[Currawong]

This issue with bad solder joints is unfortunately a good example of what happens when Chinese goods become popular - the makers get rushed and become sloppy. My Little Dot MKV has a poorly finished front plate as I bought it at the height of its popularity.

If anyone from Zero or audio-gd are reading, this is a suggestion to you all: Don't become sloppy and rush manufacturing your gear or you'll lose your reputation as fast as you gained it.

 

[NumpXP]

sorry to interrupt your discussion,but if i were to roll headphone opamp, do i have to swap both of them, coz i'm seeing 2 opamps near the headphone jack.

thanks

 

[BigTony]

Has anyone compared this DAC/Headphone combination to the Beresford DAC with HP out? Curious as I own the Beresford, and it seems my DV 332 is dead, so I'm looking into another amp that I would be happy to open up and fiddle with?

Cheers

BT

 

[ccschua]

Hi guys,

PP has given the thumbs up for the 3 OPA (1 in dac and 2 in headphone). Anyone more has some review ?

 

[Hales]

Hey Pete -

I agree that the soldering should be cleaner than it is - even at this price. When I was initially looking over the board I found 4 or 5 circuits that I thought were shorted, but my multimeter (Fluke model 16) only showed 2 circuits actually shorted by sloppy solder. I cleaned them up with a plastic tweaker tool and engineer's picks and the readings on the meter went back to normal.

My Zero is also still outgassing fumes from the transformer after 4 weeks of use. I think its the smell of the phenol resin they may have used to insulate it. Whatever it is, its got a hyrdrocarbon smell to it.

I now have a sealed my Zero. I attached a low profile heat sink inside the case to the bottom of the lid and a large aluminum heat sink to the top of the lid. This keeps the heat down while sealing up the vents on the back of the lid. Sealing the vents keeps the smell inside the unit. The next step is to move the transformer and AC into a separate enclosure. This should also make room for the new dedicated 3v power regulation I am working on for the receiver chip's jitter prone (when the power is badly filtered or shared) VA input.

Even with all the hassles, this thing sounds great. Its definitely worth it to jump through a few hurdles for the sound you get at the end.

 

[Penchum]

Quote:

Originally Posted by ccschua /img/forum/go_quote.gif Hi guys, PP has given the thumbs up for the 3 OPA (1 in dac and 2 in headphone). Anyone more has some review ?

Hey ccschua,

I have some coming, so I can also test this. If PP says "thumbs up", my testing will just be a confirmation. His ears are excellent and his judgment is as well.

 

[Pricklely Peete]

Quote:

Originally Posted by Henmyr /img/forum/go_quote.gif Nope, I tested, and there's nothing wrong with the multiquote-function. Check! EDIT: And neither is the edit-funktion. Check! (I rather keep the almost 600 pages as few as possible)

LOL....okay Henmyr I get the point

A new thread for all the tweaks/mods/upgrades/ideas/ etc will be coming in the DIY section, so this thread will be somewhat slower in growth from that time on...I hope.

Peete.

 

[Pricklely Peete]

Quote:

Originally Posted by Hales /img/forum/go_quote.gif Hey Pete - I agree that the soldering should be cleaner than it is - even at this price. When I was initially looking over the board I found 4 or 5 circuits that I thought were shorted, but my multimeter (Fluke model 16) only showed 2 circuits actually shorted by sloppy solder. I cleaned them up with a plastic tweaker tool and engineer's picks and the readings on the meter went back to normal. My Zero is also still outgassing fumes from the transformer after 4 weeks of use. I think its the smell of the phenol resin they may have used to insulate it. Whatever it is, its got a hyrdrocarbon smell to it. I now have a sealed my Zero. I attached a low profile heat sink inside the case to the bottom of the lid and a large aluminum heat sink to the top of the lid. This keeps the heat down while sealing up the vents on the back of the lid. Sealing the vents keeps the smell inside the unit. The next step is to move the transformer and AC into a separate enclosure. This should also make room for the new dedicated 3v power regulation I am working on for the receiver chip's jitter prone (when the power is badly filtered or shared) VA input. Even with all the hassles, this thing sounds great. Its definitely worth it to jump through a few hurdles for the sound you get at the end.

Sounds good Hales.....it's a tough call to say which trail of solder will be an actual short or not. The meter confirms or denies the assumptions. I still can't quite get used to that smell...for some reason it's both repulsive and attractive at the same time...kinda like caviar

Keep us apprised of the 3V reg mod + your case build. This sounds very interesting to an old tweak happy fiddler

The current mod Pench and I have completed does a great job of cleaning up power delivery thus the benefits are felt throughout the entire dac. Your isolation of that 3V line should yield decent results. Will you have to cut traces on the main pcb in order to feed the IC ? Wheres your tap in point going to be ?

Peete.

 

[Pricklely Peete]

Quote:

Originally Posted by ccschua /img/forum/go_quote.gif Hi guys, PP has given the thumbs up for the 3 OPA (1 in dac and 2 in headphone). Anyone more has some review ?

With one caveat. The heat issue has to be addressed before I'm comfortable with 3 HDAMs in the Zero with the stock cover back on....I don't have the lid on at the moment. I'm dazzled by all the pretty lights

Peete.

 

[ccschua]

I hope the green lights is not simmering. But it is kind of fun to watch it.

The heat issue needs some attention, also is there any outcome output voltage adjustment.

The OPA uses cascoding design in class A, which gives some harmonics distortion on output. Well not all harmonic distortion is bad, especially the even harmonics. Tube amp gives more of the even harmonics and that's what tube fans loves it.

 

[alxwang]

Quote:

Originally Posted by Pricklely Peete /img/forum/go_quote.gif With one caveat. The heat issue has to be addressed before I'm comfortable with 3 HDAMs in the Zero with the stock cover back on....I don't have the lid on at the moment. I'm dazzled by all the pretty lights Peete.

My little hint to solve this heat problem:

1. Cut part of top cover. Actully what I did is just extent the grill part to fit the 140mm fan and four hole for screw to mount the fan.
2. Mount this on

Scythe Kaze Maru 140MM Cooling Fan 500RPM 10.8DBA 29.3CFM. It cost me 10$ and so quiet. Make sure using this king of screw:

- keep in mind the fan is 2.5cm height.
3. Do what ever you can do to about dust protection. I did nothing .

You can choose best position of the cut for the fan. Actually no big difference as long as the air flow exist.

The power input: Because I do care about whether can output to max(the fans need 40ma input) and I do not really want to steal anything from Zero(3 HADM in) so I just connect to it a 9V rechargeable for now. Maybe I can get this power from Zero but I need to understand Zero a little better.

 

[Hales]

Quote:

Originally Posted by Pricklely Peete /img/forum/go_quote.gif Your isolation of that 3V line should yield decent results. Will you have to cut traces on the main pcb in order to feed the IC ? Wheres your tap in point going to be ? Peete.

The info in the CD8416 can be found here - http://www.cirrus.com/en/pubs/proDat.../CS8416_F3.pdf

From the Datasheet:

"Pin 6 - Analog Power (Input) - Analog power supply. Nominally +3.3 V. This supply should have as little noise as possible since noise on this pin will directly affect the jitter performance of the recovered clock."

"A separate analog supply is only necessary in applications where RMCK is used for a jitter sensitive task. For applications where RMCK is not used for a jitter sensitive task, connect VA to VD via a ferrite bead. Keep decoupling
capacitors between VA and AGND."

From what I see:

On the Zero the VA and VD (Digital Power Supply - Pin 23) appear to share the same power supply even though the CS8416 is performing a jitter sensitive task. I consider recovering the incoming clock to be about as jitter sensitive an application as there is.

The datasheet is very clear in saying the VA supply as well as the PLL filter circuit should be kept on the same side of the board and as close to the chip as possible. On the Zero, the VA passes through, joins another supply, and traces around before being filtered or decoupled.

So I was planning to cut the circuit on top of the board right before the pass-through. I was then planning to solder in a shielded cable on the bottom of the board right beside the chip to feed the 3.3v to the VA.

Bottom of the board -

And here is where the signal passes through to the top -

 

[Pricklely Peete]

Great solutions guys !!!

I'm still not thrilled about adding active cooling so I'm sitting on the fence at the moment. I have some copper heatsinks somewhere around the house....I'll try that first..and if it's still too hot well looks like an active cooling unit may have to be installed....or get a bigger case and properly mount the regs to big sinks in the new case...not the best solution money wise.

Just thinking out loud again.

Peete.

 

[Pricklely Peete]

Excellent Hales.....I love it

Looks like a great tweak. What type of reg board are you going to use and are you going with a separate transformer ?

LC mentioned a while back about splitting and isolating the supplies but said it wasn't possible for him to do and keep the cost where it is...which makes perfect sense.

If you need parts for this, a good place I've found is Wellborn Labs. They have some very nice kits but the pricing is a little high.

For those viewing these mods, keep this in mind, at one point or another all of us have this moment in our lives "that's so complicated I don't have a chance in hell of doing all that". Keep learning, experimenting, practicing and studying and it will pay off.

Peete.

 

[Pricklely Peete]

I have to go now guys...I'll be back in 6 hours or so...depending on rush hour traffic etc...

Peete.