Build Thread for TPA BIII + Ian Async I2S FIFO + OPC NTD1 + Salas SSLV

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Thank you for a very interesting and informative thread. I am part way through reading it as I am about to change my buffalo IV stage and add Ian's FIFO stage to it.

I've come across mention of the NTD1 but having searched there seem to be a few threads dedicated to this and I can't work out which is the definitive read. Can anyone send me some links to the most up to date info and the GB?
Thank you,
Crom

please note that the 400ohm 15w resister in the bom TN15P400RFE Ohmite | Mouser
Dont have a mounting hole, which becomes a PITA to get a good contact with the heatsink.
Dont fail into the same pit fall I got into.
 
Hmmm, thanks for the help McLuxun. Do you have a suggestion about how to approach this? I love the copper by the way - it looks like a good idea as long as it'll take the heat!!

please note that the 400ohm 15w resister in the bom TN15P400RFE Ohmite | Mouser
Dont have a mounting hole, which becomes a PITA to get a good contact with the heatsink.
Dont fail into the same pit fall I got into.
 
Having done a lot of reading and spent a bit of time untangling the various threads I've put together a list of useful links. I think I’ve got this right but please let me know if different!

Hopefully these links will be useful to people just arriving at this great looking project.

Development Thread: http://www.diyaudio.com/forums/digital-line-level/154866-new-take-classic-pass-labs-d1-ess-dac.html
Build thread: http://www.diyaudio.com/forums/digi...ad-new-take-classic-pass-labs-d1-ess-dac.html
Vendor’s thread: http://www.diyaudio.com/forums/vend...jects-available-here-bal-bal-se-se-lpuhp.html
bigpandahk’s build thread (great build pictures from page 47 onwards): http://www.diyaudio.com/forums/digi...i-ian-async-i2s-fifo-opc-ntd1-salas-sslv.html

The GB sign up spreadsheet is here: https://docs.google.com/spreadsheet/...Xc&usp=sharing

Latest official schematic and BOM: http://www.diyaudio.com/forums/digi...ssic-pass-labs-d1-ess-dac-37.html#post2319922
 
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Hmmm, thanks for the help McLuxun. Do you have a suggestion about how to approach this? I love the copper by the way - it looks like a good idea as long as it'll take the heat!!
hey crom
As I measured the height of the mosfet is thickest among them, so I made sure they have good contact with the plate.
And pad the others to the same height.
Back in the days there were a GB on parts where they got to220 size resistors from texas component which was rated 8w instead 15w in the bom.
It seemed working, you might want to try that as well.
 
11216950216_0f6edfb74a_c.jpg

Need some advice on floor planning.
basic needs:
separation of ps and others
weight balancing
shortest route for i2s
Any advice?
 
I'm only learning so this needs validating but here are some things that I'd do:

- keep AC away from DC,
- only cross cables at right angles (if you have to)
- You can stack toroids on top of each other if you want. You're right about the weight distribution being a problem. In one box I put transformers underneath everything and put aluminium and steel between that 'compartment' and the one above where all the pubs went.
- keep the regulators as close to the circuit you are powering ie leads short.
- twist all AC cables together, and many argue DC too...something to do with inductance if I remember correctly.
- the dac chips don't like excessive heat.

My dac build is getting so big that I am going to use 2 boxes. All the transformers, rectification and reservoir caps in one box and then regs and actual dac stuff in the other. Alternatively, you can use copper or other metal (although I never got to the bottom of which was best) to divide the box up. Keep the transformers separate, the AC out the way and then surround the pcbs with power supplies. I was also considering mounting the ntd1 upside down to get the Heat out of the top of the box. This would mean that (in the case I'm thinking about) I could put the fifo, waveio and associated digital stuff underneath the ntd1 to keep digital connections as short as possible.

There's loads of other stuff to experiment with. The lampizator guys swear by mounting their dac boards onto chunks of wood, you should definitely do this for the transformers (make sure that the mounting screws don't just go straight through wood if possible because you are trying to stop vibrations travelling from transformer to chassis). I haven't tried it with a dac board and some of their comments are ridiculed here...but then their dacs sound pretty good so I'm of the opinion that I should try before I dismiss.

Hmmm bit of a stream of consciousness that...Hope this helps,
Crom
 
Don't know why you want weight balancing.

Your heatsink is too small for the NTD1. you better test it before put it into the casing.

You may following Ian's arrangement, stack the clock board on the FIFO with the SPDIF board next to the FIFO. This will provide you the shortest I2S route.

For PS, you need to separate the transformers only, not the regulators. The two SSLV also generate lot of heat, need a large heatsink.
 
Don't know why you want weight balancing.

It's icing on the cake stuff...I'd prefer to have evenly distributed weight if I can achieve it. It's not critical though.

Your heatsink is too small for the NTD1. you better test it before put it into the casing.

You're absolutely right. I looked into a heatsink. Qusp recommended a good one but it's half way around the world so I looked into others. I came up with this:

HAM-F10T TDK-Lambda | Mouser

The Thermal resistance figure is missing from the product data (believe it or not) but an estimation using some learning from this page HEATSINKS by SM0VPO indicates that it will be big enough if combined with a metal case.

For PS, you need to separate the transformers only, not the regulators. The two SSLV also generate lot of heat, need a large heatsink.

Definitely don't separate the regulators from the load - they should be as close as possible to the circuit you're powering. However, the best solution would appear to be separating the transformers, rectification circuit and the reservoir caps. More info here: http://www.diyaudio.com/forums/powe...e-best-divide-power-supply-between-boxes.html

Hope this helps,
Crom
 
It's icing on the cake stuff...I'd prefer to have evenly distributed weight if I can achieve it. It's not critical though.



You're absolutely right. I looked into a heatsink. Qusp recommended a good one but it's half way around the world so I looked into others. I came up with this:

HAM-F10T TDK-Lambda | Mouser

The Thermal resistance figure is missing from the product data (believe it or not) but an estimation using some learning from this page HEATSINKS by SM0VPO indicates that it will be big enough if combined with a metal case.



Definitely don't separate the regulators from the load - they should be as close as possible to the circuit you're powering. However, the best solution would appear to be separating the transformers, rectification circuit and the reservoir caps. More info here: http://www.diyaudio.com/forums/powe...e-best-divide-power-supply-between-boxes.html

Hope this helps,
Crom

my heatsink is bought from ebay 2X New Large Rectangle Aluminum Heatsink w Screw Mount DIY Power Amplifier LED | eBay
Dimension: 105mm (4.1") X 135mm (5.3") X 33.5mm (1.3"), base thickness 7.85mm (0.31")
I used two together for ntd d1. I will try to connect them to the chassis as well.
For your heatsink, make sure the base is thick enough to drill mounting holes and tap them.

Im still waiting for some L shaped aluminum angel to mount the sslv on to the case.

For the case, I ordered a 2u rack mount with 20 inch depth, should be enough to separate parts out.
 
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Nice, are you going to leave the copper plate or use it as well?

Still debating it.
But I make sure I can go with or without.
Most cpu heatsinks Ive seen use a combination of copper and alu.
For two box solution, what will you go for dc cord.
When I did my homework it looks like if I want one cord for all a decent set of connectors and pins all together will get to about 80 dollars.
Considering there are give or take 14 pins.
 
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New Dual Mono Build

Ok guys, thanks to Owen for designing this and to bigpandhahk for selling me his spare kit...we're off!

Seeing as this is a dual mono build I need to work out how to mount the DAC boards so that the signal path is as short as possible. This is the best I've come up with so far - no actual DAC board present as I'm listening to it!

An externally hosted image should be here but it was not working when we last tested it.


The idea is to mount the dac boards with the regulators facing outwards. The signal connectors will be mounted onto the bottom of the DAC boards and I'll need to create some custom cables to connect into the PCB.

Now the heatsink. The big question in my mind is whether I can mount the heatsink length-ways like this:

An externally hosted image should be here but it was not working when we last tested it.


The advantage of doing it this way is the PCB is securely mounted to the PCB with no overhang. However, this does mean that all the heat will be up one end of the heatsink. Anyone have any comment about whether this will be a problem?

If it is then I can mount the PCB width-ways like this:
An externally hosted image should be here but it was not working when we last tested it.


This will centre the heat generation on the heatsink but will mean that the PCB is overhanging (the PSUs are the heaviest part and I'd rather they were mounted to something!)

Hmmm...decisions!
 
That's a good idea as it will allow me to change the power supply with little interference to the main PCB. I haven't decided whether to put the power supplies into the main DAC box or into the separate. I want the regulator to load lines as short as possible but I also want to avoid AC in the main box. Seeing as most of the PCBs I'm using have the rectification on the boards that's going to make keeping the AC out quite tricky so my current thinking is to have the high voltage AC in the separate case along with the transformers and then run the individual low voltage AC feeds into the DAC box and shield them (or maybe twisting the cables will be enough, or running them around the corners of the case ).
 
This is a bit frustrating.
I got my case from ebay alltronics.
They shipped the wrong case for the first time.
When I got the right one I realized the bottom piece is too soft to carry the weight.
I was thinking about getting a 1/8 inch alu sheet to mount everything on it.
And then mount the sheet on the case and drill holes through the sheet for feet.
btw how's my layout looking(Never integrated something this big before).
 

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mcluxun

The heatsink for the two SSLV seems too small, you better test them with a dummy load see if the heatsink is large enough. Facing the heatsink of NTD1 upside down is not good (same as mine:(), but at least you have to put it outside your casing. It generates lot of heat and must not be trapped inside the case.

I am using a case for power amplifier with two large heatsinks at both sides in addition to the big heatsink for NTD1 and the unit is still getting very hot.
 
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