Hi Guys,
I've got some PCBs that may be of interest to you.
(Featured without volume pot and output buffer.)
A lot of pages back, I posted my results from replacing the standard op-amp output of the Mini2496 with a super-balanced output stage, as originally published by Dave Brit of the BBC. There is a clear reduction in distortion and common-mode noise from the Mini2496.
For those that don't know, the super-balanced stage provides exactly the same impedances to each phase of the differential signal, allowing the DAC to operate ideally and providing far superior cancellation of any common-mode (same on both signal phases) noise and distortion than any design that uses a single op-amp to load the DAC.
The PCB features a super-balanced input stage to load the DAC, followed by a volume pot and single op-amp output buffer. The volume pot and output buffer are optional, you can just take the signal from the output of the super-bal stage. The PCB is star-grounded, has RF filtering on the input and DC blocking caps on the output. It is designed to operate around any NE5532 pin compatible op-amps. Best to use high tolerance resistors, 0.1%.
I actually had the PCBs made for another project but stupidly didn't think about the physical size of them not fitting in the space available, doh! So, I'm happy to sell these at a loss, only £2 each PCB + P&P. I'm in London, UK. Please contact me if you want one. Simon
I've got some PCBs that may be of interest to you.
(Featured without volume pot and output buffer.)
A lot of pages back, I posted my results from replacing the standard op-amp output of the Mini2496 with a super-balanced output stage, as originally published by Dave Brit of the BBC. There is a clear reduction in distortion and common-mode noise from the Mini2496.
For those that don't know, the super-balanced stage provides exactly the same impedances to each phase of the differential signal, allowing the DAC to operate ideally and providing far superior cancellation of any common-mode (same on both signal phases) noise and distortion than any design that uses a single op-amp to load the DAC.
The PCB features a super-balanced input stage to load the DAC, followed by a volume pot and single op-amp output buffer. The volume pot and output buffer are optional, you can just take the signal from the output of the super-bal stage. The PCB is star-grounded, has RF filtering on the input and DC blocking caps on the output. It is designed to operate around any NE5532 pin compatible op-amps. Best to use high tolerance resistors, 0.1%.
I actually had the PCBs made for another project but stupidly didn't think about the physical size of them not fitting in the space available, doh! So, I'm happy to sell these at a loss, only £2 each PCB + P&P. I'm in London, UK. Please contact me if you want one. Simon
Last edited:
Hi,
I found the image with the results of a simple super-bal circuit on a bread board. Don't take the results as absolute. The PCB should work better than the bread board example.
Green is standard Mini2496 output, Red is super-bal.
Recorded into my M-Audio soundcard. The high 50Hz products are from a slight ground loop between soundcard and Mini2496.
You can see all the noise higher in the range is much reduced, due to superior common-mode rejection.
I found the image with the results of a simple super-bal circuit on a bread board. Don't take the results as absolute. The PCB should work better than the bread board example.
Green is standard Mini2496 output, Red is super-bal.
Recorded into my M-Audio soundcard. The high 50Hz products are from a slight ground loop between soundcard and Mini2496.
You can see all the noise higher in the range is much reduced, due to superior common-mode rejection.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
I ordered 5 kits from along1986090 on ebay. On all 5 kits, a 3K resistor was missing.
After mentioning that to the seller, and telling him that I will get the resistors locally, he refunded me the 1 euro for the 5 resistors. And that happened within 40 minutes after I sent him the e-mail.
That is perfect!
Haik
After mentioning that to the seller, and telling him that I will get the resistors locally, he refunded me the 1 euro for the 5 resistors. And that happened within 40 minutes after I sent him the e-mail.
That is perfect!
Haik
CS4398 Option
I see that there seems to be some CS4398 options available: CS8416 + CS4398 DAC Board Kit Support USB Coaxial Assembled | eBay
How might this compare to the AK4396?
The boards look very similar so presume most if not all of the considered upgrades on this thread remain valid.
Or would I be better off buying the oder AK4396?
I see that there seems to be some CS4398 options available: CS8416 + CS4398 DAC Board Kit Support USB Coaxial Assembled | eBay
How might this compare to the AK4396?
The boards look very similar so presume most if not all of the considered upgrades on this thread remain valid.
Or would I be better off buying the oder AK4396?
There is a separate thread for this DAC here:
http://www.diyaudio.com/forums/digital-line-level/211321-dac-cs4398-cs8416-cm102s.html
Not very active, however these two DAC boards are almost identical...
IMHO;
CS4398 sounds excellent with a pair of good output transformers... But PSU, output stage and SPDIF source will have the biggest effect on the sound - so you can't go wrong with either dac chip...
However, I found out that CS4398 is the best when driving low impedance headphones with transformers on the output (no headamp) - it gives the highest voltage output and the best sound, AK4396 gives a little distorted sound at higher volume levels and WM8741 crackles with this setup - of course DAC chips aren't made to be connected this way, but I like the sound of it
So far I've built two DAC's based on CS4398, both with transformers on the outout (UTC-A20 and Tamura TDP-1W) and the third one is on the way;
- this one will have ultra low noise PSU, shunt pre-regulators and Tamura TFP-3W on the output
http://www.diyaudio.com/forums/digital-line-level/211321-dac-cs4398-cs8416-cm102s.html
Not very active, however these two DAC boards are almost identical...
IMHO;
CS4398 sounds excellent with a pair of good output transformers... But PSU, output stage and SPDIF source will have the biggest effect on the sound - so you can't go wrong with either dac chip...
However, I found out that CS4398 is the best when driving low impedance headphones with transformers on the output (no headamp) - it gives the highest voltage output and the best sound, AK4396 gives a little distorted sound at higher volume levels and WM8741 crackles with this setup - of course DAC chips aren't made to be connected this way, but I like the sound of it
So far I've built two DAC's based on CS4398, both with transformers on the outout (UTC-A20 and Tamura TDP-1W) and the third one is on the way;
An externally hosted image should be here but it was not working when we last tested it.
- this one will have ultra low noise PSU, shunt pre-regulators and Tamura TFP-3W on the output
There is a separate thread for this DAC here:
http://www.diyaudio.com/forums/digital-line-level/211321-dac-cs4398-cs8416-cm102s.html
Not very active, however these two DAC boards are almost identical...
IMHO;
CS4398 sounds excellent with a pair of good output transformers... But PSU, output stage and SPDIF source will have the biggest effect on the sound - so you can't go wrong with either dac chip...
However, I found out that CS4398 is the best when driving low impedance headphones with transformers on the output (no headamp) - it gives the highest voltage output and the best sound, AK4396 gives a little distorted sound at higher volume levels and WM8741 crackles with this setup - of course DAC chips aren't made to be connected this way, but I like the sound of it
So far I've built two DAC's based on CS4398, both with transformers on the outout (UTC-A20 and Tamura TDP-1W) and the third one is on the way;
An externally hosted image should be here but it was not working when we last tested it.
- this one will have ultra low noise PSU, shunt pre-regulators and Tamura TFP-3W on the output
Hello
Where to find the Tamura TFP-3W transformers ?
Thanks
Serge
Unfortunately almost nowhere...
Keep an eye on ebay, once in a while you can get some "egzotic" transformers for little money... - UTC, Tamura, Lundahl, Peerless, Jensen... Just check the datasheet first...
Also, there is a lot of info on transformers in this thread;
http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac-403.html
Tamura transformers on e-bay. Not cheap:
2 X TAMURA TFP-3W 200 OR 600 OHM CT : 600 OHM CT 30Hz TO 20KHz AUDIO TRANSFORMER | eBay
The auction has ended, but maybe you can ask the seller, he might have more.
2 X TAMURA TFP-3W 200 OR 600 OHM CT : 600 OHM CT 30Hz TO 20KHz AUDIO TRANSFORMER | eBay
The auction has ended, but maybe you can ask the seller, he might have more.
So, I was intrigue with this DAC and decided to give it a try.
I bought one fully populated board and one bare board with SMD chips only.
Since I don't have any source with spdif output, therefore I need to get a USB to SPDIF converter.
Spent a couple of hours last night to assemble a quick and dirty one and got it working the first time (thanks to countless hours spent on this thread)
The USB input is connected to my laptop, running JRiver.
So far the sound is not too bad, considering the cost.
Now I will start the journey by changing parts one by one as defined in this thread and hopefully learn the sound differences on each change made. Hopefully my old and rusty ears still can still pick them up.
The plan for bare board with SMD chips is to build one like sterlingmck and experiment with different output buffers and converters.
Thanks guys for introducing me to another exciting thing to try in life.
I bought one fully populated board and one bare board with SMD chips only.
Since I don't have any source with spdif output, therefore I need to get a USB to SPDIF converter.
Spent a couple of hours last night to assemble a quick and dirty one and got it working the first time (thanks to countless hours spent on this thread)
The USB input is connected to my laptop, running JRiver.
So far the sound is not too bad, considering the cost.
Now I will start the journey by changing parts one by one as defined in this thread and hopefully learn the sound differences on each change made. Hopefully my old and rusty ears still can still pick them up.
The plan for bare board with SMD chips is to build one like sterlingmck and experiment with different output buffers and converters.
Thanks guys for introducing me to another exciting thing to try in life.
