Here you can see which resistors can be shorted. They are in the feedback circuit of the headphone amp, and by shorting them, the amplification factor becomes 1. In other words - just a buffer. In DA10s one part of the 5532 opamp is used for differential to single ended signal converter and the other - as headphone amp. By the way, there is no relay, which disconects the headphones from the amp. They are always connected and you can hear all kinds of wanderfull pops an clicks during power-on and off cycles.
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My first external DAC - Semibreve DA10S Stereo Audio Decoder
- Thread starter Cal_Cobra
- Start date
soarer1961
New Member
Тank you very much. I will try
ow81
Active Member
So just remove the capacitor you have circled in the photo?
Mine sounds ok at -12 to -14 dB but initially sounded terrible. To be honest I don't really need the spectrum analyser. So should I remove the resistors and just place a solder bridge between the contacts? Sorry if I don't sound the most knowledgeable I'm slowly teaching myself electronics.
Thanks
Yes. Just remove that small capacitor. Please note that this is valid for DA10s with spectrum analyzer and 4 RCA at the back! The version with 3 RCA and volume bar at the display doesn't seem to have such circuit inside.
To the ear problems start at -12dB or even -10dB - depends on how loud is the music on the recording. But if you hit the DAC with full scale 1kHz tone, it starts to distort at -14dB.
I'm very sorry that mine stooped working, otherwise I would have provided oscillograms with explanation.
The easiest way to remove this component is to use relatively big melted solder blob, which joins both sides of the component. This way you can melt the solder on both sides at the same time and the component will float, ready to be removed. After that use flux to help removing the excess solder from the board and clean the board with alcohol (to remove the flux residue). I believe you can find helpful videos on this topic online.
As for resistors - you don't need to remove them, if you don't want to. The short will be exactly the same with or without resistors. This is to reduce the signal level for the headphone output!
soarer1961
New Member
Finally, I did it and it really helped. Thank you mate
Very nice!
In general, this is one very badly designed DAC. Sorry to say that.
I have reverse engineered some parts (like pinouts of connectors, etc.). Only thing that is unknown is the RGB controller for the volume knob light.
The reason for this effort is that I'm trying to make my own board and use some of the critical parts (hopefully still working - BT module, DAC chips, part of the power supply, some connectors, entire display assembly).
And I'm trying to learn (DAC design) in the process.
In general, this is one very badly designed DAC. Sorry to say that.
I have reverse engineered some parts (like pinouts of connectors, etc.). Only thing that is unknown is the RGB controller for the volume knob light.
The reason for this effort is that I'm trying to make my own board and use some of the critical parts (hopefully still working - BT module, DAC chips, part of the power supply, some connectors, entire display assembly).
And I'm trying to learn (DAC design) in the process.
ow81
Active Member
The Bluetooth capability of my unit seems to have packed up now. The unit has just been sat in the same place since I got it but now when I try to pair with a new device it doesn't show up and if I try using it with a previously paired device the connection is unstable to the point where music isn't listenable. I guess it's probably a solder joint or something, will have to open it up and have a look I guess.
ow81
Active Member
I finally got round to doing this today, I had previously thought the unit had packed up and chucked it in a cupboard, out of sight, out of mind. I got it out because I thought I'd try it using my streamer which sounds poor with it's internal DAC. So I removed the capacitor as you described and it's now working much better, thanks for the help. The Bluetooth problem was just me being stupid, I must have connected to my Alexa once which is always on, the DA10S only seems to allow one BT device to be connected so the Alexa was connecting automatically every time I switch the device to BT mode, so when I tried connecting my phone it kept saying "connection denied" or something. So I've gone into the settings in Alexa app and made it forget the DA10S, simple, duh! I since bought another DAC from SMSL which does sound better to be fair, but anyway I guess I have a spare now! Thanks for the advice though mate very useful!
Almost one year later, probably no one cares anymore, but I want to share my work in progress.
I've made my own version of the circuit, almost nothing like the "original". Except Bluetooth module, Amanero clone, the actual DAC chip and the optical receiver, nothing else is original. Still work in progress. I have much fun making the firmware. It is not easy, I'm not a programmer, but it is fun. It was ton of joy when I heard the first sound out of it.
So, basically, I use just one of the 2 DAC chips. New power supply for analog part - better filtered, transformers for coaxial input and output (for isolation), digital isoators for Amanero interface, relays and mute transistors for both line-out and headphones, DIR (digital interface receiver - PCM9211) for digital interface routing (or multiplexing) - it was actually cheaper than few discrete multiplexers. ES9038 can handle input switching on its own, but whatever... I did what i did.
New display - IPS with better resolution. It looks very good in person.
New MCU, because the chinese one is, uhmm...., strange. And, of course, because I have dev tools for STM32 on hand.
What else - I don't know. It still needs lot of work on software and some work on hardware. Headphones amp can be improved, also there is room for improvement for the noise floor (I mean - it is not audible, but there is room). Also the output levels are not exactly right, I need to choose a target - 1Vpp, 2Vpp or something else. Etc...
Oh, and I found out that chinese clone of Amanero only supports DSD64 and DSD128, instead of advertised up to 512.
Here are some photos:
I've made my own version of the circuit, almost nothing like the "original". Except Bluetooth module, Amanero clone, the actual DAC chip and the optical receiver, nothing else is original. Still work in progress. I have much fun making the firmware. It is not easy, I'm not a programmer, but it is fun. It was ton of joy when I heard the first sound out of it.
So, basically, I use just one of the 2 DAC chips. New power supply for analog part - better filtered, transformers for coaxial input and output (for isolation), digital isoators for Amanero interface, relays and mute transistors for both line-out and headphones, DIR (digital interface receiver - PCM9211) for digital interface routing (or multiplexing) - it was actually cheaper than few discrete multiplexers. ES9038 can handle input switching on its own, but whatever... I did what i did.
New display - IPS with better resolution. It looks very good in person.
New MCU, because the chinese one is, uhmm...., strange. And, of course, because I have dev tools for STM32 on hand.
What else - I don't know. It still needs lot of work on software and some work on hardware. Headphones amp can be improved, also there is room for improvement for the noise floor (I mean - it is not audible, but there is room). Also the output levels are not exactly right, I need to choose a target - 1Vpp, 2Vpp or something else. Etc...
Oh, and I found out that chinese clone of Amanero only supports DSD64 and DSD128, instead of advertised up to 512.
Here are some photos:
Attachments
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ow81
Active Member
Cool so have you used the original PCB or have you made a custom PCB? The screen is different right? Looks much better than the original. What opamps are you using, I was going to use opa1612 mounted on DIP8 board for mine. I have my Project Streambox S2 going through the DAC by optical cable. The DAC I know isn't completely flawless but it sounds a lot better than the DAC/analogue output in the Project unit. I made the modification that I suggested , removing the capacitor to disconnect the spectrum analyser, no more distortion now! The analyser doesn't really do anything useful, just looks kinda nice I guess. I have another DAC now too from SMSL and to be honest I don't think the Semibreve unit is that much worse.
I designed the PCB. It is 1st edition, so some small mistakes were discovered. The idea is to fit inside the original enclosure.
For Semibreve "original" I can only say that it was very badly designed. You don't have to have expensive measurement tools to see how noisy the power supply was. Yes, it is inaudible, because it is high frequency, but still.. Also the loud pops at the output on turn-on / off... - unacceptable.
Anyway. I think that there is a point in audio quality after which improvement or differences are not noticeable for the naked ear. So I'm not surprised that you can enjoy DA10s. After all, it is not a professional gear, where you might need "extra room" in the dynamic range or noise floor for your sound mixing and tuning. It is perfectly listenable, if you don't use the headphones output, of course...
For my project I use LM4562 for I/V conversion stage. It can be found cheap in SOIC8 package. For summing amp and headphones NE5532 is the choice for now (they are even fake ones). I'm not finished experimenting with the schematic. Sometimes bad thing happen when poking with oscilloscope probe and I don't want to sacrifice good op-amps in the process. Fake 5532 sound very very good for what they are (and they are dirt cheap - like 2 USD for 10pcs delivered from China...). Really, I'm very surprised how good they are, knowing that they are fake.
I think changing op-amps is little bit overrated. Surrounding circuit can make way bigger impact on quality. For example - bad choice of resistor values can bring up the noise. Bad choice in feedback loop can lead to instabilities, etc.
I will not pretend that I'm an expert. I'm just an dull guy, which makes experiments with electronics in his bedroom.
BTW, the display is dirt cheap too - it was something like 2.5$ from China.
For Semibreve "original" I can only say that it was very badly designed. You don't have to have expensive measurement tools to see how noisy the power supply was. Yes, it is inaudible, because it is high frequency, but still.. Also the loud pops at the output on turn-on / off... - unacceptable.
Anyway. I think that there is a point in audio quality after which improvement or differences are not noticeable for the naked ear. So I'm not surprised that you can enjoy DA10s. After all, it is not a professional gear, where you might need "extra room" in the dynamic range or noise floor for your sound mixing and tuning. It is perfectly listenable, if you don't use the headphones output, of course...
For my project I use LM4562 for I/V conversion stage. It can be found cheap in SOIC8 package. For summing amp and headphones NE5532 is the choice for now (they are even fake ones). I'm not finished experimenting with the schematic. Sometimes bad thing happen when poking with oscilloscope probe and I don't want to sacrifice good op-amps in the process. Fake 5532 sound very very good for what they are (and they are dirt cheap - like 2 USD for 10pcs delivered from China...). Really, I'm very surprised how good they are, knowing that they are fake.
I think changing op-amps is little bit overrated. Surrounding circuit can make way bigger impact on quality. For example - bad choice of resistor values can bring up the noise. Bad choice in feedback loop can lead to instabilities, etc.
I will not pretend that I'm an expert. I'm just an dull guy, which makes experiments with electronics in his bedroom.
BTW, the display is dirt cheap too - it was something like 2.5$ from China.
ow81
Active Member
I've recently upgraded my amplifier to a Yamaha AS501 from the budget RS202d, the DAC sounds rubbish through the new amplifier the sound is really unbalanced, I'm wondering if the DAC output is too hot or something, did you measure this? I'm using my DAP instead at the moment which sounds much better for now. Maybe the better amplifier shows the DAP up more?
ow81
Active Member
I should mention too that I did the capacitor mod, which made the DAC sound good with the old amplifier, but it sounds really bad with the new amp, reducing the volume control doesn't really improve the situation, everything sounds really muddy with the DAC through the new amplifier which has much better specifications. I'm confused.
audiodacman
New Member
Hello, wouldn't it be better to buy the LM4562NA right away?Nice to hear you like it
does work on preamp?
Last edited:
I really don't know...
Did you check back with your old configuration (the old amp etc)?
If the differences are so obvious, there is something very wrong. There is a possibilty that the output is too hot. This is relatively easy to check - you can make simple atenuator with resistors (for example 22k or 47k). Look online how to make voltage divider with resistors and test your theory fot hot output.
In my opinion (not very popular I would guess), if the output levels are the same, DAC and DAP (digital audio player?) should sound the same...
Don't bother. Remove the offending capacitor first. It will make huge difference (this is actually bad design and demonstrably makes the sound worse).