[Bill Allen]

Quote:

Originally Posted by skibum /img/forum/go_quote.gif Have to say I am pretty content with my VALAB 3.0 even with the reclocked SPDIF input. My interest is also out of my curiosity about how reclocking circuitry works. Why does the Chameleon play 96/24 were my VALAB will only get to 48Khz? Anything higher and lots of distortion, but I can hear the music. When you say "termination" what do you mean?

The USB receiver chip inside the Chameleon is capable of 96/24, while the USB chip inside the Valab is limited to 48/24.

I am speaking of the I2S termination at the DAC chips. There is a transmission line effect with I2S depending on length and impedance of the cable/board trace combo. The I2S bus is set with resistors at the DAC chips for overall proper impedance load. Its actually more complicated than that but that's what I know. I cheat by playing a 96/24 music file and keeping changing the termination resistors until the popping and clicking stops. Once you have the correct value replace them with surface mount resistors. Without a scope and proper training that's my best advice to the DIY'er.

There is no set standard like 75 ohms for Spdif.

 

[skibum]

Quote:

Originally Posted by Bill Allen /img/forum/go_quote.gif The USB receiver chip inside the Chameleon is capable of 96/24, while the USB chip inside the Valab is limited to 48/24. I am speaking of the I2S termination at the DAC chips. There is a transmission line effect with I2S depending on length and impedance of the cable/board trace combo. The I2S bus is set with resistors at the DAC chips for overall proper impedance load. Its actually more complicated than that but that's what I know. I cheat by playing a 96/24 music file and keeping changing the termination resistors until the popping and clicking stops. Once you have the correct value replace them with surface mount resistors. Without a scope and proper training that's my best advice to the DIY'er. There is no set standard like 75 ohms for Spdif.

So that's what those resistors in between the 74AC74 Flip Flop's and the TDA1543's are for? Once you changed your termination resistors to get 96Khz working would 44.1Khz & 48Khz still work?

I only use the SPDIF input on my VALAB and it works only to 48Khz. Would be nice to get 96Khz out of it....

 

[Wood]

Quote:

Originally Posted by taiphan /img/forum/go_quote.gif Hi everyone.. firstly thank you your sharing your mods and ideals.. i've been following with keen interest over the last few months as i own both the original valab and the new chameleon. can i please ask a couple of questions. 1) i used a Trend audio usb to Spdif converter then coxial into the chameleon. The trend can be powered by usb or external 5v. my question is if i tap into the chameleon's 5v power line to power the Trend aswell, will this have an impact on the chameleon's performance or can the power supply handles it? 2)my Chameleon power supply unit (yellow wire mod) makes a buzzing noise under load (when the dac unit is plugged in), is that normal? the buzzing is audible if i am close enough to it. i emailed Kevin about it but he doesn't seem to care much. thank you in advance. ps. ordered the parts, can't wait to mod mine.

Hi, taiphan

1, I have done this with a Musiland usb-spidf convertor and it worked well. I dont know if the current drain from the Trends is higher which might cause a problem, lowering the over all power for the dac chips. If you try it look out for that. Also a risk of ground loop noise.

2. If you mean a mechanical buzz, that might just go a way with time, or you could try reseating the transformer, or moving the psu on its side etc. If you mean audio buzz from the speakers it is likely to be a ground loop problem. If so Google 'ground loop'.

If its a ground loop thingy and nothing sorts it from Google, an ADUM isolator like the Ultravox might do the trick. Which, if your using USB you should get anyway I recommend such devices as de rigueur, for files up to 24/96, also it would give clean power to your Trends.

 

[mmerrill99]

Quote:

Originally Posted by Bill Allen /img/forum/go_quote.gif Yes Steve had first tried the standard 3.3V output from the Pace Car, and while it worked, he found the sound quality lacking. Converting the Pace Car I2S output to 5V changed everything, I think its safe to say the Chameleon needs 5V for optimum operation.

OK



Quote:

Agreed! But I for one like one stop shopping, are you going to offer an ADUM product?

I don't see much demand for it -what I should say is if the demand was there, maybe




Quote:

Reeheeheally! I will PM you.

OK but can't tell you much until I release it.

 

[MikeW]

Hey guys,

been awhile since i've made a post. Don't have a whole lot to add. I have not made any changes since I wired the input board direct to the dac board (bypassing traces, jumpers). I've been so pleased with the sound that I've felt no need to go further. I also managed to fry my damn reclock board again lol. It's real easy to put that little person in backwards. I wish they would have "Keyed" those boards so they would only go in one way. I'm not to bothered by it though, as I really did not like the way the reclock board was sounding for me. At first I loved it, but when I damaged my first reclock board I had to live without it for a month or so. Then I bought another one, and never could adjust to this reclock sound as i'd grown to love it without. The reclock board always did add a significant amount of noise to my dac as well. I don't know if im just extra sensitive, or if there was something wrong with my board. Both reclock boards had the same level of noise. I tried a few things to resolve it but nothing worked. I think my next step will be to get something like the HiFace. Right now I feed it digital spdif from my X-Fi, I think it sounds a little better then usb input. Im sure there's lots of room from improvement here.

 

[marcelnl]

it is my firm belief that any additional digital step adds digital grunge, which usually is audible as noise or sonic edges where they do not belong. I'd be so happy if it would be possible to have the simplest of schematics, as Bill suggests, just an I2S source and a DAC chip or even a dedicated resistor based DAC....
With Bill it is my experience too that the simplest of designs such as the triode SETs of the thirties and fourties sound damn good when built with high spec components and put together with someone who knows what he is doing.

 

[Wood]

So true, and why digital is such a hard nut to crack. If we think about the simplicty of an analogue source, needle vibrates in a groove, and creates a small electric current......and thats it, done. The digital journey is so long, there are many many oportunities to introduce noise.

I used to think (with a bit of encouragement from Philips/Sony) digital must be perfect because there is no analogue signal in the digital domain, just 1's and 0's. Does anybody remember the demonstration drilling holes in CD's and then showing how they still played perfectly?

Oh well! Thats one mod I guess I should not of tried.

 

[marcelnl]

I personally would have hated to have gone the analog road, just to get totally crazy over all the plops and crackling of dust and scratches......but I totally agree wit you Wood.....

Prob with analog is that the signal is so tiny that it opens up a different can of worms, even without RIAA and all that. I've heard a couple of noteworthy turntables but none was cheaper than my other favorite the Ongaku.....(Goldmund reference,with a Kutsu element)
With CD it is easier to get to a level close to that, and the better the digital system is the more freely the music flows. With my 1541 gold crown the music was flowing, it was singing along, my Valab has yet to get to that point but it has its own merits like a superb low end.

It is all trade offs, yet I still hope I can ever get back to the point where my goldcrown was just before it passed on......
Simpler usually is better, so I am not even sure whether 16 1543s is the way to go.

It's the journey that counts...

 

[Bill Allen]

- Rant on- if you look at high performance audio playback in general it shocks me how many compromises are accepted. Take a good hard look, every interface is compromised what a sham. As I started down the road of no-compromise's in my audio system it was evident in very short order that I would be blazing the trail myself if anything was to get done correctly.

When I can't get something done myself its seems I have to cajole the expert into doing the right thing. Even if they know it the proper coarse of action. Take Jkeny's reluctance to offer USB galvanic isolation. Why? He simply can't find a reason/effort/energy/finances to jump this last hurdle. Even if its not economically viable it doesn't mean he shouldn't try it for himself and share the results. It's this reluctance to go the last mile, the time factor, this capitalistic reality, this ego centric driven society that holds all real progress back. I refuse to cave in to this reality. (Sorry JK for using you as a small example, I know on the other hand you busy blazing your own trails).

I blazed the trail for direct I2S connection on the Chameleon DAC, make your own excuses for not doing the right thing. The reality is this is the superior interface for these DAC chips and I was damned if I wasn't going to get the job done by hook, crook, or cajole. However I am afraid getting a manufacture to do I2S right at a reasonable price is not going to happen. Their various agenda's prevent such recourse. You are just going to have figure out how to get-er done yourself. I am here to help. -rant off-

 

[Wood]

Apart from yourself Bill, I am suprised there is so little interest on this thread for the potential of an ADUM isolator device. It makes a very noticible difference with direct USB.

For now, I prefer it as a seperate device, as there is always that little doubt that it might bring its own jitter, unnoticable with noisy usb, but noticable with a higher resolution device like the hiface.

As a seperate device, it will be possible for me to evaluate the hiface with and without it. Peace of mind stuff. Though in truth I doubt, very much, that the ADUM would cause more problems then it solves, anything that dumps the dreaded pc ground loop, can come round for tea anytime.

 

[mmerrill99]

Quote:

Originally Posted by Bill Allen /img/forum/go_quote.gif .......Take Jkeny's reluctance to offer USB galvanic isolation. Why? He simply can't find a reason/effort/energy/finances to jump this last hurdle. Even if its not economically viable it doesn't mean he shouldn't try it for himself and share the results. It's this reluctance to go the last mile, the time factor, this capitalistic reality, this ego centric driven society that holds all real progress back. I refuse to cave in to this reality. (Sorry JK for using you as a small example, I know on the other hand you busy blazing your own trails). ................

Bill, I think you're misrepresenting me - I didn't say I wasn't willing to try the ADUM (hell, I discussed this device on a number of other forums a long time ago & have one of these ADUM boards but haven't stuffed it yet) - I just didn't want to incorporate it into a box for others to buy - that's why I suggested you buy it separately & try it - why wait for me - I'm not holding anybody back from trying it? In terms of effectiveness, boxing it up confers no sound quality benefit whatsoever.

I do have other areas I'm researching & I'm hoping that others might take Wood's lead & get themselves an ADUM (Ultravox) & report back - this is how to advance the goal of better audio, no?

 

[errnst]

I like the idea of isolating away from the computer power supply. I was glad when wood first mentioned the ultravox. I ordered one this afternoon to use with my valab dac. I use usb all the time. It will take a few weeks for the ultravox to get here, but i will try it and report my findings.

i am unsure what to do about the power supply for it.

 

[taiphan]

Quote:

Originally Posted by Wood /img/forum/go_quote.gif Hi, taiphan 1, I have done this with a Musiland usb-spidf convertor and it worked well. I dont know if the current drain from the Trends is higher which might cause a problem, lowering the over all power for the dac chips. If you try it look out for that. Also a risk of ground loop noise. 2. If you mean a mechanical buzz, that might just go a way with time, or you could try reseating the transformer, or moving the psu on its side etc. If you mean audio buzz from the speakers it is likely to be a ground loop problem. If so Google 'ground loop'. If its a ground loop thingy and nothing sorts it from Google, an ADUM isolator like the Ultravox might do the trick. Which, if your using USB you should get anyway I recommend such devices as de rigueur, for files up to 24/96, also it would give clean power to your Trends.

hi Wood,

Thanks for your reply.

The Ultravox sounds like a good idea. How are you powering your Ultravox? from the Chameleon PSU? or will any "walmart" PSU will do?

also i was just wondering if everyone uses the upsampling board? i get random cracking in the music playing from Foobar, but if i pause the music and play again, it goes away. I figure this must be something to do with the upsampling board. Am i on the right track here because the random cracking is driving me nuts.

thanks

 

[Wood]

Quote:

Originally Posted by taiphan /img/forum/go_quote.gif hi Wood, Thanks for your reply. The Ultravox sounds like a good idea. How are you powering your Ultravox? from the Chameleon PSU? or will any "walmart" PSU will do? also i was just wondering if everyone uses the upsampling board? i get random cracking in the music playing from Foobar, but if i pause the music and play again, it goes away. I figure this must be something to do with the upsampling board. Am i on the right track here because the random cracking is driving me nuts. thanks

Try adjusting the buffer value in Foobar, I find with wasapi I get clicks unless its set to 0, with ASIO, I get clicks unless set to 2000ms.

Ultravox runs fine of a 12v wallmart. In the end I settled for a 12v 7ah SLA Battery because then the input is totally isolated from the ground

 

[Newk Yuler]

Quote:

Originally Posted by Wood /img/forum/go_quote.gif Apart from yourself Bill, I am suprised there is so little interest on this thread for the potential of an ADUM isolator device. It makes a very noticible difference with direct USB.

The AD evaluation board includes their companion isolated regulated DC to DC converter chip but audiophile applications will be limited. It operates like another switching PSU from the secondary side. I expect the Ultravox is a better choice.