As previously stated use 120 ohms, this will provide enough current for the zener to operate (1.25v / 120R gives 10mA). The LM317 regulates to ensure there is 1.25volts between the output and adj pins so if we assume the voltage drop across the 1N4148 is 0.7 volts then the zener will need to be roughly 2 volts (1.25+0.7) below the output voltage.
For 5V output use a 3V zener, or led(s)
12V, use a 10V zener
15V, use a 13V zener
etc.
The zeners are connected in parallel so the volt drop across each is the same as the drop would be across one.
No, it doesn't work the same way as the normal divider which sets the output voltage. The resistor is there to provide a current through the zener. You can get 1V steps with zeners as explained above since Vadj + the 1N4148 = approx 2V. Why do you need to adjust +/-0.2v anyway ?
SimontY said:
Just looking for some options whether it is more economical to change the DAC & clock or get an external DAC. The price of a decent clock module is already close to 40~50% the price of an external DAC. By the way, what do you think of this?
http://cgi.ebay.com.my/16-9344MHz-L...ageNameZWD2VQQcmdZViewItem?_trksid=p1638.m122
fossil2k said:
That's an interesting observation. You'll never find me praising the standard player (or variations of) at its original price-point. I found my standard CD63KI to be harsh, thumpy, with average detail levels and lacking all subtlety.
The player is a good one to modify due to having a popular crystal frequency, good enough chassis, an abundance of reasonably priced 2nd hand units and massive support and upgrade documentation here and elsewhere. It's the Ford Mondeo of CD players (that's the car I own, and upgrade lol).
Lastly, the sound attainable through extensive upgrading is, with the exception of the slightly blunt delivery*, stunning.
Simon
* Actually one player doesn't seem to have this - Brent's. I'm not sure what I have yet to do to completely eradicate the slightly brute-force approach the player sometimes takes to making music.
Contrast this to an Arcam CD72 or SACD played on a cheap Pioneer, where the sound is more delicate and graceful (but arguably lacking bass).
fossil2k said:
Almost any aftermarket clock (with it's own regulator and, preferably, own supply, is better than the rubbish clock provided by Marantz !!
If you opt for the external DAC route, the cheap ones are no better and require further mods. as well !!! (to the DAC and also to the CD-P)
Stick with the existing CD63/67 and follow the mods here.....
Andy
