L30, Crackling, Sy-DAC1002 Question

[6th0]

I’m a DAC/amp newb who just put together a desktop system. While troubleshooting crackling in my newly built system I ran across something I can’t explain.
I play 44Khz 16 bit FLAC files from my PC through USB to a Topping E30. The E30 was connected to a SY-DAC1002 amp via RCA, then out to some old (but unused until this week) Advent Heritage H200 desktop passive speakers and BIC F12 sub.

From a volume standpoint, I barely get about 10% on the amp before my family complains in the other room. Oh, yeah…

But, when the E30 is in DAC mode I will get all sorts of crackling in the speakers but I don’t crackling when the E30 is in preamp mode. Such an AWFUL distraction that pulls me right out of the music. Also, when I play music out of iTunes and the E30 is in DAC mode, I don’t get crackling. I usually use MusicBee as a player, but Foobar gives me the same problem. I first figured that the problem is that there is an issue playing higher FLAC quality files through USB or the speakers.

Although they are 15 years old, I happen to have three pairs of H200 “new in the box” and I’ve swapped them out. However, they were in my attic and probably all subjected to extreme heat over the last 15 years. All of them had crackling issues. Maybe a speaker issue? I have some JBL 530s on the way to me as I type, so I can eliminate speaker issues by next Thursday.

I received a Topping L30 today and put it in between the E30 and the SY-DAC1002. When I put the L30 in PRE mode to play out of the speakers, turned the L30 volume all the way up so as not to restrict the amp, and put the L30 gain to -9.9dB, the volume on the SY-DAC1002 amp went way down so that to get the equivalent “family complaint” volume was about 30% of the dial instead of 10%.

Also, there is no crackling when I put the L30 in Head Phone Amp mode with some cheapo Koss KPH30i. This tells me that the issue is either: the amp or the speakers. There was some talk about clipping with this amp and some DAC’s: https://www.audiosciencereview.com/...pa3255-dsp-amplifier.14315/page-5#post-483262 Maybe the E30 DAC puts out too many volts for the amp? Keep in mind that as a newb I may have no idea what I'm talking about

When I put the L30 gain at 0dB, the volume went up (but not as much as the E30 directly to the SY-DAC1002) and the crackling in the speakers went away!

Why would the volume go down and the crackling go away when the L30 is configured in -9.9dB but emerge again at 0dB?

How do I get rid of this damn crackling--in good conscience I really can't throw any more money at it!

Any insight would be appreciated because I have a ton of cash wrapped up into this configuration. And...damn, I sure did find that you don’t go down the audio excellence rabbit hole, the rabbit hole finds you and sucks you down! My condolences my friends...

--6th0

 

[Blur]

Couple of thoughts. Because the E30 works without crackling in pre-amp mode my first thought is clipping the amp in the speaker setup. Pure DAC mode fixes the output close to 2 volts RMS while pre-amp mode allows you to control the volume output. At 0dB in pre-amp mode you get no crackling?

One thing to try is use optical input to the E30 and see if that helps. I have read one account that they needed to actually install Topping's USB driver and their crackling issue went away. They were also using USB to feed the DAC.

Let us know if you fix it.

Here is the driver:
http://www.tpdz.net/newsinfo/435189.html

 

[Toku]

I’m a DAC/amp newb who just put together a desktop system. While troubleshooting crackling in my newly built system I ran across something I can’t explain.
I play 44Khz 16 bit FLAC files from my PC through USB to a Topping E30. The E30 was connected to a SY-DAC1002 amp via RCA, then out to some old (but unused until this week) Advent Heritage H200 desktop passive speakers and BIC F12 sub.

From a volume standpoint, I barely get about 10% on the amp before my family complains in the other room. Oh, yeah…

But, when the E30 is in DAC mode I will get all sorts of crackling in the speakers but I don’t crackling when the E30 is in preamp mode. Such an AWFUL distraction that pulls me right out of the music. Also, when I play music out of iTunes and the E30 is in DAC mode, I don’t get crackling. I usually use MusicBee as a player, but Foobar gives me the same problem. I first figured that the problem is that there is an issue playing higher FLAC quality files through USB or the speakers.

Although they are 15 years old, I happen to have three pairs of H200 “new in the box” and I’ve swapped them out. However, they were in my attic and probably all subjected to extreme heat over the last 15 years. All of them had crackling issues. Maybe a speaker issue? I have some JBL 530s on the way to me as I type, so I can eliminate speaker issues by next Thursday.

I received a Topping L30 today and put it in between the E30 and the SY-DAC1002. When I put the L30 in PRE mode to play out of the speakers, turned the L30 volume all the way up so as not to restrict the amp, and put the L30 gain to -9.9dB, the volume on the SY-DAC1002 amp went way down so that to get the equivalent “family complaint” volume was about 30% of the dial instead of 10%.

Also, there is no crackling when I put the L30 in Head Phone Amp mode with some cheapo Koss KPH30i. This tells me that the issue is either: the amp or the speakers. There was some talk about clipping with this amp and some DAC’s: https://www.audiosciencereview.com/...pa3255-dsp-amplifier.14315/page-5#post-483262 Maybe the E30 DAC puts out too many volts for the amp? Keep in mind that as a newb I may have no idea what I'm talking about

When I put the L30 gain at 0dB, the volume went up (but not as much as the E30 directly to the SY-DAC1002) and the crackling in the speakers went away!

Why would the volume go down and the crackling go away when the L30 is configured in -9.9dB but emerge again at 0dB?

How do I get rid of this damn crackling--in good conscience I really can't throw any more money at it!

Any insight would be appreciated because I have a ton of cash wrapped up into this configuration. And...damn, I sure did find that you don’t go down the audio excellence rabbit hole, the rabbit hole finds you and sucks you down! My condolences my friends...

--6th0

First of all, I think the SY-DAC1002 is a mistake of the SY-DAP1002.
This problem occurs because the input voltage of SY-DAP1002 is different from general audio equipment.
Although the signal voltage of RCA unbalanced connection for consumer audio equipment is specified as 2V, SY-DAP1002 specifies the input voltage as 0.77V (600Ω 0dB). If you connect the output of a general device to the SY-DAP1002 as it is, the input becomes excessive and the sound is distorted.
To prevent this, it is necessary to lower the input voltage of SY-DAP1002 sufficiently.

 

[6th0]

First of all, I think the SY-DAC1002 is a mistake of the SY-DAP1002.
This problem occurs because the input voltage of SY-DAP1002 is different from general audio equipment.
Although the signal voltage of RCA unbalanced connection for consumer audio equipment is specified as 2V, SY-DAP1002 specifies the input voltage as 0.77V (600Ω 0dB). If you connect the output of a general device to the SY-DAP1002 as it is, the input becomes excessive and the sound is distorted.
To prevent this, it is necessary to lower the input voltage of SY-DAP1002 sufficiently.

Yes, you are correct. It should be SY-DAP1002!

The E30 preamp is not known to be a good one, but since I have an L30 in between the E30 and the amp, I've used the preamp in L30 instead. Setting the amp to a max setting I use the L30 for volume which keeps the L30 to about the 1:00 position. I don't hear crackling there.

It is disappointing to hear that there is a such a voltage difference. Is .77V documented somewhere or is there another thread about it?

 

[Toku]

Yes, you are correct. It should be SY-DAP1002!

The E30 preamp is not known to be a good one, but since I have an L30 in between the E30 and the amp, I've used the preamp in L30 instead. Setting the amp to a max setting I use the L30 for volume which keeps the L30 to about the 1:00 position. I don't hear crackling there.

It is disappointing to hear that there is a such a voltage difference. Is .77V documented somewhere or is there another thread about it?

Previously I worked on the design of professional audio equipment such as TV stations. In professional audio equipment at that time, 0dB was specified as 600Ω / 1mw / 0.77V.
When I was checking the SY-DAP1002 of 3e audio this time, I felt that the allowable level of the input voltage was lower than 1V.
So I wondered if they designed to these standards.
The standard unbalanced signal for consumer audio equipment is 2V, but it was 1V before, but with the times, it escalated to a high voltage.
As an aside, in the professional world, the conversion of balanced/unbalanced was done using a transformer. However, in consumer equipment, a conversion transformer is expensive, so a pseudo-balanced circuit is created using a semiconductor circuit such as an OP amplifier, which is called balanced connection.

 

[6th0]

https://www.audiosciencereview.com/...pa3255-dsp-amplifier.14315/page-5#post-482503

What matters is the voltage going into the DAP1002. With the E30 in DAC mode, you are getting 2V out and causing clipping in the DAP1002.

Should I always seek to maximize the gain from the DAC or preamp to the power amp's input, or will there be a sound quality difference if I use a lower gain but turn the amp volume up? In this case is it best to to find .77V on the pre-amp dial on the L30 to max out the input of the DAP1002 versus say .25V on the L30 and use the amp as my main volume control?

Lately I've turned the DAP1002 up to 3/4's full volume then used the L30 gain to set speaker volume as my mood dictates. This way I can go to headphones knowing that I have only one place to adjust. However, that probably means that if I don't set the L30 gain to a set .77V, then I could be losing some sound quality if I go below or above this.

I don't mind switching to using the amp as the volume control.

On the L30, is there a way to know that I'm at .77V or do I just eyeball turning it to less than halfway up.

 

[Toku]

Should I always seek to maximize the gain from the DAC or preamp to the power amp's input, or will there be a sound quality difference if I use a lower gain but turn the amp volume up? In this case is it best to to find .77V on the pre-amp dial on the L30 to max out the input of the DAP1002 versus say .25V on the L30 and use the amp as my main volume control?

Lately I've turned the DAP1002 up to 3/4's full volume then used the L30 gain to set speaker volume as my mood dictates. This way I can go to headphones knowing that I have only one place to adjust. However, that probably means that if I don't set the L30 gain to a set .77V, then I could be losing some sound quality if I go below or above this.

I don't mind switching to using the amp as the volume control.

On the L30, is there a way to know that I'm at .77V or do I just eyeball turning it to less than halfway up.

The best way is to set the E30 to Pre mode and reduce the output level to -10dB. I set it that way when connecting the E30 to the SY-DAP1002. The root cause is that 3e audio was designed according to old audio signal standards.