Replacement for 7807
Hi fmak,
Going back to the original post I suggest to replace the 7807 with a LT1086. I made a small PCB for this and placed a much larger heatsink with the LT1086 on the back panel of the CDP. I replaced the now famous resistor across the regulator with a diode. [BTW the CDPX-333ESD had even somewhat larger current demand; but in this model Sony used a larger heatsink; without the resistor]
(Digital) powersupplies are difficult to probe in a CDP. It depends very much were you put the ground clip to the PCB. With all the clocks running its looks really not quiet. Also Sony has the habit; I don't dare to say silly habit any more; to distribute the ground over the board by means of a large number of jumperwires. This is not exactly what you call a groundplane or decent high frequency technique but unless you wish to design a new PCB you have to live with it. See the nice PCB in the Trading Post section of this forum made by Jocko for a example what I mean.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3013
On the other side a double sided PCB is a pain in the bud if you wish to replace components for upgrade or repair.
Of course you can try to improve the bypassing on the powersupply with low impedance high frequency caps.🙂
Hi fmak,
Going back to the original post I suggest to replace the 7807 with a LT1086. I made a small PCB for this and placed a much larger heatsink with the LT1086 on the back panel of the CDP. I replaced the now famous resistor across the regulator with a diode. [BTW the CDPX-333ESD had even somewhat larger current demand; but in this model Sony used a larger heatsink; without the resistor]
(Digital) powersupplies are difficult to probe in a CDP. It depends very much were you put the ground clip to the PCB. With all the clocks running its looks really not quiet. Also Sony has the habit; I don't dare to say silly habit any more; to distribute the ground over the board by means of a large number of jumperwires. This is not exactly what you call a groundplane or decent high frequency technique but unless you wish to design a new PCB you have to live with it. See the nice PCB in the Trading Post section of this forum made by Jocko for a example what I mean.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=3013
On the other side a double sided PCB is a pain in the bud if you wish to replace components for upgrade or repair.
Of course you can try to improve the bypassing on the powersupply with low impedance high frequency caps.🙂
I guess that means you like it.
I can't think of a single thing I have designed/built that I wouldn't change if I had to do it again. Including this board. But in engineering, you usually have to decide when enough is enough. Some designers I know anguish over which of 20 versions they should go with. I ship the first one that works, and start tweaking immeadiately. Doesn't mean the next one will be better, just different. Which explains why no two things I've built are the same. (Sometimes gives me trouble when a customer manages to ruin one with their tweaking. I can't remember which one they have until it comes back.)
In the commercial environment, sometimes enough is when your boss comes and snatches it out of your hand and puts into production.
OK......so everyone is wondering.......what is the first change I would make on this board
Putting the 2 polarity signs on the silkscreen I forgot. . Any subsequent tweaking would most likely revolve around making a nicer/easier layout.
Jocko
I can't think of a single thing I have designed/built that I wouldn't change if I had to do it again. Including this board. But in engineering, you usually have to decide when enough is enough. Some designers I know anguish over which of 20 versions they should go with. I ship the first one that works, and start tweaking immeadiately. Doesn't mean the next one will be better, just different. Which explains why no two things I've built are the same. (Sometimes gives me trouble when a customer manages to ruin one with their tweaking. I can't remember which one they have until it comes back.)
In the commercial environment, sometimes enough is when your boss comes and snatches it out of your hand and puts into production.
OK......so everyone is wondering.......what is the first change I would make on this board
Putting the 2 polarity signs on the silkscreen I forgot. . Any subsequent tweaking would most likely revolve around making a nicer/easier layout.
Jocko
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