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Old 17th September 2009, 11:16 PM   #491
JohnW is offline JohnW  Hong Kong
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Hi muz640,

The A******* Dac is at final prototype stage - going to T0 (which means a small Qty. built by engineering deptment) - then to PP and then to full production - the process takes about 2 months.



John
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Old 18th September 2009, 05:37 AM   #492
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How long are 2 chinese month?
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Old 18th September 2009, 07:14 AM   #493
muz640 is offline muz640  Australia - Aboriginal
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Quote:
Originally Posted by JohnW View Post
Hi muz640,

The A******* Dac is at final prototype stage - going to T0 (which means a small Qty. built by engineering deptment) - then to PP and then to full production - the process takes about 2 months.



John
If you want to send me one for evaluation purposes that would be great

Its possibly the most eagerly anticipated Dac in the history of the world!
I think i can wait two months, ive got my stopgap (new) Dacmagic, thats been holding its own. It will be interesting to compare eventually! (i feel if i have to wait any longer my ear hair will have grown so long i wont be able to hear anything anyway)

Last edited by muz640; 18th September 2009 at 07:18 AM.
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Old 18th September 2009, 10:00 AM   #494
IanAS is offline IanAS  England
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Quote:
Originally Posted by JohnW View Post
The A******* Dac is at final prototype stage - going to T0 (which means a small Qty. built by engineering deptment) - then to PP and then to full production - the process takes about 2 months
John, just asking out of curiosity, has it already had listening testing and refinement or does that happen at this stage? I was talking to someone from another company a few months ago and he said they did none! The product went from the drawing board to the shops. They knew nothing about running in capacitors before listening to their effect! It could have been though that that man just didn't fully know what went on there during the prototyping. I'd be interested in knowing what you choice of capacitors are these days. These Nichicon conductive polymers I fitted to this DaCapo really do seem to clean up and bring together the upper parts of the sounds. So far, two weeks in, bass seems to be a bit quiet though. It would be intersting to know if the Sanyo OsCon, and others, sound any different to these.

IIRC did you mention that there are no chip Op-Amps? So therefore no problem choosing which one sounds best (or is that 'sounds least bad') Otherwise, which chip Op-Amps have you chosen to use? I was wondering about replacing the BB OPA604's in the DaCapo and wondering what to use there. I was looking at some discrete differential Op-Amp modules, but read that many of them have poorly matched inputs (and often low gain bandwidth product, poor transfer linearity, and high distortion and noise!), so not so good for joining the balanced lines from the DAC chip(s).

Are you missing out ALL the copper track in the analogue stage as to my ears copper track sounds veiled, blurry, dull, muddled? In the old 7350 DAC I was using, just missing out 20mm of it and joining the resistors and capacitors from chip pin to chip pin was a not difficult to tell audible improvement Also got the same result in a couple of integrated amplifiers and a pre-amp. The Pre was the biggest improvement as they had maybe 10 inches of it per channel.

Can you re-shape this new DAC into an 8 channel version preceded by what ever is used to decode / translate home theatre audio so we can at last have the same quality for the rear (and centre) speakers when watching / hearing a film / TV in DD / DTS, or the new even better HD DD / DTS, as we do when listening to some music without pictures? A 4 channel version would do for my use as I don't use a centre or sub.

Cheers,

Ian

Last edited by IanAS; 18th September 2009 at 10:22 AM.
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Old 18th September 2009, 07:04 PM   #495
Betto is offline Betto  Italy
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John,
what happened to the current dumping class A amp project that was mentioned some time ago on this thread?
Regards, Betto
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Old 25th September 2009, 08:10 PM   #496
IanAS is offline IanAS  England
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I have another few improvements for the DaCapo.

• Add a Nichicon Conductive Polymer capacitor, 820µF 6.3V, going +5V to ground, after each of the last two LM317 regulators (nearest to the DAC can) (one cap for each of left and right channel) that feed the logic chips in the DAC can. Even though in there are already five 22uF Tant chip caps each with a 0.1µF chip cap, each pair decoupling each of the 5 chips per channel, the 820µF improves the upper end of the sound, bringing it together and reducing a kind of splashyness / glare. Further reducing the veil. NOTE: Before doing this, I first added a back (protection) diode across each of these 4 regulators, as stated as a requirement in the LM317 data sheet.

• Add a 0.1µF poly prop cap across the ± supply pins of each of the two OPA604 output OpAmps. I plan to increase this to 0.3µ to see if that's even better.

• I then added a black gate to each of the 820µ caps and that was a further refinement and also filled out the bass, as they often do.

• We tried different mains leads, all ones we made ourselves, all differing in resistance, capacitance and inductance. All sounded very different. One gave a much larger bass than the others which brought forward the bottom area nicely as there was far too little as it was. So you can count suitable mains cable selection as an improvement too.

Last edited by IanAS; 25th September 2009 at 08:17 PM.
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Old 7th October 2009, 08:13 AM   #497
loris.p is offline loris.p  Italy
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Hi JohnW, R U and the new dac OK?
When all this started I had a newborn cat. Now I guess my cat is bigger than your dog :-))
I see that sometimes you take a look at this thread, that's becoming a thread about the sex of the caps :-)
I'd like to tell you this:
if you definitely abandoned the project of repairing my da capo board ( with his new made traks and new caps :-( sigh, sigh )
if you don't need them for “electronic surgery”
if you don't need them for whatever reason
if you find them
if you have the time to do it
could you please send back the hdcd and 18bit filters anf the clock lock dic at my expense,
so I can have my cardinal/ordinal (now I have 2 ordinals) at theyr best while I wait for your new dac?
Since your FIFO mailbox will probably never be emptied, if you mail me I can answer by sms of by fax.
Thanx
Loris
ps would it be difficult to put the ordinal into the cardinal? I guess I'd need a connection cable, an on/off cable and a power/on one..........
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Old 7th October 2009, 09:03 PM   #498
loris.p is offline loris.p  Italy
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JohnW,
today I opened the last ordinal I bought.....
it had two "ORRIBLE OPTICAL D.I.C."........
Loris
ps forget about the question about putting an ordinal into a cardinal
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Old 21st October 2009, 03:01 PM   #499
loris.p is offline loris.p  Italy
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:-))))))))))
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Old 26th October 2009, 10:34 PM   #500
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Default Big problem must be seen. Need your help. Please

Hi,
Please help me to give your advice about replacing capacitors for Dacapo DAC

Please look at the photo: this is the original condition of capacitors before being removed out of the board.
IMG_0127.jpg
According to the photo of the capacitors( capacitor 1,2,3,4) you can see the polary as : (- +) , (- +) , (+ -) , (- +)

And the photo of the board after removing capacitors:
You can the board printed as: (- +) , ( + -) , ( + -) , ( - +)
IMG_0138.jpg

I think the capacitor number 2 was inserted INCORRECTLY by manufactory. However, my DAC did work perfectly.

Now the old-leaking capacitors must be replaced. I do not know which way to go:
1- Accept the mistake of manufactory ( replace exactly as photo)
2- Go as the board print : (- +) , ( + -) , ( + -) , ( - +)

Dacapo’s owners, I highly appreciate if you could open your Dacapo and give me your advice

Julio
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