• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

PhiDAC hex kits with pre-built filters

With SMD soldering the challenge I find is in not using too much solder. I only rely on the flux in the solder itself but that burns off very quickly - perhaps I'd do better to use additional flux on all components as I do on very fine pitched parts.

Thanks for the feedback on the sound - yes its one of the puzzles of developing DACs by ear to distinguish between what's caused by the DAC and what's on the recording. Only playing a wide variety of recordings I find can help with determining that. Ultimately though its down to satisfaction from the music and not being distracted by some characteristic brought into that by the DAC.
 
Member
Joined 2002
Paid Member
It really helped me a lot in soldering the SMD parts when I used thin soldering wire.
0.5mm solder and 0.5mm tip on the soldering iron.
I applied flux paste with a small brush on the PCB pads.
I find it easier to solder the ICs first, then the transistors, then the resistors and capacitors.

George
 

Attachments

  • smd soldering tool.jpg
    smd soldering tool.jpg
    591.5 KB · Views: 489
Member
Joined 2002
Paid Member
I set up this PSU for the PhiDAC hex from parts I had.
I wound the common mode choke. 3.1mH, 45mOhm. 17turns bifilar winding of 0.38mm enamel wire over a toroidal ferrite core (12.5mm OD, 7.7mmID, 6.4mm height)
The cap multiplier is a left over from some old project (probably for an JLH headphone amplifier).
The LM317 voltage stabilizer is Elvee’s brain child: D-Noizator: a magic active noise canceller to retrofit & upgrade any 317-based V.Reg.
Static measurements of the whole PSU look good.

George
 

Attachments

  • 10-FFTs of LM317 DeNoiser and shorted probe.jpg
    10-FFTs of LM317 DeNoiser and shorted probe.jpg
    151.9 KB · Views: 137
  • 9-combined FFTs (REW).jpg
    9-combined FFTs (REW).jpg
    187.1 KB · Views: 117
  • 8-LM317 DeNoizer out-zoom.png
    8-LM317 DeNoizer out-zoom.png
    47.9 KB · Views: 99
  • 7-capacitance multiplier out-mV.png
    7-capacitance multiplier out-mV.png
    16.2 KB · Views: 101
  • 6-coil out-mV.png
    6-coil out-mV.png
    33.1 KB · Views: 96
  • 5-bridge out-mV.png
    5-bridge out-mV.png
    37.5 KB · Views: 109
  • 4-varying mains.png
    4-varying mains.png
    70.4 KB · Views: 434
  • 3-stable mains.png
    3-stable mains.png
    58.2 KB · Views: 441
  • 2.jpg
    2.jpg
    517.8 KB · Views: 461
  • 1-schematic.JPG
    1-schematic.JPG
    619.2 KB · Views: 466
Member
Joined 2002
Paid Member
The two FFT plots in the previous post seemed a bit suspecious to me.
The testing chain was: 100MHz (x1) probe, into an Hameg 203-7 oscilloscope. The Y out of the scope into the M-Audio USB Audioplile soundcard, then reduction of the gain (-14.073dB) in Audacity to compensate for the increased gain of Y out. I noticed that smoothing in REW’s RTA plays some tricks in the vertical scaling.

I run the test again. This time the testing chain was: 100MHz (x1) probe, into my AD620 test preamplifier in (x1) single ended configuration, then AD620 output into the M-Audio USB Audioplile soundcard.
FFT plots vertical scaling is proper now.

George
 

Attachments

  • FFT of LM317 DeNoiser and shorted probe.jpg
    FFT of LM317 DeNoiser and shorted probe.jpg
    118.2 KB · Views: 91
  • combined FFTs (REW).jpg
    combined FFTs (REW).jpg
    155 KB · Views: 101
Member
Joined 2002
Paid Member
First public appearance of the test-run (industrial design disgrace of the year)
Nevertheless, they all work together harmoniously :)

George
 

Attachments

  • DSCN5556.JPG
    DSCN5556.JPG
    652.8 KB · Views: 180
  • DSCN5555.JPG
    DSCN5555.JPG
    622.5 KB · Views: 183
  • DSCN5553.JPG
    DSCN5553.JPG
    617.2 KB · Views: 161
  • DSCN5552.JPG
    DSCN5552.JPG
    616.9 KB · Views: 241
  • DSCN5551.JPG
    DSCN5551.JPG
    659.4 KB · Views: 244
What is the function of the switch on the board?

Hi Wong - its a digital phase switch. The DAC's normally non-inverting (true phase) but if you flip that then it becomes inverting. Note the TDA1387 chip itself is inverting, presumably because its recommended to use it with an opamp I/V stage which inverts.

Thanks for the feedback @Dingo Dingo, @kp93300 and @r8833. The JLSounds interface is an isolating one? If so that normally makes a significant difference.
 
George,

I think thats a picture of a older board. I have a V3 board
on my JLS board I left pin5(A1) and pin6(A6) alone.. didnt use.

On V3 board there is 20 pin header

pin 11 (BCLK_I2S) > clk
pin 13(DATA_I2S) >data
pin 15(LR_CLK_I2S) > ws
gnd >gnd

jumpers on B1 and B2

Rich