Valab NOS DAC - subjective listening and modifications - Page 98

Just starting my Mods - Dueland caps!

Hi Everyone,

I have a Luxury version that I am planning on doing the following:

1) Replace output caps with Dueland 4.7uF Copper Foil caps.
2) Replace Output Resistors with Texas Components T2575 340 Ohm resistors.
3) Replace the 8 DAC Caps with Rubycon Blackgate FK's.

I have bought a small metalbox to fit the HUGE Duelands into. I also have a few extra Blackgate Caps that I may put in...

These Dueland Caps are EXPENSIVE! Looking forward to see if they were worth it....

I have attached some photos.

Can't wait to start!

scott

wow your amp must have some pretty seriously low input impedance. even my 3.9uf duelunds were overkill and with most of my amps I could have got away with 1.5-2uf.

I wonder with these super caps, would you not need them on the rest of your gear to get the full benifit?


Strangly though, I onece swapped teflons with obligato, back and forth, between my Yaquin valve buffer and the Valab. Despite the signal having to go through both types of cap, I could still hear a difference once it passed to the speakers!

absolutely not. do you have to change all of the resistors in the valab to TX2575 to hear a difference? for sure it doesnt hurt, but I tend to look at choices piecemeal, but with a whole system approach; kind-of a modular world-view. as you know the most expensive doesnt always mean the best for any given circuit.

each component has its influence on sound and that influence is passed onto the next component. for sure if possible its nice to end on a pure note though IMO, so I try not to leave bottle necks at the output

But say youve got your nice duelands on the output of the valab, and then a couple of standard mundorfs on the input of your amp, sure, dueland - mundorf, would be better then mundorf - mundorf, but your still going to end up with mundorf performance, a lot of the dueland magic would be lost, would it not?

I have been using 330R Shinkoh tants as I/V resistors for several months, but had too much sibilance. I put in a pair of Takman metal films 2 days ago, and the sibilance is tamed. I don't know how they will age, though.
Pat, I bought the Valab solid silver digital cable (sorry for waiting so long), and it seemed to strip the fuzz from around instruments. I'm not sure if I like it, but the rest of my system is so variable (I built most of it), that I'm not sure of anything!
The DC-30W cleaned up the bass (mainly), but changing from OPA627s to AD825s in the crossover made a big change as well.

Thanks, is there a quick way to test that without committing to ordering more parts? I just don't happen to have any spare RCA plugs lying around I believe you when you say these aren't stellar performers, but this has never happened without modding. Needeless to say, I have not mucked with anything near the plugs... We will see

A quick way of checking is to use a meter to see if there is signal to the output of the RCA's on the suspect channel

hmm, well i'm not sure about the location of the 'magic' but there is always another component after a cap, whether it be another cap, a resistor, a transducer (and crappy piece of wire) changes are cumulative no matter the quality the ideal is NO cap, but I guess yes if I could change all the caps in my system to duelund I would

Some more titbits on the Cameleon

http://www.head-fi.org/forums/f7/ter...ml#post6272767

How much to spend to get nothing

To right, have no input caps on my Charlize 2, never had any reason to complain about those caps, and the cost nothing.

Trouble is you have to stick them somewhere else

I was planning on going through my Naim preamp first. I don't have a dedicated amp just for this project at the moment - but maybe.... hmmm...

thats not necessarily true, if the source is well designed and/or uses a servo on output there is no need for a signal caps at all. even on my new portable the ibasso Fiquest. there are no caps in the signal path whatsoever and it sounds wonderful. many dacs will have no DC offset these days and even if they do there are other ways to get rid of it that are superior to a cap. a high quality transformer for example. or by injecting bias current into the input of a buffer. etc etc

if you have to trust other manufacturers to produce gear that has no offset then maybe you are in more of a situation where they are needed, but if you control the process there really are better ways.

but of course for the valab yes there is need for a cap and a good excuse for a nice one.

Talking about no caps, qusp, have you ever tried blackgate nx hiq in super e configuration as output caps?

yeah I use that in my D10 dac/amp



works very well, I used super E in both the power rail and output caps. it doesnt have to be blackgates and you can use one polar and one non-polar as well. I have found FK with N type (not NX) to be great in the power section. these are NX type because they are smaller, allowing me to have more capacitance. I prefer N to NX of the non-polar blackgates.

also you can see my opamp configuration isnt exactly stock either