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Chameleon DAC listening and modifications - Page 16

post #226 of 1144
Quote:
Originally Posted by PatOMalley View Post
there is only one way to tell.
from the drawing it looks like it only sets 75ohms in the incoming leg of the transformer then goes to ground. it looks like it can just be removed. The transformer is already at 75ohms on it's incoming leg and my output transformer on my CDP is 75ohms sooooo
Hi Pat,

I didn't read all posts of the Chameleon thread yet so I just bumped onto this one. Although the PE transformer has a 75R input this does not mean that it acts like a resistor.
The best thing is to terminate your SPDIF (or wordclock) signal at both ends. This minimises reflections even when the cable impedance is not exact. If you only terminate the source (the cd player/transport in your case) you increase the chance on reflections and impedance mismatch.
post #227 of 1144
Quote:
Originally Posted by Bill Allen View Post
I have to say that Rhodes has me intrigued with using a Paul Hynes SR1-MR with a more heavy duty power transformer. Scottie ... more power!
I took the decision not to do any compromises with the Chameleon.
An Ultra lownoise power supply is THE way to go and therefore another SR1-MR fort he Chameleon will be ordered soon.
The plan for now is to make 3 different power supplies:
1. A SR1-MR for the +7.8V DC to the DAC Board.
2. A Q-mini (gold) regulatorboard for +5.0V DC to the TCXO's only
3. A Q-mini (gold) regulatorboard for +5.0V DC to the rest of the digital board.

All with seperate power transformers.

If feeding the TCXO's a seperate powersupply will be to hard to do points 2 and 3 will be 'joined' together.
post #228 of 1144
Very nice wood, what size are those Jupiters anyways? So we can all known the max size cap this chasis will fit. DxL in MM would be best.

Quote:
Originally Posted by Wood View Post
Found a way to fit that teflon, hot glued to the bottom of the terminal connector and board.

Then had to take the coax/opt switch out in order to squeeze in these guys.

Just fit with the lid, very nice.

No room for now for the power in bypass, but I will find a way
post #229 of 1144
Hi Mike, there the 5.5uf caps currently on sale at Partsconexion.
post #230 of 1144

A Blizzard of Activity

Wow this is more like it ... a blizzard of activity.

Rhodes - you're a madman! Warp Factor 9 Mr. Sulu.

I just performed these two recent mods.

1. Tony's FRM (Film Reservoir Mod)
2. Nugent's FIM (Floating input Mod)

Pictures here at the end: Picasa Web Albums - Bill - Chameleon

For the FRM I recycled both 10uf Wima Film Caps, soldered them together for 20uf, added some silver wire leads, and tacked them down to the positive and ground input posts for the DAC board. Shazzam! The soundstage jumps, more vibrant, more dynamic ... more everything. Like the acronym FRM it just firmed things up. Thanks Tony!

For the FIM I had the luxury of oversight by watching what everyone was doing and found a simpler and safer way to add a .1uf film cap to pin 3 of the pulse transformer. Stick a small screwdriver underneath the secondary side of the pulse transformer and alternately heat pins 3 & 4 and rock these pins off the board. Bend pin 3 out and solder one end of the film cap (I used a NG Jupiter .1uf) here and solder the other end back in the hole pin 3 came out of. No messing with the tiny trace. Next I just soldered pin 4 (ground) back down to the board. Finally I soldered silver wire leads directly from the Spdif RCA jack directly to the input of the pulse transformer. Pin 1 is positive and Pin 2 is ground. The 75 ohm surface mount resistor lives between them. This is floating the Spdif input, as the ground of your transport does not see the ground of the DAC. It's floating there with the pulse transformer providing galvanic isolation. Kapish!

The FIM really sharpened up the soundstage, like focusing a camera lens. Subtle ... yet profound at the same time. Depends if your system can resolve these differences. Massed violin's now have individual voices, the melodic line sounds more real to life, the toe taps freely if you know what I mean. Brass sounds like brass, bass is less bloaty, tighter deeper, I can sense the air in the room of the recording. From experience I know this to be the sound of lower jitter. This may all sound like ******** to some of you but trust me all that detail is there on those 16 bit recordings ... if only we can extract it!

For me the FIM is the way to go, I tried grounding the Spdif RCA jack and adding a .1uf there as the Audiocom wiring diagram suggested. Sorry it didn't sound nearly as good with my system. Your mileage may vary, just depends on how clean your Spdif input signal is as Rhodes suggests. Mine is pristine being fed from a Pace Car, unfortunately the only thing the receiver board can do for me is add more jitter. I plan on direct I2S input from the Pace Car down the road but for now the FIM is my best connection. Thanks Steve!
post #231 of 1144
Got some caps in the mail today, just finished this job up. I was a little bummed the 100UF silmic2 where a bit to large to replace all the caps on the Digital input board. Got most of them though.. Everything went pretty smoothly. Do those caps on the digital board and reclocker look fine? it's the only way I could attach them.

Anyone got some suggestions for some caps for those 2 100 uf smd tant's that are left on the digital board? I almost shoe-horned the 100uf Silmic's in, but it was very sloppy looking. I was thinking, perhaps Panasonic FM, or those Os-Con's. I don't know where to buy the Os-con's though, Panasonic FM's are readily availible at digikey for 16c each.

Listening to it now, does not sound to great hehe, sounds like unburnt in caps. Give it some time.. the waiting. Although, it's immediately "Smoother" and seems to have a "blacker" background, I feel like I can hear farther into the music, but there is no lows or high's yet. I still get more noise then i'd like.

Still waiting on my TX2575 175R's. They got about a week lead time. I've also got some Cardas CTFA rca's on order. They are not "high end" but I think anything will be better then these stock rca's, the golds already wearing thin. I've also decided on a MultiCap RTX .1 UF film cap for the digital input spot. SPDIF is not to much a priority for me now as all my listening is thru USB at the moment. I'd really like some of you to compare the USB to SPDIF /w the reclocker in play.

Warning: Random Thoughts below


I wonder how a Vishay 1837 .1uf would sound in place of that little green cap that's attached to the pulse transformer. It's a pretty small cap, would hang there fine I bet. Someone should try that.

Unfortunately, I can't find any size information on the Jupiter 5.5 UF, so it does no good as a size tool. Anyone find the size of these Diameter X length?

Are the dac coupling caps "In the Signal path" or not? Im still not certain on this.

you can see clearly, on the Reclocker board, the 24/16 bit "jumper" i was talking about. It's under the Silmic2 at on the bottom of the board. it has a little arrow leading to it. If you bridge those 2 pads you get 24bit.

Hey bill, I'd like to see pics of your power supply mod if you get time to post them
LL
LL
LL
post #232 of 1144
The Chameleon Schematics was updated and can be requested for the Chameleon DAC owner. However, little was modified. If you want it, just mail Michael for it.

Quote:
Originally Posted by hifi2001 View Post
I was busy in the last few days not keeping up with this forum, but man you guys move fast with your mods :-)

about this pulse Xfrmr cap you will find that it does go to pin3 and it is not in schematic (but will, after Michael get a chance to update the schematic). In my case, I had to cut the traces on mine to insert that film cap in there. . With my early adopter version, cutting that trace was probably the most difficult mod I had to do so far... I ended up soldering one leg of the cap directly to pin 3 and trust me I almost lost the entire digital board and had a very sore set of eyes... I am quite positive, that once Michael runs out of his initial batch of this board he will add proper spaces for this cap. With this said, let's figured out how much space this cap will need and provide feedback to Michael so that hopefully they will take this into account when they introduce version 2 of this board...
post #233 of 1144
Dac's been playing for 6 hours now, i took a break and came back for a listen. I would not think anything could happen in 6 hours but it's already sounding better. Im listening to Jazz at the Pawn shop, man o man, im hearing things that where not there yesterday. Holy crap, that slight whisper pppffh at the last note of a sax, and spatial cue's that just where not there before, very cool. I can't wait for full burn in. I won't really know how much is coming from the Dac coupling caps and how much is because of the cap swap on the Reclocker/Digital input board as I did both of these upgrades at the same time. I will say this, it's very worthwhile upgrade, and only cost me 12$ in caps
post #234 of 1144
Quote:
Originally Posted by MikeW View Post
Got some caps in the mail today, just finished this job up. I was a little bummed the 100UF silmic2 where a bit to large to replace all the caps on the Digital input board. Got most of them though.. Everything went pretty smoothly. Do those caps on the digital board and reclocker look fine? it's the only way I could attach them.

Anyone got some suggestions for some caps for those 2 100 uf smd tant's that are left on the digital board? I almost shoe-horned the 100uf Silmic's in, but it was very sloppy looking. I was thinking, perhaps Panasonic FM, or those Os-Con's. I don't know where to buy the Os-con's though, Panasonic FM's are readily availible at digikey for 16c each.
i'm thinking you could be messing with the signal integrity with what you are doing here, replacing caps indiscriminately in the digital section's decoupling is a recipe for bad sound. tantalum in the analogue signal path is pretty horrible, but for decoupling they are quite fast and do their job quite well, if you are going to replace it I would choose a high quality ceramic organic polymer. the oscons are good here too, but there is a reason datasheets often call for tantalum. You could try bypassing with a silver mica or other small film like WIMA MKPS, they would work nicely too. The caps in the digital section should really be kept to the same capacitance, its not like the analogue section where its cool to just up the size in most cases (other than filter of course) so unless you have actually planned something out with a specific end in mind with upgrading caps in the digital section, similar caps should be used, electrolytic caps of any quality simply are not as fast as the cheapest films or ceramic, so in the digital filters and decoupling I would steer away from using them without knowing what you are doing.

all of the above is of course my opinion, and no way would I say dont play, thats what these dacs are great for, I also suggest looking at the datasheets for ideas on decoupling mods as they are a great resource that is often overlooked

Quote:
Listening to it now, does not sound to great hehe, sounds like unburnt in caps. Give it some time.. the waiting. Although, it's immediately "Smoother" and seems to have a "blacker" background, I feel like I can hear farther into the music, but there is no lows or high's yet. I still get more noise then i'd like.
i'm thinking you need to sort out your power supply, I suspect this is where the noise is coming from, or a borderline ground loop

Quote:
Are the dac coupling caps "In the Signal path" or not? Im still not certain on this.
no they arent, they are decoupling the power supply pins of the dac chips

@ Rhodes nice one on the minigold regs, coffin has designed some great little regs there, mine are on the way shortly too. i've been going a little regulator crazy lately. I just finished off some sjostrom SSR01/02, salas shunts, JSR04, JSR06 on the way and some of those new version mini gold. have you got your PCBs yet for them or are you waiting like the rest of us for the new boards to ship?
post #235 of 1144

wima crush

Here is how I put in those recycled Wimas, I wanted to put them as close as possible to the solder point, and found they just, and I mean just, fit under those big caps.

The oscons I am using are 270uf but seem ok. Temporary though, as I've never been a big fan of oscon sp, a bit hifi to me. But what to get, bg n, oscon sep? Actually Ive used silmic in digital decoupling before and they were ok. What would you recommend as bypass value here qusp, 0.01uf? Vishay Rodenstein are another option.
LL
LL
post #236 of 1144
Hmm dang, your gonna ruin my party Qusp hehe. Aside from the cap's the soldering look ok?

Well, I did keep the tantalum SMD's they would be pretty easy to swap back. I wonder what I should do here... Maybe let them burn in for a couple weeks and swap the Tant's back for a listening comparison. Or just buy some Sanyo Oscon's ? I know the older dac's did not use Tant's for digital decoupling, I think they used Organic polymer, not sure, little silver caps with a blue polarity indicator, short and stubby.

Where can you buy Os-con's in the needed Capacitance, oh yeah that's another thing, I did keep all the Capacitance values the same as what I replaced, only 2 values. 10uf and 100uf.

Would it be safe to use a 6.3 volt cap on the digital decoupling? I can't find a Silmic2 10v 100uf, but there is a 6.3 volt that might fit better.

I did suspect I have a power supply problem, as I measured AC on the +5v rail, (0.036 volts) and none on the +7.5 volt rail. But when I asked about it here I did not get much response, and I asked Teradak directly and he blamed my meter. The same meter that measures nothing on the +7.5 volt rail, and measures the same 0.036ac on the +5 volt rail day in and day out. Anyway, even if there is ac on the +5 volt rail I have no idea how to fix it, or where it is coming from.

Hey wood, exactly what did you do with those Wima's in the dac section are they filtering the incoming power? How is that wired up? Could you do this inside the PSU instead of the dac? Looks like you solered the 2 wima's together, ran a wire from +7.5 to one side, and a wire to ground on the other side.

It looks like Vishay/Sprague purchased Os-Con from sanyo? Anyways I found these at Mouser, supposedly they are pretty comparable to Sanyo. What do you think of these? They are quite spendy..

http://www.mouser.com/ProductDetail/...O5XNndJocJ4%3d
post #237 of 1144

Got it

Quote:
Originally Posted by MikeW View Post

Hey wood, exactly what did you do with those Wima's in the dac section are they filtering the incoming power? How is that wired up? Could you do this inside the PSU instead of the dac? Looks like you solered the 2 wima's together, ran a wire from +7.5 to one side, and a wire to ground on the other side.

Yes and yes
post #238 of 1144

Power supply addition to try

Mike, you can wire the caps at the power supply end of things but that kind of defeats the purpose. You want to have them right at the source of the drain, not 12" of wire away. You can tap them right at the DAC chip board where you see the 7.6v and ground jumpers.
post #239 of 1144

Power supply addition to try

BTW, I re-read Mike's post and this mod is NOT meant to further the filtering of the supply to the DAC chips. It is meant as a current reservoir. That is why you will get more punch and clarity to the music when you install the mod. Perhaps that is why you thought it was fine to apply it on the DC-30 side of things.
post #240 of 1144
yeah, i thought it was a filter. Is there a way I could attach a cap to the +5v input of the dac as some kind of power filter? Maybe just reverse what wood did? but put it on the +5v rail instead. (since my 5v has ac in it). It also looks like wood has wired his up wrong if he was trying to do this "power reserve mod"

Edit: i just checked the noise level, and it does seem improved slightly over what it was before these mods. Every little bit helps. Im still not convinced that it's not working as intended and it's just alot noisier then the old valab. It's not a ground loop either, I have my Amp and Dac plugged into a power conditioner with "Isolated" outlets.
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