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Chameleon DAC listening and modifications - Page 30

post #436 of 1144
Originally Posted by marcelnl View Post
Pat: try make your own cable, especially the digital kind is very rewarding and it provides a ton of insight !
How would you ensure its 75ohm, or is this irrelevent when using 2 trannies?
post #437 of 1144
I've never really worried about the 75 Ohm, as it seems impossible to me to get that right and its the combined geometry of the cable that matters.

Capacitance is key, and the beauty of DIY is that you can tinker until you find a local optimum for your setup.
You could use HQ Satellite dish coax or the likes but the results I have heard by just using f.e two lengths of twisted inductor wire outperformed most fancy coax cables I have heard including high End interlinks (vdHull and the likes also buy off the reel)

The 50 ohm story DKD Instruments (about coax impedances)

Velocity factor (VF) of common coaxial cables (Coaxial cable velocity factor information)

Transmission line problems Transmission line problems. solutions that help in understanding

Practical Line-Driving Current Requirements Practical Line-Driving Current Requirements

Impedance matching for microphones Shure - Professional Audio - Products

s/pdif interface epanorama.net/S/PDIF Interface
post #438 of 1144
marcelnl, just made up a 25cm litz 4 silver wire cable, its certainly an considerable improvement over the bog standard copper digital interconnect I was using. Didnt try before because of the 75 ohm fuss. But then I am a sucker for silver in the sig path.

Update: Interesting, after some listning, I noticed the sound was too smooth/polished, switched back to the bog standard 75 ohm cheapy cable and more texture.
post #439 of 1144
don't mess with Litz....what cable geometry did you use and what insulator?

A digital cable needs to break in for a good long period and the silver (any conductor) may be directional.

happy cabling ;-)
post #440 of 1144
wire was burn't in, lose teflon, but will try again later, because those bgs are all over the place at the moment, so I don't know what I am listning to.
post #441 of 1144
Thread Starter 


Originally Posted by marcelnl View Post
Pat: try make your own cable, especially the digital kind is very rewarding and it provides a ton of insight ! Buy some hich Q RCAs (or even better replace all cinch with solid silver BNC connectors) some thin 5N annealed silver or platinum wire, paper and silk or cotton and you're in business!
Might as well go for BNC right?
Might as well tweek this thing till the wheels come off.
post #442 of 1144
No love for poor opamps around here. They are hard to replace for their size and convenience though. Some have tried to make "Discrete" opamps, ala Audio GD's "Moon, Sun Earth" a discrete "Drop in replacement" for your standard opamp. Similar to the Burson Buffer. However, upon listening it's been shown that the best of breed opamps actually perform close or better then these discrete designs. Not saying opamps are better, but they are better then the massive discrete drop in replacements that have been made for them. There have been some real advancements in recent times too, look at the LME 4562, for example. If discrete was the only thing that mattered we would all be listening to 300$ Gilmore Lite's. But why does an M3 that stuffed full of opamps outperform it?
post #443 of 1144
I think we are talking about two distinctly different things here, Opamps stink at phase linearity and TIM due to the high slew rates and high negative feedback emplyed to get specs showing one gazillionth of a percent distortion.

A discrete Opamp is yet another compromise, space, just have a look at the 'L Audiophile and AN designs and you know what it means and if you have half a chance listen to those designs. I'm not familiar with the amps you mention but I'd guess that the one outperforming the other got more things right, discrete is only worth something if the designer knows what he is doing. I've heard (expensive) tube amps that were crap and those were easily outperformed by my daughters chip amp in her HIFI set but that does not mean that tubes suck.

Pat: replacing the standard RCAs is required anyway.
post #444 of 1144

Wima DAC chip caps

Originally Posted by marcelnl View Post
I for one was not aiming at Opamps in a DAC but in general, IMHO the only place they are tolerable is in budget portable gear and I'd still suggest replacing them with discrete components ....

Bear in mind that all this sort of stuff, as with transistors, was designed to shrink gear sizewise NOT to improve SQ. They got their priorities wrong back in the fifties, the choice should not have been to go to the moon but to design better audio tubes!
(dunno what I would have done without the allmighty computer, having a tube monstrosity with the calsulating power of the first electronic calculators would be an interesting challenge today )

For the WIMAs ; I'd advocate using 2*10uF for speed, not just because I'm cheap

Pat: try make your own cable, especially the digital kind is very rewarding and it provides a ton of insight ! Buy some hich Q RCAs (or even better replace all cinch with solid silver BNC connectors) some thin 5N annealed silver or platinum wire, paper and silk or cotton and you're in business!

Good show on the 75 Ohm, less is more (as usual in a well designed circuit)
As they say in Germany ; Limitation shows the master
I think that 10uF would be fine as well. One might try leaving in the original SMD caps and paralleling the 10uF Wima's if they are worried about total capacitance. I really just hate the break-in stuff and the usual sound of the 'lytics. I finally hit about 350 hours on the BK caps (and the whole unit as well) and the sound really blossomed. Very nice indeed. The whole soundstage opened up, became clearer and a little smoother sounding overall.
I would agree with Marcel about the digital interconnect. Though I did purchase mine I feel the general theories and experiences hold true. Mine are solid silver (flat and polished) and terminated with Silver Bullets as are all my DIY interconnects. I have tried a few others that Bill Allen had on hand and mine were clearly superior. One was an earlier generation of the same cable (Ridge Street). Chris Van Hause at VH Audio told me that just using his silver cable would not quite do the trick for a reason that I cannot remember exactly. Sorry for that brain fade but that does not preclude you finding your own solution. Good luck.
post #445 of 1144
I hooked up the yellow wire a few minutes ago, out of curiosity. Bass does seem to be slightly better, but it's not a huge difference. Perhaps because of the mods i've already done have made the effect less. I will say this though, I no longer have buzzing noise no matter what I set the dac voltage too. Before anything higher then 7.55 and I had very very slight buzzing noise, with the yellow wire I tried between 7.5 and 8.4 volts and there was not the slightest buzz or noise at all anywhere in between.

Im not sure i'll leave it here, I may set it back to the blue wire and set the dac chips to 7v, i listened to them at 7v last nite and was pretty happy, I think they do sound better there then at 7.5 /w blue wire.

I am concerned with heat though, I don't want to chop my chasis up, woods suggestion was pretty cool with the washers to make an air gap in front/back. I wonder if this is enough alone.

When you lower the dac chips voltage it also lowers the max output voltage. For example at 7.55 volts I can run a 40 hrz test and get exactly 2v output. (no clipping) Lower the dac output to 7v and this drops to 1.85 volts (anything higher will clip). Does this have any negative effect on performance?
post #446 of 1144
Thread Starter 

Chopped up!

A few holes in the top with an added heatsink up there.
Nice aluminum cones on the bottom. I kind of like it:

post #447 of 1144
Wow it heats up pretty good. To much heat for my liking. I put the blue wire back on @ 7v on dacs. I can't hear much difference tbh.
post #448 of 1144
what heat, the DAC chips use the power and the only thing the yellow wire does is to provide the voltage regs with a bit more space to do their thing. Ifg anything it is the voltage regs that burn off a couple of additional watts.
The voltage you set for the DAC chips will affect heat production and the output current, I'd tinker with that until you have the best sound and be happy .
1.8 V output should be enough for any power amp, I would not worry about the output voltage at all if the sound is better.
post #449 of 1144
yeah im talking about the DC30W chasis gets quite abit hotter. Not the dac.
post #450 of 1144
as long as you do not burn your fingers on it (or the heatsinks) everything should be OK.....
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