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M-Audio MobilePre - signal path upgrades

post #1 of 2
2/20/10 at 2:26am
Thread Starter 
I have cracked open my MobilePre and want to plan out some upgrades. My setup is ubuntu-studio Linux running jack realtime sound server, M-Audio MobilePre, and cmoy (OPA2227) headphone amplifier.


Headphone Amp
Attached is what I believe to be the headphone preamp.
JRC : 3414A = Believed to be an opamp ?datasheet?
C107 / C106 = op-amp protection?
R76 / R66 = ?
R77 / R67 = ?
C109 / 108 = ?

My thinking is to replace C107 / 106 with jumpers.
Does anyone have a datasheet for this 3414 chip? I would like to upgrade this to a burr-brown unit.
More Ideas?


DAC
A few candidate chips so far as I can tell:
AKM : AK4532VF
TI : TAS1020A

More op-amps
TI : LM339 (seen in image, I think this may be for the "clipping" LEDs)
JRC : 2115 (several of these, appear to run all other stages in/out)

Any thoughts would be greatly appreciated!

Thanks!
LL
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post #2 of 2
5/13/11 at 1:30am

Hello,

Just looking at  the same device, using it for pro-audio. The input stages are JRC NJM2115 opamps. You could try replacing these with AD8617 (low noise).

C109/R77 is protection of the opamp against static discharge, little to no influence on audio performance. You might try replacing C107 with a higher capacity value.

 

Succes!

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