Review and Measurements of Topping D10 DAC

[Veri]

Measurewise there's not really a difference comparing OPA2134.

If there's no measureable difference, what do you suppose you're hearing / determines the better bass control?
op-amps could marginally improve (or break) amp implementation, but rolling op-amps in a DAC? Eh..

 

[777]

Tested the OPA1642 for the I/V of D10. Similar Sound compared to OPA2134 but Bass is little better under control.
Measurewise there's not really a difference comparing OPA2134.

Edit:
It is not always the best solution implementing the fastest OPAmp for I/V!

OPA1642 for I/V conversion ? This op-amp has almost the same speed. GBP of 11Mhz instead 8Mhz like OPA2134. Slew-rate the same, 20v/us. Try another one with SR minimum 50v/us and GBP bigger than 50Mhz.

 

[Krunok]

Man, if you do not understand what I talk about, put your hand on book and read. OPA2134 is slow for a I/V conversion if you want the best results. Is has high output impedance at hundred of khz and megahertz. OPA2134 is suitable for voltage low-pass filter.

No problem, let's discuss OPA2134 specs.
"Slow"? To which exact OPA2134 parameter are you referring?

High impedance? I didn't know I/V converters require low impedance outputs. Why would I/V conversion require that?

 

[Krunok]

Tested the OPA1642 for the I/V of D10. Similar Sound compared to OPA2134 but Bass is little better under control.
Measurewise there's not really a difference comparing OPA2134.

Is that really so? Can you post photos of the board with OPA1642 soldered and screenshots of your measurements?

 

[Krunok]

OPA1642 for I/V conversion ? This op-amp has almost the same speed. GBP of 11Mhz instead 8Mhz like OPA2134. Slew-rate the same, 20v/us. Try another one with SR minimum 50v/us and GBP bigger than 50Mhz.

50MHZ? Because you are using D10 as a receiver in walkie-talkie, or..?

Or you are saying that 50MHz analog signal is present on output pin of the DAC chip and I/V converter has to deal with it?

 

[777]

High impedance? I didn't know I/V converters require low impedance outputs. Why would I/V conversion require that?

Ok, QED

 

[Krunok]

Ok, QED

Is that so?

Let's try this way: can you calculate what kind of output impedance is necessary for I/V converter in a DAC like D10 so we can check if OPA2134 has it or not?

And if OPA2134 doesn't have output impedance large enough how comes they used it as an output buffer as well?

 

[Krunok]

Btw, I'm just listening to a Sennheiser Mommentum headphones connected directly to a D10 analog outputs and the sound loudness and quality don't seem to share your opinion about OPA2134 high output impedance.

But I do seem to hear it is struggling with some music material because of low slew rate and GBP of only 8MHz..

 

[HAL9000]

If there's no measureable difference, what do you suppose you're hearing

Perheps everything in front of the DAC.
We can measure differences in DAC marketing. Like audio zealots…But It is utterly irrelevant how any element of the audio chain behaves, good or bad, when there are a few zeros in front of the measurement. For example, if a good speaker delivers a whopping 2% distortion it's of no consequence whatever if the DAC adds 0.000005% distortion, the amplifier 0.2% distortion, the cables 0.00000003% distortion and so on. Distortion (and hiss) is cumulative from DAC to speakers and the element along that chain with significantly the most 'distortion' masks and hides the shortcomings of all the others. Also everyone here has different components that behave differently in front of the DAC ....

 

[777]

Btw, I'm just listening to a Sennheiser Mommentum headphones connected directly to a D10 analog outputs and the sound loudness and quality don't seem to share your opinion about OPA2134 high output impedance.

But I do seem to hear it is struggling with some music material because of low slew rate and GBP of only 8MHz..

You do not know nothing about i/v conversion. Read a book.

 

[Krunok]

You do not know nothing about i/v conversion. Read a book.

And yet you, a self-proclaimed expert on DACs and op amps, failed to provide a single answer to any of my questions.

Let's see them again and give you another shot to prove yourself:

1. What is max frequency on DAC's output pin and how is op amp's gain at 50MHz relevant to processing (I/V conversion) of DAC's output signal?

2. How is SR of 20V/us not enough for op amp used in I/V conversion so op amp with SR 50V/us is needed?

3. What minimal output impedance op amp needs to have to be used for I/V conversion?

 

[guenthi_r]

Can you post photos of the board with OPA1642 soldered and screenshots of your measurements?

Maybe tomorrow.

 

[guenthi_r]

3. What minimal output impedance op amp needs to have to be used for I/V conversion?

Should it not be INPUT impedance?
ES9018K2M = ca. 760 ohms output impedance, the D10 board adds another impedance.

 

[Krunok]

Maybe tomorrow.

We are counting on it. Otherwise some of us may come to idea that you didn't do it at all. I mean, we don't know each other so we can only trust arguments based on photos, screenshots and links to articles, right?

 

[guenthi_r]

We are counting on it. Othwewise some of us may come to idea that you didn't do it at all. I mean, we don't know each other so we can only trust arguments based on photos, screenshots and links to articles, right?

Very aggressing today?
Are you "we"?

 

[Krunok]

Should it not be INPUT impedance?
ES9018K2M = ca. 760 ohms output impedance, the D10 board adds another impedance.

I don't know what he wanted to say, but he said "output impedance" of the op amp.

Input impedance of OPA2134 (and any other op amp) is much much higher than output impedance of ES9018K2M, look at page 5 of the spec sheet.
But then, maybe @777 thinks it's not high enough..

 

[Krunok]

Very aggressing today?
Are you "we"?

"We" who are following this thread.

Do you find asking for photos and measurement screenshots aggressive?

 

[777]

We talk here about I/V conversion., not about low-pass filter, buffer or RCA summing. We must to have almost zero output impedance until at 100Mhz. OPA2134 can't do that. Again, read about i/v conversion.

 

[guenthi_r]

"We" who are following this thread.

Do you find asking for photos and measurement screenshots aggressive?

No, but your agressive "style" of communication.

Welcome to my ignore list @Krunok

@amirm is this the "new" style of ASR-Forum?

 

[guenthi_r]

We talk here about I/V conversion., not about low-pass filter, buffer or RCA summing. We must to have almost zero output impedance until at 100Mhz. OPA2134 can't do that. Again, read about i/v conversion.

@777 give it up, @Krunok just wants to annoy you..