Valab NOS DAC - subjective listening and modifications - Page 103

if your going to spend big money on batteries why not just get a power regenerator from ps audio. seems like the ideal, cost is no object solution.

edit: First Post on page 100

feeding Valab

I have some news related to last November's discussions concerning the quality of signal input on the Valab.

Steve Nugent (Empirical Audio) is in the process of implementing M2Tech async firmware into a big hardware upgrade and was asked his opinion of the HiFace. He said it's an excellent product for the price and the current Off Ramp with Ultraclock and a good USB cable is slightly better.

The Ultraclock is the high end $800 part versus the $300 Superclock 4 that's in the $1k Off Ramp I compared to the Valab's USB input back on page 74.

That, my friends, is one hell of a seal of approval.

The key to all this is just to make a dac as intelligent as an external hard disk or printer duh!

Perhaps they might build the protocols into usb 3, then again prob not. Im using an even cheaper Musiland 01 USD, its makes a big difference, if you upgrade the caps in it.

A recent opinion comparing HiFace and Musiland 02

http://www.head-fi.org/forums/f46/us...ml#post6280373

I bought my TX2575's while I was in the states but you can get Charcroft Z-Foil Resistors in the UK:

Charcroft Z-Foil Resistors for Audio homepage

well big money? A decent 8000mAh Lipo will set me back some 40 euros, throw in a Low Z AT type reg and some caps from the stockpile amassed over the years and I stay far from the several hundred euro PSU I end up with otherwise. I'll happily charge the thing with the DAC on the PSU I'll create with the bits already present on the board.

Lipo not fast enough? Has anyone ever found specs on that? I seem unable to find data beyond the fab max currents of the thingies, but no other audio relevant data -sure would like to do without the regulator only using some bypass Capacitors to get rid of any grunge. Wishful thinking maybe, we'll see when the time comes.

Found the UK link too, but those seem overpriced 'handcrafted' relabeled pieces using the previous version, the spec and pics appear to be copy pasted straight from TX....

several hundred dollar PSU I can put together a kickass PSU with multiple high quality regs for well under the 200USD mark

errmm, but what about supplying several different precise voltages all within +/-5% you gonna do that all with resistor networks and caps? sounds like a total PITA, just use a few quick regs (with or without batteries) and be done with it. batteries dont supply constant current, the voltage will start to drop the moment you apply power. you want a reg with CCS, like class A for power supplies. if LiPo4 was really good for audio someone would be using it in portable amps as they do manage to pack heaps of energy in a small space and that would be perfect, but noone is using them that I have come across. you could use them in conjunction with a large bank of fast caps for a reservoir I guess, but still think a reg is a better idea.

hdnt seen those rebranded TX R's wow pricey alright. but I guess what else do i expect from British audiophile suppliers. you guys pay the most insane prices for anything there. HiFiCollective is crazy prices

Hey qusp, be fair, the price of our audio hardware is on a par with the price of our music CD's , ....consistancy

the day that the fact nobody uses something like Lipo batteries for audio keeps me from researching the option will hopefully coincide with the day I die ;-)

Again, the important specs seem missing and what I see sofar seems quite compatible with this sort of 'audio', they keep a steady voltage until the power is used up and then the voltage drops very rapidly.
Reg or not in the supply remains to be seen, these Lipo s are capable of 120 A steady state while maintaining a pretty steady voltage.

I pride myself lucky not to be from the UK, I'll source the TXs from the cheapest supplier in true Dutch tradition ;-)

Which is.....the company itself?

I concur gentlemen, and in fact have just done so, very nice people there in Texas I must say!

New Chameleon thread

http://www.head-fi.org/forums/f7/cha...ations-465039/

fair comment, for sure give it a go without regs, seems like more trouble than its worth to me, battery + reg + reservoir would be the way to go. we need regulators on wall power because its not fast/accurate enough, why batteries would be is beyond me and it doesnt supply the correct voltage. anyway i'm interested to see what you come up with.

ok, like I said I havent really looked too far into them, but any battery I have used doesnt maintain a steady voltage at all, steady current yes, steady voltage no. NiMh is my fave, but it operates like this too.

good choice, they are seriously the most friendly corporation I think I have dealt with. so willing to help and for quite small orders. they also seem very keen for the feedback we give them on performance.

Janet is a really nice lady

PSU

Here is a close up of part of the DC-30W psu, it has trimmers so you can change the voltage to the chips, that has big effect on the sound, not the quality IMO but presentation.

yeah yeah I realize, but those are references for the regs thats what I mean. the voltage across those combined with the reg provides a voltage reference, fixed value resistors are superior so once you find a good setting, measure the resistance across the varistor and replace it with a fixed value resistor of that value.

I concur with Qusp on the benefits of a fixed resistor vs the variable one on the voltage reg.
BTW: What voltage do you find to be ideal? (knowing that 8 V is the absolute max rating for the 1543 and 7.4 is a typical voltage for Lipo 2cell batteries)?

has anyone ever tried the TX resistors or an improved version on the DAC bias current and cares to share their findings?

In my experience modding my Marantz CD player (ao gold crown 1541 , home grown analog tube end stage using E86C's with I/V conversion using Dale resistors and a NiMH for negative bias current etc.) changing the capacitors and Resistors around the DAC to better quality stuff gave a slight but worthwile improvement in definition.