Arcam CD92 dCS Ring DAC

[tpd]

In this post I am sharing some initial measurements for an Arcam CD92 CD player I recently picked up, featuring the dCS Ring DAC. I say initial measurements because the CD player came to me with some problems, most likely caused by aging capacitors. But after some warm up it plays enough to do some listening and some measuring.

There's a story here, which I'll fill out in more detail when I have a bit more free time. The short story is that I auditioned the first generation of this player, the Arcam Alpha 9, in about 1999 when it was new to the scene. I was hugely impressed. Unfortunately the price was just above my purse at the time. When I could afford one again... they were extremely hard to find in working order. When a barely working specimen came on market recently, I guessed that I could address the apparent problems, made a lowball bid, and came away with my White Whale, finally.

Does it live up to the hype? I'll let you decide.

I can tell you why it probably impressed me at the audition: fairly hot 2.36V output.

 

[tpd]

Here are my initial measurements.

1k 0dBFS

1k -6dBFS

Frequency Response

Multitone

Jitter

1k -6dBFS comparison with restored Magnavox CDB-460 (TDA1541)

Comparison with JVC XL-Z331 (US version of XL-Z335 measured by NTTY)

 

[bachatero]

Looks not quite as good as modern DACs but still transparent!

 

[Scytales]

dCS Ring DAC circuit board designed for Arcam :

The photo is taken from this webpage, where the author states the op amp used on the board are OP275, AD797 and OPA2134. Obviously, a Pacific Microsonics PMD200 digital filter capable of decoding HDCD discs is used as well as a couple of Field Programmable Gate Arrays (FPGAs) or 1 FPGA plus 1 Application Specific Integrated Circuit (ASIC), which must have been very costly at the time (around 2002). There are also inductors near the shielded output jacks. Is the analogue post-DAC output filter a passive job ?

That's a lot of material resources for a not so impressive result.

Nevertheless, I have in my library a test of an Arcam CD92T (T= added CD text function) published in the April 2002 issue of the German magazine Stereoplay. The published FFT analysis at about 315 Hz@0 dBFS with an AP2722 shows a much better and cleaner result than is visible above, with only two power-supply related spurious, both below 120 dB under full scale output, and harmonic distortions under -100 dB relative to full scale.

Something may be amiss with this particular item or with the test set-up.

 

[nerdstrike]

I'm a big fan of the "THIS IS A 115V PART" labels. Somebody screwed up in assembly at least once!

Seems like the mains hum and cloying harmonics hurt the numbers quite a lot.

 

[LTig]

Noise is rather high and dominated by power supply hum - could be caused by aging caps.

 

[audio_tony]

When the OP mentioned Arcam & ring DAC I thought they may have been referring to the original ring DAC player (Arcam CD9)

Here's a full test of the CD9 from 1998 by HiFi Choice.

The PDF was too large to upload here - so click on the link above to access it.

 

[NTTY]

Thanks for the measurements. There's a problem indeed. Lot's of low level random noise and PS is heavily leaking too, it's probably related.

 

[tpd]

Preview of likely restoration path. https://www.condoraudio.com/wp-cont...am-CD92-CD-HDCD-Player-Restoration-Repair.pdf

 

[tpd]

When the OP mentioned Arcam & ring DAC I thought they may have been referring to the original ring DAC player (Arcam CD9)

Here's a full test of the CD9 from 1998 by HiFi Choice.

The PDF was too large to upload here - so click on the link above to access it.

Thank you for the link.

It's my understanding that all of the Arcam ring DAC players use the same "Alpha 9" daughter board containing the dCS Ring DAC implementation. For example, a CD92 is a CD72 with some on-board DAC parts left off (a Wolfson IIRC) and the daughter board added.

The CD23 review posted earlier shows the same arrangement. The main board looks otherwise identical. Clever of Arcam to get six models (at least) out of a pair of PCBs.

Also of note: if you don't have the original remote, all of these players respond to standard Philips/Magnavox signals. I've been using the remote from my CDB-650.

 

[VientoB]

I wonder how many reviews and auditions back in the day were swayed by the high output voltage.

 

[Scytales]

Some reviewers were perfectly aware of the importance of comparing devices at matched levels.

The Hifi Choice staff at the time of the above mentioned review was led by Paul Miller, which is an expert in audio measurements, and it was regularly stated in the pages of the magazine that listening comparisons were done at matched levels.

I also know for a fact thanks to the testimony of a trust-worthy former insider of an Hi-fi company that in Germany, the staff of the Stereoplay magazine used to use a Burmester 808 preamplifier which incorporates a trim level feature on each and every inputs, a trim level feature of two separated line outputs and an integrated RMS voltmeter to adjust their respective levels with test tone. Presumably, this preamplifier, which incidentally is still in production more than 40 years after the release of its first version, was used to conduct listening comparisons between sources or power amplifiers.

 

[Vini darko]

Did some work on a alpha 8 cd player. Couple of warning words , the ribbons that attach the dac modual to the main board are are a pita to reattach and like to peel contacts. Also the traces on the pcb are very prone to lifting so keep dwell times down to the minimum.
Maybe Arcam improved things from my player (1998) but internal shots of your player look the same set up.

 

[VientoB]

Some reviewers were perfectly aware of the importance of comparing devices at matched levels.

The Hifi Choice staff at the time of the above mentioned review was led by Paul Miller, which is an expert in audio measurements, and it was regularly stated in the pages of the magazine that listening comparisons were done at matched levels.

I also know for a fact thanks to the testimony of a trust-worthy former insider of an Hi-fi company that in Germany, the staff of the Stereoplay magazine used to use a Burmester 808 preamplifier which incorporates a trim level feature on each and every inputs, a trim level feature of two separated line outputs and an integrated RMS voltmeter to adjust their respective levels with test tone. Presumably, this preamplifier, which incidentally is still in production more than 40 years after the release of its first version, was used to conduct listening comparisons between sources or power amplifiers.

I remember when DVD players first came out HiFI Choice were raving about them sounding as good as £100 CD players. Yes HiFi Choice did level match. Who did at a hifi dealer when auditioning, though?

 

[audio_tony]

I remember when DVD players first came out HiFI Choice were raving about them sounding as good as £100 CD players.

There were several DVD players reviewed in the HiFi Choice I got the Arcam review I posted above from.

If anyone is interested, I can scan and post those reviews too.

 

[Scytales]

There were several DVD players reviewed in the HiFi Choice I got the Arcam review I posted above from.

If anyone is interested, I can scan and post those reviews too.

Spare yourself the hassle: https://www.worldradiohistory.com/Hi-Fi-Choice-UK.htm

 

[DSJR]

Thanks for posting this test

I remember the Alpha 9 well and my stint came to an end just as the better built models like this were being established. The original 'FMJ' case was far more substantial again with a good price hike to justify it...

I was never quite sure of the Alpha 9 and CD92, kind-of preferring the better priced Alpha 8Se and 82 players as they sounded more 'grounded' for whatever reason (bloody subjectivists ), although memories are old and jury is out.

If you can do some gentle remedial work on this well-used player's power supply at least, you may get hum components down nicely. Arcam were thorough as regards jitter, which was a bit of a technical if not subjective issue back then and they bought Paul Miller's test suite I recall, this long before the AP systems used today.

Would be interesting to test the bottom model of this range too if possible (CD72?) to see what exactly the differences were and if today, without the 'more expensive is better' vibe, any real sonic difference is there at all...

 

[audio_tony]

Spare yourself the hassle: https://www.worldradiohistory.com/Hi-Fi-Choice-UK.htm

Excellent, thanks for that. There's goes an afternoon!!

 

[tpd]

Would be interesting to test the bottom model of this range too if possible (CD72?) to see what exactly the differences were and if today, without the 'more expensive is better' vibe, any real sonic difference is there at all...

This is on my to do list if the right CD72 comes around. It would be super interesting to see measurements side by side of players whose only difference is the DAC.

 

[tpd]

I wonder how many reviews and auditions back in the day were swayed by the high output voltage.

I can only speak for myself, but I know my audition was not level-matched.

The audition comparison was between three CD players: Arcam Alpha 9, Rega Planet, and something from NAD. The Arcam clearly stood out from the others on material I knew very well.

Rest of the system I don't recall as clearly. I can see the speakers in my memory but couldn't tell you what they were. Something "with a similar presentation to my Spendors" whatever that may have meant. My own system at the time was Dynaco PAS3 > British Fidelity > Spendor SP2/2. Venue was Stereo Exchange in NYC.

I don't miss buying audio equipment in the pre-Internet world.