You're welcome Northernsky
So, please check again your voltages on Tantalum C27/26/15/16.
Please confirm you've measured positive side of the caps (+).
If previous request is correct, then I suspect U3 (MIC5205 3.3V) to be faulty.
Check U3 pins 4 (Gnd) & 5 (Vout) values, according to attached pic.
Here we are:
C27+: +3.29
C26+: +3.59
C15+: +3.25
C16+: +3.26
U3
P1: +4.91
P2: +0.0
P3: +4.93
P4: +1.22
P5: +3.26
I got the same measure on U5 and U6.
Concerning U4
P1: +4.91
P2: +0.0
P3: +4.93
P4: +1.57
P5: +3.59
As I already reported I saw a flash while soldering U3!
northernsky
Best way to power TOSLINK for SUBBU V3 DAC
Hi,
I've recently got the TOSLINK module from ebay for my SUBBU V3 DAC. Module description says that it would operate from +6~20V regulated or unregulated supply. The TOSLINK chip itself needs +5V to operate. Now I am puzzled what is the best option to power the module?
I see three possibilities:
1. bypass the on-board regulator and use the +5V supply from SUBBU DAC PSU
2. tap off the unregulated DC from SUBBU DAC PSU just after the smoothing caps
3. increase the output of SUBBU DAC PSU to +6V by modifying the R1/R2 and use it to power the DAC and the TOSLINK module in a standard way
Could some one suggest the better option of the three (or the alternative if it does not suggest a separate PSU)?
Thanks,
Oleg
Hi,
I've recently got the TOSLINK module from ebay for my SUBBU V3 DAC. Module description says that it would operate from +6~20V regulated or unregulated supply. The TOSLINK chip itself needs +5V to operate. Now I am puzzled what is the best option to power the module?
I see three possibilities:
1. bypass the on-board regulator and use the +5V supply from SUBBU DAC PSU
2. tap off the unregulated DC from SUBBU DAC PSU just after the smoothing caps
3. increase the output of SUBBU DAC PSU to +6V by modifying the R1/R2 and use it to power the DAC and the TOSLINK module in a standard way
Could some one suggest the better option of the three (or the alternative if it does not suggest a separate PSU)?
Thanks,
Oleg
CD player project with Subbu DAC
http://www.diyaudio.com/forums/digital-source/255887-shigaclone-mkii-black-builders-thread-115.html
Subbu DAC inside
http://www.diyaudio.com/forums/digital-source/255887-shigaclone-mkii-black-builders-thread-115.html
Subbu DAC inside
Hi,
I have a question regarding the TOSLINK and coaxial S/PDIF connections. Originally I planned to connect the two in parallel to the DAC to have a possibility to use optical or coaxial connection interchangeably. But now I wonder... is it a good idea to have them simultaneously attached to the DAC or I should use a switch and connect only one of the connectors to the DAC board at a time?
Thanks,
OlegSh
I have a question regarding the TOSLINK and coaxial S/PDIF connections. Originally I planned to connect the two in parallel to the DAC to have a possibility to use optical or coaxial connection interchangeably. But now I wonder... is it a good idea to have them simultaneously attached to the DAC or I should use a switch and connect only one of the connectors to the DAC board at a time?
Thanks,
OlegSh
I think I just destroyed my dac board! I was trying to clear solder bridges off of 9023 and adjoining pads. Turns out it was following traces to pads apparently and solder braid and heat took mask off on right side. I still have some of the same on the left and I don't want to go after. I am out of chipquick right now but I don't think news will be any better when I can get cleaned off. Are there ANY bare DAC boards still available anywhere???!!??? I am so PO'ed at myself right now> PLEASE HELP if you can. Thanks for any help!!
Steve
Steve
Hum when using TOSLINK
Hello,
My SUBBU DAC is finally playing music (see attached). I use the TOSLINK to connect it to my PC but I've got a problem with audible hum/noise. When source is muted the output is nearly silent but starts to hum as soon as the audio signal is present. The hum is not loud and I guess it is there due to the ground loop introduced via TOSLINK power GND which is common with the DAC power GND.
You may wonder why to use TOSLINK at all and have the trouble? The answer is simple - I have not a single source which has coaxial SPDIF output...
So could someone advise me how to solve the ground loop problem with a minimum effort? I already explored the possibility to use pulse transformer to isolate the TOSLINK module from the DAC risking to worsen the SQ... or install a separate set of rectifier+smoothing cap to power the TOSLINK. Actually I am not sure if the last option would provide enough isolation to break the ground loop either...
Any idea which helps to get rid of the ground loop but does not require using separate PSU is welcome!
OlegSh
Hello,
My SUBBU DAC is finally playing music (see attached). I use the TOSLINK to connect it to my PC but I've got a problem with audible hum/noise. When source is muted the output is nearly silent but starts to hum as soon as the audio signal is present. The hum is not loud and I guess it is there due to the ground loop introduced via TOSLINK power GND which is common with the DAC power GND.
You may wonder why to use TOSLINK at all and have the trouble? The answer is simple - I have not a single source which has coaxial SPDIF output...
So could someone advise me how to solve the ground loop problem with a minimum effort? I already explored the possibility to use pulse transformer to isolate the TOSLINK module from the DAC risking to worsen the SQ... or install a separate set of rectifier+smoothing cap to power the TOSLINK. Actually I am not sure if the last option would provide enough isolation to break the ground loop either...
Any idea which helps to get rid of the ground loop but does not require using separate PSU is welcome!
OlegSh
Attachments
OK, just tried powering the TOSLINK adapter with the battery, so no ground loop of any kind. The hum is still there. It has the form of digital packets interfering with the analog side. During the silent periods while playing music - almost no hum, but as long as the music comes out the hum rises to. So now I am really confused as to what can cause digital signal interference with the analog side?
My system is:
PC optical out ->TOSLINK adapter + SUBBU DAC -> MyRef Fremen Edition -> Zaph ZDT3.5.
The volume is controlled by the PC, so DAC to amp runs at full swing...
Any idea as to where to look for solution is welcome!
OlegSh
My system is:
PC optical out ->TOSLINK adapter + SUBBU DAC -> MyRef Fremen Edition -> Zaph ZDT3.5.
The volume is controlled by the PC, so DAC to amp runs at full swing...
Any idea as to where to look for solution is welcome!
OlegSh
Please disconnect the PE wire from the superfluous PCB in the middle and test if things are OK. Your case already has PE connected to it for safety.
If still not OK then please disconnect the blue wire from the Toslink PCB and test.
You are asking for real trouble.
If still not OK then please disconnect the blue wire from the Toslink PCB and test.
You are asking for real trouble.
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Hi Jean-Paul,
Thanks for the hints. I've tried it all already before posting here. That little superfluous PCB is the ground loop breaker. It has a 35 A capable bridge rectifier soldered underneath. It works as intended but even if disconnected makes no change to the hum.
May be it is SNR problem due to the low output volume from the PC? The hum level does not depend on the volume setting. It is either present together with the music playing or it is absent when there is no music but it does not attenuate with the volume setting...
So the problem is still there...
PS: and what is the problem running DAC to amp without a volume pot?
Thanks for the hints. I've tried it all already before posting here. That little superfluous PCB is the ground loop breaker. It has a 35 A capable bridge rectifier soldered underneath. It works as intended but even if disconnected makes no change to the hum.
May be it is SNR problem due to the low output volume from the PC? The hum level does not depend on the volume setting. It is either present together with the music playing or it is absent when there is no music but it does not attenuate with the volume setting...
So the problem is still there...
PS: and what is the problem running DAC to amp without a volume pot?
The ground loop breaker is normally used at the power amp. All connected devices can/must have their cases connected to PE but signal GND can be kept "lifted" from PE. I even keep signal GND of sources floating and never have ground loops but many will condemn this for some reason (while being fully legal here). Signal GND is connected to the power amp by means of the RCA connectors of all sources anyway. Maybe your power amp has a small GND loop problem that only turns up when driven "open" ? Try another power amp if you have an extra one.
Regarding the question: what will happen if, let's day, the + of the power supply wire comes loose of the DAC ? Or what if the DAC chip gets unreadable data ? Or what if the DAC breaks down and gives a last DC pulse to the amp ?
No volume control between pre- and power amp or DAC and power amp awakes the "woofer killer" in even the best DACs ! Plain and simple bad practice, many can testify that. After the first pair of burned woofers many change religion
Regarding the question: what will happen if, let's day, the + of the power supply wire comes loose of the DAC ? Or what if the DAC chip gets unreadable data ? Or what if the DAC breaks down and gives a last DC pulse to the amp ?
No volume control between pre- and power amp or DAC and power amp awakes the "woofer killer" in even the best DACs ! Plain and simple bad practice, many can testify that. After the first pair of burned woofers many change religion
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Thanks Jean-Paul! I'll examine the problem down the road... Will open the amp again but in principle the grounds of the left and right channels in my setup never meet again after they leave the DAC...
As a temporary volume attenuator I'll fit a 10k Alps pot that I have lying around while I'm finishing my R2R attenuator. I've already got a couple of "thunder strikes" through my speakers when muting/unmuting the sound in the PC... The speakers survived but it wasn't pleasant to my ears to say the least...
As a temporary volume attenuator I'll fit a 10k Alps pot that I have lying around while I'm finishing my R2R attenuator. I've already got a couple of "thunder strikes" through my speakers when muting/unmuting the sound in the PC... The speakers survived but it wasn't pleasant to my ears to say the least...
Hi all, I was wondering if anyone had ventured into doing a solder stencil for the subbu or if gerbers were even available, only need cream layer which shouldn't reveal any proprietary information. Thanks, I am starting my second board [killed the first one] and thinking of waiting for reflow oven I am constructing [uno/rocket scream].
Thanks,
Steve
Thanks,
Steve
