Integer resampling would not affect sound quality. So 44.1 > 88.2 would sound exactly the same. Non integer resampling like 48Khz > 44.1 theoretically may alter the sound, but new ASRC chips are so good nowadays you can't really hear the difference.
I use Raspberry Pi's and run both Volumio and Moode. It upsamples the music before feeding it into an ADAU1701 DSP. The DSP then outputs i2s which I feed into the MA12070s.
ADAU1701 is a simple to implement DSP but the drawback is it does not have a built in ASRC, so it will work only with a single sample rate or it's integer multiples. I listen to exclusively to 16bit/44.1 anyway so it doesn't matter.
I use the DSP as an active crossover. I build speakers (too many) and too lazy to design my own passive crossovers. Although a USB transport would be nice
Would you believe that was my first SMD project? I had been resisting SMDs for many years but finally decided to take the plunge after realising that all the nice chips and new components were coming out as SMD only.
But as a background, I've been soldering and making my own PCB's for many years now, so I'm quite familiar with PCB assembly.
No, I don't have a reflow oven. I was really unsure of my skills, so instead of spending a ton of cash, I just built my own based on this project:
https://electronoobs.com/eng_arduino_tut161.php
Unfortunately, I was impatient and did not turn out looking so nice. But it works well. Set the temperature and timing right, use leaded 63/37 eutectic solder paste and things should come out right.
As for the ATTiny, a timer relay would be the nice hardware solution. But since these chips were made for battery operation, there is a command that you can put at the end of the script to shut down the microcontroller. Draws only a few microamps. Most importantly, the noisy oscillators are shut down. Need to do a bit more reading on how to do this.
Do you use the heating plate with a cover to prevent uneven temperature distribution?
You got a really smart layout on your amp especially the provision for these big coils.
Do you mind to share your gerber files?
You got a really smart layout on your amp especially the provision for these big coils.
Do you mind to share your gerber files?
What do you mean by "original"?
I got two from this seller. Took 10 days for delivery.
https://m.de.aliexpress.com/item/10...lgo_pvid=44fdfe0a-202c-41b1-a516-fe5eabe9267e
I got two from this seller. Took 10 days for delivery.
https://m.de.aliexpress.com/item/10...lgo_pvid=44fdfe0a-202c-41b1-a516-fe5eabe9267e
I mean IC MA12070P, not complete board.
And i found interesting boards like this:
https://www.aliexpress.com/item/1005003760847071.html
And i found interesting boards like this:
https://www.aliexpress.com/item/1005003760847071.html
No, I don't use a cover, but that's an idea.
The temperature distribution is not perfect, the solder paste starts to melt from the centre to the edges, but it only take a maximum of 10 seconds before everything melts, so I don't think it's an issue for small boards.
Here are the gerber files for the PCB plus the circuit diagram. The values of the inductors are very small, 1.5uH vs, for example, TPA3255 of 10uH. So I can use 30a inductors and still be very compact.
BTW, The PCB can be used for both the analog and digital version of the MA12070. Just substitute input resistors R2,3,4,5 with 1uf capacitors for analog use. The PCB already has an allowance for 5mm pin spacing film capacitors.
What happens if i run a 32bit file on MA12070P and Amanero (or other USB transport that have 32bit support)? MA12070P DAC do not play that or resempling to 16bit or 24bit? I have too many flows that have 32bit...
64bit is the default word length setting, so 32bit is fine. If the PCM word format is left justified (default), then you probably don't need to make any register changes.
So i really can play music or film with 32bit 196kHz?
I'm think that for Amanero needed i2s, not left justified...
This is from datasheet:
i2s_format PCM word format:
000: i2s
001: left justified (default)
100: right justified 16bits
101: right justified 18bits
110: right justified 20bits
111: right justified 24bits
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Yes. it will take 32bit/196khz. There is no option for right justified 32 bits because it is the same as the default left justified (64 words in each word select signal i.e. 64bits/2 channels = 32 bits per channel)
However, I'm not sure if 32bit i2s is supported, since it appears that it only supports a maximum of 64 words per word select signal and i2s skips the first word, which leaves it short of 1 bit per channel.
Anyway, 24bit depth is already plenty. Most amps have a SNR of 100-110dB which is between 16bit (98dB) to 18bit (110dB) equivalent SNR. Anything more will have your softest passages drowned in noise and the loudest distorting.
Although some music is marketed at 24bit, it is a 16bit, or at best 20bit mastering padded with extra zeros to make up 24bit. It is impossible to listen to true 24bit because it's beyond our listening range anyway.
The 24/32 bit INPUT capabilities for this amp are mainly for losses software volume control of 16 bit audio.
However, I'm not sure if 32bit i2s is supported, since it appears that it only supports a maximum of 64 words per word select signal and i2s skips the first word, which leaves it short of 1 bit per channel.
Anyway, 24bit depth is already plenty. Most amps have a SNR of 100-110dB which is between 16bit (98dB) to 18bit (110dB) equivalent SNR. Anything more will have your softest passages drowned in noise and the loudest distorting.
Although some music is marketed at 24bit, it is a 16bit, or at best 20bit mastering padded with extra zeros to make up 24bit. It is impossible to listen to true 24bit because it's beyond our listening range anyway.
The 24/32 bit INPUT capabilities for this amp are mainly for losses software volume control of 16 bit audio.
From early on in this thread frequently the question came up if someone was willing to design a board for the Merus chip. Obviously you did it and you seem to have done a great job.
If more people where interestet in your iteration would you be ok with it if a batch was produced?
If more people where interestet in your iteration would you be ok with it if a batch was produced?
I'm not talking about sound quality. If MA12070P does not support 32bit - there may be no sound at all. The music or movie will play in the player on the computer, but there will be no sound. I have come across this on XMOS
If someone already tried 32bit input with USB trasport - write if it works or not
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Looks like 32bit i2s will work. The data signal is delayed by 1 cycle all the time.
You will just need to set the 0x35 register to 0x00 (000 for i2s) to match your XMOS output. Good luck!
You will just need to set the 0x35 register to 0x00 (000 for i2s) to match your XMOS output. Good luck!
Sure, happy to share.
After making a few amps, I have a few minor changes in mind. Won't improve the sound quality, but more the set up and control of the amp. If you wait about 1-2 weeks, I will get the new design out.
Super thanks.
May I ask who is interestet in one or more boards?
Don't fear the soldering process
Patrick demonstratet that the components can be soldered with relatively simple means.
It can be done on the stove plate if you keep a close eye on it.
May I ask who is interestet in one or more boards?
Don't fear the soldering process
Patrick demonstratet that the components can be soldered with relatively simple means.
It can be done on the stove plate if you keep a close eye on it.
According to Figure 8-3 in the datasheet 32 bit I2S format is supported. The "missing" bit occurs at the beginning of the next word select.