifier, and…

I'm going to cheat a little here. My comments on the Sonic Frontiers Power 3 monoblock power amplifier are a Follow-Up to Brian Damkroger's review in the April 2000 issue...my feelings differ significantly from Brian's.

The Power 2 power amplifier sat in my listening room for more than a year. Over that time, and however much I resisted the prospect, I ended up choosing it—over every other amp and with almost every speaker—for enjoying music. Sure, the Bryston 7B-STs had more slam and punch, the Simaudio Moon W-…

Tyll Hertsens started HeadRoom in 1992, marketing headphone amplifiers that included a proprietary Crossfeed circuit to a really tough…

Let's dance, little schoolgirl
The Grace m902 is a natural comparison for the pimped-out Desktop. They're within striking distance in price ($1700 vs $2095), they both allow analog…

Description: Desktop headphone amplifier/line preamplifier with optional D/A module. Amplifier: Operating voltage: ±15VDC. Operating current: 50mA from each supply. Input impedance: approx. 70k ohm. Output impedance: approx. 0.5 ohm. Maximum output: 250mA. Maximum voltage gain: 19dB. DAC: Supported data formats: 16–24-bit/44.1, 48, 96kHz. Supported physical interfaces: TosLink, coaxial, USB.
Dimensions: 6.25" (160mm) W by 3.25" (83mm) H by 6.25" (160mm) D. Weight: 1.4 lbs (0.6kg).
Serial Number Of Unit Reviewed: None visible.
Prices: $2095 (total,…

Digital Sources: Apple PowerMac G5 computer; Ayre C5-xe, Musical Fidelity X-RayV3, Sony CDP-CX400 CD players.
Preamplifiers: Conrad-Johnson ACT2 & CT-5.
Power Amplifiers: McCormack DNA-500, Moscode 401HR.
Headphones: AKG-501, Etymotic ER-4S & ER-6, Grado RS-1, Sennheiser HD-580 & HD-600.
Loudspeakers: Dynaudio Focus 140, Thiel CS2.4.
Cables: Headphone: Stefan Audio Art Equinox, Sennheiser HD-600/Cardas. Interconnect: Shunyata Research Aries & Antares, Viola Labs Silver Balanced. Speaker: Shunyata Research Lyra. AC: Cardas…

Looking first at the HeadRoom Desktop's performance in the analog domain, its input impedance was very high, at approximately 100k ohms across the audioband. It didn't invert signal polarity and the output impedance was a very low 1.6 ohms at all frequencies, from both the headphone jacks and the rear-panel RCA jacks. (This figure includes the series resistance of 6' of interconnect.) The maximum voltage gain at 1kHz depended on the setting of the front-panel gain switch. With this in the central, Low position, the Desktop attenuated the input signal by 8.1dB.…

When I reviewed HeadRoom's maxed-out headphone amplifier and DAC in the April 2006 Stereophile, I commented that I'd be following up in a few months with some notes on the "plain" Desktop unit, sans the Max amplifier module ($499), Max DAC option ($399), and Alps volume control ($199). Indeed, I was "hard at work" listening to a basic Desktop with the Home amplifier module (a $199 upgrade from the Standard module that comes stock in the $599 Desktop).

Then HeadRoom's Tyll Hertsens called me to repossess…

Genesis makes some very large systems, with midrange and treble drivers arranged on large panels and, usually, separate bass cabinets. These designs demand…