OP
- Thread Starter
- #161
In which case they were outputting the same digital signal to the DAC. So you listened twice to the same DAC. Or did I misunderstand something?
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Accuphase DP-70 Review (CD Player)
- Thread starter NTTY
- Start date
If i am correct one was output coaxial the other output optical into similar IN of the dac . Could switch with input selection of dac remote control
Out put dac was rca to an integrated amp
I did not find listening differences between the two cd players playing same CD at the same time, i mean no audible differences thrown at face that tells you '' no doubt of audible differences'' ... So conclusions ( easy for me as i am not the owner) were straight forward
It happen i had in my car several CD that my buddy had in his collection
It would have been interesting to listen an entry level cd player with good measurements compared to a costlier CD player
OP
- Thread Starter
- #163
That’s because the digital output was the same between the two CD Players, and the DAC output was the same too.
I had to smile when I saw how thoroughly they check the casing and front panels for tiniest schratches and rejected one sample because of a tiny scratch invisible to the camera. When designing a prototype I had a test sample of aluminium brushed / beadblasted anodised by about 20 companies in Germany and they all failed to do this flawless... About the German cometitor Burmester the legend goes that he contacted 200 companies to polish and put chrome on their front panels until he settled on one. 99.9% oft them did not understand that flawless means flawless. But this quality comes to another cost besides the price: Best results are achieved with primary aluminum,the aluminium that is "fresh" out of the earth and needs to be processed with a lot of energy and poisoneous chemicals. The reason: 70% of the aluminium on the market is recycled and whereas the alloys do meet the physical specifications, they are not pure when being recycled as you do not get completely the other metals out of the melt. Though such impurities are less than 0.5%, anodizing shows them. Hope I described this well, I am not a native english is not my native language...OK, another Accuphase tour spoken in English!
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OP
- Thread Starter
- #165
It is very clear, thanks for the insights!
Incidentally, I own a few BU-1C drives, which are fitted in the Accuphase DP-70 and DP-80. They were part of a project in which I wanted to develop a CD player from scratch, using linear drives as the basic principle – the patents and copyright for the system (and for the CD in general) have since expired. To extend the lifespan of the Sharp LT022MC laser diode (which was the only laser diode available at the time and is found in every CD player manufactured between 1982 and 1985), I increased the values of the feedback resistors for the op-amps that amplify the laser signal from the photodiodes. This trick can be used to reduce the laser current. It does introduce a bit more noise, but it is filtered out during the formation of the eye pattern. By the way, the laser runs along one side of the steel rod via a ball-bearing roller—the roller can be adjusted for height, allowing the laser to be realigned so that it is perpendicular to the plane of the CD.
Because of the Philips tonearm – which is just as much a technical gem as Sony’s linear drive – I was briefly in contact with Lou Ottens, who had helped develop the CD for Philips based on the Videodisc technology. He expressed a bit of frustration that Philips had discontinued the swingarms. And at Sony, too, one wonders why they didn’t simply continue producing the linear drive – after all, once a certain volume is reached, production costs should fall over the years...
Also, someone was able to replace the laser diode of the BU-1C: https://vintage-audio-laser.com/A-l-atelier-page-54
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Doesn't find my 30 year old transport
They focus primarily on first- and second-generation CD players. It was a time when, so to speak, precision engineering and tradition met new technology…Doesn't find my 30 year old transport
Excellent I found my first CD player, a Sony CDP101 and my second, the CDP-552Es and DAS 702ES. The 552 stopped working when my son had it but the DAC still worked fine when I last tried it.
I keep meaning to do a level matched comparison between it and a modern DAC but haven't got round to it.
Bought a CDP-101 new - in 2014!!! It was stored for 30 years with 2 other units, in the box was a catalogue of the first CDs and a bordeaux-colored cloth for cleaning the CDs. It failed after two weeks, as the weak amplifiers driving the tracking motor and tray overheated because of the dried up grease. Known problem and there is repair advice and how to replace the amps with better types on the net. After swapping the amps and lubricating it plays fine. Frankly, I think one could be tricked in a blind test to pick the CDP-101 over other players as his flaws sound good. I also own a Toshiba XR-Z70, which was the base of many clones from other companies. And a Nakamichi OMS-5II, but heavily modded with an ESS 9018 Dac.
CDP-101 is an atrocious sounding player due to the foolery with the output filtering Sony has done and the DAC timing error.
In a blind A-B test one should easily pick out the Sony as it has a weird sound signature.
I had 2 or 3 of these over the years for sale, ergonomics wise they are much more modern en sophisticated as compared to Philips but sonically the Sony don't hold a candle to Philips CD100/101 from the same era.
Also the Sony are overly complex as well.
In a blind A-B test one should easily pick out the Sony as it has a weird sound signature.
I had 2 or 3 of these over the years for sale, ergonomics wise they are much more modern en sophisticated as compared to Philips but sonically the Sony don't hold a candle to Philips CD100/101 from the same era.
Also the Sony are overly complex as well.
No foolery with the output filter besides it had to be very steep. Every Japanese player from the first and second generation was built like this until they were able to produce 16-bit oversampling DACs. Also you KNOW that it is the CDP-101, know about the delay between channels, which adds to stereo width, a trick used in mono to stereo filters. I have the CD-104, which uses the same components as the CD-100, yes, seems to sound smoother. Still I would say signature and not better or worst. I think , one misconception about digital was, that the „warm blanket“ of vinyl and compact cassette was suddenly gone. Consumers heard a very pristine copy of the studio master and thought it sounded harsh. Hope that the CDP-101 will be tested here one day, the Marantz- CD 73, same components as Philips CD-100 was already…
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It really isn't and I don't understand how that myth has prevailed so long.
This video includes some basic measurements (from 5.35) and an A/B sound comparison between the player and modern streaming system at 8.28
Great Video! Promote to home page! 
So the HiFi Enthusiasts’ race for better Dacs/Players was more or less a race for lower output impedance. I think 12bit was even discussed as a CD standard, as this equals the S/N ratio of analog tape. But the engineers knew they needed more bits as ladder resistor Dacs could not achieve the theoretical resolution in practice… After finishing this post, I will listen to Joe Jacksons’ “Body and Soul” on my CDP-101. Flawed digital recording from 1983 on a flawed player from 1982, but it sounds punchy and brilliant:
So the HiFi Enthusiasts’ race for better Dacs/Players was more or less a race for lower output impedance. I think 12bit was even discussed as a CD standard, as this equals the S/N ratio of analog tape. But the engineers knew they needed more bits as ladder resistor Dacs could not achieve the theoretical resolution in practice… After finishing this post, I will listen to Joe Jacksons’ “Body and Soul” on my CDP-101. Flawed digital recording from 1983 on a flawed player from 1982, but it sounds punchy and brilliant:
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Souzoukan Technical Report is one of the best Youtube channel about hifi electronic and loudspeaker techniques.
My brother just bought a second hand Accuphase dp600 which is using this Sony pick up. I emailed Accuphase jp to know whether some khm230aaa were still available in case of failure and the answer is no6'37'' in the video, top left corner: a box (full of?) Sony KHM-230AAA laser optical pick-up mechanisms.
The optical pick-up used in Sony SCD-555ES, SCD-XA777ES and SCD-XA9000ES amongst others and unfortunately known to loose its ability to read the SACD layer of hybrid discs over time (although this very mechanism in one of my disc players still works flawlessly after 25 years of operation).
This make me think that a knowledgeable technician should properly investigate the failure mechanism of this pick-up, because there are some clues that it may be related to some mechanical issues rather than laser diode break down.
My own sony scs 555es suddenly stoped reading sacd and hybrid sacd discs a few months ago. However, the red laser dedicated to the sacd layer is still glowing. Electronic or mechanical issues may be involved as you suggested.
I will try asap a stock khm230aaa pick up bought at musi24.de a few years ago but I'm not confident since this dealer is suspected to sell chineese copies. As far as the khm230aaa is concerned, I ordered recently on ebay a so called original new one (nos) but at the end, the axis of the spindle disc is to short by 2mm and the laser head hits it when it comes close to the center... which explains why I found the blue plastic protection broken...
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Bad choice! They are not repairable. Same for the older 7xx, 8xx, 9xx. Maybe the 950 and 1000 still are, from the older models.My brother just bought a second hand Accuphase dp600 which is using this Sony pick up. I emailed Accuphase jp to know whether some khm230aaa were still available in case of failure and the answer is no
I'd use it as DAC only or quickly sell it before it stops reading SACD (assuming it still does).
You also cannot just swap another KHM230AAA laser in it, it needs knowledge and careful alignment, especially for SACD layer.
The biggest problem is that even the 80's models with BU-1 or KSS-27x will easily outlive the new SACD ones.
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