Volumio is like disease - it has completely taken over me and there is no cure for it.
I use My oak Volumio transport for my tube PCM63-K DAC but it wasn’t enough for me.
Few weeks ago, after I read few words from @gkkpch and @Wheaten I bought WYSE3040. Nice, small, functional and works realy nice with Volumio. With WiFi, Lan, BT, USB and headphone jack is good platform to make some “MMM” (Multifunctional Music Machine).
I had a dream… so I found few parts in ma workshop, few parts I ordered and started to create a monster.
I’m aesthetics so front panel is from natural wood, this time I chose walnut with 7" display. I want more functionality than I have in My Oak Volumio so I decided to add Compact Disk transport. Important for me were front USB and headphones.
A moment of thought and a day of work later, this was created:
Photos from inside next time. Now is only naked 3040, transport CD, Xmos converter, transformer with power supply for tubes and few auxiliary relays for controls all parts. Will be added PCM DAC, tubes for DAC and probably more ( if I find place for it )
Why ?? Because I monitoring USB voltage and sometimes drop to 4,6V. I heard sound distortion, I disconnected the CD and display, but the voltage on the USB still dropped.
This is strange because the current consumption measured even with the LCD connected and during CD playback was about 1.8A at a voltage of 5.1V. Peak at start was maximum 2,3A.
I changed PSU for WYSE3040, now is feed by regulated 5A power supply unit with 8V 6,25A toroid transformers. I give 5,1V and with the same current consumption USB voltage is still on the same level. No sound distorsion.
Strange the stock supply is rated at 5V/3A.
I have to admit, all that I have connected is a Wifi dongle and USB DAC.
Did the input also show voltage drops or Or only the USB ports?
No, only USB port shows voltage drop. Input was still on 5,1V.
My WYSE is connected to XMOS converter via USB, first when I heard sound distorsion I thought that is a problem with XMOS and DAC but after that I heard few times relay knocking.
Maybe I start at beggining:
I have all time powered WYSE and use monostable switch on front panel soldered parallel to WYSE power switch. I also have inside power supply unit for tube but I want powered tubes only when Volumio is ON and for this I use arduino relay module. I have soldered wires from USB power supply pins, if WYSE is powered on and has power on USB than switch on relay which power on tube PSU. Sometimes when voltage drop arduino relay module was switched on/of. I connected this USB power swires to multimeter and observed. To be shure I connected to USB port USB monitoring stick
and saw the same voltage drop. Now on my PSU USB power is still about 4,9V. I think WYSE never give me more.
Relays like this rely on continuous power to operate, dawning the current from the USB ports. You should opt for pulse relay’s. They only need a pulse to switch to a state and stay there, until the next pulse is received.
It is a mini relay. It takes measured 0.018 A. I use the same in my DAC to cut off signal on output RCA until tubes are stable.This 0.018 A it’s realy nothing and nothing change on test with Dell PSU.
As you see I mounted tubes on back panel because of place inside. Because of the same reason I need to prepare other one DAC PCB - smaller
It is almost finished. I prepare tube analog, all power supply, I add two colours power switch with relay ( it is green after WYSE start but with output RCA bypassed to the ground… After 1,5 minute when tubes are ready to work timer power on relay - ground from RCA is cut off and power switch is red. It is mean that DAC is ready to play).
Yesterday I finished DAC. All parts I need soldered. It is simply R2R DAC. Only CS8412 receiver and 2 x PCM56 current outputs straight to the tubes. Last night I connected everything and adjusted conversion resistor. Still outside for test.
DAC is on two old BB PCM56. I cut voltage output ( with internal op-amp ) and use current output. It goes on cheap but one of my favorite tubes - ECC85.
DAC is very simply, only 2 x PCM56 DAC with receiver, any selector, any op-amp. I use linear PSU,
Tubes connected in simply SRPP mode with one double triode on chanell. I powered it via good linear PSU, fully regulated with toroid transformer 250V - 0,25 A / 8,5V - 3A. You can use lower voltage but for me in SRPP sounds the best is 300V DC ( in SRPP triodes are in serial connection and voltage is half that you give from PSU ).
I connected WYSE 3040 with DAC through Amanero USB/SPDIF converter.
