Hello folks
I bought this headphone amp on Aliexpress a long time ago because i wanted to try it out; Leory SD05
I thought i would share a bit about it because after a few modifications it sounds too too impressive after i did some mods on it, before it did sound amazing too but sadly with a bit too much bass. The seller included this in the Aliexpress page
Response looks pretty good, i do have the hardware to test it myself so i'll upload a response test when i get the time to do it. Even though the bass is heavy i did still enjoy it, with the impressive low THD of 0.003% at 50mW @ 32 ohm
Theres also another MAX4410 based headphone amp i really wanna test but sadly my money bag isn't the biggest currently and i am getting a bit too many amplifiers currently vs how many i use soo.. But heres the link to it; Aiyima MAX4410
I gotta say, i am not impressed with the "protection" they have done to the input wire itself, already seeing it broken and slowly tearing itself apart. I am not expecting it to run 1 month without me in need of replacing the wire with whatever i got in stock but i am going to be impressed if it does. It is breaking apart when it is going inside the device though the hole as shown here
Time to talk technical!
Inside the device itself the main chip was scratched so i had to investigate and found out it was based on an MAX 4410
It also have a battery charging IC(the 5 pin) which is a LTC4054 and sadly also some bass boost has been done, but after a bit of motification on the PCB i removed it, also going to add a 3.3V LDO as the MAX 4410 is only rated for MAX 3.6v so on a full charge it runs at 4.2v and it can do that for a LONG as idle with no audio playing but headphones connected it draws 10mA
So here's the things for the nerds, what i have motifyed;
At the red boxes is the bass filtering, to "disable" it you'll have to remove the 2 capacitors in both boxes. It did indeed make the sound experience much better.
The yellow one is more like a repair, after i charged my device the device kept staying on forever until battery voltage got too low, so what i had to do was simulate out from the two resistors, which i had done some reverse engineering on to figure out what would be most suitable, it turns out it was a p channel mosFET so i took a AO3407 which was the only i had in storage and it worked perfectly, only thing is.. It still gets too much voltage, so next is for me to cut the trace from the drain of the mosFET and mount a LDO from the mosFET to the testpoint above to regulate it to 3.3v and then make a shutdown function that turns off if the voltage on the battery is lower than 3.5v or something like that
Heres a picture of the backside, it isn't the most beautiful looking at because of that hotsnot on the battery wire/audio in. Also wth is going on with that
Hope somebody else will find it as amazing as i found it! I will give some updates on my modifications and so on!
I bought this headphone amp on Aliexpress a long time ago because i wanted to try it out; Leory SD05
I thought i would share a bit about it because after a few modifications it sounds too too impressive after i did some mods on it, before it did sound amazing too but sadly with a bit too much bass. The seller included this in the Aliexpress page
Response looks pretty good, i do have the hardware to test it myself so i'll upload a response test when i get the time to do it. Even though the bass is heavy i did still enjoy it, with the impressive low THD of 0.003% at 50mW @ 32 ohm
Theres also another MAX4410 based headphone amp i really wanna test but sadly my money bag isn't the biggest currently and i am getting a bit too many amplifiers currently vs how many i use soo.. But heres the link to it; Aiyima MAX4410
I gotta say, i am not impressed with the "protection" they have done to the input wire itself, already seeing it broken and slowly tearing itself apart. I am not expecting it to run 1 month without me in need of replacing the wire with whatever i got in stock but i am going to be impressed if it does. It is breaking apart when it is going inside the device though the hole as shown here
Time to talk technical!
Inside the device itself the main chip was scratched so i had to investigate and found out it was based on an MAX 4410
It also have a battery charging IC(the 5 pin) which is a LTC4054 and sadly also some bass boost has been done, but after a bit of motification on the PCB i removed it, also going to add a 3.3V LDO as the MAX 4410 is only rated for MAX 3.6v so on a full charge it runs at 4.2v and it can do that for a LONG as idle with no audio playing but headphones connected it draws 10mA
So here's the things for the nerds, what i have motifyed;
At the red boxes is the bass filtering, to "disable" it you'll have to remove the 2 capacitors in both boxes. It did indeed make the sound experience much better.
The yellow one is more like a repair, after i charged my device the device kept staying on forever until battery voltage got too low, so what i had to do was simulate out from the two resistors, which i had done some reverse engineering on to figure out what would be most suitable, it turns out it was a p channel mosFET so i took a AO3407 which was the only i had in storage and it worked perfectly, only thing is.. It still gets too much voltage, so next is for me to cut the trace from the drain of the mosFET and mount a LDO from the mosFET to the testpoint above to regulate it to 3.3v and then make a shutdown function that turns off if the voltage on the battery is lower than 3.5v or something like that
Heres a picture of the backside, it isn't the most beautiful looking at because of that hotsnot on the battery wire/audio in. Also wth is going on with that
Hope somebody else will find it as amazing as i found it! I will give some updates on my modifications and so on!
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And finally some tests of frequency respons!
I didn't do a response test of the amplifier with the bass boost but here is the device with the function removed
And i thought it could be better so i invistegated and tried to change the input Capacitors from 1µF to 2µ2 which gave some pretty sweet results!
I gotta say.. It is getting better and better!
I didn't do a response test of the amplifier with the bass boost but here is the device with the function removed
And i thought it could be better so i invistegated and tried to change the input Capacitors from 1µF to 2µ2 which gave some pretty sweet results!
I gotta say.. It is getting better and better!
96 dB/mW.
50mW, it's enough for you ?
You use it at home or outside ?
I have Shure 750 DJ and SE535.
Both outside and at inside the house. The IC delivers 65mW at 32 ohms so that is fine for me, mostly i am sitting in a bus and my headphones are open that means i am listening at a lower volume
It would indeed give a bit more, you can also set the gain according to the datasheet by adding a feedback resistor
"Choose feedback resistor values between the 4.7k
and 100k range."
https://datasheets.maximintegrated.com/en/ds/MAX97220A-MAX97220E.pdf
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