I have considered the Broskie Unbalancer as well. My problem is that I would like to keep the balanced outputs. It should work just fine with 1 board. You have an output Z of 134 ohms so no trouble driving a tube input. With more boards you do not get more output voltage, only more current. The existing voltage level is much higher than typical current drive on most DACs. With a gain of 10 in the tube output stage you will end up with maybe 6 volts rms output IIRC, which is plenty. Right now I am running SE into a 12au7/6DJ8 Aikido preamp. Transformers are a great solution for letting you use the balanced outputs and also be able to drive SE or balanced input stages. They also act as a LPFilter, block DC, have excellent CMMR and are simple to implement. Problems are expense and the need for more output boards or a buffer.
There are lots of output options baked into the DDDac recipe by Doede and we can all pick what we like best. It’s nice to hear what everyone is discovering about this versatile and great sounding DAC
There are lots of output options baked into the DDDac recipe by Doede and we can all pick what we like best. It’s nice to hear what everyone is discovering about this versatile and great sounding DAC
I am still optimising my 16 Dac boards DDDAC. I am running a 300VA transformer with 25 + 25 V secondaries which allows me to use a 2R2 resistor in the R1 position for extra smoothing.
I still want to run 16 Tent boards in the future so I am making sure I will have enough power to run them.
As the voltage and current is a lot higher than standard, I have made some PCB`s with wider tracks, hole centres for the MBR20200 changed to fit a DSA70C200 rectifier and changed the TIP122 holes for TIP142 which mounts underneath the PCB and onto the heatsink.
The R1, R2 and R6 holes moved and increased in size to take 1.4 mm wire for remote mounting.
C1 and C3 have centres for Mundorf 10000uF 63V capacitors. So now plenty of power available when I convince Doede to make me a main board with more buffers to supply the I2s to 16 Tent boards
I still want to run 16 Tent boards in the future so I am making sure I will have enough power to run them.
As the voltage and current is a lot higher than standard, I have made some PCB`s with wider tracks, hole centres for the MBR20200 changed to fit a DSA70C200 rectifier and changed the TIP122 holes for TIP142 which mounts underneath the PCB and onto the heatsink.
The R1, R2 and R6 holes moved and increased in size to take 1.4 mm wire for remote mounting.
C1 and C3 have centres for Mundorf 10000uF 63V capacitors. So now plenty of power available when I convince Doede to make me a main board with more buffers to supply the I2s to 16 Tent boards
Attachments
I am still optimising my 16 Dac boards DDDAC. I am running a 300VA transformer with 25 + 25 V secondaries which allows me to use a 2R2 resistor in the R1 position for extra smoothing.
I still want to run 16 Tent boards in the future so I am making sure I will have enough power to run them.
As the voltage and current is a lot higher than standard, I have made some PCB`s with wider tracks, hole centres for the MBR20200 changed to fit a DSA70C200 rectifier and changed the TIP122 holes for TIP142 which mounts underneath the PCB and onto the heatsink.
The R1, R2 and R6 holes moved and increased in size to take 1.4 mm wire for remote mounting.
C1 and C3 have centres for Mundorf 10000uF 63V capacitors. So now plenty of power available when I convince Doede to make me a main board with more buffers to supply the I2s to 16 Tent boards
How's the sound of 16 x DAC boards compared with 8x and 4x???
12V PSU heatsink for Darlington pair TIP 122
Hi there,
This may be helpful to those building 12V - PSU supplied by Audio Creative.
The heatsink that comes with the kit for TIP 122 is 50mm high there is a alternative heatsink that fits perfectly in PCB and is 63.5mm high, Model SK 129 63.5 (refer attachment)
Running 3-4 DAC boards with this larger heatsink makes TIP 122 run noticeably cooler.
The only disadvantage I can see to using this 63mm heatsink is the additional height as it may cause clearance issues with some enclosures.
Cheers Johno
Hi there,
This may be helpful to those building 12V - PSU supplied by Audio Creative.
The heatsink that comes with the kit for TIP 122 is 50mm high there is a alternative heatsink that fits perfectly in PCB and is 63.5mm high, Model SK 129 63.5 (refer attachment)
Running 3-4 DAC boards with this larger heatsink makes TIP 122 run noticeably cooler.
The only disadvantage I can see to using this 63mm heatsink is the additional height as it may cause clearance issues with some enclosures.
Cheers Johno
I have found that the more Dac boards used, the separation, depth and transient attack gets better.
Another mod to do on the main board, is to change the LF50 to a Micrel MIC29500 which has a 5A capacity and attach a small heatsink to it especially if you are using the Wave IO board.
It seems to cut down the bedding in time. I am used to waiting about 4 weeks for everything to settle down after doing any mods before its full potential is realised but I just tried it with the Micrel regulator and I had instant depth with the speakers disappearing as when fully bedded in.
If it improves even further, I will be very pleased with the results
Hi Johno,
Yes it could be a choke instead of the resistor. I am going to make a separate power supply so I can take the power supply out from the Dac case. I will have more room to try different value resistors and chokes without having to disable the Dac while I change things.
I will have the resistor/choke wiring points changed over to a plug/socket arrangement which will make swapping components a lot easier.
About output options, would this active I/V be a good idea for this DAC? I assume to remove output resistors and capacitor on mainboard.
Can use both rca and balanced out on this if I read correctly
The Legato Discrete Balanced I/V Stage
Can use both rca and balanced out on this if I read correctly
The Legato Discrete Balanced I/V Stage
I would say no, it defeats the concept of the passive I/V, which is totally linear and has no disadvantage over a complex piece of electronics doing basically the same
what do want to gain here ?
I like the sound of my Sowter I/V transformers and am just turned off by the thought of more active devices between dac chip and amp. I'm also not taken in by the latest "state of the art" opamps as high spec does not guarantee the best sound. They are the product of rivalry between the semiconductor manufacturers imho.
