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Chameleon DAC listening and modifications - Page 35

post #511 of 1144

Cinemag heads up

If anyone is interested in trying Pat's Cinemag addition, I got word from them that they are about to produce a small run of the CMOB-2S transformers. You probably should drop by the website and get in contact with them. (They are $22.10 USD a piece not including shipping.)
post #512 of 1144

Yellow Wire DC30W

Well, got the Yellow wire running, I let it run for a good 5 hrs and I felt it was still quite hot, but perhaps not to much so. I can definitely hear the difference running the Dac chips at 8V (a must to prevent clipping with 175R)

I put some 1/4 nylon spacers between the front and back plates, and put the unit upside down, I flipped the front face plate, and rewired the switch and LED. Now the hottest part of the chassis is facing straight up.I also put some larger feet, they are not huge but about 3x bigger then stock. I think the air gaps in front and back are probably more effective and look better then drilling holes. Im still undecided if I want to put a heatsink on top or not, it would surely help, but im not sure if it's needed, and it would be pretty ugly. I got some pics below.

Edit: I did have to replace the stock screws with longer ones to make the 1/4 spacers work.
post #513 of 1144

USB Help needed

I try USB today and no sound (SPDIF and optical work fine)...
when connecting USB to the DAC from my laptop, it does see "Teradak 96k USB audio" from sound and audio window. I am using Itunes on MS Windows XP SP2 and I hear only sound from laptop speakers.
Does it suppose plug and play? Do I miss something? any driver needs to be installed?
can you guys shed some info.? Sorry for this type of novice question.
post #514 of 1144
I've just plugged in a Chameleon unit that I purchased from a fellow Head-Fier. I've got it hooked up to my Technics SL-P770 CDP (4xPCM56P) through SPDIF. Right off the bat I've noticed that it's a little thin sounding compared to my good old CDP through analogue out. The bottom end is definitely tighter than my CD player though, definitely not as boomy.

I'll listen for a few days before I decide whether or not I like the sound

Edit: Here it is sitting in my humble setup:

post #515 of 1144
make sure your software (itunes) is set to output to the Dac. It should be somewhere in the options menu's.

As for windows sounds, when you have 2 "Audio devices" like this you must set one as default for windows. This can be done from the control panel. I don't use xp anymore so I can't check exactly where on this end. Buried somewhere under multimedia section in control panel.

Originally Posted by sinrouge88 View Post
I try USB today and no sound (SPDIF and optical work fine)...
when connecting USB to the DAC from my laptop, it does see "Teradak 96k USB audio" from sound and audio window. I am using Itunes on MS Windows XP SP2 and I hear only sound from laptop speakers.
Does it suppose plug and play? Do I miss something? any driver needs to be installed?
can you guys shed some info.? Sorry for this type of novice question.
post #516 of 1144
Thread Starter 

can you say bass?

I put those caps on the DACs on the VALAB but forgot or was not really sure of their impact as I did it right away. But after all the mods on the Chameleon it really shows. Tons of bass. Better image separation. Tons of bass.

I used 47uF Nichicon Fine Gold. I also scarified another BlackGate [one of the few who like them] on the power in. I tossed the little links that were there and used the leads from the cap to connect power and ground from DAC board to lower board.

I am glad I waited to add these caps because the impact is enjoyable. Next up is 1uF Jupiter caps because I think those old school wax caps might be a sympathetic sound with the transformer and wiring the power direct from the power input to the BK cap. I do like the Obbligato's but I think they are now adding too much thick tone. [ I thought this before the new BG went in.]

[another crap your pants moment]
post #517 of 1144
Pat, you have a PM.
post #518 of 1144
Thanks Mikew.
I managed to make it work on XP OS.
Just like to share with those who run player on XP OS, we need to un-map KMIXER. The instructions are fro this link. Wavelength Audio, USB DACS, Setup information for Windows based Computers
post #519 of 1144
I did some more test with resisters yesterday, I put the original 160R back in. I could go as low as 7.5 volts with those before clipping. With 180R I have to go to 8.2 volts, and at 175R around 8.05 volts. It looks like if you want to run at 7v you will need something like 140r.

This is hooked up to a computer via SPDIF, (same results with usb). And very controlled, specific test. The issue, like the valab may not be readily noticeable in alot of music, and some may enjoy the sound of clipping. But it is there regardless.

also, messing with the passive IV, combined with Dac Voltage, combined with output voltage... it's more complicated then a couple resisters and trim pots. Really this should be done with an o-scope. Doing it by ear is hard because just because one frequency range is clean does not mean the whole spectrum is, as I learned the hard way. I've been using a 40hrz tone where clipping is very easy to identify and adjusting my settings until everything was clean, low and behold it clips quite badly at the higher frequencies.

I was reading about the 1543 dac's on another forum, and came across some o-scope readings with the filter vs no filter. And the non-filtered scope did look bad, however the filter is still a compromise, yes it looked better on the scope. But the reason was the original source also looks bad and the filter only smooths it out(while also ringing like a bell), while the non-filtered just presents it as it is. Both ways are wrong.

I still seem to sense a lack of dynamics at 8v and the yellow wire attached. I wonder if the psu has enough power. Unfortunately to use those expensive TX2575's I must do one of two things, either run the dac at 8v or run it lower and attenuate the digital signal. (lower the volume before it reaches the dac). Ideally i'd like to run at 7v with the blue wire and have no clipping issues. But im unsure of the exact I/V resistance needed. It's well below 160r though. And i'd have to toss the 20$ 175r's.

Wood: Are you running 175r at 7v? You must be clipping like crazy? Hook it up to a computer and test it.
Pat: I know you are running the same resisters as me, what voltage to the dacs? I did notice minimal clipping even at 7.85
post #520 of 1144

Little fan for yellow wire

Decided to add a fan with its own power supply to avoid noise. Keeps the case a couple of degrees cooler. So far so good.

Mike, have been listening out for clipping at 7v, but cant hear anything wrong, but will let you know as soon as I do.
post #521 of 1144
I've been playing some more and found out way most of you are not seeing clipping.

With 175R and the output voltage trim pot maxed / near maxed out, at 7.85 volts. There's no clipping in the mid-high frequencies and very very little in the low frequencies, so small that you may never hear it in music. As it disappears at -1 DB and is barely audible at -0 DB. So to hear it you'd have to have music that hits 0 DB in the sub 200 hrz range. And then it would be very small/hardly audible.
post #522 of 1144
I have looked everywhere. Where do you buy this thing?
post #523 of 1144
Most of the stuff I listen to tends to be classical, and older rock/pop/jazz/blues etc so as you say, they tend to be lower output, esp classical.

A lot of new recording have been doctored by the studio engineers and the levels are pushed right up to 0db, again like you say. Shame because I can't enjoy new releases as much as I would like to, sounds compressed and flat, no depth. In fact even remastered stuff is often wrecked this way, which is why I only like original master recordings. Prob sounds good on a ipod type thing, but not real gear. Its ridiculous that an old clapton/cream recording destroys recordings by bands like Wheezer and The White Stripes, which otherwise I like.

Getting back to the point though, I'm not getting clipping, even with say, for instance, Neutral Milk Hotel, though its deliberately distorted in the recording, and at 0db.

Are you getting this clipping often, or just occasionally?

Update, listen to the first track on this webpage, http://www.miller-mccune.com/culture...composer-8507/

I get a lot of distortion, is this the clipping you hear Mike?

When I play it with the volume on the sample turned to 1/2 volume its fine. I don't get this happening with any of my music, this is the first time I've heard anything like this. My ears tell me the output from the website sample is too high, compared to my usual volume output but it doesnt show as anywhere near 0db on the computer volume control, it just shows normal, very strange. Do you get clipping from all your sources, or just your computer?
post #524 of 1144
Originally Posted by Netdewt View Post
I have looked everywhere. Where do you buy this thing?
TeraDak Audio Electric Company

I think its the only place at the moment, direct.
post #525 of 1144
My computer is the only source i've tested. I do have a CD transport but I don't use it often. This clipping happens via USB or SPDIF. There's nothing wrong with my computer as transport. The only difference is it allows me to easily test the dac with test tones and special software (like SineGen). If i could do these test with my CD player I have no doubt the result would be the same.

That said, It's not as if I can't adjust it to get no clipping at all. Right now for example there's no clipping, but i've got to run the dac chips at 8v, there's no way around it for me. To not get clipping at the low end (40 hrz) or the high end. I can run as low as 7.65 voltage and get clipping only at the low end.

The other option is to run at whatever voltage I want, and lower the volume in my player software etc. The lower the voltage go's the more I'd have to attenuate the signal.

The example file you gave me was such poor quality to begin with I did not listen to it for long. I only test with lossless, high quality music /samples.

get a lossless version of Sarah Mclachlan's Angel and play it at full volume. This song really makes clipping very obvious.

The file on that webpage sounded like crap at any volume and I heard no difference at max or half.

Download SineGen - Open Source Software - Tucows
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