LKS Audio MH-DA003
Apr 27, 2017 at 11:51 PM Post #677 of 838
About using Burson V5D opamps in LKS DAC. Here are the answer from Burson :

v5d.png

So i am safe to use the V5D now.
Thank you Burson.
 
Apr 28, 2017 at 4:53 AM Post #680 of 838
Initial impressions out of the box is positive.
Sound quality wise, it is better than the 003+CCHD950X in every aspect, it about ties with the Schiit Yggdrasil for imaging, instrument separation, sound staging and presentation.
It has more bass slam and impact than the Yggy.

Compared to the 003+Pulsar the 004 is a bit cold and flat especially on the midrange and the soundstage is somewhat smaller.
The 004 falls apart on complex highly compressed tracks, instrument separation and imaging collapses which does not happen on the 003+Pulsar.
The 004 beats the Pulsar combo on bass slam and weight of the low notes, very tight and very deep, not heard that from a DS DAC before, to me, flabby ill defined bass is the hallmark of almost all the DS DACS I have listened to.

My unit has been burning in for about 2weeks.


Sound underwent a lot of changes.
On Day 1 almost all highly compressed pop and rock recordings sounded like the Chipmunks were doing the songs, thankfully this started to subside in the following days.
 
Apr 28, 2017 at 5:02 AM Post #682 of 838
Initial impressions out of the box is positive.
Sound quality wise, it is better than the 003+CCHD950X in every aspect, it about ties with the Schiit Yggdrasil for imaging, instrument separation, sound staging and presentation.
It has more bass slam and impact than the Yggy.

Compared to the 003+Pulsar the 004 is a bit cold and flat especially on the midrange and the soundstage is somewhat smaller.
The 004 falls apart on complex highly compressed tracks, instrument separation and imaging collapses which does not happen on the 003+Pulsar.
The 004 beats the Pulsar combo on bass slam and weight of the low notes, very tight and very deep, not heard that from a DS DAC before, to me, flabby ill defined bass is the hallmark of almost all the DS DACS I have listened to.

My unit has been burning in for about 2weeks.


Sound underwent a lot of changes.
On Day 1 almost all highly compressed pop and rock recordings sounded like the Chipmunks were doing the songs, thankfully this started to subside in the following days.
 
Apr 28, 2017 at 5:05 AM Post #683 of 838
The 004 falls apart on complex highly compressed tracks, instrument separation and imaging collapses which does not happen on the 003+Pulsar.

What can we do about? Also, the very unusual high temperature worries me about the performance, damage and life in long time.
 
Apr 28, 2017 at 5:09 AM Post #684 of 838
Peoples are turning head to another Chinese made DAC-the matrix audio x sabre pro. And I start wondering how many of ESS 9038pro and MFG's support are released to the market?
 
Apr 29, 2017 at 7:36 PM Post #686 of 838
I'm away for a couple of weeks, I come back and find that b0bb has got himself a 004 - awesome! And the tweaks have started!

My 004 listening is somewhat starting anew as I've just changed out my power amps (Cyrus x300 sigs --> Quad II 80's).
 
Apr 30, 2017 at 1:58 AM Post #687 of 838
I am staying with my MH-DA003. And i dont believe the new DA004 can have better sound than my "modded" DA003.

Unless the new 9038pro DAC that fix the heat isssue in the DA004 orthewise there are no chance i choice the DA004
 
Apr 30, 2017 at 4:26 PM Post #688 of 838
b0bb,
How many degrees did the temperature of the caps lower when you installed the heat shields?

Another thing to try would be to put a piece of copper foil tape (still with paper backing on it....to keep it stiff) between the transistors and caps. This would absorb the heat but because it has the paper on the back, it would not radiate into the caps. It could be mounted so it would not touch the transistors.

You could also use several layers thick conductive glue copper foil and mount them directly on the transistors to act as heatsinks.....if you made them tall enough....the heat would go up and not back much.

I will try both methods and see what reduces the heat the most. Like the copper foil shield method best as it is easy and fast.

Wrapping the caps with the heat shield material WILL change the sound. Better? Worse? They sound great now.....don't personally like this option.
 
Apr 30, 2017 at 7:42 PM Post #689 of 838
b0bb,
How many degrees did the temperature of the caps lower when you installed the heat shields?

About 4ºC

This extends the life of the caps by 50% (0.6yr 0.9yr)
Using Nichicon's calculator for the Fine Gold (UFG) 85ºC/1000hr
Temp (ºC)Lifetime in years
590.6
550.9
501.2
451.8
402.5
Nichicon make the KA (UKA) audio cap 105ºC/2000hr
Temp (ºC)Lifetime in years
595.5
557.3
5010.3
4514.6
4015
Extensive heat sinking will bring down operating temps to the range of 45-50ºC, the 2yr lifetime of the Fine Golds make this hardly worthwhile in my view.

However with the KAs there is substantial gain in the usable lifetime.
Wrapping the caps with the heat shield material WILL change the sound.

This is to be expected. The thermal shields did not degrade the sound, there was less breakup on highly compressed tracks and the very low bass notes gained a small increase in the heft and impact.

I put it down to a reduction in thermal stress.

Degradation from the heat will eventually catch up and ruin the cap, the heatshield buys time until a better solution is found.

(PS this new interface is terrible, where did the table editor go?)
 
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May 2, 2017 at 4:47 AM Post #690 of 838
Heatsinks on the I/V output transistors, this is an experiment to see if heatsinks reduce the ambient temps around the caps.
9936807.jpg

9936808.jpg


Ambient temp dropped to 51ºC, this is a substantial change from the 59ºC in the unmodified stock case.
9936809.jpg


Location of the thermocouple
9936810.jpg



The current choice of heatsink is a 21ºC/W unit, larger heatsinks won't fit due to the space constraints.
This current arrangement show that there is much to be gained by adding heatsinks to the output transistors.
The heatsink temp was about 60ºC, not bad considering it is connected to 2 transistors, the vent area above the transistors feels noticeably warmer, so the heatsinks are dissipating the heat as expected. More importantly it is preventing the heat from radiating into the nearby caps.

I took the opportunity to thermally couple the 2 halves of the output pair, this stabilizes the DC operating point of the opamp and reduces the DC drift.
Somewhat unexpected was an improvement in sound quality, the soundstage got much deeper and wider, did not expect this as the 004s soundstage is already very good.
 

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