[donunus]

ahhh whoops, I spoke too soon. i guess the time of day matters(voltage fluctuations) because the noise is back even using optical.

 

[MikoLayer]

I take it Valab DAC is for losers that just can't get any chicks, or that's how we are looked upon

Getting back to topic, most seem to rate the inputs coax > optical > usb in that order. Is there a particular reason why? There is no hum with my USB input as far as I can tell.

 

[donunus]

mine had an intermittent hum depending on the voltage of the different times of the day. Now there is only slight static at full volume on the amp when no music is playing

 

[PatOMalley]

USB: unused

TOLSINK: best on first use compared to coax. coax seems duller, grey. Toslink improved when glass calbe was used - more focus, separation, and dynamics

COAX: vastly improved upon adding pulse transformer. now using solid core Belden interconnect. beats toslink.

 

[hebegbnz]

Quote:

Originally Posted by hebegbnz /img/forum/go_quote.gif Hey team Month 4 with my Valab DAC. Sounds great very happy with it. Played with various inputs and so far settled on the coax input from my PC. A few weeks ago noticed a mechanical hum. Not bothered as I cannot hear it in the music and the speakers are in another room. However, it is also interfering with my TV reception. It causes interference on one TV channel only. Unfortunately it is my kids favourite channel. So no TV while I am playing music. Yes, I win that arguement. Emailed Kevin, he said yes you may get some hum and the interference can be dealt with a power conditioner. A friend lent me a rather expensive power surge suppressor (Tripp-Lite) that has reasonably good specs for noise filtration, but alas no change. Any clues? I saw Chris Omalley's post on grounding, however I have the MArch 09 DAc so it should separate earthing. I haven't taken the lid off in case I have to send it back. Any direction appreciated Cheers

Any one with any RF interference issues. I am progressively ruling out things for this annoying issue and intrigued to know if anyone else has experienced it?

Unplug all inputs > Interference on TV but minimal
Put my hand on the case > and it goes away
Plug in my coax input > The TV is lit up with red diagonal lines and white static
Turn off the DAC and it all dissappears

It appears to be amplified by the COAX or USB inputs. Tried Ferrite clamps on various cables with no result. It has been suggested that I put the DAC in a steel, grounded cabinet. There must be an easier solution?

Any Clues

Thanks in advance

 

[MikeW]

try putting dac on a different circuit then your TV, try lifting the ground on your TV/DAC. (Cheeter plug), try a high quality power conditioner, or isolation transformer. Try somthing like ERS paper on your dac. Honestly, it sounds like you have a ground loop somewhere. Evidenced by putting your hand on the chasis, and also creating a ground loop with coax cable and USB, an optical cable does not have a ground, hence there is no way to create a loop with it. There are products on the market that help with ground loops, like Isolated power conditioners, the cheapest being monster units. Ground loops can be very frusterating, i'd start by playing with cheeter plugs.

 

[MikeW]

I read in another thread that you only need a transformer on one side of the equation either at the transport or the source, and it's better to have it on the transport. So I wonder if the dac will still be improved by a pulse transformer, if the transport already has one.

 

[PatOMalley]

Quote:

Originally Posted by MikeW /img/forum/go_quote.gif I read in another thread that you only need a transformer on one side of the equation either at the transport or the source, and it's better to have it on the transport. So I wonder if the dac will still be improved by a pulse transformer, if the transport already has one.

My NAD C541i has a buffered coax output with a 75ohm transformer.
I am here to tell you that using a transformer on the DACs input greatly increased my listening pleasure. A lot.

 

[errnst]

alrighty, 9 weeks with the valab, still cannot bring myself to remove it from my system long enough to have a good look at what is inside, i only have good things to say, i have had no problems with any kind of noise or vibration

the interconnects i am using are fairly plain, they send the signal through some series-butt filters. I also wrapped the outside of the interconnects in tin foil for that special space geek look and to suppress some more noise.

I have a voltage regulator that lets me set my line voltage at 110 volts, i never ran this dac without it. Yesterday i made a mains conditioner based on John Risch's design. Jon_Risch's Web Site Now i am even happier!! the bass is tighter and louder, more detail everywhere, especially the highs, i put another mains conditioner on the preamp, now i can hear the singers breath

Aopen + ubuntu linux -> Valab nos dac-> Conrad Johnson PV3 -> Dynaco Mark III + Rotel RB870X -> focal, vifa, isoberic bass, housed in rounded and top-narrowed low-resonat enclosures

 

[errnst]

great, my dac is not working, suddenly the yellow led goes completely off and never on any more, the red led beside the power supply works just fine, no sound, anyone got any ideas why that might be?

 

[errnst]

ok, i had a nap, woke up, found and fixed the problem mentioned above, nothing to do with the DAC, it was a manufacturing defect in the power conditioner that i made, shoddy solder joint needed attention, funny that with one leg of the supply open, the red led beside the power switch lit up, i wonder if that is a bad sign.....

 

[cloverp]

i use my valab dac via usb, but the machine failed to lock, usb light flashing all the time, lock has no light, also the volume icon on my task bar also flashes, i have had this problem since i received it in feb 09, but the sound coming through has no problems

anyone has similar experience and know a way to fix this?

 

[MikeW]

The lock light does not come on for usb, this is normal operation. The usb light always flashes, this is normal operation. As for your problem, i'd try checking the connection first. Sounds like a loose cable.

 

[GNR]

Hi all - new around here, first post etc...

I have just ordered this Valab dac from ebay as my trusty Audio Alchemy dac in a box has finally died. I got the 'revision 11' version (seperate psu) after much research and quite a bit of reading (this thread is massive!)

My AA DITB was modded with a burson dual opamp (tricky fit) and various power caps and regulator mods, i loved the sound of it so I'm kind of hoping this new dac will hit a sweet spot with me and it's seems like it's mod friendly with a bit more room to play with than my DITB!

I'm going to be running this into my headphone amp (cmoy variation with a burson opamp) and my preamp Yaquin MS-12B has anyone tried this DAC with the Yaquin?

 

[Kooka]

Hi, did anyone test the differences in sound quality comparing the 3 versions now available? I mean the "stock" one, the Luxury version and the one with separate power supply? Any advise..?