SB2 internal 3.3v PS

[mamsterla]

I have done a number of mods to my SB2 - replaced the PS Cap with Rubicon bypassed by smaller caps, used WBT digital output and have an external linear PS. I would like to replace the internal switching 3.3v supply with a LT1086-3.3 from my linear external PS. What component(s) comprise the internal 3.3v switching supply? I may use the SB2 for radio, so I do not want to remove the 12.8MHz oscillator. I may remove the headphone opamp. Any other thoughts for a digital only transport? I have looked at Red Wine and Bolder for their thoughts so far.

-MA

[bakos]

I thought the linear PS only improves the analog output. Would it also reduce jitter on digital output?

I would love to be able to use SB2 (or the SB3 that is in the mail) as my digital source. SB2 and lossless files is fine for background listening, but for critical listening I find that it doesn't come close even to my old Theta Data II Universal transport.

Please post your experience with the digital stage mods. I am not interested in the analog stage, just the best possible digital out to feed my DAC.

Thanks!

[seanadams]

SB3 uses a linear reg for the 3.3 rail. I recently posted some specifics on how to bypass the 3v3 side of SB2's dual switcher, but due to poor search technology and laziness I can't find it right now. Basically remove the diode/inductor on the 3v3 side and you can feed in a linear supply.

[Rupert Dacat]

SB3 uses a linear reg for the 3.3 rail. I recently posted some specifics on how to bypass the 3v3 side of SB2's dual switcher, but due to poor search technology and laziness I can't find it right now. Basically remove the diode/inductor on the 3v3 side and you can feed in a linear supply.

I have searched your recent posts and could not find the one you refer to. It would be nice to have a little more info than just that quoted directly above.


Thanks,

Rupe

[Mr Perceptive]

It in my thread!!!

http://forums.slimdevices.com/showthread.php?t=17284

I initially took a different approach and lifted the +Vcc leg on the 74HCU04 and connected 3.3v directly to it from a small super regulator. I derived the input supply from elsewhere on the board.

Unfortunately the lifted leg did not survive, neither did the one on the replacement 74HCU04 that I put in, fortunately the minimum buy quantity from my supplier was 20 so I have 19 more to go (if the SB2 PCB will survive that long!

I did get sound out of the second 74HCU04 but not for long enough to do any comparisons!

Hope that helps

Mr Perceptive