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Problems with HLLY DMK-IV DAC.

post #1 of 11
10/23/10 at 2:05am
Thread Starter 

Hi head-fi's.

 

First off thank you for this great forum. I have been reading a lot of your guys posts, the last couple of months. It's great to see that there's somebody outthere that really knows their stuff.

Anyway...

 

After reading some different tests and reviews regarding USB DACs, I decided to buy a HLLY DMK-IV.

It arrived yesterday and I was VERY exited about it.

 

I connected to a (friend of mines) setup containing a CAV A8M 6.1 amplifier and a set of Mission 704 speakers.

This system has been running with another DAC previously, but now it was time to do some comparison.

At first I was very happy for the audio-quality from the HLLY, with the volume set at 10 on the DAC.

We made some different tests, and there was no doubt that this DAC definitely had a great reproducing of the audio....BUT:

Now a BIG problem accured...The volume from the DAC were increased to 20, and somehow the treble became very aggressive, and the bad/mid range was like "moved backward". There were no doubt...It sounded completely wrong, and the output-range was very none-linear.

When at the lower output stage (like 10 on the DAC) it sounded ok, but the higher volume, the more "wrong" it sound.

When reaching the volume at 30 the sound was completely horrible. The signal was totally distorted and clipped. Going to vol 35 made the signal almost disappear be replaced by some "tch, tch, tch (totally distortion).

 

I tried the DAC in 3 other setups and the problem was exactly the same.

 

Have any of you guys experienced similar problems? 

Any comments on this would be highly appreciated.

 

The DAC is going to be used in my car, for an audiophile car-pc setup, so I really hope that some of you can point me in the right direction for solving this problem, as I can't wait for it to be integrated...

 

Thanks in advance

 

Regards from Denmark

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post #2 of 11
10/23/10 at 2:28am
Thread Starter 

Another thing...

When changing the balance it distorts even more. When moving the balance to left/right the treble becomes VERY aggresive, and the signal distorts and clips extremely, even at only "vol 20"...

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post #3 of 11
10/23/10 at 2:35pm

Are you using the pre-amp out of the HLLY DMK-IV? I have mine at the office or otherwise I would check, if the unit has a great feature is the DAC out which as I recall it is fixed.

 

DMK-IV-05.jpg

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post #4 of 11
10/24/10 at 12:31am
Thread Starter 

Thank you for the reply.

Yes, I'm using the pre-amp out. But when using the headphone out the problem is the exact same.

And what I found the most strange, is that even when vol 10, when balancing the signal to R/L it sounds completely wrong. Really wrong. The treble is taking over and the bas/mid dissapears almost.

 

Yesterday I measured the TP's with my scope, and I found some suspecious results. The DAC was ON but with no input/output Just pure idle mode-results:

The TP108 is supposed to be +15V. Measured voltage +13V

The TP110 is supposed to be -15V. Measured voltage -13V

The TP104 is supposed to be +5V. Measured voltage +4V

The TP109 is supposed to be -5V. Measured voltage -4V

 

I think these results tells that there must be something wrong in the PSU section. It is clear to me that if the voltage is too low, the output will clip/distort...Hmm!?

 

 

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post #5 of 11
10/25/10 at 12:29am
Thread Starter 

I made as calibration mistake on my scope. The actual measured voltages are +/-13.8V. But still not the +/-15V it is supposed to be.

 

Anyone who have the same DAC in here? I would like to know if it also distorts when changing the balance from center to left/right.

In my case the signal sound gets completelly different, and the sound perspective dissapears completely, while the treble is increased extremely.

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post #6 of 11
10/25/10 at 4:50pm

Hello:

 

    Never meet this problem from DMK-IV customers, You can try to connect the DAC out to your amplifier directly and see what

will happen, also please try some other amplifier with DMK-IV

 

    Regards

 

    david gao

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post #7 of 11
10/26/10 at 3:38pm
Thread Starter 

Hi David.

Thank you for your reply in here. I have tried with 3 different amplifiers. Problem still the same.

I'm sure we will find a solution, I just have to know what to do. I really would like to use the DMK-IV in my setup though!

 

I would like to have an answer on these questions:

1. Is it normal that the signal gets distort when changing the balance from the center to R/L?

2. Is it normal that the measured voltages are 1.2 volts lower than what stated at the TP's?

 

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post #8 of 11
11/17/10 at 12:46pm
Thread Starter 

Good news...

Yesterday I received a new set of CS3310 from David.

The CS3310 is the volume controlling IC, and this IC somehow defective.

 

Desoldering the old IC and replacing with the new one, solved the problem completely.

 

Problem solved, and everything is fine....

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post #9 of 11
2/19/11 at 2:40pm
Quote:
Originally Posted by -Aze- View Post

Another thing...

When changing the balance it distorts even more. When moving the balance to left/right the treble becomes VERY aggresive, and the signal distorts and clips extremely, even at only "vol 20"...




Thanks for your sharing! Now I got it, It helps me out of the problem, It's good for reference.
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post #10 of 11
3/21/11 at 4:44am

Hi. I've just received today my DMK-IV I've bought on e-bay and I seem to be having the same problem. The sounds distrorts on pre-amp out, at volumes over 34 and when adjusting balance. I've just received the unit today and wonder what I could do about it except for contacting the seller and having it shipped back to China.

Is the CS3310 replacement the only option? Anything other I could check/try to fix myself, like caps, voltages, etc.?

Is the CS3310 inside the unit in SMD or in DIP package?

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post #11 of 11
3/23/11 at 12:37pm

Hi, wonder if anyone can help me here. Today I opened the DAC and corrected some suspicious solder points (it's hand-made) but that didn't help. My problem is somewhat different, since I only get clipping at extreme volumes, otherwise the sound isn't distorted.

However I connected scope today and measured voltage at pre-amp out only to found that at max volume (40) setting it reaches 20V peak-to-peak! The voltage on DAC out is ok. On pre-amp out after I cross volume 30 setting, I enter voltage ranges above 3V, which quickly raise up to these 20Vpp ! Is there anyone knowledgeable with design of this device, who could point me to what may be wrong with my unit? I also measured voltage at the +5V test point near CS3310 and it was ok.

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