Hi folks
During the late 80s before the Japanese economic bubble burst, all the big electronic corporations were putting huge sums into R&D of their digital products and JVC was no exception, which lead to the development of their own series of DACs using a technique they developed called Pulse Edge Modulation. There weren't many DAC chips in the series, the first was the JCE4501, then the JCE4302, then the MN3550x series.
There is precious little information available about these DACs, mostly it is to be found in the service manuals of their CD players. I've compiled what info I could glean:
In the early '90s JVC developed a proprietary circuit for a more accurate D/A conversion, called P.E.M. (Pulse Edge Modulation, in contrast with the common PWM, Pulse Width Modulation) which gave a big "plus" to their CD players so that even the most die-hard audiophiles had to recognize those machines played extremely good noises.
In particular, that circuit allowed the JVC CD players to reach the limit of the maximum theoretical CD digital resolution, approaching 15.9 dB (theoretical max being 16 dB).
1993 JVC company developed A high-quality bit compression technology called K2 super encoding; (that is, today's XRCD, you can check it out)
JVC company developed a 20-bit K2 processing technology for the main purpose of the player in 1994. The purpose is The 16-bit data is converted into 20 bits, so that the reproduced sound is close to the original sound, and high sound quality is realized.
http://www.jvc.com.cn/woodcone/k2.html
P.E.M. D.D. Converter with VANS, fine pulse interface
JCE4501 – JVC bitstream DAC
JVC K2 Interface, a circuit that reduces jitter by resampling the pulses with a short-duration gate just ahead of the single-bit JVC JCE-4501 DAC chip.
K2 technology is used in front of the digital filter
JVC D2000 DVD player uses K2 with JCE8001 – last K2 chip produced
JCE4302a is a DAC with 8 times filtering inside. JCE4301a doesn’t. It must be preceded by one. For example, ym3414 filter chip, JCE4300 is a pure K2 processing chip. Filter chip, without any 4 times 8 times filter. Just pure K2 processing
The DD (Digital Direct) converter is carried in the D / A conversion part.
In the DD converter, the digital signal is converted into a 1-bit operation pulse wave that changes based on the crystal clock, and is directly converted to analog. Therefore, unlike the conventional ladder type D / A converter, since the bit amount is not piled up, zero cross distortion due to the amplitude error does not occur in principle, and the reproduction ability of a minute level is greatly improved. Furthermore, the excellent characteristics of a dynamic range of 100 dB or more and a distortion rate of 0.0017% or less are realized.
The DD converter consists of three parts: digital filter + noise shaper + PEM / DAC, all of which are digitally processed.
During the late 80s before the Japanese economic bubble burst, all the big electronic corporations were putting huge sums into R&D of their digital products and JVC was no exception, which lead to the development of their own series of DACs using a technique they developed called Pulse Edge Modulation. There weren't many DAC chips in the series, the first was the JCE4501, then the JCE4302, then the MN3550x series.
There is precious little information available about these DACs, mostly it is to be found in the service manuals of their CD players. I've compiled what info I could glean:
In the early '90s JVC developed a proprietary circuit for a more accurate D/A conversion, called P.E.M. (Pulse Edge Modulation, in contrast with the common PWM, Pulse Width Modulation) which gave a big "plus" to their CD players so that even the most die-hard audiophiles had to recognize those machines played extremely good noises.
In particular, that circuit allowed the JVC CD players to reach the limit of the maximum theoretical CD digital resolution, approaching 15.9 dB (theoretical max being 16 dB).
1993 JVC company developed A high-quality bit compression technology called K2 super encoding; (that is, today's XRCD, you can check it out)
JVC company developed a 20-bit K2 processing technology for the main purpose of the player in 1994. The purpose is The 16-bit data is converted into 20 bits, so that the reproduced sound is close to the original sound, and high sound quality is realized.
http://www.jvc.com.cn/woodcone/k2.html
P.E.M. D.D. Converter with VANS, fine pulse interface
JCE4501 – JVC bitstream DAC
JVC K2 Interface, a circuit that reduces jitter by resampling the pulses with a short-duration gate just ahead of the single-bit JVC JCE-4501 DAC chip.
K2 technology is used in front of the digital filter
JVC D2000 DVD player uses K2 with JCE8001 – last K2 chip produced
JCE4302a is a DAC with 8 times filtering inside. JCE4301a doesn’t. It must be preceded by one. For example, ym3414 filter chip, JCE4300 is a pure K2 processing chip. Filter chip, without any 4 times 8 times filter. Just pure K2 processing
The DD (Digital Direct) converter is carried in the D / A conversion part.
In the DD converter, the digital signal is converted into a 1-bit operation pulse wave that changes based on the crystal clock, and is directly converted to analog. Therefore, unlike the conventional ladder type D / A converter, since the bit amount is not piled up, zero cross distortion due to the amplitude error does not occur in principle, and the reproduction ability of a minute level is greatly improved. Furthermore, the excellent characteristics of a dynamic range of 100 dB or more and a distortion rate of 0.0017% or less are realized.
The DD converter consists of three parts: digital filter + noise shaper + PEM / DAC, all of which are digitally processed.
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The upload attachments isn't working so I can't post the rest of the data I have, hopefully it will be fixed soon.
Here's a list of players that used the JCE4501 chip:
JVC JCE4501 – YM7121C
OPTIMA-6
JVC XL-R304
JVC JCE4501 – YM7121B
OPTIMA-5
JVC XL-V151
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V152
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V242
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V251
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V252
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-Z451
JVC JCE4501 – SM5840DP
OPTIMA-5S
JVC XL-Z551
JVC JCE4501 – JCE4300 – SM5840DP
OPTIMA-5S
JVC XL-Z552
JVC JCE4501 – JCE4300 – SM5840DP
OPTIMA-5S
JVC XL-Z1050
JVC JCE4501 – JCE4300 – YM3414
OPTIMA-5S
VICTOR XL-Z900
JVC JCE4501 – CXD1244
JVC EXU-901A – OPTIMA-4 (40S)
Here's a list of players that used the JCE4501 chip:
MODEL
DAC-chip, Dig. filter chip, other
Laser Pick-up / Mechanics
JVC XL-F108JVC JCE4501 – YM7121C
OPTIMA-6
JVC XL-R304
JVC JCE4501 – YM7121B
OPTIMA-5
JVC XL-V151
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V152
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V242
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V251
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-V252
JVC JCE4501 – CXD2554P
OPTIMA-5S
JVC XL-Z451
JVC JCE4501 – SM5840DP
OPTIMA-5S
JVC XL-Z551
JVC JCE4501 – JCE4300 – SM5840DP
OPTIMA-5S
JVC XL-Z552
JVC JCE4501 – JCE4300 – SM5840DP
OPTIMA-5S
JVC XL-Z1050
JVC JCE4501 – JCE4300 – YM3414
OPTIMA-5S
VICTOR XL-Z900
JVC JCE4501 – CXD1244
JVC EXU-901A – OPTIMA-4 (40S)
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Good info Ian. I used to be collector of JVC stuff. I still have some stuff left. Had two K2 JVC cd players, gave one to a friend. I keep one around, nice sound.
interesting tidbits of info for sure Ian, but i'm wondering what one is to do with this info? the spec is handily beaten by dacs designed for mobile phones these days. is this more just info for the archives? JVC gear from that era was great kit; no doubt about that. is there anything truly novel though? it sounds like an early DSD like process?
Now hopefully the interesting bit - I happen to have not one, but two JCE4501 chips. I searched in vain for adapter PCBs to fit them so ended up using a fairly novel method to mount them to a PCB by flattening the legs and soldering thin wires to each.
The datasheet shows that there is a pin that when left unconnected, puts the chip into mono mode, so I should be able to use both chips together to make a stereo DAC, something I don't think JVC ever did as even their top end players appear to only have had a single chip.
The datasheet shows that there is a pin that when left unconnected, puts the chip into mono mode, so I should be able to use both chips together to make a stereo DAC, something I don't think JVC ever did as even their top end players appear to only have had a single chip.
Attachments
I've copied the wiring from the JVC service manuals - they made loads of players with almost identical PCBs, the digital and analogue sides of the chip are fed separately by +5V supplies. For the digital front end and analgoue output circuits, I will have to devise new circuits rather than copy what JVC did in order to get the best out of these chips. I'm thinking a nice discrete I/V converter would work well with these, not sure what chips will work as digital filters, the Yamaha YM3414 and Sony CXD2554P are both supported, and some of the better JVC players used the SM5840DP, but I'm thinking that I should be able to use a more modern chip.
Attachments
The datasheet states that the inputs (it has two) of the JCE4501 are 18-bit 8fs serial. I take this means that this chip has to be used with a digital filter that is capable of 18-bits and 8x oversampling - can output 384Fs clock rate?
I know the the Yamaha YM3414 and Sony CXD2554P are both supported, and the SM5840DP, but those are all old chips and I keep reading that their performance is much worse than the modern equivalents, the YM3414 for instance, is said to be jittery.
So what I need to know is what other options I have for digital filters that will work in this application? Should I be looking at sample rate converters like the AK4125, AD1896 and CS4322?
I know the the Yamaha YM3414 and Sony CXD2554P are both supported, and the SM5840DP, but those are all old chips and I keep reading that their performance is much worse than the modern equivalents, the YM3414 for instance, is said to be jittery.
So what I need to know is what other options I have for digital filters that will work in this application? Should I be looking at sample rate converters like the AK4125, AD1896 and CS4322?
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