[mrdon]

BG,

I don't know what version you have but you should have been able to loosen all 4 screws on the back (and 2 on the front) and slide the pcb out without an issue. So what happened?

I wouldn't recommend repeating this "terrorist rookie school homework" again. You could have ruined a perfectly good working device but you didn't' so you must have been like a surgeon with kitchen scissors in hand.

I would suggest that you make an investment in a good soldering iron and some desoldering braid, as Pat suggested. Practice on an pcb pulled from an old broken device.

 

[Bad-Gerbil]

as the person who took an angle-grinder to his existing soldering iron, in order to get a finer point on it - I think I will invest in a new iron, as you suggest.
I may sit back and listen to some music for a bit anyway, before delving into the DAC again.

BG

 

[errnst]

Alright! I built a 7.5V DC power supply out of salvaged transformers and capacitors. All i bought was a 6 dollar voltage regulator. Overbuilt is describing it mildly. I fed this to the floating dac board, and left the stock power supply to take care of the data section. It is a real improvement. Bass is all there and tighter. Surprising how much the top end opened up as well. There is a noticable improvement in clarity right accross the board. Been listening non stop for hours, incredible what this little dac can be driven to do. Beautiful. I might even say valabulous!



i have not yet added 47uf 16v caps to the dac chips, i am a bit unsure on which ones to get, i dont think i will get blackgate, i dont want to wait for too much burn in, or re-burnin so i am trying to figure out what would be good to use otherwise,

 

[PatOMalley]

I used Nichicon Fine Gold. cheap enough and good enough.

 

[skibum]

OK, It appears this thread is slowing down but I still have a serious problem with my version 3.0 (Luxury) VALAB.

I have replaced the 8 DAC caps with Blackgates, installed Texas Component Resistors, removed ALL the output filtering, have a star ground and installed Dueland Output caps.

When I turn my VALAB on the sound is full of static and distortion for the first 3-8 minutes. Over that time the output voilume diminishes and eventually the static dissapears and eventually the output sounds excellent.

At this point the DAC board is NOT screwed to the chassy case with the 3 screws.

If I now press down on the dac board so that the DAC chips are touching the case the static returns. If I then gently tug on one of the caps to pull the DAC board away from the case the static goes away.

If I turn the VALAB on with the entire board out of the case an resting on my table top it still takes 3-8 minutes for the static to deminish and the sound quality to become good. But I can press down on the DAC board all I want and the static will NOT return.

Do I have some type of grounding problem with my case? Do I need some type of filtering???

I have spent HOURS on this and gotten no where..

Any suggestions appreciated!

 

[highendman]

Forgive me if this has been covered. I didn't see a discussion of the exact same thing.

I made the mistake of cleaning the DAC pins and one or more of them failed. I ordered 10 more DAC chips from China and swapped them out for 8 new ones. The unit works and sounds great, so I thought.

If I leave it on for a day or more there is light static, almost LP popping kind of sound coming from the right channel. I can make this go away temporarily by turning the unit off and then back on. It seems to be heat related, because it will work properly for a longer period of time if I let it cool off for more time.

Mine has the DIR9001 mod as well as most of the usual mods. With the Texas Components 340Rs on the output, it was really sounding nice.

Thank you.

 

[skibum]

Quote:

Originally Posted by highendman /img/forum/go_quote.gif Forgive me if this has been covered. I didn't see a discussion of the exact same thing. I made the mistake of cleaning the DAC pins and one or more of them failed. I ordered 10 more DAC chips from China and swapped them out for 8 new ones. The unit works and sounds great, so I thought. If I leave it on for a day or more there is light static, almost LP popping kind of sound coming from the right channel. I can make this go away temporarily by turning the unit off and then back on. It seems to be heat related, because it will work properly for a longer period of time if I let it cool off for more time. Mine has the DIR9001 mod as well as most of the usual mods. With the Texas Components 340Rs on the output, it was really sounding nice. Thank you.

Hello Highendman, I also ordered 10 new DAC chips from China and replaced mine. It did nothing to solve my problem.... My problem is related to the DAC chips touching the case. When they touch the case I get a static sound. If they are not touching the case the static eventually goes away. Putting electrical tape on the bootom half of the case does not help. Might want to pull your board out of the case and turn it on - the static sound might go away.

I have attached a picture to show all the components that I removed from the DAC board. Does anyone see anything that I should NOT have removed?

 

[skibum]

I would like to thank MikeW for telling me about the inductor. It solved my static problem! I ended up buying a 1mH Radial Inductor that is about 5 times the size but much more durable than the one that was installed.

If you are having any type of static sound on your 3.0 version put a new inductor in your DAC board.

Sounds GREAT but now that I have it set up in my system the output voltage is low. I have adjusted the blue variable resistor on the board to maximum output but it is still very low. Besides changing the resistance of my IV resistors is there another option to get more output voltage? I currently have 340 ohm Texas Compnent resistors installed, don't really want to change those babies....

 

[highendman]

Thanks for the info Skibum.

Replacing the line filter inductor with a larger one got rid of your static?

 

[marcelnl]

Quote:

Originally Posted by skibum /img/forum/go_quote.gif I would like to thank MikeW for telling me about the inductor. It solved my static problem! I ended up buying a 1mH Radial Inductor that is about 5 times the size but much more durable than the one that was installed. If you are having any type of static sound on your 3.0 version put a new inductor in your DAC board. Sounds GREAT but now that I have it set up in my system the output voltage is low. I have adjusted the blue variable resistor on the board to maximum output but it is still very low. Besides changing the resistance of my IV resistors is there another option to get more output voltage? I currently have 340 ohm Texas Compnent resistors installed, don't really want to change those babies....

2Volt nominal output not enough

Not sure what you use as your next stage but there might be a voltage divider in the amp you;re using, removing/altering that might do the trick.

My power amp needs the 2 V to be brought down to something like 700mV.

 

[skibum]

Quote:

Originally Posted by highendman /img/forum/go_quote.gif Thanks for the info Skibum. Replacing the line filter inductor with a larger one got rid of your static?

No, I replaced it with a Radial 1 mH Inductor. This is the same value, but much more durable. Instantly killed all static sound. I attached a picture of the inductor that I installed. This is what I bought:

1mH Radial Inductor 0.44A 1 mh Milli Henries henry one on eBay (end time 25-Mar-10 21:48:35 GMT)

 

[skibum]

Quote:

Originally Posted by marcelnl /img/forum/go_quote.gif 2Volt nominal output not enough Not sure what you use as your next stage but there might be a voltage divider in the amp you;re using, removing/altering that might do the trick. My power amp needs the 2 V to be brought down to something like 700mV.

I have no idea if I am getting 2 Volt nominal or not. I have no tools to measure this. I am feeding this into a Naim NAC 112 preamp.

 

[marcelnl]

just connect it to your poweramp wo pre amp to test, your pre amp might be off spec.
Beware the power amp probably is going full blast so start with a test CD with -40dB or thereabouts....
Your pre amp might have inputs that are designed for a higher level signal, or try a differnet input.

 

[skibum]

Quote:

Originally Posted by marcelnl /img/forum/go_quote.gif just connect it to your poweramp wo pre amp to test, your pre amp might be off spec. Beware the power amp probably is going full blast so start with a test CD with -40dB or thereabouts.... Your pre amp might have inputs that are designed for a higher level signal, or try a differnet input.

Thanks Marcelnl, will try. I did not have this problem before I modded my DAC though.... ???

 

[marcelnl]

not sure what you modded, but usually you have these effects in one channel mostly indicating an error in soldering a component here or there..same prob in both channels usually indicates a systematic or logoc error, wrong value for a component or fundamental misstake made somewhere....

hope this helps.