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

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#441
I'm almost scared to ask this question, here goes

If SPDIF is normally sent on an 75ohm cable why are we using 50ohm internally.

I realise that it's not just the SPDIF they are being used for.

By the way I'm getting cheaper prices (than Digikey) at Mouser for the Emerson cables & connectors if you buy in US dollars.
 
#442
iancanada said:
Please show me waveform of all three SCK and WS and SD signals form S/PDIF board I2S output port when you switch to optical input.

Ian
Click to expand...

Ian

All three signals, thanks.
 

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#443
DQ828 said:
I'm almost scared to ask this question, here goes

If SPDIF is normally sent on an 75ohm cable why are we using 50ohm internally.

I realise that it's not just the SPDIF they are being used for.

By the way I'm getting cheaper prices (than Digikey) at Mouser for the Emerson cables & connectors if you buy in US dollars.
Click to expand...
yeah but you lose the free shipping (for $200 orders) if you do that at mouser, its a case by case basis whether its cheaper overall.


where is spdif being used on these cables? i2s is being used on these cables mostly. besides its all about the cable and the termination, not the signal

50 or even 100 ohms is used for both internal and external coax for data or instrumentation cables as well. as long as its consistent, or an appropriate transformer is used to interface 2 different types, its all good.

normally 75ohms is used for external spdif (BNC) use, with 50ohms internally, but with fifo its all i2s carried on 50ohms uBNC
 
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#444
qusp said:
yeah but you lose the free shipping (for $200 orders) if you do that at mouser, its a case by case basis whether its cheaper overall.


where is spdif being used on these cables? i2s is being used on these cables mostly. besides its all about the cable and the termination, not the signal

50 or even 100 ohms is used for both internal and external coax for data or instrumentation cables as well. as long as its consistent, or an appropriate transformer is used to interface 2 different types, its all good.

normally 75ohms is used for external spdif (BNC) use, with 50ohms internally, but with fifo its all i2s carried on 50ohms uBNC
Click to expand...

I guess the question is more applicable to me as the new BIIISE I have a a place for a 50ohm connector on the SPDIF input

I didn't realise how small the suckers where until I saw the one that already on the BIIISE Ext MCLK input.
 
#449
good one Brian, they are easier to solder than some other parts these guys are soldering, so once the mental barrier is overcome the body and technique takes over. one thing I would say is dont use the add solder to tip, then touch to connection method, it would be too easy to get a little bit on the rim of the connector. If you do, that can be cleaned off mostly if its on the outside; with some braid and flux, but best avoided as can make the shape and thus impedance of the connection incorrect. It can also damage the cables.

also curved tweezers are recommended

flux is your friend
 
#452
DQ828 said:
Is there a mini 75ohm cable/connector you can recommend to take from the to BIII SE SPDIF input to the OTTO & then on to the BNC connector that will be on the rear panel? Or should I just stick with the 50ohm

thanks for the video link

What sort of temperature are you using on the solder iron?
Click to expand...

I personally just use a piece of regular wire, or a twisted pair from CAT5.

I use Kester 63/37 solder with NoClean flux, 0.15" diameter. (Kester# 24-6337-8806). I generally solder at about 650F. A clean tinned tip is everything.
 
#456
iancanada said:
Waveform looks perfect. Please measure them on the three diodes at the fifo board to see if signals keep same. Other wise, check up you I2S cable.

Ian
Click to expand...

Ian

It should not be the I2S cables as the USB through backdoor works perfect. I bypass the FIFO and connect the SPDIF directly to the BIII, it works with either USB or Optical. It seems that the FIFO does not recognize the signal from optical. Strange!!
 
#458
bigpandahk said:
Ian

I believe the problem is caused by the dual clock board. It doesn't switch the sf to match the source. It always state at 96!!

Anyway, I will have the i570 to replace it.
Click to expand...

bigpandahk,

I suspect your isolator board, if there is anything wrong with the control signals, you will lost the Fs auto switching function.

Try removing it, run dual xo from FIFO directly. If it's working then the isolator board is the criminal.

Ian
 
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