[Wood]

Will let you know how I get on with the jkenny 'salamander'  usb direct to i2s board. I am hoping it will improve the sq considerably but not interfere with the 'soul' of the dac.

 

[realmassy]

Does anyone compared the USB input of the Valab against the SPDIF?
I'm using a Ubuntu netbook with MPD and the USB input and I'd like to try squeezebox touch or a sonos player. But I don't know if the quality of the SPDIF is as good as the USB one.

 

[Wood]

Tricky, for me, I found (stock) with usb I get more detail but more jitter than from the spidf, from my computer, (the spidf may be masking the noise but also some detail).
 
If you add a input transformer, such as the pulse, to the spidf input it will beat the usb especially with a CDP as source.
But using an isolation adum device such as the Ultravox on the usb, will give better results from a computer than spidf from a computer.
 
I am using an ultravox at the moment and get very good results from pc usb, tonally rich, balanced and less mush. 

 

[realmassy]

Thanks for your reply Wood.
It sounds like I'll be better sticking with USB input, as I don't have any DIY skill to add a pulse transformer to the SPDIF input.
As for the USB isolator, what about this?
Does it need an external PSU?
Also, do you know anything with an external case? I know it may sound silly but I can't put that naked board in the hi-fi rack in the lounge
Thanks

 

[Wood]

That should do the job, a few of us Valab/Chameleon oweners  got great results with this one http://diyparadise.com/shop/index.php?main_page=product_info&cPath=3&products_id=124, 
 
some discussion here, http://www.head-fi.org/forum/thread/465039/chameleon-dac-listening-and-modifications/945#post_6642007
 
Be aware though that if you plan to use a Hiface at some future date, the adum device will not work with it.

 

[Dynobot]

Quote:

Does anyone compared the USB input of the Valab against the SPDIF?
I'm using a Ubuntu netbook with MPD and the USB input and I'd like to try squeezebox touch or a sonos player. But I don't know if the quality of the SPDIF is as good as the USB one.

I have an older non reclocking version and a newer reclocking version.
 
For me both are very close but ultimately I ended up using USB with a Wireworld cable.
 
Also I don't see it being done anywhere here but changing the stock IEC inlet to a Furutech made marked improvements in both clarity and a more relaxed natural sound.

 

[Wood]

Nice tip, thanks!
 
These dacs seem to respond very well to these sorts of mods.
 
I do know that Pat used a small piece of copper pipe to shield the IEC with good results.

 

[realmassy]

I may post a "want to mod" in the for sale section  
@dynobot: do you really notice some difference using an aftermarket USB cable? That sounds like an easy mod (though not cheap!)

 

[Dynobot]

Quote:

Nice tip, thanks!
 
These dacs seem to respond very well to these sorts of mods.
 
I do know that Pat used a small piece of copper pipe to shield the IEC with good results.

Yes very slight, not enough to warrant buying one to be honest.
 
I tried Stock, Belden Gold, Wireworld Ultraviolet, longs ones 20+ feet with extension and short ones less than 3 ft.  Belden seems to have more energy a bit harder sound, Wireworld is smoother but very close to a short stock cable.  Very long we kinda un-listenable after a long time.  I'd say just get a good very short cable.
 
Here is my re-clock version with a little modding done.  Only new IEC, soldered the IC's to the board, and bypassed the fuse. 
 

 
Quote:

I may post a "want to mod" in the for sale section  
@dynobot: do you really notice some difference using an aftermarket USB cable? That sounds like an easy mod (though not cheap!)

 

[realmassy]

Few updates on my Valab story
I tried a USB galvanic isolator (http://electronicsshop.dk/galvanisk_isolation.htm?currency=USD) and yes, there's an improvement over the standard USB connection.
There's not a specific area where the improvement is more evident, but all parameters seem to benefit: so soundstage is more 'on focus', the highs are cleaner and so the bass.
The difference is not huge, but is there. Bear in mind I'm still using a printer cable, and not an aftermarket one.
 
And yesterday I tried the Valab with a Sonos Zone Player: as expected the SPDIF input is slightly worse than USB of  my Ubuntu box. 
Honestly not a big deal, considering the Sonos is a wonderful device, easy to use and setup, with a great app for the iPhone.

 

[digger945]

Quote:

Few updates on my Valab story
I tried a USB galvanic isolator (http://electronicsshop.dk/galvanisk_isolation.htm?currency=USD) and yes, there's an improvement over the standard USB connection.
There's not a specific area where the improvement is more evident, but all parameters seem to benefit: so soundstage is more 'on focus', the highs are cleaner and so the bass.
The difference is not huge, but is there. Bear in mind I'm still using a printer cable, and not an aftermarket one.
 
And yesterday I tried the Valab with a Sonos Zone Player: as expected the SPDIF input is slightly worse than USB of  my Ubuntu box. 
Honestly not a big deal, considering the Sonos is a wonderful device, easy to use and setup, with a great app for the iPhone.

You should try the Valab with the Bridge. Very nice.

 

[open_air]

I'd like to try a pulse transformer in my own new-ish VALAB DAC, but I don't believe I have a cap that's blocking DC at the preamp's input, which, if I'm not mistaken, is a factor in how Pat has implemented his LL1574. Can anyone tell me where I should solder the pins?  I'm guessing there has to be a cap between at least one of the pins and the coax connection?
 
Thanks.
 
--Alan
 
Quote:

 

 

 

[open_air]

Bumpity-bump for sad panda.  I really want to solder in a pulse transformer, but I fear messing something up.  I'm tempted to do exactly what is illustrated in the photograph, but I'd prefer not destroying my gear.  Anybody?

 

[Wood]

Check your schematic for your TX. I attached mine so the positive and ground input pins are soldered directly to the spidf ground and center positive, and then moved the wires from the circuit board that are currently soldered to the spidf positive center and ground to the center and ground outputs on the TX.
 
As a tip, always photograph your layout before you do a mod, that way you can refer to the photo, for reversing a mod, if there is a problem later.

 

[open_air]

Thanks for you answer.  I haven't purchased the transformer yet, hence no idea about hookup options.  Sounds fairly straightforward to implement, but I was just paranoid about passing a too-large DC signal on to the preamp/amp.  Thanks!