A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

[AudioH]

Originally Posted by Bas Horneman

It actually is balanced already.

Thank you Bas

I thought so, but how do I connect the XLR connectors ? Directly to the output pins ? If so is a DC decoupling capacitor required for both -ve and +ve legs ?

Regards

[Jan Deckers]

Hi,

as far as I heard, or read on Audio Creative site, for balanced output you don't need output capacitors.
Dick (one of the owners of Audio Creative) tested a TVC "preamp" with balanced input and he directly plugged the dac into it.....and he was very, very enthousiastic about that. Stil have to try that too with a different preamp myself.

[dhbiker]

damn you guys with your pictures... i'm considering about getting DDAC myself too but you know how the students pockets are

*hopefully* i'll order it in summer

[dddac]

Originally Posted by AudioH

Thank you Bas

I thought so, but how do I connect the XLR connectors ? Directly to the output pins ? If so is a DC decoupling capacitor required for both -ve and +ve legs ?

Regards

hope I am not too late

the DC voltage between the POS and NEG output is indeed very low, just a few mV or sometimes even below it. If you use only these two to connect to a balanced system, than things are fine, as for DC blocking.

but, you should not connect the common terminal in that case, as than you will see two times 2,7 Volt DC. in this case you need the output capacitors.

I know from one DDDDAC builder who is using a tube amplifier stage directly after the DAC and actually uses the DC voltage in the bias from the first tube, avoiding coupling capacitors....

there are several possibilities and situations. Every one should check his specific situation and make the appropriate circuit connections.

in doubt, just email me .....

[dddac]

Originally Posted by zjaakco

Hi Doede,
I have read your explenation on your site, and make mine decision to make one.
Words are words, but still there is something , I think your design is right.
Mine knowwlegde is not sufficient to design the delay in the I2S line.
So, I have order a waveIO board, and collecting / buy parts.
Still a few questions, I can't determine what is the L or R channel, i have read the
blue line in the delay circuit. and,
you use a output trafo, are you still use the A B iv resistors on that position, or
a ristor on the sec side?
I have good experiens with an outputtrafo.
Regards,
Zjaakco

Thanks for positive feedback

on the left right question. if you check my circuit diagram, you see on page 2 at the right the connections to the dac. they are indicated as right and left channel. the left channel is the one with the most delay ... hope this helps?

the resistors are needed to do the DC biasing of the DAC output, so they have to stay. I also use a secondary load of 10k.this has been very arbitrary and can be left out or lowered or whatever. it is only to dampen the transformer a bit for the small peak round 200kHz. I could not hear a difference, but could measure it, so I left the 10k in to go kind of sure ...

[zjaakco]

Hi Doede.
Thank you for your explenation.
Regards
Zjaakco

[Almeg69]

I have placed my order for the kit of parts and will look forwards to putting it together.

No doubt I will be back here later for advice ....

[AudioH]

DAC Kit arrived yeesterday. Quality of boards is truely excellent ! Will start assembling this evening.
Many thanks for repsonse to balanced output query.
Regards

[dddac]

Originally Posted by AudioH

DAC Kit arrived yeesterday. Quality of boards is truely excellent ! Will start assembling this evening.
Many thanks for repsonse to balanced output query.
Regards

great, let me know what you think !
and....
keep posting pictures

[IanS1]

Originally Posted by dddac

great, let me know what you think !
and....
keep posting pictures

Yes, we need more pictures, preferably with cases. Still haven't decided how I'm going to case mine so need some ideas.