I bought tis dac from ebay thinking I could do sommething with it and a couple of regulators.
Am I right when I say that there are 3 regulators neede?
https://www.ebay.com/itm/1145514035...var=414734175880&_trksid=p2060353.m2749.l2649https://www.mouser.se/datasheet/2/1082/ES9038Q2M_Datasheet_v1_3-1923484.pdf
VCCA pin 12 3,3v
VCCA pin 27 3,3v
DVCC pin 13 3,3v
And pin 15 is Digital core voltage nomilaly +1,2v supplied by an internal regulator from DVCC.
And I´m going to use my Tube I/V.
Am I right when I say that there are 3 regulators neede?
https://www.ebay.com/itm/1145514035...var=414734175880&_trksid=p2060353.m2749.l2649https://www.mouser.se/datasheet/2/1082/ES9038Q2M_Datasheet_v1_3-1923484.pdf
VCCA pin 12 3,3v
VCCA pin 27 3,3v
DVCC pin 13 3,3v
And pin 15 is Digital core voltage nomilaly +1,2v supplied by an internal regulator from DVCC.
And I´m going to use my Tube I/V.
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The photo of the PCB shows a 15-0-15v DC input, so I assume that any necessary conversion is carried out on the board.
Yes I thought of giving thedifferent voltages a regulator of their own.There is a 12v input for the dac chip.
The 15-0-15v is for the analog opamp I figure.
I havent gotten the board yet,any one else got a board like this?
The 15-0-15v is for the analog opamp I figure.
I havent gotten the board yet,any one else got a board like this?
I don’t have that board, but had purchased another DAC from that maker, and another DAC in a case.
I avoid anything from that maker now, as the DAC board killed the front end on a nice old amp, and the one in the case stopped working for the person I bought it for.
I hope it works out, and things are better for you with this one.
I avoid anything from that maker now, as the DAC board killed the front end on a nice old amp, and the one in the case stopped working for the person I bought it for.
I hope it works out, and things are better for you with this one.
I think you're meant to use either the +/-15V inputs (which are then regulated down) or the 12VDC input (which the standing PCB near the connector then splits into a +/- voltage).
I have an older version of what is probably the same board, and all the lower voltages are generated from the +/-15V voltages via SMD regulators, so you only need to provide the highest voltages and the board then takes care of the rest.
I have an older version of what is probably the same board, and all the lower voltages are generated from the +/-15V voltages via SMD regulators, so you only need to provide the highest voltages and the board then takes care of the rest.
There is a very long existing thread on pretty similar Chinese ES9038Q2M boards: https://www.diyaudio.com/community/threads/es9038q2m-board.314935/page-371
Short answer to your question is that the dac chip itself has four different power rail inputs:
VCCA -- analog RF stuff
DVCC -- digital stuff
AVCC_L -- Left channel analog reference
AVCC_R -- Right channel analog reference
Some other things on the board that could use separate regulators include:
Clock
MCU
Output stage opamp +- rails
The board you have is probably not the best one for modifying, although one could play around with it for learning purposes. IIRC, did get one of the version you are asking about to see if I could recommend it for modding purposes. Decided there was not enough free ground plane area on the bottom to add corrective circuitry, among other issues.
The overall biggest problems with the Chinese ES9038Q2M boards were found to be (1) quality of the output stage, and (2) quality of the AVCC_L and AVCC_R regulators. Once those things are fixed, then fixing other things can make some further but smaller improvements in sound quality.
EDIT: Some of the boards can be operated from either a single +15 rail, or else from separate +-15v rails. Jumpers on those board select which option to use. The -15v rail is only used for the output stage opamp, otherwise its negative rail is jumpered to ground.
These boards really need a real four op-amp output stage. (IV stage followed by filter.) [That is four op-amps per channel or four dual op-amps for stereo. That is one of the big cost cuttings on the cheap boards and a serious degradation, in my opinion.]
Here is the one I used (the no-THD hump version): https://www.diyaudio.com/community/threads/es9038q2m-board.314935/post-6517557
Here is the one I used (the no-THD hump version): https://www.diyaudio.com/community/threads/es9038q2m-board.314935/post-6517557
Thanks I´ll read the link.
I´m thinking of using Tube output with resistor I/V.
For ESS dacs with resistor I/V, depending on the resistor value, the dac chip is to some degree operating in voltage output mode. In voltage output mode distortion is much higher than in current mode ('current mode' implying virtual ground opamp type I/V). Its that ESS dac chips are switched resistor designs with a low output impedance, say, as verses some dacs that use switched current sources to provide higher output impedance.
Also, oversampling sigma-delta dacs tend to have a lot of RF noise mixed in with the analog audio output. The noise can sometimes audibly affect downstream circuitry so its normal to use some additional filtering after the I/V stage for further attenuation of unwanted noise.
Could be that some tubes and or transformers would have some benefit in terms of RF noise tolerance and or useful bandwidth limiting. However distortion produced by voltage mode operation of the dac chip would probably be expected to remain.
Also, oversampling sigma-delta dacs tend to have a lot of RF noise mixed in with the analog audio output. The noise can sometimes audibly affect downstream circuitry so its normal to use some additional filtering after the I/V stage for further attenuation of unwanted noise.
Could be that some tubes and or transformers would have some benefit in terms of RF noise tolerance and or useful bandwidth limiting. However distortion produced by voltage mode operation of the dac chip would probably be expected to remain.
Stereo separation is better with two AVCC supplies, but its possible for a shared supply work reasonably well.
I have some LT1963 regulators but don't prefer them for audio.
However, do like cheap ebay LT1083 boards like the ones at: https://www.ebay.com/itm/224551139147?epid=10048667653&hash=item34484a774b:g:wJYAAOSwvCJhAhE-
The boards contain two completely separate positive regulators (no shared ground). To use one of them as a negative regulator requires it having its own dedicated transformer winding, since the output terminals, Vcc+ and GND, have to be swapped at the load. One reason I use those boards is because positive and negative rails can have matched regulator characteristics.
However, do like cheap ebay LT1083 boards like the ones at: https://www.ebay.com/itm/224551139147?epid=10048667653&hash=item34484a774b:g:wJYAAOSwvCJhAhE-
The boards contain two completely separate positive regulators (no shared ground). To use one of them as a negative regulator requires it having its own dedicated transformer winding, since the output terminals, Vcc+ and GND, have to be swapped at the load. One reason I use those boards is because positive and negative rails can have matched regulator characteristics.
I prefer LT1963 regulators everywhere where noise is not a concern. A far improvement over the 79xx and LM317 old devices.
IME LT196 and many other LDO voltage regulators tend fare poorly in subjective listening tests. There are only a very few IME that are exceptions. This is nothing new and did not start with me. Still do my own listening tests anyway, and report what I find. People are free to take it or leave it. Other than that the S/N ratio in here is starting decline. Anyone interested in further discussion on the matter is free to PM.
Not surprisingly, you have your own proprietary understanding of signal and noise in the S/N ratio.
I am about to connect the dacboard soon:
But I wonder Is 49 ohm a good value to use as a IV resistor? How high will the voltage be out?
But I wonder Is 49 ohm a good value to use as a IV resistor? How high will the voltage be out?