Tír Na HiFi

randytsuch wrote:<snip>

...but the 1.2V reg is a switcher, so you need to account that.

I'll assume 80% efficiency for this switcher, which should be close.

.08a x 10v = .8va
.8va * 80% efficiency = .64va
.64va / 1.2v = .53a =530 ma on the 1.2v.


I used a LT1764 because I had them, but it was really easy to do. You just need some wire, a cap, and the 1764, see my blog for the details. It is a 3a part, and maybe overkill, but it works
http://randytsuch-audio.blogspot.com/20 ... dding.html

Dang, I hate it when logic, engineering, and science roll over my TLAR!

I'll use an LT1764, LT3080, or LT1963 (I already have the latter two on hand, but they do require a couple of additional components to work).

I had planned to use Acko's AKR75 1v2, which is rated for 200ma continuous with 500ma peaks. I'll measure the current when I get it going, likely after Christmas.

THANKS!

Greg in Mississippi

P.S. Randy, is that ferrite sheet on top of the FPGA? I used that on my SuperJuli@ mod, but can't say I noticed much of a difference.

Rick
Yes, I'd pick J2, but I've used capacitor pads myself, and that's worked out fine.
I guess I'd actually pick whatever is closest, to make the wire as short as possible.

Nige
I agree, I don't switch grounds myself, I switch voltages and make the best ground connection I can.

Greg
I took a quick look at the datasheet, I think the 1963 is a lower current version of the 1764, but it still does 1.5A so it will work fine for this.

I'd wager if you connect it like I did, it will supply 1.2V with just a little cap on the output.

Randy

Asked SOEKRIS about the ground and he answered. The Norse Gods have granted me a favor?.

I must say that half his answer took me by surprise. He recommended using the solder pads of the removed electrolytics or the ground points for the XLR outputs. My instinct was that is wrong. I should have learned by now that my instincts lead me astray.

My switch is on the other side of the board so I will use the cap pads.

I am using a BELLESON 1.2 volts reg. The strange thing is I read 1.4 volts. IS there something else strange or did they send me one with the incorrect resistor? I wonder if that is enough to blow up the FPGA? That would be great, wouldn't it?

THANKS, again, Randy for your counsel on the ground!

Maybe try putting a load on the belleson with a resistor.

10 ohm resistor will draw around 80ma, make sure the resistor is adequate wattage

Well, BELLESON tells me I should use 5 volts instead of 3.3 on the 1.2 v regulator.

Don't think it is a good idea to use the WAVE IO supply for that.

Rather disappointing. Not sure just what to do. Other than building another supply ... Or getting another regulator. Fairly obvious choices but neither is very attractive.

Moved the ground from the input ground to the power supply caps pads and I guess I still have something going wrong. Even with the switch off I get the flashing green LED. Can't imagine where there is a short unless something got in one of those vias when I was clearing the board?

Tomorrow I will connect the thing and find out if it works at all.

Not sure what I will do if it doesn't. Can't imagine doing this all over again!

Might be in permanent LP land, which would not be a bad thing at all.

Oem version

if its cheap enough it might be worth another modding session

Looks like that one would be much harder to work with.

No easy access to powering the fpga, is there?

Are you being cruel?

I figured out why the ground switch is not working. I plugged the 1.2 v reg ground into J2.

So now, I either have a short on the positive rail of the resistor stack or I have a defective regulator. Sure hope it is the regulator since I cannot find a short. I have SCRUTINIZED the board with a loupe over and over and I see nothing wrong.

Going to give it one more go and if I fail I am going to take the easy way out and get the SCHIIT Yggdrasil. Ric Schultz has suggested some easy (obvious) ways to improve it and those DACs would probably be much easier to try the battery power scheme. Not that I am anxious to buy a finished product but at this point I am losing my resolve. I worry I am too old for this!

One thing he mentions is removing the circuit from the case which is what I would normally do. I have asked SCHITT is they would sell me the thing without the case. That would make it a little easier. Those DACs they are using cost $100.00 each in small quantities at MOUSER and they are using four of them. They have to be better than average.

Looking at the datasheet the dac is 6 mm square and can use up to +- 33 volts for power. I have no idea how much SCHIIT is using but that could eliminate battery power as an option. Sure is a tiny chip.

Yes, I know this is pathetic but I have no desire to go through all of that again if it doesn't work.

A confession to be made: I found a length of wire along one row of the level shifters.

My voltages are coming up very equally. Relative difference 0.08 volt, who knows how accurate the meter is, though it is a good one.

Installing a ground from the 1.2 reg's pin to the star ground at the switch does not stop the green LED from lighting, the voltages are turned off at the battery. Nigel, since you are using a ground switch does your green LED keep going no matter the position of your switch?

Now I cannot get the computer to turn on so I cannot verify it works. The small A123s I was using for the 12 volts rail have failed. I connected the POWERFLOWER and it still would not turn on. Removed the CMOS battery last night and hope it will start again.

Sorry about the soap opera.

rickmcinnis wrote:A confession to be made: I found a length of wire along one row of the level shifters.

My voltages are coming up very equally. Relative difference 0.08 volt, who knows how accurate the meter is, though it is a good one.

Installing a ground from the 1.2 reg's pin to the star ground at the switch does not stop the green LED from lighting, the voltages are turned off at the battery. Nigel, since you are using a ground switch does your green LED keep going no matter the position of your switch?

Now I cannot get the computer to turn on so I cannot verify it works. The small A123s I was using for the 12 volts rail have failed. I connected the POWERFLOWER and it still would not turn on. Removed the CMOS battery last night and hope it will start again.

Sorry about the soap opera.

Dont panic
Panic is the enemy

I Dont have gnd switched on the DAC
If you have + and - voltage permanently connected their is a sort of gnd connection though the batteries it may not be exact 0v but likely something close to it
Switch in +/- and leave gnd permanently connected at least till u get functionality
I'd be far more worried about no green light
1.2 and 3.3 need to be turned on together
Have you no other reg to get 1.2 v

More good news - the 1.2 reg is now showing 1.19 - changing that ground connection helped something.

3.3 supplies are equal per my meter and stable at idle. Will be interesting to see what happens while it is playing. Showing 3.319 for both.

Finally got the computer started and since there is no memory of what it sounded like I am installing the new player. Always a pain since, yet again, I did not make notes of how I got it on the SATADOM and will have to re-learn it.

Having to rely on the POWERFLOWER. I wonder if battery supplies do not like sitting still? I left the chargers on and voltages read correctly for all but the 12 volts rail but, so far, it will not start the computer. Hoping running with ATX for awhile will make it hunger for clean power.

I should be proud that I have made digital audio so painful. Perfect sound forever comes at a price, right?