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-   -   Help needed on Gigawork DAC !!! (http://www.diyaudio.com/forums/digital-line-level/169597-help-needed-gigawork-dac.html)

nick974 1st July 2010 11:21 AM

Help needed on Gigawork DAC !!!
 
2 Attachment(s)
Hi There !

After having read so many good reviews on the gigawork dac (LM DAC3), I've purchased the DAC (CS4398+DIR9001+upsampling board) from the chinese seller snow48_6. I received it 2 weeks after, in very good condition.

However, I cannot get it work ! :( I discovered that the RCA analog outputs are always shorted to ground (relay controlled by the digital receiver never clicking...) When I connect the DAC using the USB connection, I have a signal on the first OPAMP ; I tried the coaxial SPIF input but no success...

I suspect that I have a problem with the receiver... Does anyone have any experience using this DAC with the DIR9001 receiver ?

Also, here is a couple of strange things I noticed... (have a look on pictures !)
- The pin 1 on the receiver module is connected to one side resistor...
- The capacitor surrounded by a red circle seems to be a resistor on the photos I found on the internet...

Any help would be apprieciated !

vinodt1347 7th January 2011 05:56 PM

Hi,
Any further updates. I was thinking of buying this also

piero7 7th January 2011 06:37 PM

2 Attachment(s)
Quote:

Originally Posted by nick974 (Post 2232249)
Hi There !

After having read so many good reviews on the gigawork dac (LM DAC3), I've purchased the DAC (CS4398+DIR9001+upsampling board) from the chinese seller snow48_6. I received it 2 weeks after, in very good condition.

However, I cannot get it work ! :( I discovered that the RCA analog outputs are always shorted to ground (relay controlled by the digital receiver never clicking...) When I connect the DAC using the USB connection, I have a signal on the first OPAMP ; I tried the coaxial SPIF input but no success...

I suspect that I have a problem with the receiver... Does anyone have any experience using this DAC with the DIR9001 receiver ?

Also, here is a couple of strange things I noticed... (have a look on pictures !)
- The pin 1 on the receiver module is connected to one side resistor...
- The capacitor surrounded by a red circle seems to be a resistor on the photos I found on the internet...

Any help would be apprieciated !

To work correctly, DIR9001 must be connected to that resistor
Yes this is a resistor

nick974 7th January 2011 07:35 PM

Hi Everyone !

I completely forgot to give the final result... I was able to get it to work ; the power supplies were not connected connectly, and the relay was always shorting outputs to ground.
I haven't tested out the SPDIF connection but the USB works fine ; I have replaced the AOPs, sound is much better ; I haven't made any other modifications... But I was thinking to remove the second amplifier stage, and the connection through the relay.
I will test it out as soon as I have some spare time !!!

Regards.

poirson 18th March 2012 07:48 AM

2 Attachment(s)
Hello
I'm interested by mod on this dac, I have the same with some mods from the precedent owner.

There are 2 double aop cause this dac can use different dsp. But with a cs4398 only one simple aop is necessary.

Can I get out directly from R63 C72 and R62 C71 ?

Thanks

mavallarino 14th April 2012 11:30 AM

Quote:

Originally Posted by poirson (Post 2950585)
Hello
I'm interested by mod on this dac, I have the same with some mods from the precedent owner.

There are 2 double aop cause this dac can use different dsp. But with a cs4398 only one simple aop is necessary.

Can I get out directly from R63 C72 and R62 C71 ?

Thanks

Hello all,
I've been playing with a similar dac for about a few years. I originally purchased it since it had all three inputs, coax, optical, usb. This dac has been collecting dust for some time since it had a similar switching problems during evaluation. Since I have always had intentions of bypassing its output stage with my own output stage I didn't think the relay would eventually be a problem.

Just the other day I finished the new output stage and it still has the same issue, the relay cuts the digital source signal after 30 sec. - 1 min.. To my surprise the relay is connected to the original outputs (I'm using the V- left and V- right directly from the dac chip.).

If I short the rely will it provoke other problems with switching between the other digital sources?

From the schema that's posted here it doesn't indicate where how the rely is shorted by the digital source.

Thanks in advance for any input.
M

mavallarino 16th April 2012 07:49 AM

2 Attachment(s)
I've contacted the seller (producer?). They were kind enough to send a schema.

I have the digital controller CS8416 and the CS4398 DAC chip as combination.

I'm hypothesising that the culprit is in the connection from the CS8416 (connection from the transistor to pin 14 of CS8416) to relay circuit. However there are voltages on both and current passing.

Does anybody know off hand if it would be recommended to permanently bypass the relay or is it required for a muting circuit? How does the controller "communicate" with the relay circuit?

Apologies in advance but I am new to these electronics!

Extreme_Boky 16th April 2012 10:22 AM

Quote:

Originally Posted by poirson (Post 2950585)

Can I get out directly from R63 C72 and R62 C71 ?

Thanks

yes

Boky

Extreme_Boky 16th April 2012 10:28 AM

Quote:

Originally Posted by poirson (Post 2950585)

Can I get out directly from R63 C72 and R62 C71 ?

Thanks

yes

Boky

mavallarino 16th April 2012 11:10 AM

Quote:

Originally Posted by Extreme_Boky (Post 2987226)
yes

Boky

In my case I am taking the outputs directly from DAC chip, namely OUT L- and OUT R- respectively. Since I am bypassing all OPAs there is no feedback to correctly close the relay thus the relay switches open after 2 minutes of playback.


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