Wednesday, August 14, 2013

Review: Grundig CDP 70 (1993)

Grundig CDP 70
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.


The story of Grundig is a sad, yet typical one. Established by Max Grundig in 1930 the company once was Europe's biggest manufacturer of home electronics. Globalization took its toll in the early 80s when Grundig began to struggle. The influence of Dutch giant Philips, starting in the early 70s, grew until both merged in 1984 with Philips taking over complete economic control in 1993, the year the player reviewed here was released. But Grundig couldn´t be saved, it went bankrupt in April 2003. Since then the company has been smashed into several pieces. Its home electronic division emerged out of bankruptcy as a subsidiary of the Turkish Koc Holding. Grundig now exists in name only and lends its prestigious name to cheap home appliances and crappy HiFi electronics.

Grundig's penultimate series of home electronics (dutch advert)
It´s actually painful for some people because this company was an important part of the post-war Wirtschaftswunder ('Economic Miracle'), many Germans connect fond memories with Grundig. Take me for example (although I returned to Germany long after the 'Wirtschaftswunder' ended): over the course of more than 20 years I owned three TVs manufactured by them. The second set was the most interesting, it featured their patented 'Space Fidelity' technology that was able to create quasi-Surround sound out of only two loudspeakers without digital signal processing. I´d have loved to present a photograph of that TV set... but I can´t, it seems to be extremely rare. Well, it also was extremely ugly so maybe there´s a reason that it´s so uncommon. Nonetheless, it was the best sounding TV set I´ve ever heard.

Grundig CDP 70, detail: plastic everywhere
But now to the Grundig CDP 70. Judging from the design and the product finish it must have been a cheap device. It looks really really ugly, clunky and not sophisticated. Sorry, Grundig, but the Japanese did this better most of the time. There´s lots of empty space inside of it, allowing usage of parts usually found in stationary devices. One condenser for example is so huge that I was shocked to find it there. Manufacturing quality isn´t too good since buttons wobble, the lid creaks and tolerances... well, let´s say, Grundig didn´t seem to think that they were important. It also might be quite rare, 'cause I cannot find any information for it online, no one owns it, no one sells it. Which is a disgrace really; it´s actually a well sounding player. Operating it feels awkward, the display for example shows the tracknumber by default - and nothing else. You have to press 'Memo / Time' to enable the time-setting. When you look inside you immediately notice that there´s Sony everywhere. Indeed, half of the ICs on the mainboard are from Sony. The 1-bit DAC for example is the CXD1167Q, a converter also used for several stationary CD players from NAD. The rest of ICs produced by the then still huge giant care for motor / spindle control, error correction and system control. The line-out is amplified by the BA4510, the headphone out by the NJM3414... the latter featuring a horrible performance.

Grundig CDP 70, a rare and not very beautiful looking player
Listening test

Never use the headphone output! It is one of the worst I´ve ever listened to, in this case the audible performance is mirrored perfectly by the measurements you can find below. But the line-out is something entirely different. The most obvious difference to the reference files is that the Grundig CDP 70 diminishes very high frequencies (not so much) and very low frequencies ('bit more). Mids are left completely alone, yet, due to the slightly capped frequency ends, they sound more forward. Reduced treble also affects resolution and detail; definition & general delicacy of high frequency details are impaired (audiophiles would call it 'microdynamics'). Stage performance is close to the reference, stability, width, placement and size of instruments are a match. Depth however isn´t, the stage as rendered by the CDP 70 is flatter and lacks a small amount of air & ambience. Dynamics are slower yet consistent over the whole frequency band. The muted treble / bass also influences attack and punch; they are close but not the same. But the character of the reference files is retained well, only a small amount of aggressiveness is added. This player has so far been a surprise, I never expected it to perform that well. Recommended - but only if you use the line-out exclusively.

Sonic Balance:
Stage / Ambiance:

Listen for yourself!

In this section you can compare my reference files to the recorded output of the Grundig CDP 70. 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 Grundig CDP 70 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.

Grundig CDP 70, close-up
Fancy graphs (measurements)


Grundig CDP 70, showing RMAA's quality assessments
Grundig CDP 70, frequency response
Grundig CDP 70, noise floor
Grundig CDP 70, total harmonic distortions + noise
Grundig CDP 70, intermodulation distortions
As you can see there´s nothing to see. No, really. The only things to bitch about are the frequency response and the too high noise floor. The graph exhibiting total harmonic distortions + noise serves to show how RMAA disinterprets the high noise floor as being caused by the test signal itself. This isn´t true of course, the noise is almost unchanged by the sine, and all distortions are safely below -100 dB. Therefore I´d call the result 'Very good' instead of 'Good'. But not all is well:

Grundig CDP 70, CCIF IMD
The Sony DAC/digital filter sucks at rejecting aliasing components. In the hyperband you can find several aliases being dangerously loud in volume (have a look at real-world-examples in the section 'Listen for yourself!'). The passband (audible band below 20 kHz) looks very good though, displaying only a small amount of inaudible distortions. Nice performance, especially for a 20 year old, portable CD player.

Grundig CDP 70, impulses
No surprise here. This impulse response is modeled after the first CD players released by Philips and Marantz (back then a subsidiary of Philips) in 1982. Those used a 14-bit DAC, combined with 2 fs oversampling and an analogue aliasing filter. This filter produced no pre-ringing but loads of post-ringing and a severe phase error. Many audiophiles however felt that this combination sounded very musical compared to the symmetrical Japanese filtering on CD players produced by Sony. Since Grundig was part of Philips in 1993 it´s no wonder that they employed a similar (in this case digitally working) aliasing filter.

Grundig CDP 70, jitter
I think that jitter won´t pose a problem on the CDP 70. High frequency jitter is close to assumed audibility, low frequency jitter isn´t. Since I didn´t hear exaggerated brilliance (typical signs of high frequency jitter) or muddied lower mids and bass (low frequency jitter), I think that it´s inaudible. Though... the noise floor looks weird. Perhaps caused by something like a 'jitter rejection mechanism' (??), the power supply or something else.

Headphone out

Grundig CDP 70, frequency response, several impedances
Grundig CDP 70, total harmonic distortions + noise, several impedances
Grundig CDP 70, intermodulation distortions, several impedances
Oh my God! What was this headphone output engineered for? To point out how many distortions can possibly be poured into a player that was perfect to begin with? This is really awful, I won´t even describe these to you. This headphone output isn´t suited for ANY headphone at all. The frequency error alone... blegh, forget it. This is a portable unit, yet its headphone output is a complete waste, I don´t understand it.

Last update: 14.08.2013

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