[Newk Yuler]

Quote:

Originally Posted by skibum /img/forum/go_quote.gif I really do not understand how a reclocking circuit works so I will spend some time and try to figure out. I think there must be a way to connect the SPDIF input directly to the DIR9001? How is the connection made on the previous boards that do not have the reclocking cuircuit on the SPDIF input?

I'm not certain but the luxury version may be based on the last straight version of the Valab with the 2nd TCXO attached to the top of the DAC board. The 2nd TCXO there was put in line before the DAC board. USB in that version went through 2 TCXOs and forced the SPDIF/DIR9001 through the second one. The luxury version may be the same with it integrated into the PCB. Unless you have some pretty advanced DIY skills it may not be worth thinking about a way around the 2nd clock in the luxury version. If you have the skill and you figure it out, you'd be doing a new, useful mod for the Valab thread. Good luck. Seriously.

 

[Newk Yuler]

Quote:

Originally Posted by thermalbat /img/forum/go_quote.gif Hi Newk Yuler, Ya know, now you got me thinking(and that's never good); I'm 99% sure that my Dac is the one that you describe, and if that's the case, maybe I would be better off getting the Hiface and trying that with this Dac. Hmmm. Rich W

The March 09 version with the 330r IV resistors is ideal because it solves a signal saturation and distortion issue, but it's more important that it's not the version that came out a few weeks later with the 2nd TCXO board bolted to the top of the DAC board. The March 09 version and those before it are ideal for use with a Hiface.

If it's not a problem for you, you should remove the top of your Valab and look inside. This is the soon to be next version with the 2nd TCXO board strapped to the top of the DAC chips board. You shouldn't see that board.

Also, if you have one of the March 09 bench modded with 330r IV resistors, the resistors may appear more loosely soldered to the PCB. In the 2nd picture at the link above one of the IV resistors is below the bottom right corner of the bolted-on TCXO board. If one of those looks like it was hand soldered and floating a bit higher above the PCB, you probably have one of the bench revised Valabs from March 09. That also means your DAC was hand tweaked on a scope before it was sent to you. No telling how quickly the 330r resistors were included in the circuit manufacturing process. We could go into identifying the bands on the resistors but this is probably an easier way of identifying the revision if you find the hovering resistors.

I'll mention for anyone with half decent soldering skill that there are a few relatively easy mods for the Valab that will make a big difference in sound quality. The output cap mods, IV resistor mods, DIR9001 pins 13 and 14 to 3.3v mod, and the addition of a pulse transformer behind the coax SPDIF jack. The output caps and the pulse transformer are pretty easy and will make a huge difference. If you're happy with the quality of the audio in stock form, the pulse transformer mod will add a lot of value to using a Hiface. You'll have to spend quite a bit of time looking back through the 2 major Valab threads here at HeadFi but all the information is there.

Now if you'll excuse me, I have to spend 700 USD and then watch last night's Doctor Who episode!

 

[thermalbat]

Hi Newk Yuler,

Well, I did as you suggested and opened up the valab-no sign of any second
TCXO board, but the resistors didn't appear to be added on.

I tried to get the color code, but my 55 year old eyeballs ain't what they used
to be-near as I could tell : brown or orange/green/red/silver.
My Receipt for the PayPal payment to Kevin was dated 3-20-09.

I think that I'll go ahead and order the HiFace and take it from there-maybe
I'll try some of the mods later on.
Thanks for steering me in this direction, I think this might be a better approach than buying the MK-1.


Rich W

 

[errnst]

has anyone ever experienced this coming from their dac.... a sweep signal that lasts about 1 or 2 seconds, starts at  low frequency and sweeps up to high frequency and then it is gone.... this has happened about once a month at apparent random moments....

 

[skibum]

Quote:

has anyone ever experienced this coming from their dac.... a sweep signal that lasts about 1 or 2 seconds, starts at  low frequency and sweeps up to high frequency and then it is gone.... this has happened about once a month at apparent random moments....

Nope, I have never heard that.     Maybe something upstream of the DAC?

 

[errnst]

Quote:

Nope, I have never heard that.     Maybe something upstream of the DAC?

possibly, i have thought of that... any other ideas out there?
 

 

[thermalbat]

Hi all-  I'm so glad that I posted on this forum-I went with the Hiface and the results are excellent.  I can't believe the
difference!  Now, it's on to bypassing the output caps. I read Steve Nugent's recommendation on Computer Audiophile's forum-
"3.3uFd V-Cap oils bypassed with .22uFd Sonicap Platinums".  That post was a while ago, so I was wondering if that is still
a good option-or is there a different combo that I should try?
 
      Thanks,  Rich W

 

[skibum]

Quote:

Hi all-  I'm so glad that I posted on this forum-I went with the Hiface and the results are excellent.  I can't believe the
difference!  Now, it's on to bypassing the output caps. I read Steve Nugent's recommendation on Computer Audiophile's forum-
"3.3uFd V-Cap oils bypassed with .22uFd Sonicap Platinums".  That post was a while ago, so I was wondering if that is still
a good option-or is there a different combo that I should try?
 
      Thanks,  Rich W
 
I have the HiFace also, it really cleans up the sound!
 
If you can afford it try a pair of 2.7uF Dueland VSF Cu Caps:
 
http://www.duelundaudio.com/VSF_Capacitor.asp
 
I have a pair of 4.7uF in mine but Bill Allen has a pair of 2.7uF in his Chameleon and he
says they are good down to around 25 Hz.  The 2.7uF would have saved me A LOT of money.....
 
Have you replaced the IV resistors yet?  Everyone seems to agree the Texas Components TX2575 are amazing:
 
http://www.texascomponents.com/pdf/tx2575.pdf
 
Have fun!
 
Skibum
 
 

 

[thermalbat]

Hi Skibum-
 
  Thank you for the reply. I've read up a little on those caps and they sure do look interesting.
Will they fit in a standard Valab DAC (March '09 model without the 2nd TCXO)?
Should I bypass the stock caps (Two metal can Tantanium 10uf/16v), or just replace them with the
Duelands? 
 I'm new at this modding stuff, but seems like a lot of fun-maybe a new hobby!
 
     Thanks,   Rich W

 

[skibum]

Quote:

Hi Skibum-
 
  Thank you for the reply. I've read up a little on those caps and they sure do look interesting.
They Duelands are huge and will not fit in Will they fit in a standard Valab DAC (March '09 model without the 2nd TCXO)?
Should I bypass the stock caps (Two metal can Tantanium 10uf/16v), or just replace them with the
Duelands? 
 I'm new at this modding stuff, but seems like a lot of fun-maybe a new hobby!
 
     Thanks,   Rich W

The Duelands are far to large to fit inside the standard Valab box.  You have to buy another box to put them in.
 
The caps you buy will replace the stock caps.  Throw the stock caps in the bin!
 

 

[MikoLayer]

I doubt I will ever get a chance to have another shot at fixing mine until mid June (got my hands full with the dissertation), but I do have plans to do so all in good time...
 
In the meantime, I am trying to decide if HiFace is worth a try. $150~$180 + shipping seems a but steep, but haven't heard nothing but praises so far and I have far exceeded my projected budget at the beginning anyway
 
Has any of you had a chance to compare it to Musiland 01 USD? 
 
http://www.diyaudio.com/forums/pc-based/166376-m2taech-hiface-vs-musiland-monitor-01-usd-2.html
This thread got me thinking which one I really should get...
 
In the event I do happen to pick the HiFace, is it the BNC or SPDIF version I should go for? My luxury version valab DAC has the following mods done to her: DIR9001, texas component resistors, mundorf SIO output caps, russian teflon input caps.

 

[skibum]

Quote:

I doubt I will ever get a chance to have another shot at fixing mine until mid June (got my hands full with the dissertation), but I do have plans to do so all in good time...
 
In the meantime, I am trying to decide if HiFace is worth a try. $150~$180 + shipping seems a but steep, but haven't heard nothing but praises so far and I have far exceeded my projected budget at the beginning anyway
 
Has any of you had a chance to compare it to Musiland 01 USD? 
 

http://www.diyaudio.com/forums/pc-based/166376-m2taech-hiface-vs-musiland-monitor-01-usd-2.html
This thread got me thinking which one I really should get...
 
In the event I do happen to pick the HiFace, is it the BNC or SPDIF version I should go for? My luxury version valab DAC has the following mods done to her: DIR9001, texas component resistors, mundorf SIO output caps, russian teflon input caps.

I have the HiFace and in my system it really cleaned up the sound.  Huge improvement for the money spent.  It comes with either a RCA output or a BNC output.  Either way it is a USB to SPDIF interface so it outputs SPDIF - you just have a choice of two different connectors.

 

[MikoLayer]

oops, what I really meant was RCA vs BNC in the light of what is likely to work better on a valab with the above mods applied to it. Thanks again.

 

[dexter3d]

OK my Valab (late '10 version) started to buzz (I mean 'outside' buzz), and before it was dead silent. What? Others with the same experience?

 

[marcelnl]

both th evalab and the chameleon thread seem to be abandoned, but pls describe the outside part of th ebuzz you;re experiencing....
 
Sometimes as chassis starts to buzz when the power phase is reversed.