Sound
I was immediately taken by the sound of the DNA-1; it was warm, sweet, punchy, and eminently musical. What really caught my attention, though, was its ability to throw a palpable soundstage in which instruments…
search
Overall, I found the DNA-1 well-built and attractive. Component quality was excellent, with 1% metal-film resistors and Wima capacitors throughout. Looking inside the DNA-1 gave two strong impressions: the layout and execution appear to be perfectly realized, with no afterthoughts or kludgy Band-Aids, and the product's emphasis is on sonic quality, not lavish cosmetics.
I'll close the listening impressions with a capsule comparison of the DNA-1 in relation to other superb amplifiers: the reference VTL 225W Deluxe monoblocks, Krell KSA-250, and the Boulder 500AE that so captivated J. Gordon Holt.
First, the DNA-1 had tighter, deeper, faster, and better-defined bass than the VTLs. In the mids, the VTLs had greater lushness and ease, with unparalleled liquidity and harmonic rightness. It is this quality that makes the VTLs so special. The VTLs also threw a deeper soundstage, but the DNA-1 had a slight edge in keeping individual instrumental lines distinct…
Sidebar 1: Specifications
Description: Solid-state stereo power amplifier. Rated power output: 150Wpc RMS into 8 ohms (21.8dBW), 300Wpc RMS into 4 ohms (21.8dBW), 500Wpc RMS into 2 ohms (21.0dBW) (bandwidth and distortion not specified). Output current: 50A peak per channel. Input impedance: 100k ohms. Input sensitivity: 1.2V. Frequency response: -3dB at 0.5Hz and 250kHz. Rise time: ±2µs. Slew rate: 50V/µs. S/N ratio: 88dB, "A" weighted. Damping factor: >100 (1kHz, 8 ohm load). Output impedance: ±0.1 ohm. DC offset: ±5mV. Signal polarity: non-inverting.
Dimensions: 19" W by 7" H by…
Sidebar 2: 1992 Review context
I auditioned the McCormack DNA-1 in my reference system without the usual Muse Model 18 subwoofer. The presentation's low-frequency performance would thus be determined by the amplifier under scrutiny and not be obscured by the powered subwoofer's contribution. After removing the Model 18 subwoofer from the room, I spent some time with the VTLs driving the Hales System Two Signatures by themselves—something I hadn't done for months. My favorable impressions of the Model 18's contribution to the system's overall musicality were confirmed. The Model 18…
Sidebar 3: 1992 Measurements
The DNA-1 ran relatively cool, even after the one-hour preconditioning period at one-third rated power into 8 ohms. Although the heatsinks were hot to the touch, they were cooler than most amplifiers subjected to this conditioning.
Input impedance at 1kHz was a calculated 99.5k ohms, consistent with the manufacturer's specification of 100k ohms. The DNA-1's gain was very high, an input voltage of 100mV at 1kHz producing an output voltage of 4.18V. This gain ratio corresponds to a decibel gain of 32.4dB, implying a sensitivity for full output of 828mV…
Fig.5 shows the DNA-1's distortion waveform (lower trace) when a 1kHz test signal (top trace) drives the amplifier to produce 107W into 4 ohms. The distortion level was 0.075% under these conditions. The distortion waveform reveals the presence of higher-order harmonic products.
Fig.5 McCormack DNA-1, 1kHz waveform at 107W into 4 ohms (top), noise and distortion waveform with fundamental notched out (bottom, not to scale).
This analysis is confirmed by fig.6, a spectral analysis of the harmonic products created when the DNA-1 reproduced a 50Hz test signal at 72W into 4…
Robert Harley wrote about the McCormack DNA-1 Deluxe in March 1995 (Vol.18 No.3):
Since the McCormack DNA-1 was introduced in early 1992, this $1995 power amplifier has been one of the safest recommendations I could make (footnote 1). The amplifier combined uncommon musicality with the ability to drive any loudspeaker load with ease. Specifically, the DNA-1 had a smooth, grain-free treble, a liquid midrange, articulate bass, and a spectral and rhythmic coherence many more-expensive amplifiers lack. In addition, the DNA-1 had excellent bench performance, particularly the ability to…
Sidebar: 1995 System
The DNA-1 Deluxe saw time driving Genesis II.5 loudspeakers and Apogee Slant 6es (see my review in this issue). With the Genesis, the DNA-1 Deluxe drove only the ribbon midrange and tweeters, not the woofers, which are powered by Genesis's dedicated servo amplifier. Although auditioning the amplifier in this way won't tell you anything about its bass performance, it was highly revealing of the Deluxe's midrange/treble qualities and soundstaging—particularly because I'm so familiar with the Genesis driven by the reference-quality $12,000/pair Audio Research VT150…
Sidebar: 1995 Measurements
The McCormack DNA-1 Deluxe had very similar measured performance to that of the DNA-1, but bettered the original in some respects. I'll report only the differences in measured performance (see my original review for the full measurements).
Distortion levels into lower impedances were lower in the Deluxe than in the DNA-1. Fig.1 shows the THD+N percentage vs frequency curves at 2.83V into 8, 4, and 2 ohms. It can be seen that reducing the load impedance doesn't result in appreciably higher levels of distortion. For comparison, the DNA-1 had much higher…
Kalman Rubinson wrote about the SMc modifications for the DNA-1 in November 2000 (Vol.23 No.11):
As a public devotee of the DNA-1, I have been besieged with e-mail from dedicated McCormack fans asking about Steve McCormack's SMc Audio modifications to the original DNA-1, DNA-0.5, and DNA HT-1 amplifiers (footnote 1). But, being a seasoned but reforming tweaker, I take a dim view of most aftermarket modifications. Sure, most of them will make a difference; but lacking a reference or A/B comparison, how can you know the difference is a positive one? In this case, the original designer…