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Valab Dac-First Impressions - Page 9

post #121 of 1577
11/23/08 at 12:12am
Thread Starter 
Type Live.com into the google search bar, when there type bodum or kitchen knives into the live.com search bar, the first result will show 25% discount for E-Bay, click on that and it will take you to E-Bay, the live.com logo with the 25% discount should be at the top of the page, now do a search for Valab or whatever you want to purchase. You only get the discount by purchasing through the "buy it now" option. make sure the discount logo is at the top of the page when you make your purchase. Once you pay for it E-Bay will send you a message in your E-Bay account saying you have a discount, click on that and you will set up a live.com account, it takes a couple of days then it will show on your live.com account that you will be getting a cashback in approx. 6 weeks. You pay full price initially then 6 weeks later the discount amount will be deposited in your Paypal account which you must have to get a discount.

Phill
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post #122 of 1577
11/23/08 at 12:17am
Meh, 25% discount US only.
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post #123 of 1577
11/23/08 at 12:33am
For USB input, this direct I2S -> TDA1643 is better, especially replacing high precision XO. This method avoid the extra modulation/demodulation on I2S<->SPDIF. Some says this additional modulation/demodulation introduces different feeling.
Quote:
Originally Posted by Fidelity View Post
Thanks for the info, which method is better, via the CM108 right?
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post #124 of 1577
11/23/08 at 12:49am
As the other DAC, the higher precision XO improve the detail and depth. Our experiences show the 1 ~ 3 ppm TCXO is enough. Anyway, the higher accuracy XO, the better is for the audio quality.

Generally speaking, different parts make different sound. Except XO, the most important parts is the output capacitors. The capacitors can be used 10uf ~ 220uf. These valuses are appeared in others 1543 schematics. We don't have enough experiences on all of the values. The original one is an electric capacitors. You coule replace them with Solen/Wima/Rifa type capacitors.
Which one is better? It depends on your amplifier and your personal taste.
Quote:
Originally Posted by defec View Post
Hi. what XO would you recommend that we get to install in our dacs and what capacitors are the most important to replace? Are there any brands/types/values that you recommend? Thanks.
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post #125 of 1577
11/23/08 at 12:51am
Thanks Phill. that's good to know.
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post #126 of 1577
11/23/08 at 12:54am
Except USB portion, these 2 DACs are almost the same. The differnces are only the layout and cooling method. These two DACs will show similar quality if the parts are the same.

Quote:
Originally Posted by Ricey20 View Post
I'm thinking the Valab is superior in its USB-I2S>TDA1543 right? If I'm not going to be using usb would the gigalab or valab sound better you think?
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post #127 of 1577
11/23/08 at 1:04am
Quote:
Originally Posted by TeraDak View Post
As the other DAC, the higher precision XO improve the detail and depth. Our experiences show the 1 ~ 3 ppm TCXO is enough. Anyway, the higher accuracy XO, the better is for the audio quality.

Generally speaking, different parts make different sound. Except XO, the most important parts is the output capacitors. The capacitors can be used 10uf ~ 220uf. These valuses are appeared in others 1543 schematics. We don't have enough experiences on all of the values. The original one is an electric capacitors. You coule replace them with Solen/Wima/Rifa type capacitors.
Which one is better? It depends on your amplifier and your personal taste.
TeraDak, thank you for the responses. Do you have any recommendations of a new high precision XO to place inside the unit? It doesn't have much room for a reclocker on it's own circuit board. Would a Tentlabs XO work?

XO

It needs a clean 5 volt single. I don't know if one is already there or not.
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post #128 of 1577
11/23/08 at 1:10am
We are deeply involved in these 2 Dac design.
We can answer most of the technique issues on these 1543x8 DACs. If you can DIY, thse DAC will be very interesting.
Honestly, we ignored the importance on choosing the capacitors because of limited budget. This issue was solved. We made these DAC manually, but we fully tested them before shipping. However, the testing process may be not long enough. We are still cooking on how to improve the stability test of this DAC. Anyway, the new design will solve all of the issues appeared in the previous one.

Quote:
Originally Posted by tubes View Post
Hello TeraDac, are you involved with the Teradac NOS dac? If so, you're input here concerning these dacs would be greatly appreciated. I am not put off by the problems I have had with my dac as the Valab is one of the best dacs I have heard in certain areas, if over time this dac can be improved by parts swap or design improvements I would love to know. I would like to add that if a more refined version of these dacs could be built using good reliable parts I would be happy to pay a modest increase in price.

Phill
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post #129 of 1577
11/23/08 at 7:47am
Quote:
Originally Posted by defec View Post
TeraDak, thank you for the responses. Do you have any recommendations of a new high precision XO to place inside the unit? It doesn't have much room for a reclocker on it's own circuit board. Would a Tentlabs XO work?

XO

It needs a clean 5 volt single. I don't know if one is already there or not.
Maybe a 12.288MHZ TCXO could work better?
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post #130 of 1577
11/23/08 at 8:31am
Sure, the Tentlabs should work for this economy machine. Maybe it is too much for this Dac.
In this compact Dac, we don't use any fancy power for the TDA1543 and digital circuit. But the simple circuit works well. This economy Dac is defined as a product not a kit, so there is no much room to modify it. However, you can power it with another power box.
Quote:
Originally Posted by defec View Post
TeraDak, thank you for the responses. Do you have any recommendations of a new high precision XO to place inside the unit? It doesn't have much room for a reclocker on it's own circuit board. Would a Tentlabs XO work?

XO

It needs a clean 5 volt single. I don't know if one is already there or not.
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post #131 of 1577
11/23/08 at 8:44am
This XO is used for USB. Therefore, the frequency of the XO should be 12.0000 M. TCXO works well from 1 ppm to 3 ppm. Some 1 ppm economy TCXOs made in China are enough. The C/P ratio is high for them. These China made TCXO were also used in some of the other Dacs appearing in this forum past.
Quote:
Originally Posted by Kooka View Post
Maybe a 12.288MHZ TCXO could work better?
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post #132 of 1577
11/23/08 at 9:54am
Quote:
Originally Posted by TeraDak View Post
This XO is used for USB. Therefore, the frequency of the XO should be 12.0000 M. TCXO works well from 1 ppm to 3 ppm. Some 1 ppm economy TCXOs made in China are enough. The C/P ratio is high for them. These China made TCXO were also used in some of the other Dacs appearing in this forum past.
Of course about the frequency you are totally right.
But about the quality, do you think a common chinese TCXO is better than the Toyocom already installed? It does not look an extremely cheap choyce. For sure Tentlabs is better but even the installed clock does not look all that bad to me... at least not much worse than the ordinary chinese TCXOs.
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post #133 of 1577
11/23/08 at 11:40am
So its safe to order one of those DACs now or is there a high probability getting a (cap-)toaster instead of a DAC?
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post #134 of 1577
11/23/08 at 12:18pm
Thread Starter 
According to their E-Bay ad they have made changes with better parts. So far I am the only one that has had a problem, it may not have been bad caps, it could have been caused by a faulty regulater etc.. I am still waiting for an updated version to arrive.

Phill
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post #135 of 1577
11/23/08 at 7:06pm
All this talk about reclocking makes me curious.
Does the stock VALAB have any reclocking module already implemented to it? If so does both the SPDIF and usb input are reclocked?
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