M-Audio Delta 1010 Power Supply Unit

Hi folks,

for those who are interested in the M-Audio Delta 1010,
here is a "layout-pic" and the schematic of the PCU.

I´ll post my questions and suggestions later ...

looks like the Alesis PSU:

http://www.groupdiy.com/index.php?topic=32448.0

And here is the schematic.

Thanks for the link Svart !

Yes, that´s a voltage-doubler that´s used to generate +15 and -15 Volt
and two half-wave retifier to generate the +5 Volt rails.

My idea is to build a large power-supply to power my three Delta 1010 at once.
I did some measerements for that purpose under full load after each regulator.

Current draw at the output of U4 (+15 Volt) is 238mA.
Current draw at the output of U5 (-15 Volt) is 235mA
Current draw at the output of U6 (+5 Volt for DACs) is 283mA.
Current draw at the output of U23 (+5 Volt for ADCs) is 165mA. 

The current draw at the input-plug is 1,866 A @ 10,6 Volt AC.

But there is something strange about the +5 Volt rails.
Why do they use two separate regulators instead of one larger IC ?

Was is only for economical reasons or is there a necessarity to separate the ADCs and DACs +5Volt rails ?

The 7805 manuals says: " ... If adequate heat sinking is provided, they can deliver over 1A output current ..."

I measured 165 mA for the ADCs and 283 mA for the DACs, that´s 448 mA together, should be not such a big deal for this regulator ...

The next strange thing is the AK4393 manual (page 19) says:
" ... AVDD is supplied from analog supply in system and DVDD is supplied from digital  supply in system ..."
What does that mean ?

The +5 Volt rail from U6 (marked E in my picture) runs to pin 18 of the AK4393 (AVDD) and via R174 in Channel 8 to pin 2 (DVDD).
R 174 is 10 Ohm, Voltage at pin 18 is 4,99 Volt and at pin 2 4,95 Volt. Is that the difference between analog and digital supply 10 Ohm ?

Telmar said:

The next strange thing is the AK4393 manual (page 19) says:
" ... AVDD is supplied from analog supply in system and DVDD is supplied from digital  supply in system ..."
What does that mean ?

Click to expand...

This is just a passing guess.. but the two 5v supplies are there to feed the analog and digital 5v circuits independently for isolation purposes.  A standard thing in ADC/DAC type circuits.

I would have thought it was to remove the need for heatsinking the regulators, with 9V AC, you will have somewhere around 12V or so as the unregulated rail, meaning the regulator will be dropping 7 V or so. At ~300mA that means the chip is dissipating 2.1W which is high but not impossible for a TO220 package without a heatsink. I am not at all sure I would want to add another watt to that.

A second regulator is almost certainly cheaper then adding the mounting hardware and metalwork to heatsink a single one.

Regards, Dan.

Okay,

since I got my DAW (computer) in a 19-inch-case I want to put my converters in a second 19-inch-case.
What I don´t like are the external AC-transformers. I use three 1010s, so I got three of them.

My idea is to built a 19-inch-box with a bigger and more cleaner +5 / +15 / -15 Volt DC power-supply to feed them all.
I think it´s a good idea to have no 50 Hz AC inside the units and have them all connected to the same PSU.
And last but not least they are all connected to the same ground.

In other words the three should work more like a single 24 (30) Channel converter.

What do you think ?

Any update on this?  

My understanding of the 1010 is that it has a solid architecture but they economized on the PSU and the clock. The clock is a little out of my skill level so I've been looking at PSU mods and came to the conclusion that doing exactly what Telmar described makes good sense, depopulating the entire PSU, replacing the DC plug with a multi-pin connector that brings the power rails in from a stronger, cleaner power supply mounted in an external enclosure...  anyone have any success with this project or even try it yet?


(can't believe this is my first post here... wow.  been lurking for years, sending PMs from time to time... I really thought I had posted before)