Chameleon DAC listening and modifications

[PatOMalley]

On my old VALAB 8x NOS DAC I was using a tube buffer to great effect. I swapped in my 600:600 CineMag transformers and it made an incredible difference. Voices are texturally real ... er.

So output transformer coupling is back in play.

Weird how MORE wire can make a nice impact.

 

[MikeW]

it's kind of annoying as it looks like the default PSU was underspeced from the start. Wonder if it would be worthwhile to build a proper power supply, like a Sigma 22.

 

[marcelnl]

you'd be surprised how much gear is running on fumes, techies usually calculate the bare bone minimum requirements (having 'if I can't measure it it'll make no difference" or the bean counters economize a design afterwards......
Building a nice separate power supply for each voltage and each channel could just be worthwile, especially for this design.
One big toroid with a double 12V secondary winding could be a start.

 

[Bill Allen]

I want to make it perfectly clear to everyone that just because I would personally like to see more current out of the TeraDak DC-30 for the Chamaleon DAC does not mean that I find it fundementally flawed. Fact is the DC-30 does a fine job on the stock 9V AC blue wire and performs even better on the 12V AC yellow wire with the Chameleon DAC. This being a modification forum being the only reason I brought the subject up.

Getting maximum performance from a price limited product is what this thread is all about.

In fact as a DIY guy I find the DC-30 very functional and an incredable value. It offers 2 separate "low noise" regulated DC supplies, both variable from 2-12 volts with up to 2.5 amps of current, all fully assembled and ready to roll for $120. Awesome deal with endless possibilites.

Power supplies are some of the most under rated devices in the audio playback chain. This is after all where the electrons that provide the amplification that move the speakers actually come from. In an ideal world each electrical device would have its own properly designed power supply. However reality is far from that ideal world. Would I like to have a heavy duty “purpose built” power supply for the Chameleon? Yes. Do I expect to get that kind of custom product from a $399 DAC. No!

While I may pursue an even higher performance power supply down the road because that is my nature. Do not underestimate the perfomance of the dynamic duo of the DC-30 & Chameleon DAC, even in stock form.

But please for the love of Pete, first things first, do remove those brown chiclet analog filter caps from the DAC board and unlease the flood gates that are the hallmark of true NOS DAC’s.

 

[MikeW]

I should have mine in a few days. Will be nice to tear into it. Im getting into DIY alot more now, I recently built a Cmoy, and Recabled my headphones. My soldering skill has greatly improved, and im thinking of tackling SMD soldering soon. I've also learned the basics of the Digital Multimeader, I don't know how I ever got along without one before. I also learned how to use Solder wick, what a piece of cake. I picked up some much better tools (soldering station, nice tweezers, solder wick, nice multimeader etc) Just using better tools helps so much, it's ridiculous how crappy the radio shack iron is! I never could get solder out of the holes in thru-hole de-soldering, until I mastered the solder wick, makes it so easy! Im going to do some more small projects, and continue my DIY journey, eventually perhaps i'll be skilled enough to tackle a Beta 22 & Buffalo, with a nice Sigma 22 PSU.

Edit: Still can't fix my Valab 3.0! I've measured so many things, everything seems to be ok. I't's so strange, there must be a problem in the PSU section. All the dac chips measure correctly, the output measures right, i've checked the voltage out of every leg of every dac chip, out of the i'v resitors, out of the bead magnets, going into the output caps, going into the dac board. it's all perfect. But the dac still has Terrible blast of static when first turned on, and takes 30 seconds to 1 minute to stabilize, i've also replaced all 8 of the TDA1543's with new ones. I've triple checked all my connections, and ran several continuity test on suspect areas, i've wired Point to Point, around suspect connections. All to no avail. Also when I put the board back in the Chasis it will never stabilize, I experimented with it in the chasis, and it works fine until I screw the Dac board down, even 1 screw int he dac board will cause it to never stabilize. I've checked and rechecked for shorts, there are none, unless there's a bad connection between the Dac Sockets and the board somewhere, I can't figure out what the hell is causing this. I also experimented with putting one screw in the dac board, tightening it down, and turning the unit on, measure the output with the Multi, and it never stabilized, then while turned on, and continuing to measure output, I losen the screw several turns and bam, stabilizes.

 

[marcelnl]

Mike, your circuit board may be cracked...if unscrewing a screw make this much of a difference I suspect a hairline fracture somewhere.
Not having seen the circuitboard I do not know whether it is dual or multilayer (guess double or even just single layer) You may be able to cure that by running some solder over it once detected but detecting its location may be difficult.
You may be able to pinpoint it with cold spray (cans can be had from electronics shops), perhaps someone else has ideas for you.

Bill; we'll leave Pete alone for now I was merely saying the same as you; that many PSUs are underdesigned. I also find this piece of equipment tremendous value for money, yet if we are looking at squeezing peak performance out of it I'd quickly jump to the PSU (after doing the most obvious mods such as analog Caps etc).

 

[hifi2001]

Quote:

Originally Posted by MikeW /img/forum/go_quote.gif I should have mine in a few days. Will be nice to tear into it. Im getting into DIY alot more now, I recently built a Cmoy, and Recabled my headphones. My soldering skill has greatly improved, and im thinking of tackling SMD soldering soon. I've also learned the basics of the Digital Multimeader, I don't know how I ever got along without one before. I also learned how to use Solder wick, what a piece of cake. I picked up some much better tools (soldering station, nice tweezers, solder wick, nice multimeader etc) Just using better tools helps so much, it's ridiculous how crappy the radio shack iron is! I never could get solder out of the holes in thru-hole de-soldering, until I mastered the solder wick, makes it so easy! Im going to do some more small projects, and continue my DIY journey, eventually perhaps i'll be skilled enough to tackle a Beta 22 & Buffalo, with a nice Sigma 22 PSU. Edit: Still can't fix my Valab 3.0! I've measured so many things, everything seems to be ok. I't's so strange, there must be a problem in the PSU section. All the dac chips measure correctly, the output measures right, i've checked the voltage out of every leg of every dac chip, out of the i'v resitors, out of the bead magnets, going into the output caps, going into the dac board. it's all perfect. But the dac still has Terrible blast of static when first turned on, and takes 30 seconds to 1 minute to stabilize, i've also replaced all 8 of the TDA1543's with new ones. I've triple checked all my connections, and ran several continuity test on suspect areas, i've wired Point to Point, around suspect connections. All to no avail. Also when I put the board back in the Chasis it will never stabilize, I experimented with it in the chasis, and it works fine until I screw the Dac board down, even 1 screw int he dac board will cause it to never stabilize. I've checked and rechecked for shorts, there are none, unless there's a bad connection between the Dac Sockets and the board somewhere, I can't figure out what the hell is causing this. I also experimented with putting one screw in the dac board, tightening it down, and turning the unit on, measure the output with the Multi, and it never stabilized, then while turned on, and continuing to measure output, I losen the screw several turns and bam, stabilizes.

MikeW: If you plan on venturing into SMD soldering I would highly recommend that you get one of those magnifying glass with alligator clips attached work stattion units. You won't believe how handy they are when you have to solder into SMD devices...

On the subject of your Valab 3 making initial noise, have you tried to connect a different source into it? Perhaps another CDP? And see if the issue is still there...

 

[MikeW]

do you mean the cheap "helping hands + magnifier", they cost about 10$? I did get some of those, they are very helpful, especially with soldering cables & connections. I did try more then one source as well. I've tried most things, Bill Allen clued me in, in a private email as to what may be going on, I think he may be on the right track, but he's requested that I keep this thread on topic, so no more Valab speak here.

 

[MikeW]

got my dac today, letting it burn in. I notice the bass is so much better then my previous Valab, right off the bat. I'll try to refrain from further listening impressions until it's go some hours on it.

Packaging was A+, much better then any Valab was packaged. A word on the heat from the PSU.

Upon looking at the Pics, I notice the Voltage regulators are using the Chasis as heatsink, now I remember, both my Valab 2.1 and 3.0 the heatsinks attached to these Voltage reg's got to hot to touch, you literally could not hold your finger on them for 5 seconds. Keeping this in mind, seems like a very hot Chasis would not be much of a concern, for the DC30.

 

[rhodes54]

I also got my Chameleon today (after being stuck at the customs for 14 days) and it's playing perfectly. Can't give any Judgement yet as I'm listening at work through small speakers.
There is a slight problem with mine though: I have got a hum in the audiosignal which is most likely coming from the DC-30 power supply. I'm sure it's not a grounding or digital problem. It is still there when no source is connected. I tried different setups but the hum is just there always.

I have to say that you have to turn your volume up quite a bit but it just annoys me.

Is there anyone with the same problem here?

Thanks!

 

[Wood]

never had that problem, perhaps when you get it home it will go away if it is just a grounding problem.

Was looking at the caps today I think they are Pansonic FM 1000uf 35v, which are pretty respectable. Those two 10k resistors look straightfoward to upgrade for peace of mind if doing the yellow wire mod.

 

[hifi2001]

Quote:

Originally Posted by rhodes54 /img/forum/go_quote.gif I also got my Chameleon today (after being stuck at the customs for 14 days) and it's playing perfectly. Can't give any Judgement yet as I'm listening at work through small speakers. There is a slight problem with mine though: I have got a hum in the audiosignal which is most likely coming from the DC-30 power supply. I'm sure it's not a grounding or digital problem. It is still there when no source is connected. I tried different setups but the hum is just there always. I have to say that you have to turn your volume up quite a bit but it just annoys me. Is there anyone with the same problem here? Thanks!

This is not normal. Just curious, did your Async board came installed in your DAC? Be aware of the jumpers that need to be removed if Async board is in circuit.

 

[rhodes54]

I'm pretty sure now that the hum is coming from the power supply. There is a 0.14V AC present on the 7.8V DC output going to the DAC board. The 5.0V DC output looks perfect and has no AC present. This means that the 0.14V AC is most likely causing the hum.

We checked for groundloops but there weren't any .

We also did some other measurements this afternoon using an Audio Precision P1 and the results are quite good for a NOS dac.
Here are some pics with a description. Sorry that they are blurry but I took them with my mobile phone.

Total Harmonic Distortion:


Signal To Noise Ratio:


20Hz to 20Khz Sweep:


The HUMMMM:

 

[rhodes54]

p.s. I forgot to tell that i've been contacting Tentlabs about the use of capacitors on the digital input. I trust this person without any doubt when it comes to digital audio as he is very experienced with this.

To keep the story short:
When using an input transformer this is the correct thing to do:
1. The value of 0,01uF is too low. It should be 0,1uF (100nF) because the crossover point for SPDIF should be below 100Khz. It sounds much better.
Best cap to use: a good quality 0,1uF filmcap.

2. The SPDIF input should not be decoupled from ground with the other 0,01uF cap when using a transformer. Best thing is to connect it to the chassis right away. This is the best way to avoid EMC and it doesn't matter that it is connected 'hard' to the chassis because we are using a transformer.

As a picture always says more than a thousand words:

 

[Chris Adams]

First post. I just want to thank everyone for the incredible information provided for the Valab and Chameleon dacs. I'm just about ready to jump on a Chameleon as soon as I sell an item or two. I'm not much of a diy guy yet but with all the info and some soldering skills, I'm willing to learn. Bill and Pat, your info and pics have been great learning tool for me.

Cheers!