Integrating the HiFiDIY.net mini 1793 DAC into an amplifier

matherp · 20th November 2010, 03:04 PM

I want to integrate a hifidiy.net mini 1793 DAC into an amplifier I'm building and have been reading Audio Component Grounding and Interconnection to try and properly understand the grounding requirements. However, the DAC uses a single two rail power supply whereas all the components in the amplifier will use three rail supplies where the common is the centre zero volt rail which will be connected to the chassis.

If I understand the DAC circuit correctly, it is using a LM1875T to create a virtual ground. So to properly integrate it into the amplifier my assumption is that I should remove this together with the voltage conditioning devices from the power inlet. I can then connect a three rail supply as follows: V- to LM1875 pad 3, 0 to pad 4, +V to pad 5. This will then feed the two AMS117 regulators for the digital circuitry and give the +V and -V supplies to the OPA2134 etc..

Is this the correct approach or is there a better idea?

Thanks

Peter

Francec · 25th November 2010, 01:33 AM

Bump!

Huntingdon 361 · 26th November 2010, 01:30 AM

You've got it - the LM1875 is used as an active supply splitter.

Remove the LM1875, connect V+ to pad 5, V- to pad 3 and gnd to pad 4. There's no need to remove resistors or diode.

matherp · 29th November 2010, 05:12 PM

For reference, I've made the mod and it works fine with a conventional 7.5-0-7.5 regulated DC supply.

zany · 2nd December 2010, 09:35 PM

Hi matherp,

a question about that dac board... did it come pre assembled or did you have to build it yourself? I'm new to DIY and am looking at this DAC - need to know how much work is involved...

thanks in advance.

20th November 2010, 03:04 PM	#1
matherp diyAudio Member Join Date: Oct 2009	Integrating the HiFiDIY.net mini 1793 DAC into an amplifier I want to integrate a hifidiy.net mini 1793 DAC into an amplifier I'm building and have been reading Audio Component Grounding and Interconnection to try and properly understand the grounding requirements. However, the DAC uses a single two rail power supply whereas all the components in the amplifier will use three rail supplies where the common is the centre zero volt rail which will be connected to the chassis. If I understand the DAC circuit correctly, it is using a LM1875T to create a virtual ground. So to properly integrate it into the amplifier my assumption is that I should remove this together with the voltage conditioning devices from the power inlet. I can then connect a three rail supply as follows: V- to LM1875 pad 3, 0 to pad 4, +V to pad 5. This will then feed the two AMS117 regulators for the digital circuitry and give the +V and -V supplies to the OPA2134 etc.. Is this the correct approach or is there a better idea? Thanks Peter

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25th November 2010, 01:33 AM	#2
Francec Banned Join Date: Jul 2006 Location: Port Melbourne, Australia	Bump!

26th November 2010, 01:30 AM	#3
Huntingdon 361 diyAudio Member Join Date: Apr 2010 Location: Oxford	You've got it - the LM1875 is used as an active supply splitter. Remove the LM1875, connect V+ to pad 5, V- to pad 3 and gnd to pad 4. There's no need to remove resistors or diode.

29th November 2010, 05:12 PM	#4
matherp diyAudio Member Join Date: Oct 2009	For reference, I've made the mod and it works fine with a conventional 7.5-0-7.5 regulated DC supply.

2nd December 2010, 09:35 PM	#5
zany diyAudio Member Join Date: Oct 2010	Hi matherp, a question about that dac board... did it come pre assembled or did you have to build it yourself? I'm new to DIY and am looking at this DAC - need to know how much work is involved... thanks in advance.