M-Audio Sonica Mod
Nov 12, 2003 at 12:58 AM Post #16 of 57
Other World Computing has it for $59, which sounds pretty average, but their shipping is cheap. $6.50 UPS 2nd day to a business address (IL to TX), 4.32 ground.

They're also an excellent source of Mac components in general. They're fast and reliable.
 
Nov 12, 2003 at 1:57 AM Post #17 of 57
Additionally, the Guitar Center chain of stores stocks the Sonica and Transit in the US. Visit http://www.guitarcenter.com for locations.

Same $59 MSRP, no shipping. I'm planning to pick one up this week before my next flight.
 
Nov 12, 2003 at 2:37 AM Post #19 of 57
Ordered from JandR.com this afternoon, hopefully will have it within a week.

Does anybody know if a schematic is available? I'd like to get an idea of some good cut-in points without having to spend too much time in discovery.
 
Nov 14, 2003 at 1:20 AM Post #20 of 57
Did you use the "Standard" Black Gates, or the "Coupling" series ones?

I'm going to look into beefing up or replacing the usb supply when I get the chance in a few weeks.

One thing I'm worried about in replacing the power supply is grounding issues. If I cut the traces for the USB's ground, I'm worried it could potentially wreak havoc if its the usb's only ground. Potentially I could supply just the DAC with different power, but again, I lose the signal ground between the DAC and USB-I2S chipset.
 
Dec 16, 2003 at 11:45 PM Post #22 of 57
Has anyone completed the mods mentioned in this thread? I have a Sonica and would like to perform a few or all of these. I plan to at least perform the signal path cap upgrade.

1. There was also mention in this thread to add a larger cap for more power supply line capacity. This "appears" to be C7, which is 100 uf, 10 v. Is this the right one? Has any one done this, and if so, what value was used?

2. Any other cap upgrades performed?

3. I like the idea of using a separate pwr supply, since I have a hub attached to my notebook that stays completely filled, and with only two devices having their own PS. I have a few 4 cell packs ranging from 250mA to 1000mA so would run a separate pack than that used for my amp (16 cell). Anyone know how much current the Sonica draws?
 
Dec 17, 2003 at 6:09 PM Post #23 of 57
the USB cable carries +5 and associated ground line, and the two signal lines. You could splice out the power lines from a homemade cable and connect the battery pack internally

g
 
Dec 17, 2003 at 6:33 PM Post #24 of 57
The Sonica already regulates the 5v down to 3.3, I think we could get the same improvement just by adding more caps to the 3.3v power rails...


As a test, I could throw together a linearly regulated +5v from a stack of AA's, but I don't have any decent equipment (echo mia, etc) to measure it with.
 
Dec 17, 2003 at 8:09 PM Post #25 of 57
If I'm not mistaken, the Sonica already has some surface mount ceramic caps bypassing the power supply electrolytics. Though normal ceramics like this don't sound good in audio coupling, they are very low ESR and work alright for power supply duty like this.

In the interest of saving space, you can try replacing the cheapo electrolytics there with Sanyo OSCON caps. The OSCONs are specifically designed for power duty and reject a great deal of ripple.
 
Dec 17, 2003 at 9:23 PM Post #26 of 57
Actually, I havn't traced the power to the ADC, it may be using +5v. If not, I'm going to seriously consider moving it to 5v for a better output signal strength.
 
Dec 17, 2003 at 9:26 PM Post #27 of 57
yes, keep that Ti chip on 3.3V as well as the digital supply for AKM and use clean stabilised 5V for it's analog supply..

instead that 100uF/10V cap use some Panasonic FC >470uF at least
 
Dec 18, 2003 at 1:46 AM Post #28 of 57
Well, I can't tell upon initial look whether or not the DAC is using the +3.3v power or 5. both power traces are hidden under the chip. I need to get my multimeter and other tools back from school to tell for sure.

There are other capacitors on the audio path though. The spec sheet specifies to use a 0.1uF cap to filter out high frequency noise, and I see those for sure.

I'm not entirely sure which of the other 3 electrolytics by the dac are which (DigVdd, AnalogVdd, Vcom), but they're likely candidates to be replaced with larger Panasonics since they're power related. I'm considering using maybe a 10uF and an extra 100uF on the back at each of those positions, but I'm not planning on keeping the original blue case intact.
 
Dec 18, 2003 at 2:28 AM Post #29 of 57
The DAC is definitely being fed by +3.3v, not +5. The toslink output is fed from DigVdd, so changing the AnalogVdd won't affect anything else.

The dc blocking capacitors are absolutely necessary. This dac floats around 1/2 AnalogVdd on the outputs (1.3v!). Which could be expected, its a 0-5v dac. I may still remove them when I integrate it into my Meta42, and rely on the Meta's input blocking caps only.

Even scarier:
one channel of mine floats at .6v AFTER THE BYPASS CAP!
 
Dec 18, 2003 at 2:36 AM Post #30 of 57
Additional data:
at 1khz, "0db" I get .9v RMS. The 5v will still keep me in spec with Red Book's 2v
smily_headphones1.gif
 
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