Draknodd
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This happens only if bad implemented.
Schiit Magnius use a tpa6120a2 as output stage and outputs 6w per ch @16 ohm with a sinad of 120db and 125db of snr.
Schiit Magnius use a tpa6120a2 as output stage and outputs 6w per ch @16 ohm with a sinad of 120db and 125db of snr.
This is my amateur board layout for the output buffer that I have planned. I will be using BUF634a. It is not labeled properly because I don't know how to use the software and I just wanted to come up with something I can fabricate at home and fits where the original buffer was. This contains the two buffer chips and the reserve capacitors (10uF tantalums and 0.1uF ceramic both in 1206 size).
Does the 9V from the analog board get fed back to the digital board for anything or does it only power the op-amps?
The digital board provides 3.3V through the dip pin out, on analog where the opamps are, provides 9V through a DC-DC converter
Oh thank you! I am still trying to wrap my head around this, but do you think I need the output relay if I use an output buffer with current protection like the BUF634 which I plan to use with a resistor between the output of the buffer and headphone jack? I will also tag @slavalun in this question.
I think few posts ago are discussed this topic, i think from page 186 with the post of @maxifuny
I am asking too many question today, but Merlin, when you used the ADP1613, did you copy the circuit directly from the ADI datasheet? For example the 33nF capacitor on the SS pin?
Themilkman46290
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I have a question for you guys, maybe some who has both the dsd and the dsds
Are the digital boards the same?
I know they are between ak4490, 4495,4497eq
Are they still the same in the dsds?
Are the digital boards the same?
I know they are between ak4490, 4495,4497eq
Are they still the same in the dsds?
Merlin-PT
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You'll have to read the ADP1613 datasheet and use what they say for your specific output voltage.
In my case it was easy because they have an example for ADP1613 with 12V output in page 20 and I use around 12,5V output.
If you still want to try 12V, read the datasheet and see if you can also chose the components in the 12V example, then try the 9V and the 12V and decide what's best for you.
Depending on the output voltage, you'll have to use a different value inductor and compensation circuit values.
For example, I had to use 6.8uH inductor for 12V not the 4.7uH in zishan.
Also different compensation circuit values.
Also note that the FB voltage is different in datasheets:
MP1542: Vout = 1.25 × (1 + R1/R2)
ADP1613: Vout = 1.235 × (1 + R1/R2)
@slavalun
Interesting that in ADP1613 datasheet they say the wrong inductor choice can produce higher ripple and noise, so this could explain why you saw higher noise in zishan when you increased the voltage to 12V, if you didn't increased the inductor value. I know it's a different converter but the principles should be the same.
The compensation circuit values are also different for 12V.
pag. 13 of ADP1613 datasheet:
"INDUCTOR SELECTION The inductor is an essential part of the step-up switching converter. It stores energy during the on time of the power switch, and transfers that energy to the output through the output rectifier during the off time. To balance the tradeoffs between small inductor current ripple and efficiency, inductance values in the range of 4.7 µH to 22 µH are recommended. In general, lower inductance values have higher saturation current and lower series resistance for a given physical size. However, lower inductance results in a higher peak current that can lead to reduced efficiency and greater input and/or output ripple and noise. A peak-to-peak inductor ripple current close to 30% of the maximum dc input current typically yields an optimal compromise." ....
The compensation circuit values for 12V are also different.
Maybe we could even try different values to see if noise decreases even more, but I can't measure it, don't have the equipment with the required precision.
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I assume you tried it with +-12V. What did you think?
slavalun
New Head-Fier
Before raising the voltage in the system, you need to understand what it is for and what characteristics can be better from this. To do this, I conducted many tests with a power supply of + -12 Volts and observed a deterioration in the characteristics of the IMD, TND, as well as noise emissions at the amplifier output under a load of 16 Onm. For my tasks, the power supply system on the MP1542 with the necessary adaptation and power supply + - 9.3 Volts is quite enough! I see no reason to look for problemma where there is none ...
In the latest versions, Zishan puts quite good inductors, they can be improved on inductors with better Q-factors, but they will be larger. This did not affect the measurements, but you can put it in order to calm yourself
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Before raising the voltage in the system, you need to understand what it is for and what characteristics can be better from this. To do this, I conducted many tests with a power supply of + -12 Volts and observed a deterioration in the characteristics of the IMD, TND, as well as noise emissions at the amplifier output under a load of 16 Onm. For my tasks, the power supply system on the MP1542 with the necessary adaptation and power supply + - 9.3 Volts is quite enough! I see no reason to look for problemma where there is none ...
In the latest versions, Zishan puts quite good inductors, they can be improved on inductors with better Q-factors, but they will be larger. This did not affect the measurements, but you can put it in order to calm yourself
Okay I think I'll leave mine at 9V then. I'll just change the regulator to ADP1613 because I got 2 units as a sample from ADI. And I'm not sure if the MP1542 in the Zishan is an A grade unit. I have a question about the output relay. Do I need it if I'm using the BUF634a? The Z3 that I have does not use a relay. I know the buffer has output current protection, but not DC offset protection. I will just have to settle for coupling caps in that area. What coupling caps do you recommend? I am thinking of using electrolytic caps with film caps in parallel.
slavalun
New Head-Fier
Provided that the entire circuit of the player is assembled and configured correctly, protective decoupling capacitors with an output to the BUF634 are not needed.
Thanks! How about the question about the relay? I am thinking that I probably do not need the relay using the BUF634 because it has output current protection.
Merlin-PT
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@slavalun
The adp1613 datasheet information aplies to this converter, so I take their recommendations for their converter DC noise output.
I won't bother you with what I've read about the opamp supply voltage and take your recommendation for your test conditions as a measured fact of the sound output noise.
Thanks for sharing.
The adp1613 datasheet information aplies to this converter, so I take their recommendations for their converter DC noise output.
I won't bother you with what I've read about the opamp supply voltage and take your recommendation for your test conditions as a measured fact of the sound output noise.
Thanks for sharing.
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