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Cheers Russ,
I already have the b3, so I guess that id be better to get another b3 and fit all those fiddly jumpers.
What would you estimate the db voltage gain for a 0vdb signal when using the legato with dual mono dacs?
Brad
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ok.
I have just ordered 2 x B3SE modules.
plan to stack them underneath my Legato i/v to keep them away from the heat of the Legato. hopefully will be able to mod the outputs from each so that I can stack them in that way. If they are similar to the 8ch B3 I think I can see a way to do it.
Russ,
would be good to know what the output for a 0vdbs signal is in dual mono on the Legato.
cheers
Brad
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Originally Posted by: Russ White  I would use two B3SE or two B3 I would personally not mix them - though technically it would work fine.
Yes - you can use a single Legato - the standard values will work fine - but you will have higher than normal output. cheers Russ, The 2 x Buffalo SE Dacs arrived today. how much easier would my first Dac have been if the SE version was available - no more fiddly jumpers! I am going to place both of these Dacs underneath the Legato i/v, as I am pretty sure that the heat from the Legato resistors contributed to the early failure of the Paul Hynes regulators. In order to do this I am going to need to mod the output from the Dacs in order to get combined signal from each Dac pcb to the correct side of the Legato. I will add some additional header pins underneath the Legato and wire the 1st Dac so that its combined output is on the LHS Channel. The 2nd Dac will have its output on the RHS channel and will use the 1st Dacs redundant output pins, after they have been isolated, to feed the Legato RHS input. I have a couple of questions that will help me before I get the drill out.lol. 1. Are there any benefits in placing the Dacs so that the ground shield is nearest the Legato. At this stage I can chose which way round I set this up. 2. I will probably need to drill some extra holes and alter the traces in the area that I have highlighted in the attached picture. I know that one side of the PCB has the gnd shield and I can see the power supply traces. As this is a 4 layer pcb, I need to know of there are any other traces that are hidden in the area I have highlighted. this is where I may want to drill in order to place some vias to connect up the DAC outputs and also to place some header pins ect. cheers Brad gl51otk attached the following image(s):  WP_20141125_003.jpg (87kb) downloaded 6 time(s).You cannot view/download attachments. Try to login or register.
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1) The bottom plane on the DAC is not the Ground plane. It is VDD... so, no.
2) You should not have to drill any holes, and I would strongly suggest you avoid doing so.
I will post a few pictures in a few minutes with some easier solutions...
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So, here is how I would mount two Buffalo under a single Legato... 1) Mount the AVCC under the DAC, direct soldering it (see last pic below). That will keep it out of the way, and heat should not be an issue. 2) Mount the female header from the stacking kit to the bottom of the Legato.  3) When you mount the Buffalo to the outside, the output holes are slightly off from the Legato input holes (non-standard mounting arrangement). Make some gently bends in the male stacking connector, to adjust for the offset between the Buffalo output holes.  From here, you should be able to stack the two boards together, and be able to remove the Legato easily for DAC access if needed.  4) You need to tie the left and right outputs of the DAC together. For this, I would run a 3-wire from the open side to a 3-position connector and slide it on to the bottom pins of the stacking connector. In this picture, I used two connectors, but you could solder one or both sides if you want.  5) Repeat on the other side and you should be good to go. That said, if it were me, I would mount the DACs on top, as it leaves more room for AVCC and Tridents. I have not seen a DAC fail from Legato heat before. Edited by user Tuesday, November 25, 2014 9:36:29 PM(UTC)
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Rank: Member
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Joined: 10/19/2014(UTC) Posts: 18 Location: Kent Thanks: 2 times
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cheers Brian,
that is really helpful.
Only problem for me is that I don't easily have the space in my case now everything else is installed.
I also have Paul Hynes regulators, which take up more room than the Tridents.
I will have to have a think about this, but may end up with a Dac on top and one underneath. I wont drill the Dacs!
Out of interest, would it be better to use the Minishark to process and send the I2s for the left and right channels to each DAC? I know that I would need different DAC settings, but I can even set the Minishark up to invert the output on each channel.
Brad
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