Indeed, I've been looking at this article by Linear, Increasing Output Current of the Ultralow Noise, Ultrahigh PSRR LT3042 200mA Linear Regulator. Interesting that obtaining a boost in current output via transistor does reduce the PSRR and noise specs of the LT3042 a bit. The "best" way to get more current out of the LT3042 is to parallel them.
Also interesting is that the max current of a single LT3042 is 200mA. And the dam1021's current draw on the positive rail is 180mA (per the manual). Søren, is that 180mA figure an average, or absolute max? I don't have enough knowledge/experience to say whether a single LT3042 has enough "headroom" to reliably power the dam1021's positive rail.
However, assuming a single LT3042 can supply enough current to the DAM1021's positive supply, then I can envision a pretty nice, simple purpose-built and compact power supply for the dam1021, particularly for the dual-mono use-case. Here's my quick ascii concept drawing:
Code:
AC - CMC - Rectification - Caps -- LT3042_1 - pos_rail_1
+- LT3042_2 - pos_rail_2
AC - CMC - Rectification - Caps -- LT3042_3 - neg_rail_1
+- LT3042_4 - neg_rail_2To my admittedly inexperienced eye, that seems like it ought to be pretty easy to design.
It also could be adapted to be used with the dam1121, though it looks like we'd have to parallel three LT3042 chips per positive rail (dam1121 seems rather thirsty at 400mA).
Thoughts?
Probably, but as the dam1231 already are reclocking, an additional reclocker is a waste of money....
Hi
I bought a dam1021 1021-12 in Sept. It is a rev 4 board.
I hooked up the dam1021 to my PC's RS232 port(update fw/filters).
Connection went fine (I can see the uManager).
By mistake I placed 0.99 instead of 1.06.
After typing update I got stuck there.
HyperTerminal
R0.99
I3
F5
V+00
I3
_
connected 115200 8-N-1
Did I "brick" the board ?
What can I do now ?
Please give me some advice.
Thanks in advance
I bought a dam1021 1021-12 in Sept. It is a rev 4 board.
I hooked up the dam1021 to my PC's RS232 port(update fw/filters).
Connection went fine (I can see the uManager).
By mistake I placed 0.99 instead of 1.06.
After typing update I got stuck there.
HyperTerminal
R0.99
I3
F5
V+00
I3
_
connected 115200 8-N-1
Did I "brick" the board ?
What can I do now ?
Please give me some advice.
Thanks in advance
Did you try power cycling the board ? Then doing the "+++ pause" ? You should be able to enter uManager and download the right version.
Hi all,
som pics from my build ...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Now just a little align the cables ... black cable ties .....
carsten where did you source the case from please?
Thanks for your reply
I pwrd off/on several times & it stucks at the screen shown.
PS. what is "power cycling" ?
Hi,
@all thanks for the nice words.
@all thanks for the nice words.
The housings are from https://www.modushop.biz and the metal work was made by Schaeffer AG: Home
Just to dot i's etc.... when you type the +++ you are not supposed to type anything else or press Enter. Just type +++ and wait. It's been my experience that if you don't get into uManager right away after typing +++ it's best to do a power on/off (or 'power recycle'
). Then try the +++ again.You can even try coming out of HyperTerminal and re-connecting after each power recycle....just to be paranoid!
Just to dot i's etc.... when you type the +++ you are not supposed to type anything else or press Enter. Just type +++ and wait. It's been my experience that if you don't get into uManager right away after typing +++ it's best to do a power on/off (or 'power recycle'
You can even try coming out of HyperTerminal and re-connecting after each power recycle....just to be paranoid!
Thanks v much.
Will try tonite & report back.
Howdy everyone,
First let me thank Soekris for building a great DAC and the heaps of info, care, and just intense interest you guys as the community have brought to it! It's... Wow.
I've been reading through this thread and haven't found (to someone who does basic soldering and a few input mods) any concrete info pertaining to my exact.t use case for the DAC - let me outline it:
Use: portable DAC akin to how the ODAC functions minus powered by USB.
Questions:
1. Is it possible to run the DAC off battery (say a lipro) only?
2. Because of what I read as a 7v or 12v requirement for DC, USB power is completely out of the question?
3. Are there any concrete guides that explain how to run this thing off battery? Found the disjointed documentation about how to simply connect a normal PSU all over the place.
4. Is there a defined list of mods that have been shown to increase the sound quality of this DAC?
5. Same for filters - is there a list and a consensus based on say, measurements?
6. Is there a definitive how to guide on setting up the dam1021? I know it requires a PSU and input at the bare minimum, but find the task of working with it a bit daunting.
Thank you!
Retro
First let me thank Soekris for building a great DAC and the heaps of info, care, and just intense interest you guys as the community have brought to it! It's... Wow.
I've been reading through this thread and haven't found (to someone who does basic soldering and a few input mods) any concrete info pertaining to my exact.t use case for the DAC - let me outline it:
Use: portable DAC akin to how the ODAC functions minus powered by USB.
Questions:
1. Is it possible to run the DAC off battery (say a lipro) only?
2. Because of what I read as a 7v or 12v requirement for DC, USB power is completely out of the question?
3. Are there any concrete guides that explain how to run this thing off battery? Found the disjointed documentation about how to simply connect a normal PSU all over the place.
4. Is there a defined list of mods that have been shown to increase the sound quality of this DAC?
5. Same for filters - is there a list and a consensus based on say, measurements?
6. Is there a definitive how to guide on setting up the dam1021? I know it requires a PSU and input at the bare minimum, but find the task of working with it a bit daunting.
Thank you!
Retro
If feeding it DC, you need to supply a positive and negative rail, 7-15 volts. With a single battery, you'd need a circuit to generate the inverted power, and for a typical 3.3v LiFePO4 cell, you'd need boost converters as well.
Technically no, if you drop a boost converter in there to up the voltage to something in the 7--12 volt range. But note that some USB implementations might not be able to supply enough current for the dam1021's needs. And also note that USB only supplies +5V, you'll need a circuit to generate the negative rail as well (just like with a single battery).
Not that I've seen. I did a google search for "dual rail supply from battery" and this was the first link, looks applicable. Hopefully someone will chime in here with some added thoughts.
On earlier board revisions (1 and 2) there were some fairly easy mods that made sense. The latest board revisions (3 and 4) have these mods incorporated into the design. So with the newer boards, the mods tend to fall into the more "advanced" category. For example, removing output buffer opamps to reduce power consumption and power supply requirements (probably not what you want to do for a portable headphone application). At least one person has replaced many (all?) of the on-board regulators with direct, individual battery power.
See moreDAMfilters website, and also this thread, Filter brewing for the Soekris R2R. Ultimately it's a matter of personal preference, and IMO, that's one of the major appeals of this board, that you can tune the filters to your liking. Either the website or the thread I linked had a "party pack" of filters that were the closest thing to any kind of consensus on a filter pack. Again, it's personal preference, but if you can find the "party pack", it should be a great start.
There is the official manual.
There are numerous pages on the HiFiDUINO website, such as Soekris dam 1021 R-2R DAC ILLUSTRATED GUIDE.
Also lots of useful info on DimDim's blog, Soekris dam1021 Sign Magnitude R-2R DAC.
Hope that helps!
Comparison of Soekris DAM and TDA 1387 DAC?
Hi @matt_garman
I followed your instructions on this site for modding the TDA1387 - thank you very much for those.
My question is: how do you feel the Soekris dam1021 compares as a DAC to the TDA1387 ?
I ordered a Soekris dam1021-05 rev4 board today and would be eager to know your thoughts and any 'lessons learnt'!
Thanks - Fitz
Hi @matt_garman
I followed your instructions on this site for modding the TDA1387 - thank you very much for those.
My question is: how do you feel the Soekris dam1021 compares as a DAC to the TDA1387 ?
I ordered a Soekris dam1021-05 rev4 board today and would be eager to know your thoughts and any 'lessons learnt'!
Thanks - Fitz
Last edited:
My pleasure! Glad someone else besides me found it useful.
In terms of sound quality, I'm hesitant to make any comments beyond "I could be happy with either". I didn't do any A-B comparisons between the two; in fact, much time passed between retiring the tda1387 and bringing the Soekris online. Furthermore, I didn't even have the same amps for each DAC. And lastly, these days I'm mostly doing things for the the enjoyment of learning and simply doing projects. I think my equipment quality surpassed my ear quality a while ago. So hopefully it's obvious why I shy away from making any meaningful sound quality comparisons.
That said, IMO, if the tda1387 "sound" works for you, it's really hard to beat in terms of value (i.e. price/performance).
For me, the points that make the Soekris a win over the tda1387:
- Volume control in the digital domain. Like everything, I'm sure there are pros and cons for digital versus analog volume control. I'm generally for simplicity and fewer overall components in my chain, so for that reason digital volume control makes a lot of sense. With the Soekris, you can plug in a potentiometer for volume control, or do it with a microcontroller (or SBC) which makes for a ton of flexibility. (Or fix the gain at 0 and use analog volume control downstream from the DAC.)
- User-level filter manipulation and control. There are stock filters provided out of the box, and a huge collection of filters available from the community. And the option is always there to roll your own, if you're so inclined. (I'm waiting for someone to figure out the special sauce in Schiit's megacomboburrito filter and implement it for the Soekris DACs. )
- Balanced output options: the Soekris can do balanced out natively (through op-amps), or you can parallel two boards and have "truer" balanced output (this is what I've done). Granted, this could be done with the tda1387 as well, but it requires extensive modding on that x8 board, or a custom PCB.
- Microcontroller (or SBC) control through the serial interface. As mentioned above, you can do volume control, but also filter manipulation, firmware upgrades, mode changes, etc.
- Overall more flexibility. That's really the underlying theme of all the points above. You can get a Soekris board up and running pretty quickly with a transformer and some kind of input (USB, SPDIF, TOSLINK); or you can go nuts with fancy power supplies, balanced dual mono, microcontroller integration, etc etc. I started with the former and am slowly working on the latter. And for someone like me who's primary motivation is now the simple fun of tinkering, it's a blast.
Having said all that, I would like to go back and revisit the tda1387 some day. I started to work on a custom PCB for that chip, but that project got put on the back-burner. Lots of other amps, DACs, speakers and power supplies to build in the meantime.
And I'm still not finished with my Soekris dam1021 build anyway!