| dantwomey |
I'm going through the upgrade process of the power supply in my Marantz universal player and I've come upon a question I can't answer.
Part of this circuit contains a 78R05. From what I can see this 4-pin voltage rectifier serves two functions. It produce a required +5vdc and it's part of the control circuit which turns the player on and off. I'd like to put a much better rectifier in and if this was a regular 7805 I'd have lots of options. I could and would probably replace it with one of the super regulators like ALWSR or Audiocom. I could even look at a LT1085 or similar permium quality regulator. But, because it's a 4-pin I'm not aware of any options. Does someone with more experience in this area have any suggestions?
Happy New Year! :D
Dan |
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| paulb |
| From your description, this part probably has nothing to do with the audio parts of the circuit. Is there a reason why you would want to upgrade it? |
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| dantwomey |
I'm pursuing the commonly held belief that by providing your audio equipment with the cleanest, highest quality power supply you will achieve better sound. If you look in the digital section at the Marantz CD63 & CD67 mods list thread you'll see alot of discussion about CD player power supplies.
These older players have the transformer/bridge rectifier/voltage regulator power supplies which are easy to upgrade. My universal player has a SMPS.
Regards,
Dan |
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| paulb |
| You'll need a schematic or preferably a service manual to pursue it. |
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| dantwomey |
Although having a service manual would be ideal. I think I can accomplish alot with my past experince working on my CD67 and asking a few questions here.
Regards,
Dan |
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| johnnyx |
| The datasheet is here . It is unusual, so there is unlikely to be a higher cost alternative with the same functions. You'll have to design a discrete version.:) |
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| dantwomey |
I have a request in with Andrew Weeks to see if he can adapt his ALWSR to this task.
Regards,
Dan |
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| dantwomey |
Looking at the datasheet I was thinking. Looks like Vdis to have the output turn off has to be a maximum of .8v and to turn on a minimum of 2.0V. Also there is a suggested current of 20uA for operation. I could replace this regulator with a device that would act as a switch and then feed a better quality regulator?
Regards,
Dan |
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