Hello,
Doede is thinking we all have some kind of diy man cave with nice equipment all over the place.
Probably most of us have a limited use of the kitchen because there the light is ok. Most of us also lack the knowledge so we say better be safe than sorry. If Doede tells us how to do , just then we are sure.
When i bought my house i put my speakers in the corners so visitors wouldnt notice them so easily. A month ago i had new windowns installed, replaced wallpaper by cork tiles and after that i told myself what the heck why spend so much on diy while not putting my satellite speakers in a better spot. No investment made and after all it is my living room.
Greetings, Eduard
Doede is thinking we all have some kind of diy man cave with nice equipment all over the place.
Probably most of us have a limited use of the kitchen because there the light is ok. Most of us also lack the knowledge so we say better be safe than sorry. If Doede tells us how to do , just then we are sure.
When i bought my house i put my speakers in the corners so visitors wouldnt notice them so easily. A month ago i had new windowns installed, replaced wallpaper by cork tiles and after that i told myself what the heck why spend so much on diy while not putting my satellite speakers in a better spot. No investment made and after all it is my living room.
Greetings, Eduard
Attachments
Earlier the patch for using the Pi as I2S bus master @ 384kHz was mentioned.
Today the Raspberry audio distro moOde 7.0.0 is released, which includes this patch out-of-the=box.
Today the Raspberry audio distro moOde 7.0.0 is released, which includes this patch out-of-the=box.
LF33CV should be available everywhere cheaply. Use a SMD cap for the one mentioned in the datasheet application noteand solder it directly to the pins. The legs fit the screw terminals without a need for extra wires.
I didn't hear a difference between that and the ldovr implemented LT3045.
I have noticed this, there is a separate DDDAC1794 NOS (384K) device added, nice!
There is only an issue with release 7.0.0 for the usbridge sig. Tim posted a test image, going to try this today.
No but the CMLI-15/15B is suited for single deck DAC's
A single deck DAC sounds excellent with the CMI-15/15B transformers compared to the plain jane capacitor coupling option. But the Creative Audio OPT are 600/600 ohm and designed for a 3-4 deck option where DAC has a output Z below 60 Ohms.
Cheers Johno
A single deck DAC sounds excellent with the CMI-15/15B transformers compared to the plain jane capacitor coupling option. But the Creative Audio OPT are 600/600 ohm and designed for a 3-4 deck option where DAC has a output Z below 60 Ohms.
Cheers Johno
Hi Paul,
I have installed the test version of Moode 7 that now runs perfectly on the USBridge sig. 384khz works fine on DDDAC now
+1
Today moode is updated to 7.0.1
I just got myself some more DAC boards to make a bigger tower
I don't remember... do I have to adjust the blue trimmer pots on the DAC boards in any way, or are they already adjusted to the correct setting when they are shipped from Audio Creative?
Also, is there anything I have to take care of when going from a 4-deck tower to a 8 decks? I will change the output load resistors (no big deal). Also, I believe to remember that the Doede PSU may need a bigger hetsink. Anything else? Are the stock regulators on the mainboard happy with supply 8 DAC boards?
I don't remember... do I have to adjust the blue trimmer pots on the DAC boards in any way, or are they already adjusted to the correct setting when they are shipped from Audio Creative?
Also, is there anything I have to take care of when going from a 4-deck tower to a 8 decks? I will change the output load resistors (no big deal). Also, I believe to remember that the Doede PSU may need a bigger hetsink. Anything else? Are the stock regulators on the mainboard happy with supply 8 DAC boards?
Did you get pre assembled boards? Otherwise the 40mVolt cannot be pre set of course. It is an easy check, measure the 40mV and check the roughly 2.75 volt bias between POs Common and NEG common. The absolute value is not terribly critical. It is a good final check, that all boards contribute
Second check, play a whatever sine wave 100hz to 400 H - 0dB and measure the output, this can be done with a DMM in ac position. You should get at least the same reading at left and relight AND between POS, common and NEG, common. Absolute value not critical but approx 1,2 Volt
Before you do this, make sure the power supply an handle it. 4 boards for the new tent lab boards are the max for a DDDAC power supply. extra cooling is not necessary, but nice to have With the magic supply you can run 8 boards.
The main board has no issues with big stacks, no worries
By the way how many boards are you having at after the upgrade ?
Second check, play a whatever sine wave 100hz to 400 H - 0dB and measure the output, this can be done with a DMM in ac position. You should get at least the same reading at left and relight AND between POS, common and NEG, common. Absolute value not critical but approx 1,2 Volt
Before you do this, make sure the power supply an handle it. 4 boards for the new tent lab boards are the max for a DDDAC power supply. extra cooling is not necessary, but nice to have With the magic supply you can run 8 boards.
The main board has no issues with big stacks, no worries
By the way how many boards are you having at after the upgrade ?
Yes, I got the fully assembed DAC boards. I guess they are already adjusted correctly, but I can check the 40 mV.
I currently have 4 existing DAC boards running. After installation of the new boards, I will have 8 boards.
Are you SURE the "Doede PSU" can't handle that? I thought I read somewhere that it can be done with larger heatsinks, but can't find this post anymore...
I currently have 4 existing DAC boards running. After installation of the new boards, I will have 8 boards.
Are you SURE the "Doede PSU" can't handle that? I thought I read somewhere that it can be done with larger heatsinks, but can't find this post anymore...
Ok, found it:
Seems I need a bigger transformer, too. Any suggestions for a suitable transformer to replace the stock part on the "Doede PSU"?
On DDDAC 1794 NOS DAC - Non Oversampling DAC with PCM1794 - no digital filter - modular design DIY DAC for high resolution audio 192/24 192kHz 24bit the current consumption of the DAC boards is specified as 100 mA. I guess this is not right. Doede, could you please check this and correct if necessary?
Seems I need a bigger transformer, too. Any suggestions for a suitable transformer to replace the stock part on the "Doede PSU"?
On DDDAC 1794 NOS DAC - Non Oversampling DAC with PCM1794 - no digital filter - modular design DIY DAC for high resolution audio 192/24 192kHz 24bit the current consumption of the DAC boards is specified as 100 mA. I guess this is not right. Doede, could you please check this and correct if necessary?
DDDAC Power supply upgrade to 2A
Good you found it
OK, beefing up the standard DDDAC supply - what is to take into account:
After the Rectifiers you need for optimum regulation minimum 19 Volt for 12 Volt or 7 Volt delta if your output is a bit higher - which is recommended for multiple decks (like 12,5 Volt) so let say you want 19,5 V minimum
This means you would need a transformer of 16V AC - 15Vac would probably work, as the voltage is typically a bit higher for the larger VA types - with 18V you are going to dissipate a lot of heat due to the too high headroom of DC voltage after the rectifier.
For the above reason, I would suggest to take a toroid 2x15Volt 150VA or even larger like 250VA. They are not expensive, so make it dependent on available space
I also would suggest adding another 10.000 uF low ESR capacitor directly after the rectifier.
The most important point is the now the TIP122 power loss dissipation....
So with 7 Volt delta and 2A we need to dissipate 14 watt - for the TIP122 itself no issue (datasheet: MAX: Ic=5A and Pd=65Watt) as the Rth case is ~2Degree/watt the junction will warm up 30degrees. meaning the junction will be like max 100 degrees when we assume heatsink of max 70 degrees (really worst case this should be ;-) ) This de-rates the TIP122 to 45% of 65 Watt = 29 Watt - so we are still in a very safe area with 14 watt as long as we stay below 70 degrees heatsink
assume the inside of the DAC case will be 40 degrees (warm days not so optimal venting.... than we should have max 30 degrees of temperature raise in the heatsink. I would go to be extra safe for only 20 degrees more
so we look at 20 degrees with 14 Watt for a safe case ->
Rth = 1,4 degrees/Watt
absolute minimum case would be 40 degrees (case 30 degrees, accept 70 degrees) so that would halve the thermal resistance of the heatsink
Rth ~ 3 degrees/Watt
so look for a heatsink a size of 2K/Watt I suggest that would be a nice compromise
last but not least, change the Fuse
I maybe was a bit detailed, but wanted to show everyone how you do things like this
good luck and let us know !
Good you found it
OK, beefing up the standard DDDAC supply - what is to take into account:
After the Rectifiers you need for optimum regulation minimum 19 Volt for 12 Volt or 7 Volt delta if your output is a bit higher - which is recommended for multiple decks (like 12,5 Volt) so let say you want 19,5 V minimum
This means you would need a transformer of 16V AC - 15Vac would probably work, as the voltage is typically a bit higher for the larger VA types - with 18V you are going to dissipate a lot of heat due to the too high headroom of DC voltage after the rectifier.
For the above reason, I would suggest to take a toroid 2x15Volt 150VA or even larger like 250VA. They are not expensive, so make it dependent on available space
I also would suggest adding another 10.000 uF low ESR capacitor directly after the rectifier.
The most important point is the now the TIP122 power loss dissipation....
So with 7 Volt delta and 2A we need to dissipate 14 watt - for the TIP122 itself no issue (datasheet: MAX: Ic=5A and Pd=65Watt) as the Rth case is ~2Degree/watt the junction will warm up 30degrees. meaning the junction will be like max 100 degrees when we assume heatsink of max 70 degrees (really worst case this should be ;-) ) This de-rates the TIP122 to 45% of 65 Watt = 29 Watt - so we are still in a very safe area with 14 watt as long as we stay below 70 degrees heatsink
assume the inside of the DAC case will be 40 degrees (warm days not so optimal venting.... than we should have max 30 degrees of temperature raise in the heatsink. I would go to be extra safe for only 20 degrees more
so we look at 20 degrees with 14 Watt for a safe case ->
Rth = 1,4 degrees/Watt
absolute minimum case would be 40 degrees (case 30 degrees, accept 70 degrees) so that would halve the thermal resistance of the heatsink
Rth ~ 3 degrees/Watt
so look for a heatsink a size of 2K/Watt I suggest that would be a nice compromise
last but not least, change the Fuse
I maybe was a bit detailed, but wanted to show everyone how you do things like this
good luck and let us know !
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Ah that’s great information doede, I tested the operating temperature for the tip122 when I changed my dddac for direct analog power and advise to be careful here as well, I had one fail which led to a output voltage way above what a dddac board could probably handle. (Nothing happened but there was no sign for smoke or something, just a short in tip122 so under normal condition you probably recognize that something went wrong when it’s too late ) in fact that scared me into the idea of a small voltmeter showing my output voltage for my modded psu, I’m now looking into how to do this without degrading the well filtered DC I get.
Also will ad the extra cap you mentioned to my psu, so thanks again for the hints
Greetings
Hifoli
) in fact that scared me into the idea of a small voltmeter showing my output voltage for my modded psu, I’m now looking into how to do this without degrading the well filtered DC I get.Also will ad the extra cap you mentioned to my psu, so thanks again for the hints
Greetings
Hifoli
Just to avoid any anxiety using the DDDAC
If you leave the 7810 on the boards, it is not sooo easy to blow the dac to pieces...
If you really want to kill it you have to do the following:
increase the input DC voltage to the mainboard way beyond 30 Volts...
Reverse Polarity (this goes pretty quickly )....
Have a too high voltage for a longer period (so not just a short error) say 20 Volts for many minutes or hours (not sure when the 7810 will burn out)
so yes a zener will help and the nice thing is, that when you dimension the zener like it will draw a few amps, you can fuse it and the whole over voltage problem is gone quickly
Do I do this myself? no, I never had an issue with a power supply going in such high voltages for no reason. And I do have a voltage measurement function in my DAC with the Arduino control.
If you leave the 7810 on the boards, it is not sooo easy to blow the dac to pieces...
If you really want to kill it you have to do the following:
increase the input DC voltage to the mainboard way beyond 30 Volts...
Reverse Polarity (this goes pretty quickly
)....Have a too high voltage for a longer period (so not just a short error) say 20 Volts for many minutes or hours (not sure when the 7810 will burn out)
so yes a zener will help and the nice thing is, that when you dimension the zener like it will draw a few amps, you can fuse it and the whole over voltage problem is gone quickly
Do I do this myself? no, I never had an issue with a power supply going in such high voltages for no reason. And I do have a voltage measurement function in my DAC with the Arduino control.
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The load resistors are also there for I/V conversion, right? Would it work to use a smaller resistor value to lower the output level and correct bias with the trimmers?
Yes.
That would probably "work", but the values determined by Doede are the optimum in terms of audio signal quality. Take a look at the description at DDDAC 1794 NOS DAC - Non Oversampling DAC with PCM1794 - no digital filter - modular design DIY DAC for high resolution audio 192/24 192kHz 24bit.
I wouldn't change the load resistors. If you need lower output, use a voltage divider, for instance by splitting the load resistors into two series resistors and taking the audio signal off the center tap of the series connection. Or you could use a volume pot.