[37mil]

C-media is another popular USB audio receiver chip but maybe not as much in high end audio products.

 

[Bigbwb]

the 503 is up on the site!
http://www.teac.com/product/ud-503/

 

[37mil]

This guy has got a 503 and says there's no voltage regulation after the 4 big power supply caps.
 
http://www.post76.com/x2/forum.php?mod=viewthread&tid=218824
 
He's going to build one in.
 
That's a big disappointment.

 

[occamsrazor]

  This guy has got a 503 and says there's no voltage regulation after the 4 big power supply caps.
 
http://www.post76.com/x2/forum.php?mod=viewthread&tid=218824

 
Could you explain the significance of this to a relative newbie please? Thanks.....

 

[37mil]

   
Could you explain the significance of this to a relative newbie please? Thanks.....

Power is everything! Well, in audio, clean, stable power is.
 
Normally a voltage regulator is used to provide non-fluctuating and noiseless voltage.  In fact, the 501 has 4 of them for the audio circuit (2 per channel +/-12V from the 15V transformer).  This is so important that some people like to modify these 'poor performance' parts with discrete circuits from Dexa, Belleson, and now Sparkos, which provide even more stable and noiseless power.  Without the regulators, the power coming through the mains which could be fluctuating wildly could possibly affect sound quality.
 
Having NO regulation in a product of this price point is kind of ridiculous - and strange. Well, until more people get the 503 to have a look at the circuit, we'll just have to see.

 

[occamsrazor]

 
Power is everything! Well, in audio, clean, stable power is.
 
Normally a voltage regulator is used to provide non-fluctuating and noiseless voltage.  In fact, the 501 has 4 of them for the audio circuit (2 per channel +/-12V from the 15V transformer).  This is so important that some people like to modify these 'poor performance' parts with discrete circuits from Dexa, Belleson, and now Sparkos, which provide even more stable and noiseless power.  Without the regulators, the power coming through the mains which could be fluctuating wildly could possibly affect sound quality.
 
Having NO regulation in a product of this price point is kind of ridiculous - and strange. Well, until more people get the 503 to have a look at the circuit, we'll just have to see.

 
Thanks for taking the time to explain.... If that's the case it does seem odd doesn't it? I mean Teac can't be stupid and they've obviously put a fair bit of thought into this DAC. I just wonder if it's some kind of mistake and there is actually something there to perform this function. Time will tell I guess....

 

[37mil]

   
Thanks for taking the time to explain.... If that's the case it does seem odd doesn't it? I mean Teac can't be stupid and they've obviously put a fair bit of thought into this DAC. I just wonder if it's some kind of mistake and there is actually something there to perform this function. Time will tell I guess....

The last DAC I had with no regulation was the Musical Fidelity x-dac v3 but that was well below the 503 price point.
 
I think Teac might have simplified or cost down the circuit due to price or PCB space concerns. 

 

[37mil]

The guy with the 503 linked above has removed the SO-8 package op amps and replaced with DIP sockets to roll op amps as well as changing all smd resistors in the audio path to 0.1% types.
 
The board looks so cramped even the smallest discrete op amp from Sparko won't fit.
 
There were 3 op amps per channel in the 501, all dual type.  Now there's only 2 and no mention of them being MUSES. Looks very disappointing coming from a 501.

 

[Faithless]

503 downgraded?

 

[kawaivpc1]

  The guy with the 503 linked above has removed the SO-8 package op amps and replaced with DIP sockets to roll op amps as well as changing all smd resistors in the audio path to 0.1% types.
 
The board looks so cramped even the smallest discrete op amp from Sparko won't fit.
 
There were 3 op amps per channel in the 501, all dual type.  Now there's only 2 and no mention of them being MUSES. Looks very disappointing coming from a 501.

Overall, it looks better though. Now, it supports DSD256.
Has anyone heard UD503???
Can anyone tell how it sound? 
Its retail price is 1100 USD.

 

[37mil]

  Overall, it looks better though. Now, it supports DSD256.
Has anyone heard UD503???
Can anyone tell how it sound? 
Its retail price is 1100 USD.

From a marketing perspective it looks better.
It's nice that they've put a FPGA in there for DSD256 and on the fly conversion. But having no power regulation to the audio circuit is unforgivable for a product of this price point. The guy modding his has made a circuit board for the regulator. It's already around quarter the size of the PCB of the 503 main board. That's what they took out to fit the marketable items such as the DSD256 and master clock input in. And as discussed previously, there's not many, if any, readily available 10MHz clocks that can be justifiably used with the 503 because of the cost. Having said that, the power management in the 503 looks so shoddy, it might be worth having an external clock just to isolate it from the dirty mains inside the main unit.
 
The FPGA might be implemented perfectly, and the new AKM dac chips might be superior to the burr-browns in the 501 but without properly conditioned power, it's very unlikely it can perform to anywhere near to outperforming a 501. Anyone who's bothered to change regulators and power supplies and cables will know the importance. Any differences in sound will probably be down to the implementation of the output stage - but the 501 has the nice muses op amps and the 503 doesn't.

 

[kawaivpc1]

 
From a marketing perspective it looks better.
It's nice that they've put a FPGA in there for DSD256 and on the fly conversion. But having no power regulation to the audio circuit is unforgivable for a product of this price point. The guy modding his has made a circuit board for the regulator. It's already around quarter the size of the PCB of the 503 main board. That's what they took out to fit the marketable items such as the DSD256 and master clock input in. And as discussed previously, there's not many, if any, readily available 10MHz clocks that can be justifiably used with the 503 because of the cost. Having said that, the power management in the 503 looks so shoddy, it might be worth having an external clock just to isolate it from the dirty mains inside the main unit.
 
The FPGA might be implemented perfectly, and the new AKM dac chips might be superior to the burr-browns in the 501 but without properly conditioned power, it's very unlikely it can perform to anywhere near to outperforming a 501. Anyone who's bothered to change regulators and power supplies and cables will know the importance. Any differences in sound will probably be down to the implementation of the output stage - but the 501 has the nice muses op amps and the 503 doesn't.

I'm getting both

 

[37mil]

UD-503 now selling in Hong Kong for the equivalent of USD1000.

 

[Taijitu]

Hello guys,
 
I have a little question for the owners of this DAC.
 
When I plug a headphone in the jack output, I hear a faint hum whereas it is not the case in the speakers. I tried to disconnect the other devices connected to the DAC and used a portable player as a source but the hum is still here.
 
It is not very loud but it is audible. I read in some review there should be no noise. Do I have a defective unit or is it a feature ?
 
Thank you.

 

[37mil]

  Hello guys,
 
I have a little question for the owners of this DAC.
 
When I plug a headphone in the jack output, I hear a faint hum whereas it is not the case in the speakers. I tried to disconnect the other devices connected to the DAC and used a portable player as a source but the hum is still here.
 
It is not very loud but it is audible. I read in some review there should be no noise. Do I have a defective unit or is it a feature ?
 
Thank you.

If you're referring to the 501, using my Beyer T1's I don't hear any hum at all.
 
Maybe you have a mains hum problem? Does it get louder if you crank up the volume?