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Old 17th March 2005, 03:32 AM   #1
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Default Build an Apex based CD player..harddrive??

First off, I'm no digital expert. B: I'm not a software/firmware writer, and 3: well, I dunno.

For a while I was selling modified Apex DVD players. These players basically circumvented copyright protection. This was done with a simple firmware upgrade. I made a few bucks but don't do it anymore.

Why is this of interest? You may ask...who cares. Maybe nobody but I'm gonna share anyway.

There are several Apex players of concern: AD600a, AD660, AD500(no letter with drive on the bottom), AD500w, and a NEW 'Jinxing' brand player that is identical to the AD500w that has been on the market recently. These are just the ones I have had experience with..there are others and different brands as well.

These players have an IDE interface that works perfectly well with most PC drives, this includes CD rom drives too. So what?

With the right firmware a Hard drive can be added as a slave. This firmware is a derivation of the Sampo dve631cf firmware that had a card reader. There is also software provision to SLOW A CD ROM DOWN to 1x..2x.....

These players have a terrible smps and frankly don't sound very good..or look too good either. Well, where does that leave us on the subject?

How about taking the mainboard with the upgraded eprom installed and sticking it into a nice solid chassis. Upgrade the hell out of the psu or build a new one. Integrate the Apex display, rf receive, and front panel buttons. Install a quality cd rom drive and a removable hard drive(slide out) that you can jockey to and from your PC.

What are the options for good sound quality? Can the spdif off of the Apex board be reclocked ? If so, you could do mp3's on cd's as well as a zillion mp3's on a dvd if you put a dvd rom in there...just for the convenience. Or would better results be had by messing with the spdif on the optical drive itself..forfeiting the hard drive? I am for improving the Apex spdif out..so you can have the hard drive audio. The main board and psu are littered with ultra cheap caps etc.

Anyway, it seems like a pretty quick and easy way of getting a home built, super flexible, CD/hard drive player going! I just don't know how to make it sound good.

attached is a pic of a AD500w mainboard...
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Old 17th March 2005, 07:01 AM   #2
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I bought a so called Hiteker, same as APEX, several years ago.
Reason for buying are the 5.1 analog outputs.

And also i have been wondering about changing the analog output stage to improve it. Of what i have seen , they stuck PCM1702 or PCM1704's in there. These are not the best and also not the worst DA converters.
Starting with a new supply and decoupling it at the IC's directly would dramtically improve the sound , i think.

Since the PCM's need I2S input, you'd better start reclocking at the input and stick a better opamp in !

grtz

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Old 17th March 2005, 08:14 PM   #3
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Thanks blu_line,

Sounds like good advice. I am more interested in improving a digital output, as 5.1 does not interest me, nor do any of the players I mentioned have analog 5.1. I am looking for an improvement for 2 channel here. It seems to me that this may be a really good and easy starting point for a diy cd/harddrive player. Am I off a bit here? Judging by posts I have read, I conclude that controlling a ide drive and integrating a hard drive would be the major challenge..this would be all worked out for the builder..especially the software.
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Old 17th March 2005, 08:33 PM   #4
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Well, you can probably do just about anything you want if you get the right firmware for it. I would say that you should research what the best IDE CD-ROM drives are, then build a TTL to S/PDIF converter and hook it up to that CD-ROM drive's digital out -- at least if you just wanted to use it as a spiffy transport.

This'd be similar to the various NEC CD-602 projects going on (74HCU04 & RS422 chip). That along with a decent PSU should make a good transport.

For CD Player duties, blue_line is probably right. Dump the SMPS, replace the caps with some better ones. You'll also probably need to trace out the analog section -- I'm guessing there's some nastiness in there that will need to be fixed. And finally, you can reclock it if you're feeling frisky

If there's a hack for a harddrive, so it can read FAT filesystems, I'd be more interested in the project. Your big limitation is how large of a partition you can create with FAT (unless it's FAT32, you'll be fairly limited). But it still might be interesting.
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Old 18th March 2005, 02:30 AM   #5
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I am pretty sure Fat or Fat32 is not an issue, I think that is what is necessary! The firmware is not a problem..I have patched it and used it 100's of times. I have never used a hard drive with it but it is well documented that it works well. If memory serves people have used ~80gig without issue. There is a yahoo forum called "one firmware for all" (aka OFFA) dedicated to the subject. Getting all of that to work is not a big issue;

Making it sound good is....
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Old 18th March 2005, 04:13 AM   #6
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Well, how deep to you want to get into modifying it? Also, does the player offer S/PDIF or Toslink outputs?

The easy stuff to fix on that player would be:

1) Replace the SMPS with a Linear one. Most likely you would need to measure the voltages while the system is under load. I'm guess it probably just uses +12v and +5v if it's a "computer" based system.

2) Swap out their crappy caps with something better. Panasonic FC/FM if you want to go cheap, Cerafine/BlackGate/Nichicon Muse if you want to spend more money (though Muses are arguably about the same price as the Pannys).

3) Research the analog output section. You may want a separate +/- 12v supply for this, which would require cutting traces and doing some precision soldering. You'll probably also want to replace the opamps doing I/V conversion (I think you need that on the PCM chips).

4) Look at swapping in better crystals for the player. Most likely they use a low tolerence one. You may have more than one crystal to replace.

5) If you want to spend big $$$, get a reclocking chip.

I personally think it'd be easier to get an ITX board and linear 12V PSU (5-7 amp), along with a good sound card.. But then again, this would probably be more fun
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Old 18th March 2005, 05:18 PM   #7
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The player does offer coax spidf. This is the output I would want to improve. This is the only way one would get digital out while retaining hard drive audio potential.
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Old 18th March 2005, 08:12 PM   #8
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I would say to do the HD mod then, and see how things come out to your DAC Unless you have an oscilloscope and are well-versed in digital transmission circuits, you may have some trouble coming up with mods for that box.

I would suggest mapping out the coax digital output back to the DAC and see what's inbetween. Then you can figure out if there's any parts worth replacing.

I think the PSU mod is still valid. It should remove a lot of noise and jitter from the player. Reclocking might be more valid in this case, since you're looking to use this as a transport.
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Old 3rd February 2009, 10:10 AM   #9
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* Long bump up *

I have an Apex AD-500B (which uses a different ESS-based digital board from the plain AD-500 or 500w). I upgraded the firmware long ago for region-free operation, which required physical removal of the EPROM and the use of an external EPROM programmer.

This unit is easy to modify for several reasons:

1) The PSU layout is spacious, with plenty of space between components on the secondary side. This allowed easy upgrades of the secondary electrolytic capacitors on the +5v, +12v and -24v rails - I used Nichicon HD and PW, but any low-ESR, long-life series should work fine.

2) The transport unit is a stock computer IDE (PATA) DVD drive - it can easily be replaced inexpensively, even with a CD-ROM drive if DVD playback is no longer required. This allows DVD-R and DVD-RW media-compatibility to be improved, if required.

3) The digital decoder supports decoding MP3 files written in ISO9660 format to CD-R/RW, in addition to stock CD audio. The layout of the digital board is convenient, with the DAC located at the corner, very close to the power connectors as well as the analog audio-out connector. The audio signal path length to the connector is less than a centimetre, and includes a 10uF DC-blocking cap for each channel. I replaced both these caps with Nichicon Muse SW-series caps.

4) The rest of the analog signal path is on a separate analog output board, which contains the op-amps, back-panel connectors, etc. This board is single-sided and very easy to work on. I upgraded all the electrolytics in the signal path to Nichicon Muse, and bypass caps to Panasonic HFQ and Nichicon PW. A ceramic 10 nF bypass cap next to the op-amp was replaced with a 100 nF polyester film cap.

5) There is a single op-amp for each channel on the analog board, and this is an NE5532. The supply to the op-amp is a heavily filtered, single-rail +12v from which a +6v center reference is derived. At the moment, it sounds fine with just the capacitor upgrades, but future upgrades could include an LM4562 or similar ultra-low-distortion op-amp to replace the NE5532. There are also a few small ceramics left in the filter sections of the audio signal path, which need to be upgraded to styroflex/silver mica.

In short: Although long discontinued, this is an inexpensive unit with an excellent, short, simple and easily-modified audio signal path. The digital decoder handles a variety of audio formats. It is a worthy alternative to more expensive CD-only transports like the Marantz CD63SE and similar.
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