[wistily]

Stupid question:
In the steps building guide, there is written:
"There are two pads for AC line. The LA pad is the one to use if your fuse will be off-board, such as in the power inlet module. If you will be using the on-board fuse holder, use the LB pad instead"

However, when i look at the LA pad, i think that if you don't put any fuse on the board, the LA pad goes nowhere.

Am i wrong or what ?

 

[sbelyo]

Quote:

Originally Posted by wistily when i look at the LA pad, i think that if you don't put any fuse on the board, the LA pad goes nowhere. Am i wrong or what ?

without looking at my board I seem to remember that it all connects when you install the jumpers for the required input voltage.

Example: 110 Volt = A to B and C to D

It's on the schematic

 

[wistily]

When you look at the schematic, it's like i said: LA is for an onboard fuse, and LB is for an offboard fuse.
So the doc must be wrong.

 

[sbelyo]

now I understand what you are asking.... Yes, you are correct. If you do not use an onboard fuse LA goes nowhere

What type on inlet are you using Fused or not fused?

 

[wistily]

My inlet is fused, so i think i must use LB.

 

[sbelyo]

Yes... Thats the one

 

[wistily]

I finished the PSU, it seems to work, except that i measured the ripple to 0.8 mV. This seems quite high compared to the numbers found on tangent's site. Or perhaps is it because my multimeter is not precise enough ?

 

[tangent]

Quote:

Originally Posted by wistily i measured the ripple to 0.8 mV

That's down in the noise on a lot of meters. You can't see much detail with that low a signal on most oscilloscopes. What kind is it? Can you borrow something else? If you try another type of meter and get a much different number, you know you're just looking at meter noise.

By the way, I fixed the LA vs. LB thing. Sorry about that.

 

[peranders]

0.8 mV is a quite normal value for a LM317 type regulator and if you want lower noise and PSSR you must have a much more advanced solution.

 

[skyskraper]

jung! jung! jung! jung! jung! jung! jung! jung! jung!

 

[peranders]

I'll suppose a Jung regulator isn't the solution to every problem but still one possible solution to get low noise _and_ good PSRR. The question is how low noise do you need and how high PSRR?

For it's class I think Tangent's solution is good.

A not very small solution can be seen here.

 

[tangent]

Quote:

Originally Posted by peranders 0.8 mV is a quite normal value for a LM317 type regulator

Nonsense. The LM317 is capable of 80dB ripple rejection, so there would have to be 8V (!) of ripple ahead of the regulator to get that kind of ripple at the output. Even if we presume that I designed it badly enough that it's only getting 60dB RR, you'd have to have nearly a full volt of ripple, and I assume that this was tested without a load on. No way. I don't believe it for a second.

Either the guy's test equipment isn't sensitive enough to make meaningful distinctions, or the supply isn't working right. I'm still betting on the former. I know I keep harping on measurement preamplifiers, but that's because I'm a dedicated believer. I tried it, and saw the results.

Quote:

Originally Posted by skyskraper jung! jung! jung! jung! jung! jung! jung! jung! jung!

Yes, you and the other five people who are truly willing to pay for it....

I sent out the request for comment, and the response was truly underwhelming.

 

[wistily]

Actually, when i measure the AC voltage before the regulator (between TP 3 et 5), i get 3.5-4 mV.

But when i measure AC voltage of the air, my multimeter also says between 200 mV and 500 mV

is it normal, or is my multimeter completely crap ?

 

[individual6891]

Quote:

Originally Posted by wistily But when i measure AC voltage of the air

I'm so glad my air doesn't have AC voltage

 

[blip]

Quote:

Originally Posted by wistily Actually, when i measure the AC voltage before the regulator (between TP 3 et 5), i get 3.5-4 mV. But when i measure AC voltage of the air, my multimeter also says between 200 mV and 500 mV is it normal, or is my multimeter completely crap ?

I've seen that before on occasion from decent (Fluke) multimeters... Though usually under 100 mV. Anyway, I'm not sure what causes the measurement instability... but I doubt it is a concern in regular measurements.

For measuring power supply ripple, on the other hand, any kind of instability can render the results meaningless. Using a multimeter I've occasionally measured 0 mV AC coming off of a cheap Velleman supply... other times it is higher... again it is all about measurement instability.

I've always thought the lack of interest in the Jung is a shame. It isn't really that expensive (unless of course, I'm missing something, I've only done a quick pricing on ALW's version of it) and is the pinnacle of regulator design so to speak... ah well.

While I'm posting, is there any advantage to building the Sulzer-Borbley over the STEPS? It looks simple enough that I could probably do it on veroboard.

Edit: Just took a peak at perander's link... That looks REALLY interesting... keep us up-to-date... I might want to build one.