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Schiit Magni 3+ Headphone Amp Teardown

T.M.Noble

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And this crap right there is why I have a pathological hatred of most things not Torx, Allen/Hex or triple-square. Perhaps change to Torx, @T.M.Noble ?

Cost, my friend. Torx are expensive. When you are trying to squeeze as much tech as we can into a $99 box, margins are very tight. In almost all cases the people removing screws are Schiit techs so stripped screws shouldn't be an issue for our customers unless you are very interested in voiding your warranty.
 
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amirm

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@amirm ,

Any chance of doing the same 9v 32ohm load thermal profile you did with the Heresy?
Here you go:

Schiit Magni 3+ Teardown Thermal Analysis how Hot it gets.jpg


The output transistors started to burn the tip of finger after just one minute.
 
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amirm

amirm

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And this crap right there is why I have a pathological hatred of most things not Torx, Allen/Hex or triple-square. Perhaps change to Torx, @T.M.Noble ?
To be clear, what stripped was not the screw. It was the wood screw that was attached to the plastic RCA connectors in the back. It was over-tightened so stripped the flimsy thread in the plastic.

The rest of them seem to be cross-threaded and/or brute forced fastened making them hard to remove. But not to the point of stripping the heads. I was using my precision Weha screwdrivers which have great heads but the handle is not big enough for this much torque.
 

solderdude

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Perhaps Tyler Noble can clarify what the OPA1678s are doing in the circuit--are they in the signal path 100% of the time, or only for the line out but not headphone? Or is it being used as a DC Servo or some other not-in-the path application?

Jason mentioned it is a DC servo. It must be at a really really low frequency because it looks like there is no roll-off and as good as DC coupled.
Looks like the input signal is not going into the opamp.
Would have to reverse engineer it to make sure.
 

T.M.Noble

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Perhaps Tyler Noble can clarify what the OPA1678s are doing in the circuit--are they in the signal path 100% of the time, or only for the line out but not headphone? Or is it being used as a DC Servo or some other not-in-the path application?

DC Servo.
 

ZeDestructor

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Cost, my friend. Torx are expensive. When you are trying to squeeze as much tech as we can into a $99 box, margins are very tight. In almost all cases the people removing screws are Schiit techs so stripped screws shouldn't be an issue for our customers unless you are very interested in voiding your warranty.

Fair enough. I'd have taken the extra $3 or so for nicer screws myself though (and have done so on devices that I've taken apart).

To be clear, what stripped was not the screw. It was the wood screw that was attached to the plastic RCA connectors in the back. It was over-tightened so stripped the flimsy thread in the plastic.

The rest of them seem to be cross-threaded and/or brute forced fastened making them hard to remove. But not to the point of stripping the heads. I was using my precision Weha screwdrivers which have great heads but the handle is not big enough for this much torque.

I see. I too have a Wiha set, and as great as the bits and the ratcheting wrench are, the screwdriver sucks. I just use the bits in a much nicer ifixit driver where I can stick a T-bar in for extra torque instead. At some point I'll be grabbing a nice Wera ratcheting screwdriver handle for the Wiha bits.
 

debunker

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DC Servo.

Thanks, and this makes sense. @amirm, you may want to edit your comment regarding the op amps in your original post; it is inaccurate and not entirely fair to Schiit to state, "Input signal then goes into a couple of integrated op amps (OPA1678) so all is not discrete here." The signal path is absolutely all discrete as advertised, and the input signal would not be going into the op amps in this configuration.
 

kevin gilmore

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output transistors
phpt610035pk dual pnp wired as darlington
phpt610035nk dual npn wired as darlington

vas stage
phpt610030npk dual pnp/npn

vbe multiplier
q111/q211 can't read package code

input stage
q101/102 and q201/q202 dual transistors, i cannot read the package code

jason has said this is a current feedback amplifier which means the input stage
is highly similar to marantz hdam meaning diamond buffer driving vas stage

opa1678 is servo

something like this. amir needs a much better camera,macro lens and polaroid copy stand with lighting
 

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mc.god

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Hi, am i wrong or the power supply filter caps aren't all Nichicon but 2 Nichicon and 2 Panasonic? Not that it would matter anyway...
By the way, i just ordered a Magni 3+, it's so difficult to find it and Heresy in stock here in Europe.
 
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solderdude

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you are not wrong (it is easy to see on the pics) and indeed it does not matter.

Nichicons before the regulators and Panasonics after the regulators it seems
 
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