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Old 20th October 2012, 03:59 PM   #1271
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Quote:
Originally Posted by cracra View Post
Isolation board received and populated with the smd parts.

Soldering of the smd parts is OK except the 4 resistor networks which is quite tricky. Their Soldering result has to be double checked to avoid shorting signals to ground through some unused resistors that are connected to.

I will provide a detailed listening result within one week to ensure the Isolation board complete break-in.

In the meanwhile, following a couple of hours running I have noticed a global gain of the DAC transparency i.e. Sound more coherent and natural and an increase of the PRAT. Better dynamics and separation of instruments within a darker background.

I assume this is due to an increase of the S/N of the DAC which, analogue and digital grounds are no more polluted by the FIFO ground noise.

My DAC configuration is a double Mono WM 8741 Opus DAC from TP powered by independant rails and Shunt regulators. The clock is powered by an independant rail fitted with a Bybee MusicRail device.

A design suggestion for the Isolation board would be to add an I2C isolation section to enable connecting an Arduino board to control the DAC while avoiding the pollution of their ground.

Ian, thank you for giving us the opportunity to build state of the art DACs !!
Good job! Thanks cracra four your update. Congratulations!

I'm looking forward to your testing result on the isolator board and over all system.

There is a optional isolator footprint U7 pleace on the isolator board, may have chance trying the I2C isolator on it .

Nice weekend.

Ian
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Old 20th October 2012, 04:00 PM   #1272
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I will use bench PSU to test the isolator board before connecting it to the circuit again.

Ian, I already lost the L11!!
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Old 20th October 2012, 04:09 PM   #1273
qusp is offline qusp  Australia
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sounds like a plan. do some probing around with DMM before even doing that, can you set current limit on the bench supply?
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Old 20th October 2012, 04:20 PM   #1274
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Originally Posted by qusp View Post
sounds like a plan. do some probing around with DMM before even doing that, can you set current limit on the bench supply?
I've checked all connections with DMM. The bench supply has current limit setting. Any suggestion on the value?
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Old 20th October 2012, 04:24 PM   #1275
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Jumped the 5V and pin2, connect the clock back to the FIFO. Power up and everything seems fine. LEDs on and SPDIF working. Not yet connect it back to DAC.
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Old 20th October 2012, 04:27 PM   #1276
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Originally Posted by NicMac View Post
Ian,

Got the isolater board thank you. Looks great - even the board is cut where the isolation occours

I will place the component order for this and the battery management board these days and I also think it is time for me to invest in a dedicated smd rework station (OT: any <200$ suggestions would be welcome by PM)

Cheers,

Nic
Found some from eBay(just found, not for recommendation):

SMD SMT Soldering Rework Station 2in1 Hot Air Gun Iron Welder Tip ESD PLCC BGA | eBay

New 2 in1 SMD SMT Soldering Rework Station Welder Hot Air Iron 852D 220V | eBay

Soldering wires, solder paste and flux are also importatn.

Ian
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Old 20th October 2012, 04:28 PM   #1277
qusp is offline qusp  Australia
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something about 10ma above the operating current of each side of the isolator chip, say 30ma total for both sides (I presume you will supply both sides with the same bench PSU for this testing?) the input has a quiescent current of 2mA and the output 6mA, then be generous and give the regs 10ma, which they will probably not need. actually which isolator are you using? those numbers are for the NVE part. theres not much by way of capacitance on the board so inrush wont be much of a factor
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Old 20th October 2012, 04:29 PM   #1278
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Originally Posted by bigpandahk View Post
Jumped the 5V and pin2, connect the clock back to the FIFO. Power up and everything seems fine. LEDs on and SPDIF working. Not yet connect it back to DAC.
Start as low as possible then increase. The 3.3V reg will current limit to 300mA so no point setting it higher than that. Perhaps 50mA or so would be ok starting value.
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Old 20th October 2012, 04:32 PM   #1279
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Originally Posted by qusp View Post
something about 10ma above the operating current of each side of the isolator chip, say 30ma total for both sides (I presume you will supply both sides with the same bench PSU for this testing?) the input has a quiescent current of 2mA and the output 6mA, then be generous and give the regs 10ma, which they will probably not need. actually which isolator are you using? those numbers are for the NVE part. theres not much by way of capacitance on the board so inrush wont be much of a factor
My bench PSU has two output, so I can use individual output to power each side (15mA). I am using IL260E.
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Old 20th October 2012, 04:32 PM   #1280
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Originally Posted by bigpandahk View Post
Jumped the 5V and pin2, connect the clock back to the FIFO. Power up and everything seems fine. LEDs on and SPDIF working. Not yet connect it back to DAC.
That confirmed eveything is alive. The next, you have to do 100% check up on your isolator board according to the schematics . Post a picture if possible.

Ian
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