Well, I guess that's technically possible. But why? Sounds rather complicated, if you ask me. Note that you would need a separate transformer winding for each resistor pair / DAC board...
I didn't mean to use them like that, just to test individual DAC chips. If one has too much DC offset I will replace it, I have a couple more DAC chips in reserve. When the four boards are coupled I don’t know which one makes the DC offset. Maybe all, maybe just one, I don't know until I measure each one individually.
Some time ago Doede wrote about an explosion of PCM1794 ICs without connections. I never experienced this on breadboards by myself, but I think it's better to at least connect all digital inputs to the PCB ground than leave them floating if you want to power on the board separately. In any case, offset depends on RLoad resistors precision (difference between two resistors in pair). With 0.01% precision RLoad resistors I seen significant offset only with destroyed DAC IC.
Thanks @ykhalamov. Clearly, if there is a large offset, some of the PCM1794 chips must be faulty. A friend asked me for advice, DAC with 4 boards, one channel has 2.70V and 2.70V at the output, the other 2.30V and 2.77V. The DAC sounds completely normal, only one channel is a little weaker, so it is certain that something is wrong. So I asked if I could try one DAC board at a time to detect the problem, if I take that DAC to fix it.
I would certainly not like to do irreparable damage, but to detect the problem and solve it if possible.
I would certainly not like to do irreparable damage, but to detect the problem and solve it if possible.
yes, one dac is not supplying current.... but, I have seen a few of those errors and in 9/10cases it was a cold solder joint...
re-soldering the connections between boards could help
It has been some time since I have been using the Cinemag 15/15B trafos and now have totally forgotten what was the value of the output capacitors that would be fit to drive a 4 board version? Is there more than 1 value of capacitance that can be used? Please if someone can remind this forgetful soul that.... Thanks.
Just to mention something, for all those interested, I can't recommend ISKRA transformers. Everything is good except the high frequencies, there is a lot of rounding. On an oscilloscope, for a square input the output is a sine (the function generator is 50 ohms output impedance). That rounding is not good, fine details are lost. If I could only combine the beautiful detail of a capacitor with the energetic bass of a transformer it would be phenomenal, but unfortunately unfeasible.
I haven't tried cross-linking the primary and secondary windings yet on ISKRA, because I was having fun with some other things. It may turn out that they have a slightly better sound with a different way of connecting coils. Next week I will get a few more transformers, DIY and factory made, so testing continues. Maybe somewhere there is a good and cheap transformer, although I doubt it more and more.
I haven't tried cross-linking the primary and secondary windings yet on ISKRA, because I was having fun with some other things. It may turn out that they have a slightly better sound with a different way of connecting coils. Next week I will get a few more transformers, DIY and factory made, so testing continues. Maybe somewhere there is a good and cheap transformer, although I doubt it more and more.
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Hello,
Maybe somewhere there is a good and cheap transformer, although I doubt it more and more.
Unless you come across some vintage cost no object gear cheap or even moderately priced signal transformers will degrade your DDDAC. All parts together the DDDAC gives splendid results for the money but only if you are willing to spend the right amount of money in the right places. Of course the transformers you use must fit the technical specs needed.
It looks like the transformer just introduced on the audio creative side gives a nice return on investment. It is designed to be used with the DDDAC so that is already a good starting point.
Greetings, Eduard
P.s Sowter has been bought by a bigger company so it might be possible that the ones designed by Doede with the help of Sowter will follow the dodo
Maybe somewhere there is a good and cheap transformer, although I doubt it more and more.
Unless you come across some vintage cost no object gear cheap or even moderately priced signal transformers will degrade your DDDAC. All parts together the DDDAC gives splendid results for the money but only if you are willing to spend the right amount of money in the right places. Of course the transformers you use must fit the technical specs needed.
It looks like the transformer just introduced on the audio creative side gives a nice return on investment. It is designed to be used with the DDDAC so that is already a good starting point.
Greetings, Eduard
P.s Sowter has been bought by a bigger company so it might be possible that the ones designed by Doede with the help of Sowter will follow the dodo
Hi Eduard,
yes, I already bought the good old Sowters from the new company. Production and design is exactly 1:1 from the old Sowter transformers. In fact they just bought the whole bunch, so there is only a change for me in terms of people I speak to and the bank account I pay my money to
yes, I already bought the good old Sowters from the new company. Production and design is exactly 1:1 from the old Sowter transformers. In fact they just bought the whole bunch, so there is only a change for me in terms of people I speak to and the bank account I pay my money to
Hello Doede,
I read people telling here that the quality level went down after the change of power probably not true.
I think once the engineering is done a new series is not that difficult to do.
So happy that more people will be able to get them.
But now the new black seems to be the supercaps. I already shared some info you gave to me with Andrea Mori in another thread.
Greetings, eduard
I read people telling here that the quality level went down after the change of power probably not true.
I think once the engineering is done a new series is not that difficult to do.
So happy that more people will be able to get them.
But now the new black seems to be the supercaps. I already shared some info you gave to me with Andrea Mori in another thread.
Greetings, eduard
And so it was, one badly soldered joint, I quickly found it and fixed it. That's why I don't like Lead-free solder wire. As far as I saw that joint is connected to pin 26 on PCM1794A (IoutL-).
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Hello,
Using solder with some lead content is almost mandatory if you are doing diy with not the highest level of equipment. I mean not 100% clean surfaces, not the right solder tip, not the right temperature, not the right technique and not having good access to the area.
If you have done just a single mod which needed only a few new joints THAN you can track it down by just reheating and adding a bit of solder to the joints BUT when you just soldered a 4 board DDDAC and your name is not Doede you can easily eat a few days of your life expectancy. At least i do!.
Greetings, Eduard.
P.s NOW we are waiting for the next leap in quality that will come with the use of supercaps.
Before i visited Indonesia i bought the book Islam for dummies. Right now using Aurender into wave io plus DDDDAC. I need a book going from Aurender to Roon Nucleus for dummies. There is so much associated gear and contradictory opinions. There should be something similar to online tax form as a guide. Now people need to source things all over the earth. And still get something that is not 100% optimum
Using solder with some lead content is almost mandatory if you are doing diy with not the highest level of equipment. I mean not 100% clean surfaces, not the right solder tip, not the right temperature, not the right technique and not having good access to the area.
If you have done just a single mod which needed only a few new joints THAN you can track it down by just reheating and adding a bit of solder to the joints BUT when you just soldered a 4 board DDDAC and your name is not Doede you can easily eat a few days of your life expectancy. At least i do!.
Greetings, Eduard.
P.s NOW we are waiting for the next leap in quality that will come with the use of supercaps.
Before i visited Indonesia i bought the book Islam for dummies. Right now using Aurender into wave io plus DDDDAC. I need a book going from Aurender to Roon Nucleus for dummies. There is so much associated gear and contradictory opinions. There should be something similar to online tax form as a guide. Now people need to source things all over the earth. And still get something that is not 100% optimum
Great it works again
My experience is, that 70% of faulty DACs is soldering, 29,9 % Reversed power attached and 0,1% is really component failure by it self.... (you cannot 100% exclude a possible error from that
uhm, yes.... that was the reason in the first place to make the "new" board with the embedded shunt....
The 8Volt does the most. The 3,3 V is clearly less (till a point you could say, it is not worth the investment - but that is a very personal decision)
.
There is a good lead free option called Kester K100LD. It has similar properties as lead solder. Read more in the this thread:
The way forward (Soldering).
The way forward (Soldering).
One question for Doede:
When I add an output transformer, its winding resistance is connected in parallel with the U/I resistors on the motherboard (34ohm in my DAC). As a result, the DC output voltage drops from 2.7-2.8V to a lower value. Is it necessary to correct the value of the resistor on the motherboard to keep 2.7-2.8V DC at the DDDAC output?
When I add an output transformer, its winding resistance is connected in parallel with the U/I resistors on the motherboard (34ohm in my DAC). As a result, the DC output voltage drops from 2.7-2.8V to a lower value. Is it necessary to correct the value of the resistor on the motherboard to keep 2.7-2.8V DC at the DDDAC output?
Thank you for your respone. Is there any audible difference between tent and salas shunt on 8v?