Experience with this DIY DAC ?

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#2,947
The LL1690 is an input trafo, the Digitec and A-20 are output trafos. They are completely different in construction and use. Input trafos must be terminated correctly for use in this implementation. Output trafos do not have this restriction. A scope will show this.
 
#2,948
Bill Fuss said:
Use what the manufacturer suggests. If your preamp has an input impedance near 40kohms then you just need the RC filter they show on the datasheet. If it is much higher, such as 250kohms, then I would use a 47kohm resister across the outputs along with the RC filter.
Click to expand...

My preamp has an input impedance of 47K. The manufacturer suggests 40K // 7K+400pf. Ok I'll try this.

Any suggestion for the resistors and caps?

Pietro
 
#2,949
I would use silvered mica caps and metal film resistors to insure good performance. The 47kohms input should be close enough for the load part, but a scope would be nice to confirm it. You could always parallel a high value resistor to get closer to 40kohms if you wish, the manufacturer is usually very accurate with their suggestions.
 
#2,952
Ok maybe this is a stupid question, but is a DAC like this an improvement compared to an external USB sound card like this:

E-MU Systems - 0202 USB 2.0 - USB 2.0 Audio Interface


Here in an excerpt from the specs:

Analog Line Outputs (2)

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Type: Balanced, AC-coupled, 2-pole low-pass differential filter
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D/A converter: CS4392
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Max Level: 6.7 dBV (unbalanced)
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Frequency Response (20Hz - 20kHz): 0.00/-0.01dB
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Dynamic Range (1kHz, A-weighted): 111dB
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Signal-to-Noise Ratio (A-weighted): 112dB
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THD+N (1kHz at -1dBFS): -98dB (.0013%)
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Stereo Crosstalk (1kHz at -1dBFS): <-120dB

So for the line outputs SNR is 112dB and THD is 0.0013%.
How much better are these specs for the DAC discussed on this thread ?
 
#2,955
fireworks said:
Ok maybe this is a stupid question, but is a DAC like this an improvement compared to an external USB sound card like this:

E-MU Systems - 0202 USB 2.0 - USB 2.0 Audio Interface


Here in an excerpt from the specs:

Analog Line Outputs (2)

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Type: Balanced, AC-coupled, 2-pole low-pass differential filter
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
D/A converter: CS4392
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Max Level: 6.7 dBV (unbalanced)
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Frequency Response (20Hz - 20kHz): 0.00/-0.01dB
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Dynamic Range (1kHz, A-weighted): 111dB
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Signal-to-Noise Ratio (A-weighted): 112dB
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
THD+N (1kHz at -1dBFS): -98dB (.0013%)
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Stereo Crosstalk (1kHz at -1dBFS): <-120dB

So for the line outputs SNR is 112dB and THD is 0.0013%.
How much better are these specs for the DAC discussed on this thread ?
Click to expand...

The Emu USB is quite superior to the dac's USB, but who knows what it sounds like.

Specs are for Techs, I listen with my ears.
 
#2,958
danrap said:
Guys,
someone of you knows if is it possible to put the CS43122 dac on this board??
Is it 100% compatible with the cs4398?
thank you
Click to expand...

Yes it can, I have 2 LM DAC board, V9 and V10, the receiving chip can choose either DIR9001 or CS8416, the DA chip can use CS4398' CS43122 and PCM 179X series.

An externally hosted image should be here but it was not working when we last tested it.
 
#2,959
Graemedench said:
Hey thanks Bill.

Pulled the up-sampling board out and could only get it to go upto 96Khz ?? and anything above would show a lock (relay opening) but no audio regardless of dip switch settings. I would have imagined that if the up-sampling board was doing 192-24 and I pulled the board (put jumpers in) then it sould have at leaste had the same result at 192-24 (if not better) however I'm getting nothing then. wondering if it could maybe be the small coax input filter?
Click to expand...

I have LM-DAC3 V9 and V10, the receiving chip are both CS8416, the V9 has designing problem, if you use upsampling board, the maximun sample rate you can received is 24BIT/176.4K, if you pull the upsampling board out, you can receive only 24BIT/96K, and there is nothing you can do, but the V10 is no problem for receiving 24BIT/192K.

Since the V9 DAC can't receive 192K, so I just bought DIR9001 board from LM's dealer in GuangZhou 3 days ago, the receiving chip can be changed very easy.
 
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