I auditioned the three jitter attenuators with high- and low-quality transports, with a processor susceptible to interface jitter (an older PS Audio UltraLink that uses the Yamaha input receiver), and with processors that easily reject jitter, such as the Mark Levinson No.30.5, which has near-total immunity to interface jitter. Since the No.30.5 is the first processor on the market to use the NPC5842 filter, which can pass 20-bit data (actually up to 24-bit data), it was ideal for fully assessing the DTI Pro's 20-bit output word mode and claimed resolution enhancement.
In addition to the UltraLink and Mark Levinson No.30.5, I spent some time with the Adcom GDA-600, which has a good implementation of the Crystal CS8412 input receiver, and the Sonic Frontiers SFD-2 (which uses the UltraAnalog AES20 input receiver). Transports included the Mark Levinson No.31 ($8500), the Counterpoint DA-11 ($1500), and the transport section of an NAD 502 CD player ($299).
The playback system consisted of the Genesis II.5 loudspeakers driven by the Genesis bass servo amplifier on the woofers and a pair of Audio Research VT150 tubed monoblocks driving the ribbon midrange and planar tweeters—a match made in heaven. The preamp was an Audio Research LS5 Mk.II, and interconnects included Expressive Technologies IC-1, AudioTruth Diamond x3, AudioTruth Lapis, and Transparent interconnect. Loudspeaker cables were Transparent Ultra, and digital interconnects included AudioTruth Diamond x3, Ensemble DigiFlux, NBS, AudioQuest TosLink, and WonderLink.—Robert Harley
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COMMENTS
It's good that now-classic gear is being re-measured with modern tools (and evolved skill sets).
I hope JA can get around to measuring digital gear that is STILL sought after. Such as DACs and CDPs with classic Philips chipsets: TDA1541, SAA7220, etc.
I hope JA can get around to measuring digital gear that is STILL sought after. Such as DACs and CDPs with classic Philips chipsets: TDA1541, SAA7220, etc.
To that end, I dug out the sample of the Magnavox (Philips) CDB472 that I bought in 1988 to run some modern tests on it. Unfortunately, while the transport still worked, the display just said "ERR" (for error) with every CD I tried. It looks as if the laser pickup had died in the 30 years since I last used it. :-(
John Atkinson
Technical Editor, Stereophile
I used to own that model. It was an improvement over the famous CDB650, while still retaining the 650's Hall-effect turntable motor (later transports at that price range used a cheaper "toy" DC motor).
About your issue:
Well, it could be a dead laser. You may be able to know for sure if you remove the cover, hold your Smartphone camera over the laser and press PLAY. (The phone camera will allow you to safely see the laser redness w/o hazard to direct eyesight).
If the laser is okay, some of those electro caps may be completely dried out.
FWIW, I've owned over a dozen (now) vintage CDPs and have yet to encounter a bad laser.
There are plenty of vintage audio refurb/repair houses in big cities. I recall a Stereophile YouTube post featuring one in NY (Leeds Radio???).
In any case, it's worth having device of this vintage in good working cond ... you never know when science my re-require its utility ;)
Well, it could be a dead laser. You may be able to know for sure if you remove the cover, hold your Smartphone camera over the laser and press PLAY. (The phone camera will allow you to safely see the laser redness w/o hazard to direct eyesight). If the laser is okay, some of those electro caps may be completely dried out.
Will try this. Thanks.
John Atkinson
Technical Editor, Stereophile
"...the Magnavox (Philips) CDB472 that I bought in 1988..."
My first CDP was a Magnavox (Philips) CDB-473. Not sure now, but I think I bought that in 1987.
I do think measuring legacy digital gear is important (preferably equip that's been refurbished-- replace dried caps -- but NOT modified).
I don't think such a project has been undertaken by any other major publication -- specifically one with a standardized lab and routines (test methodology) as Stereophile.
It would be good to gain insight into issues, such as certain audiophiles' preference of classic multi-bit sound, or non-oversampling.
Having a database of revised metrics would be beneficial to both manufactures and audiophiles. It's not only test gear and test methods that have improved. But the list of test parameters has also increased (linearity, jitter, Dirac pulse, etc).
And there is room for growth to this list as well . For example, back in the mid-80s, Bob Carver published some measurements (in Audio mag), regarding his Digital Lens technology. Carver introduced 'scope measurements via Lissajous pattern showing (L-R)/ (L + R) ratio from an LP record vs. CD. They looked different:
Carver 1985
http://gammaelectronics.xyz/audio_013-1985_carver.html
I don't think manufs and journalists paid too much attention. There may very well be many more objective metrics lost in the journal archives.
Hi John,
Very interesting again after a long time. Around 2000 I designed the Assemblage DAC3.1 and "jitterbug" D2D-1. I replaced the AES21 that was getting obsolete and couldn't doe 96k with a discrete dual PLL using a VCXO. According to the Clock Jitter analyzer designed by Dr Remy Fourre it had an intrinsic jitter of 1,5ps and a much lower jitter attenuation frequency. If you ever come across one of these I would be very interested how it performs on this test. Nice article thanks.
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