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Old 27th October 2009, 12:06 AM   #501
IanAS is offline IanAS  England
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Answer = 2. Go as the PCB.

You can see the original wrong capacitor had bulged at the top.

If connected backwards you new capacitor may EXPLODE it's electrolyte all over your circuit board and may even coat the ceiling of your room!

I personally have not had any electrolytic capacitors that didn't at least hiss, 'smoke' and leak straight away when connected backwards.
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Old 27th October 2009, 08:54 PM   #502
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Quote:
Originally Posted by IanAS View Post
Answer = 2. Go as the PCB.

You can see the original wrong capacitor had bulged at the top.
Hi InaAs

Your eye are really vigilant. I can see the capacitor bulged. I did test that cap, but it is still working (NOT DEAD as I thought) I should go as PCB. Thanks for your advice.

There is one question for you. As you can see the photo, there are 4 extra positions for capacitors. I did exam them carefully and found out that they were paralell with the occupied ones

I have 4 cap available, Can I solder them into the vacant positions. So in this way I have 8 caps and I will have more head room than before. Am I right?

Will the sound quality be improved a bit ? Or not significant?? Not worth doing that???

I am looking forward to your advice

Julio
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Old 28th October 2009, 10:15 AM   #503
IanAS is offline IanAS  England
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Quote:
Originally Posted by Pass lover View Post
4 extra positions for capacitors. Can I solder them into the vacant positions.
Yes
Quote:
Will the sound quality be improved a bit?
Maybe.

Another 4 of the same capacitors (Rubycon ZL / ZLH?) may or may not have an effect, but 4 or the right type of different ones will have an improving effect, as I mentioned in posts above.

4 of the Nichicon conductive polymer will improve the upper end of the sound. Just to be sure I've taken this DaCapo to two HiFi systems other than my own and done listening tests with them off and on.

NICHICON|PLF1E470MDO2|CAPACITOR, 47UF, 25V | Farnell United Kingdom

These caps give great top end and seem to be OK when across the Rubycon ZL's. Sometimes different makes of capacitor don't sound good when in parallel.

We just spent a day comparing various values of these Nichicons in various positions with standard Black Gates and some 'ordinary' capacitors that came with the DAC (not the DaCapo this time). They sound better than the Black Gate standard at all frequencies and positions but are a bit less weighty at bass. The 'ordinary' ones were making a fuzzy mush of the sound and had to be removed. Initially I soldered the decent caps in parallel with the naff ones and whilst that was still a big improvement there was still the sound effect of the naff ones there. Black gates with Nichicons soldered across them did not sound good, 'jangly' and 'super busy' and messy. Even the NX Black Gates were like this. However, on the DaCapo, after the LM317's just before the DAC can, the same NX across the same large Nichicon was an all around improvement, but especially in the bass.

Most of the capacitors in the test had been run for a month at least. Some for at least two months.

Last edited by IanAS; 28th October 2009 at 10:22 AM.
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Old 28th October 2009, 11:03 AM   #504
IanAS is offline IanAS  England
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The leads are long as it's still a trial fit. Means they caps can be easily removed without damage and re-used elsewhere.

The second pic is the Dacapo regulators on the left of the PCB. These are 16Volt caps and are before the regulators.
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Last edited by IanAS; 28th October 2009 at 11:09 AM.
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Old 8th November 2009, 09:44 AM   #505
muz640 is offline muz640  Australia - Aboriginal
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Any news on the new stuff ?
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Old 11th November 2009, 06:51 PM   #506
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I've given up, it's utter vapourware.

I bought a pair of Grado Sr325i's instead and an Ibasso D10 + Topkit op-amp rolling kit. The combo sounds sublime, and it means I can listen in piece at night...
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Old 11th November 2009, 08:42 PM   #507
russel is offline russel  Europe
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Quote:
Originally Posted by sq225917 View Post
I've given up, it's utter vapourware.

I bought a pair of Grado Sr325i's instead and an Ibasso D10 + Topkit op-amp rolling kit. The combo sounds sublime, and it means I can listen in piece at night...
Not necessarily. John did say:
"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." on Oct the 18th. Now given that if everything goes right, its not due yet. It will also, to meet that date, most likely require no last minute software bugs noted, like thats ever going to happen. No components mislaid, i.e. stolen this being China. No components with the wrong land pattern meaning scrapped PCB and reorder. I could go on but you get the picture, any time between now and mid January is when we will see these products. After that and its Duke Nukem forever country.
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Old 12th November 2009, 05:38 PM   #508
timpy is offline timpy  United Kingdom
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There's often a bit of fiddle-a8sing about after prototyping before full production begins, assuming that production don't point something out and want something changed for ease of mass manufacture etc. Be fair and give JW a little time, at least Jan/Feb I would imagine from experience. Hopefully end of Jan as Chinese new year will add two weeks if it's mid Feb.

Cheers
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Old 15th November 2009, 03:20 PM   #509
JohnW is offline JohnW  Hong Kong
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Hi Julio,

Yes - indeed you’re correct; it appears as if Capacitor #2 was incorrectly inserted during production. This would have had little measured effect due to redundancy of the design. Poor Production QC I’m afraid.

That said, Friday the 13th I bought a 50” Samsung Plasma for the family – died after an hour – incorrectly orientated E-Cap… Happens to everyone…

Returned the panel back – only to find the replacement “New unit” was used and reboxed again Friday 13th – selling Used as New happens here in Czech Rep. all the time, we get all the returns from Europe dumped upon us… We bought some house cordless phones as new – only to find they had people’s names and numbers programmed into them… new!!

Czech Rep. has very little in the way of consumer protection… the law is useless here… It appears everyone is corrupt or just small minded – guess that’s to be expected from a country of 10 million people coming to terms with commercial and personal freedoms.

John
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Old 15th November 2009, 04:43 PM   #510
JohnW is offline JohnW  Hong Kong
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Hi all,

Sorry for the lack of news on the new DAC:-

1. I’m not sure how to “Walk the fine line” between being seen as promoting a commercial product – and supporting the user’s requests on this forum…

2. While the design was originally going to be lunched under by own brand, its now been repackaged for AudioLab – and I don’t want to step on the Marketing Dept. toes – you can understand how they could be sensitive, as “Engineers” should not speak to the consumer…

I’m currently in Czech Rep. while back in China the units are approaching Pre-production – to be released before the end of the new year… As the design was originally developed as a product under Lakewest – I’m confident of the designs stability – software is different issue.

We have designed-in user upgradeability via USB as a contingency, also facilitating future upgrade path (such as user defined filters, language packs & Remote codes etc). The unit’s software is very complex due to the requirements to support various computer operating systems and configurations… Its does not help that Dominik (the software programmer (and Co. designer)) is also supporting a host of other products into production…

The good news however is that from a dynamic range it’s one of the world’s best – if not the best – over 131dB Awtd. I suspect limited by my audio analyser’s performance – not the DAC’s performance.

I choose to slightly compromise ultimate 2Vrms THD performance (still better then 0.0005% THD) – for audio performance over measured performance.

The DAC array and be operated on Current or Voltage mode. In Current-mode operation, the voltage coefficient non linearity of the DAC’s internal polysilicon resistor array is not exercised resulting in extremely low THD levels – however in Current-mode configuration it’s not possible to apply usefully amounts of Passive RF filtering before the analogue summation stage. So for ultimate audio performance (lack of Digital glare), I choose to use Voltage-mode operation – this does result in a significant voltage across the DAC’s internal resistor array (exercising the DAC’s internal polysilicon resistor array voltage coefficient non linearity), but does allow a Passive (to Ground) First-order filter before the Analogue differential summation stage to prevent RF (AM) front-end demodulation.

Sonically, this removes the nasty “Digital Edginess’” common with most DAC’s. This is a carry over from Dacapo – which also benefited from a voltage output DAC.

However – when I say worst THD in Voltage Mode – I’m talking of less then 0.0005%... at 2Vrms. The DAC also has a user selectable high dynamic range mode – with a full scale output level of 3V rms (6V Balanced) – great for directly driving power amplifiers.

I don’t wish to personally comment on audio performance, until others have had a chance to listen – but Dominik and I are VERY proud of the design (it was to be our own brand product).

The DAC also has a simple line level Analogue Pre-amplifier. The Gain is controlled in the analogue domain via a Pair of MAS 6116 in fully Balanced Mode. Unfortunately, once again due to issues with Resistor voltage coefficient linearity, this time with the MAS’s polysilicon resistors, the THD takes a hit at 0.0015% when using the Analogue Pre-amplifier Mode (This is still much lower then most Analogue Preamplifiers).

However, dependent on user’s preference (when using digital input sources), the Analogue Gain control stage can be bypassed – and Gain control performed purely in the digital domain. As the DAC has a true Data path greater then 32Bit processing combined with the state-of-the-art analogue domain (Greater then 131dB Dynamic range) – the Digital Gain control may result in superior sonic results. The user can select Analogue or Digital Pre-Amplifier mode via the front panel.

A very nice feature of this DAC in USB Mode, is its ability to control the PC / MAC Media player via Remote control… Just sit back and listen…

Sorry for the extended wait – I can understand the feelings of those who have lost faith…

John
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