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Chameleon DAC listening and modifications - Page 14

post #196 of 1144
Cheers rhodes54!!
post #197 of 1144
I would be hppy to hear some tips on handling the microscopic leads and traces.....my eyes nearly popped out doing the DOR mod and started looking for magnifying glasses today.... (had to magnify digital pictures to see whether I lifted the leads far enough, pretty embarrassing as I did use my reading glasses)
post #198 of 1144
Heh heh, I think your eyes did pop out if you mean the 'DIR' mod.
post #199 of 1144
Actually, it turns out, most of those "non critical resisters" where inductors, so they stay the same.

Thanks for the tips on the Tantalum polarity.

I've never soldered Thru-hole caps on SMD pads, it seems wrong, I'll find out soon enough.

About the inductors in the low level filter, makes you wonder if they are what is messing with the sound, more then the filter caps themselves, would be interesting to bypass just the inductors and leave a cap there.

It is hard to take it slow, but it would definitely be the better approach to mods like this.

Edit: I've been really impressed with the USB interface! In my setup, it's clearly the best sounding option, beating coax and optical. Would like to get other impressions of this.

Quote:
Mike, changing non critical resistors is something that has on the whole not been investigated with these dacs, so I, for one, will be very interested what you find there.

Be aware that the little tantalum smd caps have a dark brown strip that indicates the positive end, its counter intuitive its looks like the negative.

The digital boards on the Chameleon are more tightly packed to reduce trace length so keeping the replacement cap legs short is the way to go.

The inductors in the low level filter are bypassed if you lift one leg of each those filter caps anyway, if you haven’t already tried that, I would. All of us who have, found great benefit from this, and if it doesn’t work for you just resolder the legs.

A lot of changes there so try to make mental notes of changes in SQ as you go. I always regret when I steam in and change everything at once and then not know what change had the most benefit, or indeed what change made things worse.
post #200 of 1144
Quote:
Originally Posted by MikeW View Post
I've never soldered Thru-hole caps on SMD pads, it seems wrong, I'll find out soon enough.
I just did this upgrade today and it's easy to do, when you own a SMD de-soldering iron at least. If you don't, be VERY carefull because those traces are very fragile.
I replaced all tantalum smd caps by Sanyo Oscon SP 100uF/10V and 10uF/25V (the small cap on the dejitter board).
I managed to keep the leads to the PCB approx. 3-4mm. Shorter was just not possible with the current tip I have on my soldering iron.





p.s. these pics where taken with my phone. I will make better pics tonight
post #201 of 1144
I dont' have and SMD de-soldering device, any tips? My plan was to just use as low heat as possible and use solder wick to remove as much solder as possible and then remove the component one side at a time. I've also got a solder sucker, but the wick seemed a little more delicate.

That looks like fine work indeed Rhodes, any thoughts on what it did to the sound? Hopefully lower the noise? hehe
post #202 of 1144
If I were you Mike I would leave the solder on the pads, then use lots of solder resin on the legs of the new components and reuse that solder. Yeah and keep that iron moderate, so the solder is sticky not runny.
post #203 of 1144
what I actually do is I heat both sides of the smd component in turns, keeping the heat on moderate while holding the comp with a pair of surgical tweezers.

Once the solder is flowing I pull the comp off, not elegant but I've not yet ripped off a trace.
PLs make sure the solder is runny when soldering the new comp on or you'lll be creating a gazillion of semiconductors in each joint.

The inductors in the output filter are a no brainer, the others might be there for the purpose of keeping the digital signal in bounds and I;d hesitate to get them off without consulting an expert in digital signal processing (Teradak)
post #204 of 1144

Micro surgery

Here is that 0.01 Russky Teflon, tricky job that, smd is a breeze after that one

Could try knocking up one of these http://www.engadget.com/2006/03/07/h...oldering-iron/
LL
post #205 of 1144
I bought a desoldering iron like this half a year ago. It works great for the price I paid for it!
post #206 of 1144
Can anyone smarter then me, figure out what the 0.01 cap does, that I replaced. It seems to just sit on trace between leg 3 of the Pulse and pin 3 of the WM8805? I would like to put that leg somewhere other then hanging on the trace but cant figure it out?
post #207 of 1144
which one exactly, do you have the number in the schematic (there is one going from the input transformer secondary to ground)
post #208 of 1144
Hi yes it seems to go from t104 3 to the trace to leg 3 rxo on the wm8805, its not in the schematic
post #209 of 1144
pictures?
T104 I can not find, T101 is the input transformer of which the secondary cold side goes to ground via the 0.01 cap.
The live wire of the secondary goes straight into wm8805 pin3.
If it is not in the schematic emailing teradak would seem the best source to get its purpose cleared.
post #210 of 1144
yes the picture is just up this page my post micro surgery

http://www.head-fi.org/forums/f7/cha...ml#post6355398
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