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Pro-Ject Phono Box RS2 phono preamplifier Tom Fine March 2022

Tom Fine reported on the Pro-Ject Phono Box RS2 in March 2022 (Vol.45 No.3):

Julie Mullins's review of the $1999 Pro-Ject Phono Box RS2 in the August 2021 issue piqued my curiosity. The preamp, as described by Julie and measured by John Atkinson, seemed a good fit for my transfer-and-mastering studio.

In my work, I oversee and consult on vinyl releases, and I often remaster material originally released to the public on LP records; in such cases, I listen to the LPs in order to hear how the material was first presented. What's more, it has been an ongoing project to transfer my…

Pro-Ject Phono Box RS2 phono preamplifier The Decca Curve

The Decca Curve

The Phono Box RS2 has a rather rare playback option: the mono-era Decca LP EQ curve.

Prior to the mid-1950s, different record companies used different recording EQ curves (emphasis) and expected consumers to use corresponding (de-emphasis) curves when they played back the LPs. Many mono-era "hi-fi" preamps—for instance, the McIntosh C8 "Audio Compensator"—offered a variety of EQ options. Around 1954, the Recording Industry Association of America (RIAA) stepped in and convinced the various US labels to standardize on RCA's "New Orthophonic" curve, which became the…

Three March 2022 FollowUps: iFi, Pro-Ject, Canton

One reason Stereophile publishes a FollowUp is when the original review leaves an issue unresolved. Such was the case with Julie Mullins's review of the iFi ZEN CAN headphone amplifier and ZEN DAC Signature V2 D/A processor ($599/pair) in the January 2022 issue. JMu had found that the pair's gain architecture was mismatched. She ended up using an attenuating cable between the DAC and the headphone amplifier to keep the volume manageable. The measurements didn't indicate why the volume was too loud, so Jim Austin took a listen. You can find his report here.

Audio engineer Tom Fine has been…

Analog Corner #319: Paradox Phono 70 Signature phono preamplifier

One privilege of being a Stereophile columnist is the opportunity to cover products from smaller, less well-known manufacturers, including those that don't have wide enough distribution to qualify for a full review. One such company is Victorville, California–based Paradox. I'd never heard of them until I received an email from Terence Robinson, the company's owner. The email included a description of a phono preamplifier that so intrigued me that I asked for a review sample.

The Paradox Phono 70 ($2500) and Phono 70 Signature ($3000) are identical except that the latter uses higher-…

Analog Corner #319: Paradox Phono 70 Signature phono preamplifier Page 2

The company supplied a large assortment of load resistors—their values written on blue tape—and a generous supply of easy-to-use RCA plugs featuring screw-down terminals that make them easy to swap out. It's easy enough to learn to read resistor color bands to identify the value, or to look it up on a chart, but it's good to have the values handy and to keep pairs together.

While the Paradox approach to loading is not as easy as flipping DIP switches, it is easy, and plug-ins give you the widest possible loading flexibility. That's especially useful for people for whom loading down to…

darTZeel NHB-108 model two power amplifier

Like the proverbial pot of gold, darTZeel's golden equipment beckons. That, at least, is how it felt in January 2010, when John Atkinson and I ended our coverage of T.H.E. Show Las Vegas in the room shared by darTZeel, Evolution Acoustics, and Playback Designs. Listening to darTZeel's discontinued NHB-458 monoblocks (footnote 1) and NHB-18NS reference preamplifier (now updated), I was transfixed by the fullness of the system's midrange and overall beauty of the sound. "It was as though the system was opening its heart and welcoming us in," I wrote. "That's how warm and nurturing the sound…

darTZeel NHB-108 model two power amplifier Page 2

Delétraz also loves Peter Hammill and Van der Graaf Generator—"music from 30 or 40 years ago that's very ahead of its time. It's music that rejuvenates you from the inside; it cleanses you. To me, music is the essence of life in the universe. Everything is music. Sometimes you are glad, sometimes you are sad, but music is celestial. It's the expression of the universe as whole. I'm sure that the planets or the stars come together using some kind of music."

Delétraz ended by reflecting on his five decades in audio. "At this point, I have enough experience that if I design something, I…

darTZeel NHB-108 model two power amplifier Specifications

Sidebar 1: Specifications

Description: Solid state, dual mono power amplifier. Inputs: 1 pair balanced (XLR), 1 pair single-ended (RCA), 1 pair darTZeel BNC Zeel. Output: 1 pair WBT gold-plated copper binding posts. Nominal output power: 150Wpc into 8 ohms (21.76dBW), 225Wpc into 4 ohms (20.5dBW). Input impedance: Balanced >30k ohms; RCA >30k ohms, 5Hz–100kHz; BNC Zeel 50 ohms, 1Hz–1MHz. Output impedance: <0.33 ohms from 20Hz–20kHz (measured into 8 ohms). Gain: 26dB into 8 ohms. Frequency response: .8Hz– 600kHz, +0/–3dB. Rise time: <0.8µs. Slew rate: >88V/µs, peak-peak.…

darTZeel NHB-108 model two power amplifier Associated Equipment

Sidebar 2: Associated Equipment

Digital sources: dCS Rossini SACD/CD transport, Rossini DAC, and Rossini Clock; Synology 5-bay 1019+ NAS, Roon Nucleus+ music server, Small Green Computer Sonore opticalModules (2) and Deluxe opticalModule, Uptone Audio EtherRegen with AfterDark Giesemann Emperor Double Crown Master Clock, Linksys routers (2), and Arris modem, all powered by HDPlex 300 four-component linear power supplies (3) and HDPlex 200 LPS; Apple 2017 iPad Pro and 2017 Macbook Pro laptop with 2.8GHz Intel i7, SSD, 16GB RAM.
Preamplifiers: Dan D'Agostino Momentum HD, darTZeel NHB-…

darTZeel NHB-108 model two power amplifier Measurements

Sidebar 3: Measurements

I measured the darTZeel NHB-108 model two with my Audio Precision SYS2722 system—see the January 2008 As We See It. I performed the measurements using the balanced (XLR) and single-ended (RCA) inputs and left the internal jumpers as they had been set. To avoid triggering the amplifier's protection circuitry, I turned it off before changing the inputs during the measurements. (The amplifier took a relatively long time to stop passing signal when turned off, which implies that the power supply has a lot of capacitance.) Before starting the testing, I followed the…