[desertrat]

74HC04 is out. Much thanks to Rhodes (again!) for this mod. The instructions are pretty clear on how to do it. Of course, it is still surgery on a chipset which always makes me a little nervous. The great thing about this mod besides the sound performance is that it is nearly free. I used 68 ohm resistors because that is what I had around. The resistors are just commercial grade stuff, certainly nothing special.  I may switch to some high quality resistors in the future as per Pat's experience replacing the 100 ohm units in a similar function.
In any event, a pretty quick mod with IMO substantial sound improvements. Rhodes has described them pretty well in his original post regarding the mod. Typical jitter reduction stuff which I think most are able to discern by now. It is more open, airy, detailed (without etch), has better bass and bass definition, less grain in the treble and an overall more natural feel to the sound. Very worthwhile mod especially considering cost. One last positive note; NO long break in!!!
Thanks again Rhodes for all the work you put in on the forum. The availability of the O'scope and the posted pictures sure do help even for experienced modders.
Tony

 

[taiphan]

 
Quote:

 
 
If you use the upsampling board then I would start by replacing that clock. Replacing the clock on the USB/SPDIF board is done the exact same way except that you really need to remove the 74HC04.
If you want a detailed description in the future, just let me know.
 
p.s. I wouldn't invest one single euro (dollar) as long as your Chameleon is having that noise/distortion issues.
A view thing to try:
1. Have you measured the voltages during these distortions?
2. remove (and bypass) the upsampling board
3. It is very handy if you have a scope available, or try to find somebody who has one.
4. redo all solderspots on the PCB with leaded solder.
5. try replacing the TDA dac chips one by one.
 
 

 

HI rhodes54 & fellow modders
 
my Chameleon died again, so i followed your advice and measured the voltage and i got some weird reading. THe 5v supply is normal under load and no load. But the supply to the dac board which should be 7.5V or 8V, i got 2v under load, what the? and when i disconnect the supply from the board i got 24V with the yellow wires and 13v with the blue wires..
is my supply dead? maybe a good excuse the get the paul hynes supply.
 
maybe a dead component ? the rectifier?
 
 

 

 

[taiphan]

Quote:

circumstances dictate that i need to shop for a new dac. chameleon is the only dac on the list right now but i still would like to know more of it's possibilities before bringing in the contenders. is there any reason why a tube stage or balanced output is not desirable on chameleon? anybody with future plans for it if it's even do-able? also what do you gentlemen would consider as the biggest bang for the buck mod and how much is the cost of it? i can't wait to get my own unit to tear apart and then slowly resurrect it. 

HI Curiousmuffin,
 
 
i am using a tube stage with mine, the tube DO not improve the SQ, it give you a different sound. with the Tube stage, the sound is really lazy but warm, while the chamelon on it own is very dynamic and more detailed, however for certain songs, i prefer the tube for its warm and relax sound.
 

 

[rhodes54]

Quote:

HI rhodes54 & fellow modders
 
my Chameleon died again, so i followed your advice and measured the voltage and i got some weird reading. THe 5v supply is normal under load and no load. But the supply to the dac board which should be 7.5V or 8V, i got 2v under load, what the? and when i disconnect the supply from the board i got 24V with the yellow wires and 13v with the blue wires..
is my supply dead? maybe a good excuse the get the paul hynes supply.
 
maybe a dead component ? the rectifier?
 
 

 

 
Hi taiphan,
 
A few things you can check with your power supply:
 
Disconnect the power supply from the DAC and be VERY CAREFUL as there's 110V/230V running all over!
 
1. There is a big 10R resistor on the print. Is it burned? If not, measure if it is still 10R.
    If it looks burned or the resistor is broken then you probably have a short circuit on the power supply PCB.
2. Measure the AC voltages directly of the transformer. These are mostly a bit higher than the transformer indicates. 
3. Measure the DC voltages after the rectifier(s). These are often a bit higher than the AC voltages before the rectifier.
4. Measure the DC voltages directly on the outputs of the transistors.  Do they give a +7.6V/+5V?
5. As it doesn't appear all the time you can also check if the solderjoints on the PCB do not make short circuit with the chassis.
   The design of the older PCB was pretty bad and solder joints where VERY close to the chassis. I had a short circuit once because
   of that. A very dangerous situation and Teradak luckily made a new PCB right away which is now coming with the shipped DC-30W.
 
If you can locate the problem contact Michael, you have a warranty on the power supply as well. As long as you didn't mod it.
 
If the +5V is still working correctly you can also consider buying one Paul Hynes supply + seperate transformer. The supply for the +7.6V is the most important one and you will gain the most by replacing that one. I would advice to test with another +8V power supply first to be sure your Chameleon is alright.
 
 
 

 

 

[rhodes54]

Quote:

74HC04 is out. Much thanks to Rhodes (again!) for this mod. The instructions are pretty clear on how to do it. Of course, it is still surgery on a chipset which always makes me a little nervous. The great thing about this mod besides the sound performance is that it is nearly free. I used 68 ohm resistors because that is what I had around. The resistors are just commercial grade stuff, certainly nothing special.  I may switch to some high quality resistors in the future as per Pat's experience replacing the 100 ohm units in a similar function.
In any event, a pretty quick mod with IMO substantial sound improvements. Rhodes has described them pretty well in his original post regarding the mod. Typical jitter reduction stuff which I think most are able to discern by now. It is more open, airy, detailed (without etch), has better bass and bass definition, less grain in the treble and an overall more natural feel to the sound. Very worthwhile mod especially considering cost. One last positive note; NO long break in!!!
Thanks again Rhodes for all the work you put in on the forum. The availability of the O'scope and the posted pictures sure do help even for experienced modders.
Tony

 
Thanks for the nice words Tony. For me the Valab & Chameleon modding has been a very useful introduction into digital circuits, a place where I haven't been before. Thanks to a few friends with a lot of knowledge about digital circuits I was able to find the weak points of the design. Some are still there and can't be changed without radically changing the design, others can be done much easier.
 
It's best to change to 47R in the future as the resistance is just enough to reduce/avoid reflections and hardly affects the XO signal itself.
 
I recently looked into the design again and there are hardly things left in the digital circuit to upgrade. The only thing that keeps on bothering me is the termination of the I2S signal on the DAC board. Though this will most likely be one of those 'radical design changes' if we want to do it 99% correct.
 
Oh well, I'm still very happy with the Chameleon and it sounds absolutely fantastic!
 
 

 

 

[PatOMalley]

rhodes, getting ready to do the 74HC04 mod and i have a question.
so the two 47ohm resistors, are they in series? if so why can't we keep the 100ohm resistor in place as it adds up closely to what the two 47ohms are?
 
And if i do choose to leave my 110ohm texas resistor in place for the moment do i then just need to remove and jumper the two 100ks?

 

[PatOMalley]

a comrade informed me 6moons Steve Marsh finally completed the Teradac review.
I don't think much of it but here it is:
http://6moons.com/audioreviews/teradak/chameleon.html
 
ahem ... no bass? harumph. and why the hell no mention of output transformers? i am starting to get a complex.

 

[moonman54]

Hi Pat,
 
I didn't expect a welcome reception to the review here, but I wrote what I heard (and in three separate systems).  Beyond that, I can't offer you any other explanation.
 
Output transformers were mentioned as a possible future option in my quote of Teraguy.  Is that what you are talking about?
 
Obviously, you and others here are happy with the Chameleon.  There's no need for that to change.
 
I know that Bill Allen and Tony Landry (desertrat) switched to the Valab, and then the Chameleon, from high-end DACs, such as the Northstar Extremo and Audio Note DAC Kit (latest one and TOTL).  This was the impetus for my interest in the DAC.  I was clearly disappointed.
 
Best regards,
Steve Marsh

 

[PatOMalley]

Steve,
 
I am a curmudgeon. True enough.
 
Yes, I did see a quick mention of OPT. I can only say that bass is profound are here. I do not have cutting edge stuff, just Paradigm Studio things with a bunch of drivers that are not shy on bass at all. not sure if they accentuate bass. But I can say that bass took a nice improvement with the addition of the output transformers. Also nice inner detail with a solid topend, not exactly all tinkly airy extended, but very human. If you want layers and tonal coloring then you want an output transformer.
 
I think that matching impedance with that passive output is important. do it with a tube buffer or transformer but when you do it it makes a biiiig difference. It actually makes the other mods diminish in impact, well in looking back it does. [cough here, look for a connecting thought]
 
Maybe i was expecting more from the review. Heck, I was. If you ever get a chance add a set of 1:1 600ohm transformers in a black box between dac and pre and let us know what you think.
 
have fun,
pat

 

[moonman54]

Pat,
 
I had very limited time to do modification work on the DAC.  The plan was for Bill to send me his modified DAC.  I wish it had OPT or a tube buffer in it, as I agree that might have alleviated my criticism of the bass.  Bill's solution is to increase the level of the powered bass module in his Bastanis Apollos.  It looks like you went in a somewhat different direction...certainly different from Bill's I2S input/Nugent-modified "Chameleon" (hardly worth calling it a Chameleon any more).
 
As my last paragraph states, I am willing to do a followup on a unit that has been modified to give the unit real bass.  BTW, my WLM LaScalas are quite authoritative in the bass, too.  With my Audio Note, the bass is quite powerful.  My friend, Dan, has the Bastanis Apollos, just like Tony and Bill.
 
I think I should have auditioned your modified unit for the review!
 
Steve

 

[Newk Yuler]

Quote:

 
I am a curmudgeon. True enough.

 
Maybe it's time to consider updating your avatar.  There are many great candidates in a Google images search.  The more current pics are curmudgeonly, to say the least.  There's even a mug shot or two.
 

 

[rhodes54]

Quote:

rhodes, getting ready to do the 74HC04 mod and i have a question.
so the two 47ohm resistors, are they in series? if so why can't we keep the 100ohm resistor in place as it adds up closely to what the two 47ohms are?
 
And if i do choose to leave my 110ohm texas resistor in place for the moment do i then just need to remove and jumper the two 100ks?

 
Hi Pat, No they aren't in series. Check this picture to get the idea:
 

 
This means both the wm8805 and the USB receiver get a 47R resistor each. For the timebeing you have two options:
1. Leave the 110R resistor in place and solder two pieces of solid wire instead of the 47R resistors (see pic below). Now your Chameleon is still fully functioning (both USB and S/PDIF) though you will have reflections between the receiverchips.
 

 
2. Remove your 110R resistor and put a peace of solid wire instead and place the 110R resistor on the spots of one of the 47R resistors. The top resistor (leg 3&4) is leading to the SP/DIF receiver, the bottem resistor (leg 10&11) is leading to the USB receiver. Now you won't have reflections but either one of the two inputs will work.
 

 

 

[taiphan]

Quote:

 
Hi taiphan,
 
A few things you can check with your power supply:
 
Disconnect the power supply from the DAC and be VERY CAREFUL as there's 110V/230V running all over!
 
1. There is a big 10R resistor on the print. Is it burned? If not, measure if it is still 10R.
    If it looks burned or the resistor is broken then you probably have a short circuit on the power supply PCB.
2. Measure the AC voltages directly of the transformer. These are mostly a bit higher than the transformer indicates. 
3. Measure the DC voltages after the rectifier(s). These are often a bit higher than the AC voltages before the rectifier.
4. Measure the DC voltages directly on the outputs of the transistors.  Do they give a +7.6V/+5V?
5. As it doesn't appear all the time you can also check if the solderjoints on the PCB do not make short circuit with the chassis.
   The design of the older PCB was pretty bad and solder joints where VERY close to the chassis. I had a short circuit once because
   of that. A very dangerous situation and Teradak luckily made a new PCB right away which is now coming with the shipped DC-30W.
 
If you can locate the problem contact Michael, you have a warranty on the power supply as well. As long as you didn't mod it.
 
If the +5V is still working correctly you can also consider buying one Paul Hynes supply + seperate transformer. The supply for the +7.6V is the most important one and you will gain the most by replacing that one. I would advice to test with another +8V power supply first to be sure your Chameleon is alright.
 
 
 

 

Thanks for your help rhodes54 ,
 
my PSU is definately playing up, as i mentioned the voltage got up to 24v? how? anyway i think my killed my dac board all together.. now i get no sound. not even noise
 
 
so i am at a cross -road, should i get another Chameleon and play around with it again since i've spent so much money already on parts to mod it. Or should i cut my loses and get some think like a bel canto dac 1 or a havana?
 
we spent alot of $ on our chameleon costing almost the same as one of those "expensive dac", my question is: is it worth it? has anyone compare "our" chameleon to one of those "expensive dac"?
 
 
 

 

[rhodes54]

 
Quote:

Thanks for your help rhodes54 ,
 
my PSU is definately playing up, as i mentioned the voltage got up to 24v? how? anyway i think my killed my dac board all together.. now i get no sound. not even noise
 
 
so i am at a cross -road, should i get another Chameleon and play around with it again since i've spent so much money already on parts to mod it. Or should i cut my loses and get some think like a bel canto dac 1 or a havana?
 
we spent alot of $ on our chameleon costing almost the same as one of those "expensive dac", my question is: is it worth it? has anyone compare "our" chameleon to one of those "expensive dac"?
 
 
 

I'm a bit confused as you said that you have 24V on the yellow wires and 13V on the blue wires. But which wires are you talking about? I assume the wires coming directly of the transformer?
 
Please measure the voltages coming out of the power supply too and let me know what you measure there.

 

[taiphan]

Quote:

 
I'm a bit confused as you said that you have 24V on the yellow wires and 13V on the blue wires. But which wires are you talking about? I assume the wires coming directly of the transformer?
 
Please measure the voltages coming out of the power supply too and let me know what you measure there.

HI rhodes54,
 
It's the voltage coming out of the power supply into the dac board. 24V is when i wired the PSU up with the yellow wires and 13v is went i wired the PSU up with the blue wire (wires from the transformer).
 
so in short, when i measured the DC power output from the PSU into dac board (no connected) the voltage reading i got is as above, which is crazily high. I though my  meter was faulty but i measured other devices and my meter showed the correct reading so it wasn't my meter.
 
I've been having weird voltage reading ever since i got this dac, so i guess the PSU finally had enough.