What do you mean "higher" output current? Twisted Pear (Russ White and Brian) used to design output stages for 9018, and has output stages for 9028Pro. To design output stage for High current 9038Pro is a challenging. Just read this topics: Introducing the Buffalo III-SE-Pro 9028/9038
Introducing Mercury - Achieving escape velocity.
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Thanks you! I want to achieve the highest possible SQ from that dac so will folow your guidance on this one. I am farly new to electronics, so your help would be much appreciated.
I meant that if you use an output stage designed for a 9038PRO, which has higher output current than ES9038Q2M, for a dac that uses 9038Q2M that since the output stage was designed for the higher current of 9038PRO, the output voltage when used for 9038Q2M may be impractically low. Instead of getting 2VRMS maximum from the output stage you might only get 0.2VRMS. And signal to noise ratio may be worse than optimal.
As long as the output stage is designed to be of adjustable sensitivity and work with lower output current dac chips, then maybe not a problem. I already since advised that Mercury is configurable for different dac chips, although at $169 it may be rather expensive for use with the dac board we are modding here.
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Hi idir,
Since you express interest in learning more, MrSlim posted schematics for an output stage board and an AVCC power supply board that we recommend using. The schematics are attached to a post here:https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-301.html#post5577605
In addtion, instructions for building the output stage can be downloaded here:
Dropbox - Output Stage Instructions.zip
Besides the output stage and AVCC boards, we also replace the 100MHz clock module and add some more local voltage regulators on the dac board for sensitive circuitry. I will attach a list of posts that may be of interest for you to get up to speed on the dac project as it exists at this point in time. Unfortunately, the list has probably grown too long and I need to trim it down one of these days, but haven't done it yet. After you have a chance to look around please feel free to ask any questions you may have.
ES9038q2m v1.07 I2C
Hello all!
Thank you for shared information regarding I2C topic.
Let me share my experience with ES9038q2m v1.07 board.
I succeeded to communicate with the board via I2C only bypassing the onboard microcontroller(disconnecting sda scl mcu pins from pcb).
You need to do that because rpi i2c is operating only in master mode and if you leave onboard mcu connected will conflict rpi.
Results:
- you can scan es90x8 with i2cdump and write into the registers with i2cset linux command
- Volumio with 9018 plugin and "hifibunny3" driver is working perfectly and play all formats(including 16bit/44.1khz) ->ok, no popping
BR
Hello all!
Thank you for shared information regarding I2C topic.
Let me share my experience with ES9038q2m v1.07 board.
I succeeded to communicate with the board via I2C only bypassing the onboard microcontroller(disconnecting sda scl mcu pins from pcb).
You need to do that because rpi i2c is operating only in master mode and if you leave onboard mcu connected will conflict rpi.
Results:
- you can scan es90x8 with i2cdump and write into the registers with i2cset linux command
- Volumio with 9018 plugin and "hifibunny3" driver is working perfectly and play all formats(including 16bit/44.1khz) ->ok, no popping
BR
Thank you !
This is all i need to start the project waiting for my board to arrive. I will most certainly have a lot of questions not to flood this post i will do some reading first
This is all i need to start the project waiting for my board to arrive. I will most certainly have a lot of questions not to flood this post i will do some reading first
Hi makobd,
Don't know if you saw eslei posts about an RPi driver he modified for better sound quality with DSD, IIRC. His posts are here:
https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-335.html#post5630183
https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-336.html#post5630630
https://www.diyaudio.com/forums/digital-line-level/314935-es9038q2m-board-338.html#post5633055
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Hi Mark, thanks for the quick reply. As it seems that this problem is specific to my set-up and perhaps a bit off-topic for this thread, I moved to this other thread and provided more details and pics there.
Okay, looks like it has single-ended outputs, too. Unfortunately, it is ES9028k2m based which we don't know too much about. Don't even have a pinout diagram for one, much less a data sheet.
What parts are you thinking you might want to use with it?
I've looked into Mercury and it looks really good! Unfortunately its not inexpensive so I want to look for another alternative before going that route. I've also understood that using audio transformers wont give the THD numbers I want.. I've looked into the op amp circuit from Mr.Slim on page 301 and it doesn't look to complex for just the balanced option. With his schematic in mind, could this dc buffer be made to work for one channel? The pcb seems simple enough but I cant find any schematic for it, HIFI NE5534 DC Buffer Stereo OP-AMP Preamplifier Preamp Board for OPA627 | eBay Perhaps any op amp savy people here could tell me if modding this is worth while?
Sorry, no. Please take a look at the BOM MrSlim also posted, and the output stage build instructions I linked to. It takes proper high quality components, careful layout including a good ground plane, and appropriate power supplies to make an output stage suitable for use ES9038Q2M when excellent sound quality is the goal. It isn't easy to make a good dac, as I keep trying to explain. It is possible to make one, though, although maybe just barely.
hi, there,
on smp cb 9038q2m v1.07 board disconnecting sda scl mcu pins from pcb is not necessary,
putting on the j1 and j2 will stop the onboard microcontroller
rpi i2c -> v1.07 board i2c
rpi i2s -> v1.07 board i2s
install the "hifibunny3" driver and 9018 plugin
the sound quality already very good, highly recommended the beginner start on that then further modding. stick on smp cb 9038q2m v1.07 board is a good a good idea too.
cheers
That may work if the optional display is connected, but may not work without it.
I've seen the bom and obviously I would replace the components values to the right ones. I just thought the card looked neat with some op amp pins named and through hole components. In other threads I've seen good paint renderings for similar boards that shows where to cut and where to bridge. If we could find a suitable starting point in an existing board for the IV stage, it could enable a lot of beginners to tag along. Perhaps the new found popularity could attract some more specialist to chime in also But to me +-6db won't be of any importance, the amps I plan to use doesn't have that of an amazing SNR ratio.
I guess I'll have to buy that pcb and trace out the lines.
But to me +-6db won't be of any importance, the amps I plan to use doesn't have that of an amazing SNR ratio. I guess I'll have to buy that pcb and trace out the lines.
Haven't seen the bottom of the board, don't know it there is a ground plane. Kind of looks like maybe they used star ground. If you read what ESS says about output stages, they need to be on the same ground plane as the dac chip with no interruptions in the ground plane between the dac chip and opamps. That's the way we designed ours.
Now if you are not afraid of SMD soldering, we might be able to make it easier for you using Surfboards that can be attached to a ground plane. That's probably the easiest way to make a good output stage. But, I was asked for instructions to make one using leaded components.
Later, when someone asked about SMD and Surfboards, I posted a sketch showing how to make the I/V part of the output stage using SMD parts. If that sounds okay, I could sketch up the differential summing part, or if you already know how to lay out something like that you could do it.
We could also talk about what parts to use for an SMD BOM.
Yes unfortuneately that board doesn't use a ground plane, just star ground.I plan to use several isolated transformers in my dac, wouldn't that help the star ground issue with isolated psu just for the IV stage? I like through hole components just as much as the next guy But if someone offered a blank smd pcb I'll be the first one in on a group buy .
I'll be taking a closer look at your grounding solution also.
But if someone offered a blank smd pcb I'll be the first one in on a group buy . I'll be taking a closer look at your grounding solution also.
The ground plane is to keep signal and power return impedances as low as possible and to keep one ground current from modulating the ground at another point in the circuit. It's not a function of power supplies in particular although we should talk about that too. It has to do with the fact that adding noise to ground can be just as bad as adding noise to a signal wire. Amplifiers respond to the difference between the two, not just the signal in isolation. The critical signals coming out of the dac need an extremely stable ground plane at zero volts. Even a microvolt of ground noise is bad if we can avoid it. Remember, the dac chip is supposed to be able to do -120dB distortion, and -122dB noise. It takes a really good ground plane to get there, not just that, but that's one of the things.
How about SMD?
How about SMD?