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Music Reference RM-200 power amplifier Measurements

Sidebar 3: Measurements

One amplifier, three separate transformer outputs, balanced or unbalanced drive, and two choices for output tubes—to measure every combination offered by the Music Reference RM-200 was not practicable, so I used balanced drive and what I assumed were the Chinese output tubes MF preferred (they were only identified as "RAM Labs" tubes).

The amplifier was non-inverting, with pin 2 of the XLR jack wired as positive. Its single-ended input impedance measured 15.4k ohms at 1kHz, this rising slightly at the edges of the audioband and doubling when driven…

Music Reference RM-200 power amplifier Measurements part 2

The audibility of any distortion depends on its order. Low-order harmonics are preferable because they're musically consonant—see my essay on this subject in the Stereophile Test CD 2 booklet—and more easily masked by musical fundamentals. Figs. 9 and 10 reveal that the RM-200's distortion is predominantly third-harmonic. Fig.9 was taken with a 1kHz sinewave at a low level (1W into 8 ohms from the 8 ohm tap), with just 0.011% THD. Fig.10 was taken about 3dB below clipping into 4 ohms from the 4 ohm tap, with a low-frequency tone. The third harmonic lies at -50dB (0.3%), with the second,…

Music Reference RM-200 power amplifier Manufacturer's Comment

Manufacturer's Comment

Editor: Being both a degreed electrical engineer and an audiophile designer is walking the razor's edge. Too many "engineers" design poor-sounding products when they become slaves to the test equipment. On the other hand, too many "seat-of-the-pants" designers commit faults in the mundane engineering aspects of serviceability, stability, and knowing the limitations of the parts. With the quality of today's parts, there is no excuse for poor reliability. When I hear a manufacturer blaming a part for his reliability problem, it is all too often that the designer…

Cyrus CD 8x CD player

A week with the Cyrus CD 8x CD player

Tuesday, October 18
I think I might shave my head. So much of my hair has thinned out that most styles are no longer feasible. Flat-top? No. Mullet? No. Long on the sides? Think: Rudy Giuliani on a blustery day, or a squid going for a ride on a cannonball. The day has arrived when virtually all hairstyles look stupid on me, and I no longer care. I hate them all, and I hate having to think about them. I just want to be done with it.

I think that's also why so many people—also middle-aged men, interestingly enough—are driven to do…

Cyrus CD 8x CD player Page 2

I should start by confirming your likeliest suspicion: The CD 8x is indeed a refinement of Cyrus's entry-level CD player, the CD 6. Both products use a Philips disc transport, and both use a Burr-Brown D/A chip, with true 24-bit current output. Both are also built into more or less the same chassis, which is precision-cast in Scandinavia of a magnesium alloy that's said to reduce microphony and prevent the deleterious effects of eddy currents, among other things, owing to the fact that it's as nonmagnetic as a bowl of oatmeal. It isn't often that manufacturers or distributors actually…

Cyrus CD 8x CD player Specifications

Sidebar 1: Specifications

Description: Single-box CD/CD-R player with two pairs of analog outputs on RCA jacks and S/PDIF digital outputs on RCA and Toslink jacks. Maximum output level: 2.1V RMS. Signal/noise: 120dB at 1kHz. Total harmonic distortion: 0.002% at 1kHz. Frequency range: 20Hz–20kHz. Clock jitter: <80ps. Output impedance: 50 ohms.
Dimensions: 8.4" (215mm) W by 3.1" (80mm) H by 14.1" (360mm) D. Weight: 35 lbs (15.9kg).
Serial Number Of Unit Reviewed: CNUB0086.
Price: $1995. Optional PSX-R power supply, $795. Approximate number of dealers: 5.
Manufacturer: Cyrus…

Cyrus CD 8x CD player Associated Equipment

Sidebar 2: Associated Equipment

Analog Sources: Linn LP12 turntable, Linn Lingo power supply, Linn Ekos tonearm; Rega Planar 3 turntable, Rega RB-300 tonearm; Miyabi 47, Linn Akiva, Lyra Helikon Mono, Linn Adikt, Rega Elys cartridges.
Digital Sources: Naim CD5x, Ayre CX-7e CD players.
Preamplification: Tamura TKS-83 moving-coil step-up transformer, Linn Linto phono preamplifier; Fi preamplifier, Sonic Euphoria PLC passive line stage.
Power Amplifier: Lamm ML2.1.
Integrated Amplifier: Ayre AX-7e.
Loudspeakers: Quad ESL-989.
Cables: Interconnect: Audio Note AN-Vx, Nordost…

Cyrus CD 8x CD player Measurements

Sidebar 3: Measurements

The Cyrus CD 8x player had a maximum output level of 2.23V at 1kHz, almost 1dB above the CD standard of 2V RMS. Its absolute polarity was noninverting when the front-panel display read "PHASE NORMAL," inverting when it said "PHASE INVERTED." The output impedance was a usefully low 52 ohms across the audioband. Error correction was superb, the player coping with gaps in the Pierre Verany Test CD's data spiral up to 1.5mm in length without audible glitches. I perform this test both listening to the 500Hz tone on headphones and when a player has a digital output,…

Audio Research SP-11 preamplifier

If there is indeed a renaissance of tubes in high-end audio—and it is clear there is—much of the blame lies with Audio Research Corporation.

Audio Research president William Johnson was custom-building tubed power amplifiers for the carriage trade as far back as 1951, which means he has been making tubed equipment for longer than anyone else currently in audio. In 1961, faced with more orders than he could possibly fill single-handed, he started a modest manufacturing enterprise called Electronic Industries, which was subsequently bought out (along with its proprietor and chief designer…

Audio Research SP-11 preamplifier Page 2

The level-change increments of the volume controls are quite large at reduced settings, becoming increasingly gradual as you turn them up until, near full-up, the increments drop to about ½dB per step. For this reason, at least one control (preferably the "Level") should be operated most of the time near its full-up position, the other turned down appropriately. Running both at about half rotation causes excessive incrementing, which will usually mean the volume setting you seek is halfway between one setting that's too loud and one that's too soft.

I should draw attention to the Mono…