|
|
|
Xin Feng 10/25/02 Now I've got an audiophile-level amp - my super mini amp, what's the next? You guessed right, a good portable CD player. As newer Panasonic portable CD players no longer have line out jack, I have to turn my eyes to Sony. I went to my local Target store last night and picked up the Sony D-FJ401 among many other brands and models. I selected it because:
As soon as I got it home, I turned it on and it exceeded my expectations. The sound was clean and warm, better than the Panasonic I used to own. Plugging my super mini amp into its line out, the sound was even better and I never heard anything so dynamic! However, the most surprising thing was the digital tuner - very sensitive and selective, very close to my SRF-S83 (the best pocket radio so far). It got all my favorite FM stations and all 4 TV stations! Finally I've got a CD player that has an usable tuner. Another thing I loved very much was the strip hooker - what a thoughtful design! Now what? You guessed it right again - let's open it!
In the audio signal area, a 4066 IC is used here for pre-amp and line out and a Toshiba TA2120FN IC is used here as headphone amp. The line out is taken right from the 4066, before the headphone amp. There is no electrolytic caps in the line-out signal path. Therefore, this line out should be a very good source for an external amp. However, there are still three SMT caps in the signal path (in each channel) and they should be replaced with film caps if you want the optimal line out. Alternatively, you may simply remove the filtering caps and short the coupling caps. I've not got time to try these yet. There are two 220uF caps (#4 and 5) between the headphone jack and headphone amp and they must be replaced with 470uF caps ( I used Panasonic FC series) for fully extended bass. Other large electrolytic caps are all 220uF. Although not so necessary, I replaced them all with 330uF Panasonic caps before I closed the case because I didn't want to open the case again (not so easy). The cap right to the #3 cap was not soldered and I added a 330uF there too. As you can see, I also soldered a wire to the RF pad to boost the FM reception.
Now the sound from headphone jack has significant better bass and is full of energy. More pleasant and warmer. Hard to believe a $89 CD player and its built-in tuner can sound so good. If you don't care about headphone output and use the line out and an external amp to get the best sound, then you don't need to replace these 220uF caps. If you use a pair of headphones that are 64 ohm or higher (such as Koss KSC35), 220uF is enough and no need to replace them. If you use a pair of MX500 (32 ohm), Grado 60 (32 ohm) or Sony 888 (16 ohm), then 220uF is indeed not enough to pass low-end bass. Not all people can tell the difference though, and this is exactly why Sony does not waste money on putting in 470uF caps. Sony is not the only one who does this - I have never seen larger than 220uF caps used for DC decoupling in any portable audio. This player is very skip free. I have never used the G-protection yet, because I want the best sound and I have never heard any skip yet no matter I'm walking or biking. Like other recent players, it reads CDR/W disks, but it cannot play MP3 files. However, with a decent tuner, you really need not to care about how many songs in one disk because with the vast variety of music from radio stations, you'll never know what you'll hear and thus never be bored. I do have two small complaints though - the batteries cannot be charged while the player is being used and the tuner's reception is very poor if I use the line out and nothing's connected to the headphone jack. Overall, the designer did a great job in putting a great tuner into such a round, compact and great sounding portable CD player. Its two AA batteries last forever. I recommend it without any reservation, even if you are not going to do any mods. |
|
Copyright © 2005
Xin Feng Company
|
