That's the MQA tax. Buy a DAC without it.smsl su9 already got this chip
full name is es9039mspro, what the hell is ms inserted there
That's the MQA tax. Buy a DAC without it.smsl su9 already got this chip
full name is es9039mspro, what the hell is ms inserted there
The new one. SU-9 Pro.
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Measurements of SMSL SU9 Pro ESS9039Pro DAC - L7Audiolab
台式设备 今年五月份(2022年5月)的时候ESS发布了9038Pro芯片的下一代(?)产品,ESS9039Pro。当时有过一阵子讨论,从编号来看9039Pro更像是9038Pro的"小改",双目三林这次给我们抢先带来了 SMSL SU9 Pro 这款基于9039Pro芯片的产品www.l7audiolab.com
The first 9039? Not for smsl, I really want to say a few words about this chip. The official website of the data manual has been released. How can I see that it is a shrinking version of 9038!? The biggest feature is the more power-saving hyperstream modulator. What channels does this power saving rely on? I looked at it at a glance and saw two points from the data manual 1. The worse reconstruction filter eliminates the brickwall, adds an additional minimum phase, and worse filter attenuation. 2. For lower-frequency hyperstream modulators, mclk (MasterClock) 9038 has an asynchronous mode of 100mhz (>2048fs) and 9039 is 50mhz (1024fs). You know, the data on the 9008 white paper is 40mhz. Isn't this equivalent to doing it back... This mclk is related to the final modulation process, which affects noise shaping and also directly affects the resolution.
this "auto bias" savs money no adjustment anymore + long time stability.9039PRO and 9027PRO also have revised "recommended output stages" in their datasheets (https://www.esstech.com/products-overview/digital-to-analog-converters/sabre-audiophile-dacs/) which use a back-to-back de-glitch capacitor plus no "angst" resistor for the I/V capacitor (sounds familiar, doesn't it ;-). They also use a common-mode control loop with an extra opamp to force the output voltages to be exactly 0V rather than using a bias voltage directly.
The 9027PRO circuit shown in the datasheet looks, let's say, somewhat special... probably a drawing error...
interesting the capacitor between the outputs before the i/v circuits. Looks like the output stage is the same cr,,,,,,, like before. Did they read your posts? Why do they use the fastthis "auto bias" savs money no adjustment anymore + long time stability.
this "auto bias" savs money no adjustment anymore + long time stability.
Normally there isn't any adjustment pot, rather the proper resistor selection is made for the Vref divider ceating the bias voltage. But there still is always a residual error and yes, aging / temp changes etc can move the DC bias around.interesting the capacitor between the outputs before the i/v circuits. Looks like the output stage is the same cr,,,,,,, like before. Did they read your posts? Why do they use the fast
expensive 1611 for this task??
Yesterday it was a little late.... Today I need a little help to understand the ESS schematic.9039PRO and 9027PRO also have revised "recommended output stages" in their datasheets (https://www.esstech.com/products-overview/digital-to-analog-converters/sabre-audiophile-dacs/) which use a back-to-back de-glitch capacitor plus no "angst" resistor for the I/V capacitor (sounds familiar, doesn't it ;-). They also use a common-mode control loop with an extra opamp to force the output voltages to be exactly 0V rather than using a bias voltage directly.
The 9027PRO circuit shown in the datasheet looks, let's say, somewhat special... probably a drawing error...
Yes, it's a very fast "servo", the idea is to remove all DC and AC common-mode voltage at the outputs, up to and beyond audio frequencies.Here we can see something very fast acting (51 pF!!) integrating (compensating) capacitor and a fast OP -amp. Some Ideas?
Your answer was faster then my questionNormally there isn't any adjustment pot, rather the proper resistor selection is made for the Vref divider ceating the bias voltage. But there still is always a residual error and yes, aging / temp changes etc can move the DC bias around.
But the most important point is that the dynamic (AC) common mode signal is removed by this servo loop (a known technique in instrumentation). By this, you can use one output leg single-ended with almost no degradation wrt distortion and noise, quite in contrary to the simple biased circuits.
The CM servo loop also is the lowest noise and distortion circuit to balance an output around the output reference. In single ended mode it's a bit less good but still better than the usual approach with a subtractor circuit after the I/V's.
The CM servo loop is forming a composite amplifier loop (the I/V's being the slave buffers, paralleled). This, and the previous remark, are two reasons why you want to use a nice fast precision OpAmp here. Further, you want to have controlled conditions for the master and slave OpAmps bandwidths and very similar bandwidths are a good operating point for such a composite. Finally, using the same OpAmp type throughout is convenient and cost-effective in mass production (the 1611 will actually be 1/2 1612 in most implementations, and in a true precision application the OPA1612's will be OPA2211's -- same chip but selected for better offset ratings).
Conceptually, the whole shebang is equivalent to a fully differential OpAmp and one can use a good one but probably specs would be a bit worse than with the discrete solution, plus you're restricting yourself to non-standard parts and footprints (bad idea these days) and there is no room for optimization (like the positive feedback seen in the 9039 circuit which creates an ever so slightly negative input impedance... whatever that will do for circuit perfomance).
Thank you was very helpfull I could learn.Your answer fas faster then my question![]()
Old post here ... Can someone please explain to me why there's positive feedback on the U14 opamps? Also, why the fast servo with a 2,600Hz bandwidth? I'm used to seeing BW values under 100Hz or so.Yesterday it was a little late.... Today I need a little help to understand the ESS schematic.
Mostly we can see here some tweaks of the I/V stage, from KSTR already shown here February 2022.
The offset problem is here solved with an active stage. So far, so good. Now I was expecting a slow (integrating)
offset compensation. Here we can see something very fast acting (51 pF!!) integrating (compensating) capacitor and a fast OP -amp. Some Ideas?
View attachment 239109
It’s not a dc servo its a full bandwidth servo to suppress the broader bandwidth common mode.Old post here ... Can someone please explain to me why there's positive feedback on the U14 opamps? Also, why the fast servo with a 2,600Hz bandwidth? I'm used to seeing BW values under 100Hz or so.
Cool! Thank you for clearing that up. Is the assumption here that music signals within the filter bandwidth are differential and not common to both +/- inputs?It’s not a dc servo its a full bandwidth servo to suppress the broader bandwidth common mode.