YBA CD 1 Blue Laser CD player Measurements

Sidebar 2: Measurements

Before telling you about how the YBA CD 1 measured, I must report some serious problems with the measurement sample. First, the display flickered on and off, staying on only after I jiggled an unmarked rear-panel switch. Second, the CD 1 required repeated attempts to read the table of contents of some discs. Once the CD 1 read the ToC, it had problems searching certain tracks. The player would look for the track, not find it, then shut off. To search a later track on the disc, I had to skip just a few tracks at a time, wait for it to start reading data, then skip a few more tracks. On the CBS Test Disc, the YBA player wouldn't play through track 20; it would skip forward or start playing at 35 seconds. I suspect that the laser sled may have encountered a mechanical impediment at that disc radius.

Moreover, the CD 1 was the most ergonomically unfriendly CD player I've put my hands on. Using momentary toggle switches to control transport functions is ludicrous. The requirement that you push up a toggle switch twice to make the player read the ToC is equally annoying.

The CD 1's maximum output level was higher than specified but still low at 1.3V, a figure 3.7dB below the CD standard 2V output level. The output impedance at 17Hz was a high 750 ohms, a figure that decreased to 63 ohms across the rest of the band. At 31Hz, the output impedance measured 135 ohms. I measured a low 0.1mV of DC offset at the left channel output, 2mV at the right. Because the CD 1 wouldn't read the Japan Audio Society test disc, which has a positive-going impulse, I couldn't discover if the CD 1 inverts absolute polarity. When playing the Pierre Verany Test CD, the YBA mistracked at track 31.

When looking at the CD 1's output on an oscilloscope, I saw an unusual stairstep shape in the waveform. The waveform was also overlaid by very-high-frequency noise with a strong component at 220kHz.

Fig.1 is the CD 1's frequency response and de-emphasis response, shown using our normal scale. We can see some ripple in the frequency response, and the de-emphasis error is off the scale. Fig.2, the same data shown to different scale, shows the extent of the de-emphasis tracking error: a whopping 7dB at 10kHz, and 8.6dB at 16kHz. This suggests that the YBA doesn't actually correct for pre-emphasized discs at all! The CD 1's channel separation (fig.3) was rather low, measuring just 73dB at 1kHz and decreasing to 46dB at 16kHz.

667YBAFIG1.jpg

Fig.1 YBA CD 1, frequency response (top) and de-emphasis response (bottom) (right channel dashed, 0.5dB/vertical div.).

667YBAFIG2.jpg

Fig.2 YBA CD 1, frequency response (top) and de-emphasis response (bottom) (right channel dashed, 1dB/vertical div.).

667YBAFIG3.jpg

Fig.3 YBA CD 1, crosstalk (R–L channel dashed, 10dB/vertical div.).

A spectral analysis of the CD 1's output when playing a 1kHz, –90dB dithered sinewave (fig.4) shows that the player has a high noise level, particularly in the lower octaves. This noise is apparent only when the DAC is decoding a signal; a wideband spectral analysis (fig.5) made with a test signal of all zeros shows a lower noise level at low frequencies, but a higher noise level in the treble. Some DACs shut off when fed digital silence, to make their noise performance look better. The removal of DAC noise between figs.4 and 5 uncovers some power-supply noise at 60Hz, along with an odd energy peak centered at 7kHz. The latter is perhaps a DAC idle tone. It is also unusual to see such a wide disparity in noise levels between channels, along with the fact that the noise isn't "white" in character, but instead has more energy in some octaves than in others.

667YBAFIG4.jpg

Fig.4 YBA CD 1, spectrum of dithered 1kHz tone at –90.31dBFS, with noise and spuriae (16-bit data, 1/3-octave analysis, right channel dashed).

667YBAFIG5.jpg

Fig.5 YBA CD 1, spectrum of digital silence (16-bit data, 1/3-octave analysis, right channel dashed).

I was unable to measure the CD 1's linearity because it refused to play the fade-to-noise track on the CBS test disc, from which a player's linearity is derived. I did, however, play spot tones, and manually measured the CD 1's linearity at –70dB, –80dB, –90dB, and –100dB. At –70dB, the CD 1 had a positive error of 1.1dB (left channel) and 1.6dB (right). This error decreased to 0.76dB at –80dB (both channels). At –90dB, the CD 1 had a negative linearity error of just 0.3dB (left channel) and 0.05dB (right). At –100dB the negative linearity error increased to 2.15dB (left channel) and 1.7dB (right). This is relatively good linearity performance.

The CD 1's reproduction of a 1kHz, –90dB undithered sinewave (fig.6) shows an asymmetrical waveshape, a high noise level, and a negative DC shift. Fig.7 is the CD 1's intermodulation distortion spectrum, made by playing a full-scale mix of 19kHz and 20kHz. This is the worst-looking IMD spectrum I've seen, with lots of IMD products and a high noise level.

667YBAFIG6.jpg

Fig.6 YBA CD 1, waveform of undithered 1kHz sinewave at –90.31dBFS (16-bit data).

667YBAFIG7.jpg

Fig.7 YBA CD 1, HF intermodulation spectrum, DC–24kHz, 19+20kHz at 0dBFS (linear frequency scale, 20dB/vertical div.).

I was unable to measure the CD 1's jitter because its DAC is a surface-mount device located on the underside of the player's main circuit board. The circuit board appeared to be supplied as a whole and not specially designed for the CD 1.

Overall, the CD 1 had poor bench performance, with severe de-emphasis errors, low channel separation, high noise levels, and an alarming amount of intermodulation distortion.—Robert Harley

COMPANY INFO
Phlox Electronique
US Distributor: Audio Plus Services
156 Lawrence Paquette Industrial Drive
Champlain, NY 12919
(800) 663-9352
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COMMENTS
volvic's picture

Have owned a YBA CD1a for many years, mine does not have the blue laser but the review is correct in every aspect, it is laid back, provides lots of depth and has made me happy for many years, with only recently its internal DAC been retired for an external one and now using it as a transport only player.  It is beautiful to look at and has give me close to 20 years of fuss free performance.  Very few players can match this level of durability and sonic competence.  

Nick 

MVBC's picture

Was he wearing corduroy pants or flanel ones during the demo? Honestly, nothing beats topless French players...kiss

mcondo49's picture

Not sure what the purpose is but I do find that YBA products are very tweaky. Have had a few amps, preamps and integrateds over the years. All had great sound and a variety of tweaks that are now commonplace these days. One example - hum. Use YBA power cords and you will never have a hum problem - they were/are not grounded. Anyway, looking forward to their new lines under the new ownership. We'll see if they maintain their high standards and quirky features. 

John Atkinson's picture

Quote:
Not sure what the purpose is [of this reprint]

When we started this website 16 years ago, our goal was ultimately to have every review and article from Stereophile, going all the way back to the launch in 1962, available free on-line. Almost every review from 1998 onward and a large number from before than are now archived here, and I am slowly filling the gaps. This review reprint was specifically requested by a reader, otherwise I choose which reviews to reprint.

John Atkinson

Editor, Stereophile

Poor Audiophile's picture

I think it's great that you would reprint something based on a reader's request!

smittyman's picture

I've noticed that a lot of Sam Tellig's reviews/articles are not available on-line, including a good number of current entries on the Recommended Component list; several of integrated amps for example.  The same is true, to a lesser degree, of Micheal Fremer's reviews as well.  About half the reviews of TT's rated A or B are not available on line.  I think it is great that you are making this archival material available but I would find it more valuable to be able to read the reviews of all of the Recommended Components. 

John Atkinson's picture

Quote:
I've noticed that a lot of Sam Tellig's reviews/articles are not available on-line . . . The same is true, to a lesser degree, of Michael Fremer's reviews as well.

When we started our website at the end of 1997, we decided that the three most popular elements of the print magazine - Sam's Space, Analog Corner, Recommended Components  - would not be posted to the free on-line archives. Readers would thus have to continue purchasing the paper magazine to read them.

This policy has slowly been relaxed. When I publish a measurement follow-up on a product that Sam or Mikey has written about in their columns, their auditioning comments are published on the website, lang with my measurements. Recommended Components is also now available on-line and as a free iPad app. We are also slowly posting _all_ the Analog Corner columns to AnalogPlanet.com and have got up to September 1997 - see http://www.analogplanet.com/category/analog-corner .

John Atkinson

Editor, Stereophile

smittyman's picture

I thought it might be something like that.  I really appreciate your changing the policy and making Recommended Components available on-line.  Maybe as you make Sam and Mike's (and other's) reviews available, you could consider starting with the ones for products that are currently in the Recommended Components list; that would make the list even more useful.

Just my thoughts, I'm sure you have no shortage of advise from readers.

volvic's picture

I concur, how about some Tandberg receiver reviews - TR 2045, 2060....hmmmm? 

Nick

Lofty's picture

How about posting Dick Olsher's review of the Music Reference RM-9 tube power amplifier? Please!

John Atkinson's picture

Quote:
how about some Tandberg receiver reviews - TR 2045, 2060....hmmmm?

Stereophile never reviewed these Tandberg receivers. Sorry.

Quote:
How about posting Dick Olsher's review of the Music Reference RM-9 tube power amplifier?

Dick reviewed the RM-9 in December 1989, with a follow-up in October 1994. I'll add his coverage to the queue.

John Atkinson

Editor, Stereophile

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