[DIAR]

Thanks for the advice!

My player is Sony DVP NS900.

You were right. The cap is in the wrong place. The two circles are for two different size caps. I wasn't sure which size I was going to use.

I will be using normal components, not SMD.

Quote:

Also, will it matter that the 750Ohm resistor is placed after the 240Ohm resistor and A-O diode? And if I'm remembering the LM317 datasheet correctly (my coffee hasn't quite kicked in yet), the I-O diode placed after the A-O diode should not matter.

Hmm... I didn't quite understand what you are saying.

I plan to use a block of aluminium as heat sink.

I'm not quite sure how much load this regulator have to feed. I'll try to find out.

I use LM317 as it is quite popular in DIYAudio and they have had some good results with it. I can still change my mind if there are good suggestions!

I don't dare to lower the cap value. I believe it is chosen for a reason and it is a very good cap (Elna Silmic). Do you think it might be a good idea to plant an additional 10 or 100 uF Oscon near the DAC chip?

I attached the newest version of the module (it might be faulty)

 

[DIAR]

Here it is. I haven't tested it yet and I don't even know how to do it

 

[Megaptera]

The way you'll test it is by simply hooking it up to a power source -- just grab whatever your unregulated power source is -- and see what the output voltage from this regulator unit is. It should stay relatively steady at whatever voltage you've set with the resistors, which can be a pretty wide range. If you want to get fancy, you can hook it up to an oscilliscope for detailed testing, but simply watching it connected to a voltmeter for a litle while will do too. V+ connects to V+, V- can connect to ground here. (By the way, if you're going to use a rail splitter with this, I've found them to get unbalanced by a power regulator's current draw, so it should go after the regulator section.)

My question above basically boiled down to this: as I read your PCB, it doesn't quite match the diagram you're using (which is the LM317 datasheet's Improved Ripple Rejection circuit, right?). This is what it looks like to me, minus the misplaced cap, and labeled as in the datasheet:

D2 doesn't appear at all, but I think it's fine to keep it there, so let's not worry about that. But notice the placement of R2.

Edit: I mean the first PCB -- I just saw the new version now.

 

[DIAR]

Should I attach larger caps to input and putput while testing? How large should the load resistor be? 250 ohms --> 20 mA?

Do you mean that the new version (message 16) is allright? I've build the module using that PCB.

I'm sorry about these stupid questions. I'm a total electronics newbie and I've managed to burn atleast 4 or 5 regulator during the last couple of weeks and I'm getting enough of it

 

[Megaptera]

You could try a couple different resistor values -- if it's working, your voltage regulator should keep the output voltage constant regardless of the load.

But the os-con cap looks misplaced to me. If you follow the diagram down from the LM317's Adjust pin, it goes: the os-con cap's first lead, then the connection to the 240O resistor and diode that come from the output pin, then the 750O resistor, and then the os-con cap's other lead. Your pcb puts the os-con cap entirely after all that, instead of around it, which may give you problems.

And don't give up yet! It can be a total pain to burn a part, but once you get it working you'll forget all about the grief it gave you

 

[DIAR]

I think you have misunderstood something... It has no meaning which lead is first. They are all in the same voltage point.

 

[Megaptera]

Quote:

I think you have misunderstood something

Always a strong possibility

How's it working?

 

[DIAR]

Quote:

Originally Posted by Megaptera How's it working?

Great! I tested it last night. I soldered 100 uF cap to input and output and a put a 700 ohm resistor as load. The voltage was exactly what it was supposed to be. The next step is to try it in my CDP

 

[Megaptera]

Great! Glad to hear my concerns were unfounded

 

[skyskraper]

ok so i want to create my own powersupply module to run my pimeta on and future pimetas on something similar.

i have a few lm317's lieing around so i thought that maybe i could build the slow turn on 15v regulator shown in the datasheet:

but being a n00b still im a bit confused. the pimeta takes +/- input so if i want +/-15v i need to feed it lets say +/-20v just to be safe? i wanted to power the input circuit from an unregulated wall wart. 24v dc ones won't work for me will they? or do 24v dc wall warts supply +/-24v dc? thats the bit that is quite hazy in my mind atm.

alternatively i have a few 78L12 and 79L12. these are 12v (apparently linear) positive and negative voltage regulators. could i hook up a 24v dc wall wart (if they give +/-12v and not +/-24v) to a pair of these and have a linear regulater power circuit to use????

edit: where do i run the ground on the regulator circuits to? do i ground them to the case or ground on the circuit im using them with or or?