mains ps for DDDAC?

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rwagter

rwagter

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Joined 2002
#1
I just ordered a PCB for doede's dddac:

http://www.dddac.de

all voltafe regulators are on the PCB itself. Doede uses a battery as a powersupply.
I'd rather use a regular PS directly from mains (220V). The ultimate questions always is how to get a clean 12V to the regulators.

My first thought is use a regular 2x9V toroid with LCLC filter to get clean 12V for power to cs8412 and the clock and use a seperate supply also with LCLC filtering for the TDA1543.

Am I making any sense doing this.
 
#3
Andrea,

you mean this one ?
convertus9.gif


It looks simple enough. Why don't you use the complete PSU from tnt?

Ralph
 
#4
I wanted to experiment a little and using local shunt regulators like the TL431 ( did I forget to mention them ? :xeye: )allows me to choose whether using a separate supply for the analog and digital supplies or not (and eventually to re-use the receiver section with a 1541).
The DAC supply instead had to be variable since everyone seems to have a preferred voltage to feed the 1543...

Cheers

Andrea
 
#6
battery advantages

Hi . I don't see the advantages of building this DAC with regular power supply .. note that you need to arrange very clean 5 volt for the XO too ..

I compared both solutions and finaly dicided to go on with the battery .. it's far better . more relaxed sound , quiescency etc.

Just an opinion !

Happy Ears
 
#7
Re: battery advantages

Happy Ears said:
Hi . I don't see the advantages of building this DAC with regular power supply .. note that you need to arrange very clean 5 volt for the XO too ..

I compared both solutions and finaly dicided to go on with the battery .. it's far better . more relaxed sound , quiescency etc.

Just an opinion !

Happy Ears
Click to expand...

Hi Happy Ears,

So you did a comparison on sound-quality?

I considered the Fabian PSU solution because I thought it would be more convenient. However if the battery-solution sounds substantially better, I will go for battery.

I wondered though how good the LM 317 T is?
Doesn't these regulators themselve produce noise?
Don't they need better filtering after them?
Are there any better alternatives?

Regards,

Lucas.
 
#13
Konnichiwa,

rwagter said:
The ultimate questions always is how to get a clean 12V to the regulators.

My first thought is use a regular 2x9V toroid with LCLC filter to get clean 12V for power to cs8412 and the clock and use a seperate supply also with LCLC filtering for the TDA1543.
Click to expand...

You make perfect sense. Both DAC Chip(s) and Receiver present with their respective regulators a pretty constant current draw. This means a choke input supply is no problem to run AND you can combine as many LC cells and as much capacitance as you like.

I would suggest you decide upon the currents you are going to have flowing in each supply, then find sutable chokes (of the shelf or wind them) and combine them with large value Capacitors, I'd recommend Film Cap's. Better have more chokes and more LC cells and smaller, high quality cap's. The chokes DCR will mean that you loose a lot of voltage, use Duncan Amp's PSU Designer to simulate the resultant supply and them buy appropriate mains transformers.

Sayonara
 
#14
powersupply

Hi ,

I simply did the A>B comparison to hear the differences between regular powersupply and battery feed .

In general voltage regulators are noisy generators .. perhaps some less than let's say LM317 .. but it's always a battle to get rid of it .. CLCLCL ... and so on ?? :ghost:

Please try and taste .. grab your :car: battery tonight and listen .. I bet you will apreciate the sound . don't forget to report


Happy Ears
 
#15
The reason I use a battery is that is just sounds better then a mains power supply, cleaner sound, les nervous....

Of course you can build a mains supply, but it should be as clean as a Battery to come on the same level 😉

This is not easy and makes the design very complex. As I like it simple I take the battery, can listen 15 hours music, switch the DAC off and it is charged automatically....

Wat is the problem you ask your self????? And it is cheaper also !!!! A 7.2 Ah Battery cost 13 Euro, a charger only 29 Euro. If you want you build one yourself with a LM317.

A pros pos, I used a LT1085 may self :angel: (you never know...)

The difference I could not hear as the sonic quality which this one is famous for is only in AC applications applicanle..... but i like the low drop en power handling.

Any way..... The KEY difference for this dac simply stays the combination of reclocking AND the multiple DAC's

I rather would have this with AC power, then 1dac-8412-clock on a battery !!!

doede
 
#16
dddac said:
The reason I use a battery is that is just sounds better then a mains power supply, cleaner sound, les nervous....

Of course you can build a mains supply, but it should be as clean as a Battery to come on the same level 😉

This is not easy and makes the design very complex. As I like it simple I take the battery, can listen 15 hours music, switch the DAC off and it is charged automatically....

Wat is the problem you ask your self????? And it is cheaper also !!!! A 7.2 Ah Battery cost 13 Euro, a charger only 29 Euro. If you want you build one yourself with a LM317.

A pros pos, I used a LT1085 may self :angel: (you never know...)

The difference I could not hear as the sonic quality which this one is famous for is only in AC applications applicanle..... but i like the low drop en power handling.

Any way..... The KEY difference for this dac simply stays the combination of reclocking AND the multiple DAC's

I rather would have this with AC power, then 1dac-8412-clock on a battery !!!

doede
Click to expand...


Hi Doede,

Thanks for your answer.
I will try the battery solution.

However, I am still a little confused by the use of the voltageregulator. As Happy Ears writes: "In general voltage regulators are noisy generators .. perhaps some less than let's say LM317 .. but it's always a battle to get rid of it .. CLCLCL ... and so on ??"

In your implementation the voltage regulator is not followed by a more elaborate filtering (like CLCLCL...)
If I understand things well, the noise of the voltage-regulator can easily reach the DAC chips....?
Isn't this a pity? I mean, one had a very pure 12 VDC from the battery, but finally one introduces a lot of noise because of the need to go down to 8,5 VDC...

I was also wondering whether I could use 4 NiMH penlite (2100 mH) penlite 1,2 VDC batteries, resulting in 4,8 VDC for the VD and VA supply. How much power do these consume anyway?

And two or three groups of 7 penlites (8,4 Volt) for the VB supply.
I think you state it consumes about 0,5 Ampere, so this would give about 4 hours per battery-group.
Charging is less elegant of course, but the power-supply would be very simple and straightforward, without the need to use voltage-regulation etc...

What do think of it?

Regards,

Lucas
 
#18
Konnichiwa,

Lucas_G said:
Doede,

I just found this link here:

http://www.diyaudio.com/forums/showthread.php?threadid=985&perpage=15&pagenumber=2

There it is stated that the TL431 is really crap...
Click to expand...

One does wonder what our friend Andy had to do to get such a noisespectrum from a TL431. It must have taken either a faulty exemplar or much work (or much incompetence?) to get those kind of results.

I find the reverse to hold true, implement correctly (low resistance Voltage divider, if neccesary bypassed Anode/Adj resistor, current source feed) the TL431 is drastically quieter than any LM317 or 1085 etc. and if correctly bypassed the dynamic perfomance is also better/more consistent.

Of course, I do not sell people expensive Regulators so I can use and recommend the cheapest and most effective solutions available.

Sayonara
 
#19
Lucas_G said:


I was also wondering whether I could use 4 NiMH penlite (2100 mH) penlite 1,2 VDC batteries, resulting in 4,8 VDC for the VD and VA supply. How much power do these consume anyway?

And two or three groups of 7 penlites (8,4 Volt) for the VB supply.
I think you state it consumes about 0,5 Ampere, so this would give about 4 hours per battery-group.
Charging is less elegant of course, but the power-supply would be very simple and straightforward, without the need to use voltage-regulation etc...

What do think of it?

Regards,

Lucas
Click to expand...


Lucas_G said:
Doede,

I just found this link here:

http://www.diyaudio.com/forums/showthread.php?threadid=985&perpage=15&pagenumber=2

There it is stated that the TL431 is really crap...

Have you read this?

Regards,

Lucas.
Click to expand...



Hi Lucas,

nice work from Andy, but he starts somehow with a great dael of noise some where else.....

Kuei reacts on that already....

OK, lets keep things simple again and let not be salon-DIY 🙄

I like the idea of the 1.2V Battery cells to feed everything directly. Just put it in, the idea is absolutely interesting and then compare with the sound of the Battery (12V) and the regulators !!! Otherwise we know NOTHING again, apart from that the DAC sound very nice 😀

PS: I dont "think" regulators are producing noise themselves when fed by a battery.... but may be I am wrong (I don't have universal wishdom after all) ---> can any one react on this with some proof (no opinions please ...)

So, what I will do is measuring the FFT spectrum on the DAC power supply with use of a battery and mains-PS (with the regulator for the dac-chip). This might help this discussion.

Lucas if you would be so kind to do the 1.2Vbattery test and report ?

The theoretical discussion was very stimulating (aren't we taking action indeed??) but now it is time to do something, test and use our ears !!

"I'll be back"

doede
 
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