Home > POWER, TEST > Buffalo II Power Consumption Measurement

Buffalo II Power Consumption Measurement

Some actual measurement with my setup:

  • SPDIF input
  • External microprocessor control
  • Power supply voltage: ~ 5.4V
Measured Power Consumption Idle (mA) Playing (mA) Notes
44.1K Sample Rate



PS: ~5.4V
192K Sample Rate



PS: ~5.4V

In this post, the current for Buffalo at 5.5V was specified at 290 mA, and 350-400 mA for Placid:

Specified Power Consumption Board Current (mA) Placid Current (mA) Notes
Buffalo II AVCC Right


Buffalo II AVCC Left


Buffalo II All Other


Buffalo II Total



Single Placid, Vout=5.5V

If I had used a 5.5 V supply, I would have probably reached the 290 mA figure.

I think it is probably a good idea to set the Placid current closer to the upper range of the recommended setting (400 ma).

Update: according to the comment from Russ, having a large current margin (beyond what is being consumed by the Buffalo II DAC) is not critical at all. 20 mA plus the current through the LEDs reference is sufficient for Placid to function well.

In my case, I’ve modded the Placid’s LED reference by using a JFET with the Vgs=0 (the gate shorted to the source -and I measured the current through the transistor in this mode to be ~ 10 mA). This current is consumed prior to the CCS. Thus setting Placid to 20 mA above the maximum current consumption of Buffalo (in my case this would be ~300 mA) is sufficient, and thus the 350 mA nominal setting for Placid would be perfectly fine.

  1. Russ White
    April 14, 2010 at 22:41

    I always estimate current a little high, to give people some room for error.

    You will see little if any change from 5.4 to 5.5V Maybe a few ma.


  2. Hifiduino
    April 15, 2010 at 01:11

    Hi Russ, this time is very close to actual consumption. How accurate is the 50 mA overhead for Placid, assuming 10 mA through the LEDs (I use a jfet with Vgs=0 and measure the current, so that part is well characterized)

  3. Russ White
    April 15, 2010 at 23:16

    Its not very critical to stay at 50ma. Any range from 20-70ma would be just fine.

    You do not need to subtract for the LED current as it is taken prior to the CCS.

    The Buffalo with our AVCC module presents a nearly static load.

    The idea is just to keep the CFP(shunt) driver pumping some current.


  4. Russ White
    April 17, 2010 at 19:51

    One other note.

    The DAC does use a bit more current (not a lot) at an incoming sample rate 192khz than at 44.1khz. So make sure you plan accordingly for the highest sample rate that DAC may encounter. 🙂

    For example my total current load at VD is about 285ma at 44.1khz but is about 310ma at 192khz.

    So if you adjust your placid 350ma – 310ma = about 40ma headroom. Which is plenty.

  5. Russ White
    April 17, 2010 at 19:54

    Hah, I see you actually measured at the high and low rates too. Sorry for the redundancy. 🙂

    Also note, my parts may not be exactly the same as yours, so we will likely have slightly different current loads.

  6. Hifiduino
    April 19, 2010 at 15:11

    Russ, thanks for the feedback. Yeah, I did measure both high and low sampling rate. The interesting part is that only ~20 mA of current in addition to the LED current is required for normal operation of Placid

  7. Russ White
    April 19, 2010 at 17:07

    The LED current is not sourced from the CCS. So you don’t need to subtract it. 🙂 It is taken prior to the CCS. The only thing the consumes CCS current is the target. The excess of course is shunted away.

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