Showing posts with label multi-bit converter. Show all posts
Showing posts with label multi-bit converter. Show all posts

Monday, August 12, 2013

Review: Technics SL-XP 505 (1992)

Technics SL-XP 505
This review is part of a larger comparison containing seven eight vintage portable CD players and the penultimate of these reviews. You can find the final conclusion here.
Overview

The Technics SL-XP 505 (or Panasonic SL-S 505) probably was released in 1992 and the successor to the Technics SL-XP 300 I´ve reviewed almost two years ago. It cost roughly 250,- Euros when hitting the market and judging from the amount of specimen offered on eBay it didn´t sell that well. Perhaps because it wasn´t so different from its predecessor. Immediately visible changes include a different design, the suspension of the CD drive and illuminated Stop / Play buttons. From my SL-XP 300 the SL-XP 505 carries over the same combination of two 16-Bit MASH-DACs (one for each channel) & an 18-Bit digital filter. However, the Technics catalogue advertises the SL-XP 505 as being 'heat resistant'. And I know for a fact that my SL-XP 300 isn´t heat resistant at all, judging from dried-out condensers on the first of two models I bought on eBay. Which is why I assume that Technics modified the circuit design. Not sure about this though... I´m no engineer, I suck at reading electronic schematics.
German Technics catalogue excerpt, showing the SL-XP 505
Handling is simple, as you can see on the picture above the SL-XP 505 even came with an infrared remote control... which was sadly lost on my model. The DSP now offers a setting called 'Live', this only adds a crappy sounding hall-effect. It doesn´t matter anyway: the sound effect slide switch on my model is kaput, the S-XBS (Bass Boost) is always switched on. What I love about the portable Technics players is that they illuminate their display with an unobtrusive green light when powered by the wall charger. Here the Stop / Play buttons light up as well, featuring the same colour. It´s ridiculous but I love it! Manufacturing quality seems diminished when I compare it to the predecessor. The lid clatters a bit and doesn´t feel as solid anymore. I also think that the design has not been improved, the SL-XP 300 was the more sleek player. But it´s all about sound, don´t you think? This player was reviewed by German magazine Audio in June 1992 and awarded a 'Best Buy'. Sister magazine Stereoplay, reviewing it one month later, wasn´t so generous, they concluded that it sounded inferior to the Sony D-99. Well, what do they know? They´re unable to perform the most objective, sighted listening tests all over the net: they lack my unique testing methodology

Technics SL-XP 505 close-up

Listening test

One of the most distinctive features of the Technics SL-XP 505 is its stage response, soloists positionend to the center of the image seem to take a step towards the microphone. This helps articulation, it´s a bit like lip-reading is now easier. Generally, the stage appears to be too compact. But it is as deep and shows superior stability compared to the reference, improving holography as a result. When something veers into one direction, another thing suffers: instruments are seemingly placed behind soloists, they also seem smaller. Decay of reverb tails is reduced considerably too. Normally, this creates a dry sound signature; the Technics SL-XP 505 avoids this by sounding laid-back. High frequencies are never harsh or strident, transients are never sharp or punchy. Resolution suffers because of this, treble articulation loses precision and crispness, details are smeared. Deep bass is diminished as well, on the other hand this is alleviated by the more forward sounding center information, effectively producing a signature that sounds too warm. Reducing bass and treble impacts dynamics. Transients shed attack and punch, timing is slower, yet mids move with effortless agility and in high-speed. Still, the bloated, centric bass causes this player to sound explosive when in reality it sounds nothing of the sort. The SL-XP 505 also adds a small portion of euphonic colour, music sounds as if beautified.
All in all, the Technics is a highly characteristic, articulate, yet warm sounding player. Its sound signature is a mixture of faking a dynamic sound where none exists. Soloists will sound lovely with it, they seem to step closer towards you without invading your perceived physical distance. The Technics SL-XP 505 isn´t suited for classical music or music dependent on precise amounts of bass & treble; for these genres it´s not dynamic and crisp enough. But pop, rock and jazz will sound great with it. Recommended for people who search for character instead of balance.

Sonic Balance:
Dynamics:
Resolution:
Stage / Ambiance:
Character:

Listen for yourself!


In this section you can compare my reference files to the recorded output of the Technics SL-XP 505. I´ve uploaded several 30-seconds excerpts (fully legal) to Soundcloud for you to compare. This an example of transparency you won´t find anywhere else; what magazine offers audio examples of the device it reviews? These examples also serve to show how close to the source itself any device sounds when level differences are eliminated. I fully expect that some of my assessments might sound arbitrary to you, that is because differences with sources are tiny in reality. But please remember that EVERY other reviewer in the world faces the same problem. When you hit 'play' the files will be streamed to you in 128 kBit/s mp3, badly encoded. Therefore, I strongly advise you to download the files, they´re in 24/96 FLAC. With these files you not only have the highest quality possible, you´re also able to have a look at the aliasing performance of the Technics SL-XP 505 if you want.

Update 30.03.15: Soundcloud used to host the audiofile containing the compression artifacts. But just this day, Soundcloud decided to delete everything I ever uploaded because their automated content protection system detected several breaches of copyright.
Well, of course it did! For my reviews I need to listen to music and in order to make sound differences available to you, dear Reader, I uploaded several samples, each of them - at max - 30 seconds long. Naturally, this isn´t a breach of copyright, because a) I don´t have a commercial agenda nor background for this blog and b) I don´t advertise filesharers nor do I encourage to download things illegally. I don´t even want to mention, that only 30 seconds (!) of a particular song or piece are far too short to be enjoyed properly by anyone who attempts to be an illegal asshole. Yet Soundcloud fears the lables and their paranoia of copyright breaches which in turn prompts them to be paranoid and incompetent ninnies themselves.
I hate paranoia, I don´t want to have anything to do with stupid people / companies and everything was deleted anyway... so I decided to delete my Soundcloud account. Sorry for that, dear Reader.

Technics SL-XP 505 front

Fancy graphs (Measurements)

Line-out

Technics SL-XP 505, RMAA chart with example assessments
Technics SL-XP 505, frequency response
Well, the Technics SL-XP 505 measures as mediocre as its predecessor. The audio magazines I mentionend above sometimes described the sound as 'muffled'. While I doubt that -0.7 dB at 20 kHz will be audible they were right. Noise and dynamic range are excellent for a player working with true 16-bit technology, distortions are not. Have a look:

Technics SL-XP 505, intermodulation distortions
Technics SL-XP 505, total harmonic distortions
Igitt, intermodulation distortions should always stay below 80 dB, in case of the SL-XP 505 they come very close. If that´s audible or not, I don´t know. But it might be responsible for its characteristic sound signature. The same is valid for total harmonic distortions, they look strange. Even order distortions are at -70 dB / 2 kHz but they, along with odd order distortions, show some strange behaviour: overtones increase in level towards higher frequencies. It would be normal the other way round, usually harmonics decrease in gain. I think that something else is guilty here... but I don´t know what. We´ll try to find out with the next measurement: 

Technics SL-XP 505, CCIF intermodulation distortions
The measurement above has been 'stolen' from NwAvGuy. It is used to find out if an amplifier creates CCIF (International Telecommunication Union) high frequency distortions when under stress. What? Ampflifier? Aber yes, dear reader. What do you think a line-out is doing? It amplifies a tiny signal so that it can be transported through a bog-standard RCA cable. If it´s a bad amp with high frequency non-linearities it´ll create even-order distortions at 1 kHz, 2 kHz, and so on. It´ll also create odd-order distortions at 18 kHz, 17 kHz, etc. and 21 kHz, 22 kHz... Well, all these distortions should be below -80 dB to be inaudible. To reveal them I use a twin tone signal, the sines are at 19 kHz & 20 kHz, -6 dB. The Technics SL-XP 505 comes close, very close. But I don´t think that CCIF distortions pose a problem. Shit, I thought that this measurement would reveal something. Maybe jitter?

Technics SL-XP 505, jitter
No, doesn´t seem so... wait a minute. High frequency jitter artefacts are safely below -110 dB, so they probably aren´t audible. But low frequency jitter looks peculiar. The base of the spread isn´t wide, yet the (slim but visible) spread around the 11.025 Hz signal points skywards and vanishes right out of the picture. Is that audible? Maybe. Even so, it´s not responsible for those odd high frequency distortions revealed earlier.

Technics SL-XP 505, impulse response
Equal amounts of pre- and post ringing, tip pointing upwards: yep, this is performance by the book with correct absolute phase & linear phase filtering. Quite successful, I might add, 'cause aliasing artifacts are almost absent.


Last update: 08.08.2013

Review: Sony D-202 (1991)

Sony D-202
This review is part of a larger comparison containing seven eight vintage portable CD players and the penultimate of these reviews. You can find the final conclusion here.
Overview

The Sony D-202 was released in 1991 and was the last multi-bit converter equipped portable CD player Sony produced. Its successor, the D-111, would already feature a 1-bit DAC, just like the all the other models in their line-up 22 years ago. When new it cost 200,- Euros, not very expensive considering that only a few years prior the cheapest model would go over the counter for a whopping 350,-. Even then, Sony equipped their smallest model with rechargable batteries and a remote control (you can see the connector on the picture above). The D/A-converter on the PCB is the NEC µPD6376, a true 16-bit DAC, the 18-bit digital filter is the SM5840CP, manufactured by NPC (Nippon Precision Circuits (Seiko)). To my knowledge, this filter was also used in several stationary Pioneer CD players. To me it seems that the DAC itself feeds the line-out... if I interpret the service manual correctly. The headphone out is powered by the BA3570 from Rohm. But in my case it doesn´t matter anyway, 'cause the headphone output of my particular specimen is broken, the right channel is much louder than the left. But let me talk a minute about manufacturing quality. Tja, it sucks. The plastic feels cheap, everything creaks when moved and appearance of tolerances... brrr, I´m actually shuddering. At least the display is illuminated with the then-typical, orange LED, looking nice in the dark.

Sony D-202, front left
Before I judge the sound, a little additional story. This model and me, we go way back. I started collecting portable CD players in September 2011 with the purchase of my first CD player, the Technics SL-XP 300. I then acquired the D-220, the D-515 (horrible thing, sold it), a broken D-465 and finally the first D-202 in November. Nine months later I bought a second D-202 (the one reviewed here)... the first couldn´t read CD-R, measured awful and generally was in bad condition. Imagine, the person owning it before me lubricated its drive with motor oil, it was a wonder that it actually started! The second D-202 was in much better condition... the drive and PCB I mean. Its casing looked like crap so I took the better looking shell and grafted the working mainboard & non-oily-drive into it. Et Voilà, please welcome a new and working player, dear Reader! The reason I bought another Sony D-202 was that the first sounded promising, despite its many errors, it featured a very characteristic signature.

Sony D-202, close-up

Listening test

This characteristic sound is gone on the second Sony D-202. Differences between my reference files and the D-202 rendered files were not as big as I expected. Sonic balance misses deep bass, upper bass seems exaggerated. Brilliance area is reduced as well, this isn´t noticeable most of the time though. Resolution suffers, high frequency intelligibility is reduced. It sounds as if details audible on the reference have been turned into dust, they are smoothed. Regarding the stage the D-202 looses focus, instruments are not as seperated. Furthermore, the stage shrinks in its dimensions; it´s not as wide and not as deep. This should have helped instrument separation but it doesn´t with the result that it sounds smaller, flatter and slightly blurred. Dynamically, the D-202 sounds slower, it also loses control of transients. This is noticable on every piece (with the exception of the organ recording), the tracks 'Planet Home', 'Pinned and mounted' and 'Swim' shed much of their attack, bite, punch and snap.
These flaws are not readily audible because the Sony D-202 is able to retain the sonic character of the music. It doesn´t make the sound 'richer', it doesn´t add some beautiful sounding euphonic colourizations. In fact, it sounds slightly cold, a bit static if you will. It simply is a player sounding very well for its time but not so well today. It doesn´t fake what it cannot do anyway, staying true to what the parts on the PCB allow it to achieve. If you want a characteristic portable CD player that seems to interpret music for you, stay away from the Sony D-202. But if you want a player realistically presenting what was possible 22 years ago on a small budget, acquire it.

Sonic Balance:
Dynamics:
Resolution:
Stage / Ambiance:
Character:

Listen for yourself!

In this section you can compare my reference files to the recorded output of the Sony D-202. I´ve uploaded several 30-seconds excerpts (fully legal) to Soundcloud for you to compare. This an example of transparency you won´t find anywhere else; what magazine offers audio examples of the device it reviews? These examples also serve to show how close to the source itself any device sounds when level differences are eliminated. I fully expect that some of my assessments might sound arbitrary to you, that is because differences with sources are tiny in reality. But please remember that EVERY other reviewer in the world faces the same problem. When you hit 'play' the files will be streamed to you in 128 kBit/s mp3, badly encoded. Therefore, I strongly advise you to download the files, they´re in 24/96 FLAC. With these files you not only have the highest quality possible, you´re also able to have a look at the aliasing performance of the Sony D-202 if you want.

Update 30.03.15: Soundcloud used to host the audiofile containing the compression artifacts. But just this day, Soundcloud decided to delete everything I ever uploaded because their automated content protection system detected several breaches of copyright.
Well, of course it did! For my reviews I need to listen to music and in order to make sound differences available to you, dear Reader, I uploaded several samples, each of them - at max - 30 seconds long. Naturally, this isn´t a breach of copyright, because a) I don´t have a commercial agenda nor background for this blog and b) I don´t advertise filesharers nor do I encourage to download things illegally. I don´t even want to mention, that only 30 seconds (!) of a particular song or piece are far too short to be enjoyed properly by anyone who attempts to be an illegal asshole. Yet Soundcloud fears the lables and their paranoia of copyright breaches which in turn prompts them to be paranoid and incompetent ninnies themselves.
I hate paranoia, I don´t want to have anything to do with stupid people / companies and everything was deleted anyway... so I decided to delete my Soundcloud account. Sorry for that, dear Reader.

Sony D-202, headphone output and line-out

Fancy graphs (measurements)

Line-out

Sony D-202, RMAA chart with example assessments
Sony D-202, frequency response
Measurement results are mediocre, just what I was expecting and similar to the ones from the Technics SL-XP 505. Especially noise seems to pose a problem. Distortions are problematic too, what RMAA calls 'Good' I´d call 'Moderate' at best. Let´s have a closer look:

Sony D-202, intermodulation distortions
Sony  D-202, total harmonic distortions
I don´t know the reason for the amount of low frequency noise, maybe the power supply leaks something into surrounding parts responsible for sonics (batteries prompt the same result). Intermodulation distortions should stay below -80 dB (according to NwAvGuy), the D-202 is not able to suppress them (120 Hz spike). In this regard it´s even worse than the aforementionend SL-XP 505 (but not much). Total harmonic distortions are high, the even-order spike at 2 kHz is at -70 dB. Odd-order harmonics do not decrease towards higher frequencies, they increase. This mirrors the distortions from the SL-XP 505... maybe the multi-bit DAC is to fault? They are rumored to have magical properties in several audiophile circles... if they are the cause for these distortions I don´t want any part of them.

Sony D-202, CCIF IMD
The D-202 is unable to keep 23 kHz & 24 kHz aliasing artifacts sufficiently suppressed. But these are the only distortions digressing the boarder NwAvGuy determined. The 2 kHz alias is well below -80 dB, as are the odd-order harmonics 18 kHz & 21 kHz. I have to be realistic: this is an OK performance for a 22 years old portable CD player. Still, the low-frequency noise shouldn´t be there (but it has nothing to do with this measurement nor is it caused by it).

Sony D-202, jitter
I have no idea what causes the 'bump' at roughly 10 kHz. I´m sure it isn´t jitter-related, but I´d still love to know (any engineer around?). High frequency jitter can be ignored safely, but while low frequency jitter doesn´t show a wide spread surrounding the 11.025 Hz sine, it still reaches up high beyond -85 dB and obscures the sine which should essentially look needle-thin. Apart from this, I´m inclined to say that the Sony D-202 doesn´t jitter.

Sony D-202, impulse
No surprise here. Symmetrical amounts of pre- and post ringing denote linear phase filtering, the peak pointing upwards means that absolute phase is correctly maintained. I´d say, typical Sony performance.

Sony D-202, drive (can be replaced easily)
Last update: 12.08.2013
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