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Schiit Magni Heresy Headphone Amp Teardown

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Feb 11, 2018
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#21
It's not entirely the same power supply.
The differences are in the 3+ which has 1 Ohm added to the outputs (behind the caps after the regs) and a set of extra reservoir caps near the output devices.
Differences in hum could be caused by idle current differences and/or ground/wire routing differences as well as PSRR of the circuits itself.
From my observation of the pcb with only 4 of the 1 ohm build-out resistors per channel, it looks as though only one of the dual OPA1688 amps in each package is used. This would ease thermal stress.
An impressive little part for ~$0.50 in quantity!
 

solderdude

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#22
There is no thermal issue with this amplifier when used what it is intended for.
No one will ever draw 2W continuously listening to music.

There are 8 resistors per channel R106 to R113 and R206 to R213

Using only half of the opamps in one package would lower output power for 16 and 32 Ohm headphones
The output devices on one half of the chip would get hotter locally as well.
 
Joined
Feb 11, 2018
Messages
71
Likes
63
#23
There is no thermal issue with this amplifier when used what it is intended for.
No one will ever draw 2W continuously listening to music.

There are 8 resistors per channel R106 to R113 and R206 to R213

Using only half of the opamps in one package would lower output power for 16 and 32 Ohm headphones
The output devices on one half of the chip would get hotter locally as well.
Yes, you are right!
Thanks.
 

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