Hello,
Like Doede answered a few weeks ago if something like this happens and you dont understand how it works just replace the 4 transistors( Doede told me that the one mounted on the heatsink can take some abuse) and i would replace the two leds as well. IF you did not reverse the polarity of the power supply and if you did not use to the caps with to much voltage the caps probably will be ok.
In the attachment you can see the power supply using choke input and a special edition of Doede's power supply to feed Andrea's clock circuit with Eaton ultracap after preloading it with a Chinese charger. As you can see i pay more attention to the choke than to the power transformer..
The voltage shown as the input voltage for Doede's circuit which will give 15,7 volts to the ultracap.
Greetings, eduard
Like Doede answered a few weeks ago if something like this happens and you dont understand how it works just replace the 4 transistors( Doede told me that the one mounted on the heatsink can take some abuse) and i would replace the two leds as well. IF you did not reverse the polarity of the power supply and if you did not use to the caps with to much voltage the caps probably will be ok.
In the attachment you can see the power supply using choke input and a special edition of Doede's power supply to feed Andrea's clock circuit with Eaton ultracap after preloading it with a Chinese charger. As you can see i pay more attention to the choke than to the power transformer..
The voltage shown as the input voltage for Doede's circuit which will give 15,7 volts to the ultracap.
Greetings, eduard
Attachments
Start measuring all voltages according to the circuit which is posted on my website and see where things go wrong@doede... Merry Christmas and happy new year
A few month ago I tried to "upgrade" my primary DDDac 12V standard PSU with a choke (15mH )and a larger C3 (22.000uF). Something went wrong and I measured a strange voltage...See post 8898-8901.
Removing the non-standard components in an attempt to start all over resulted in approximately 19.1V and little change when using the 10K trimmer. Also the green LED closest to the BC560C doesn't light up. This is now an all standard DDDac PSU...
I had to put the project aside for a while because of life's other obligations (and installing a new kitchen) ;-)
I would however now like to fix my primary DDDac and I have replaced the 2 BC550C, the BC560C and the 10K trimmer... Still no change. Measuring around 19.1V DC with little trimmer change.
Do you have any idea what could be wrong here?
Greetings and thank you
Hello,
Doede's main goal is to share his ideas and convince us it is a good idea to use them lol.
That is why he makes things in a clever way so they can be used in a few ways to suit many people which all have their own '' set of goals ''
No need to get the latest '' improved '' print every 6 months which will require to change associated prints as well to have optimum results.
Audio is not that much different from mobile phone marketing strategies. Your new phone wont fit in the old protection cover, the old charger wont work and your banking app requires a new phone as well.
Greetings, eduard
Doede's main goal is to share his ideas and convince us it is a good idea to use them lol.
That is why he makes things in a clever way so they can be used in a few ways to suit many people which all have their own '' set of goals ''
No need to get the latest '' improved '' print every 6 months which will require to change associated prints as well to have optimum results.
Audio is not that much different from mobile phone marketing strategies. Your new phone wont fit in the old protection cover, the old charger wont work and your banking app requires a new phone as well.
Greetings, eduard
@Doede and Eduard.
Thank you for helping me troubleshoot the PSU-problem. I started to measure voltage at different points and noticed some strange fluctuations around the LED which didn't light up. Desoldering this LED revealed that the solder island had lifted which were invisible to the eye before the desoldering. The LED was fine and I put it back and made a patch. Now it works as it should and I then reattached the 15mH Choke + 1.3Ohm resistor as well as the 22.000uF C3 capacitor. All is fine and sounds amazing
Thank you for helping me troubleshoot the PSU-problem. I started to measure voltage at different points and noticed some strange fluctuations around the LED which didn't light up. Desoldering this LED revealed that the solder island had lifted which were invisible to the eye before the desoldering. The LED was fine and I put it back and made a patch. Now it works as it should and I then reattached the 15mH Choke + 1.3Ohm resistor as well as the 22.000uF C3 capacitor. All is fine and sounds amazing
Wow, that was a very nasty issue…. Hard to find, but with deduction and some patience you always will find out, like you did very well.@Doede and Eduard.
Thank you for helping me troubleshoot the PSU-problem. I started to measure voltage at different points and noticed some strange fluctuations around the LED which didn't light up. Desoldering this LED revealed that the solder island had lifted which were invisible to the eye before the desoldering. The LED was fine and I put it back and made a patch. Now it works as it should and I then reattached the 15mH Choke + 1.3Ohm resistor as well as the 22.000uF C3 capacitor. All is fine and sounds amazing
good to hear all is fine now and you like the tweak !
enjoy your DAC and the music …
Thanks Doede
Yeah it was a little strange since I haven't touched the green LED's since i first soldered the PSU many years ago. I must have physically pressed on one of them during the Choke-mod... I guess.
Just to be clear... I didn't claim to be able to remember the differences between PSU with the Choke-mod and without it. The DAC was under repair for at least two month so absolutely no ABX-tests here... It did however still sound amazing
I'm somewhat skeptical when people claim big improvements without being able to go back and forth when doing a modification. That's one of the reasons I have installed a stack of Relay-boards in my DDDac, inspired by yourself, so I can shift between 4 different i2s inputs. I have planned a series of ABX-tests on different streamer configurations in the future.
Yeah it was a little strange since I haven't touched the green LED's since i first soldered the PSU many years ago. I must have physically pressed on one of them during the Choke-mod... I guess.
Just to be clear... I didn't claim to be able to remember the differences between PSU with the Choke-mod and without it. The DAC was under repair for at least two month so absolutely no ABX-tests here... It did however still sound amazing
I'm somewhat skeptical when people claim big improvements without being able to go back and forth when doing a modification. That's one of the reasons I have installed a stack of Relay-boards in my DDDac, inspired by yourself, so I can shift between 4 different i2s inputs. I have planned a series of ABX-tests on different streamer configurations in the future.
Hello,
Sometimes it takes just a little force to cause a problem like this. Even applying to much heat during soldering can be the start of such a problem.
Desoldering got me into trouble sometimes . Getting a clear hole to pass the replacement part can be a problem.
Usually applying a choke with enough mH will improve things. Getting more than 15 mH to get higher DCR and omitting the serie resistor is as good thing of course.
The '' state of the art '' Audio creative is selling for the DDDAC also incorporates a choke.
MY idea is that choke input takes things even further.
Greetings,Eduard
Sometimes it takes just a little force to cause a problem like this. Even applying to much heat during soldering can be the start of such a problem.
Desoldering got me into trouble sometimes . Getting a clear hole to pass the replacement part can be a problem.
Usually applying a choke with enough mH will improve things. Getting more than 15 mH to get higher DCR and omitting the serie resistor is as good thing of course.
The '' state of the art '' Audio creative is selling for the DDDAC also incorporates a choke.
MY idea is that choke input takes things even further.
Greetings,Eduard
Attachments
Hi Doede,
Does the BB1794 used in your NOS mode still use the delta sigma part of the chip? Genuine question as I've never seen your NOS DAC described as 'Delta Sigma'?
Thanks
Hi Juancho,
Sure this is indeed intriguing and is described on my DDDAC website. So yes, the DS modulator still does the conversion work. But in the DDDAC implementation of the PCM1794 there is no digital filtering and no oversampling going on (hence the NOS). The signal output show exactly the same shape as a R2R DAC in NOS mode (like square waves etc, no ringing etc). Hope that clarified?
When working on gear that comes "before the power amp" I make a recording of the same track with the same gear after every change. Going through that library compairing the "improvements" can be quite funny.
Hi Doede thanks for that clarification. Yes, the results both in sound and measurements speak for themselves!
David