[DIY] L.K.S ES9018 DAC

[Cidious]

I've almost finished my Lehmann 2nd Lehmann BCL clone like described here in this thread:

http://www.diyaudio.com/forums/headphone-systems/285380-headamp-upgrading-lehmann-bcl-clone.html

This was my first really empty PCB project. I still have a lot to learn, but the Lehmann project already gave me a lot of practical experience with DIY building. Right now I'm focussing in on more layout and circuitry knowledge by reading, reading and reading some more.. Trying to connect it to real world stuff.

Since I want to keep one leg into the practical world I've decided to build myself a ES9018 DAC with Amanero Combo384 USB for DSD512/PCM384 streaming. The circuit is designed by L.K.S audio. Which makes some dafty looking devices. I've been in contact with the owner for a while and he seems to be a good bloke with a healthy passion for audio. He's really helpful with any question you throw at him.

https://item.taobao.com/item.htm?spm=a1z10.1-c.w9789869-11612113831.55.PTmE2D&id=25873632122

I've decided to build this DAC because of multiple reasons.

1. I like the ES9018 chip that I've heard in multiple devices.
2. I wanted a design to match the Lehmann BCL
3. I don't need al kinds of expensive fancyness like balanced ports and stuff
4. Can't be to big
5. It should be within a certain budget to keep the fun in it if I screw it up

Well this DAC suites all my needs and I've made a very sweet deal with the owner of the shop to send it to me partially assembled so I could do the rest myself. I asked him to only solder the really small parts like the chips and small resistors and stuff. It saved me ¥500 yuan which is about €65. The fully assembled package normally costs ¥2300 (€315/$350) and I got it for ¥1800 (€250/$275). Depending of the result of course, this seems to be a bargain.

I don't have the circuit schematics at hand now. They will be send to me tomorrow. So I will post them then.

I've showed the device to a well known and experienced audio enthusiast on the forums here that happens to live in the city where I'm currently living and working. He pointed out some week spots in the circuit like that the voltage regulators are quite far away from the chip and he was not fond of the way of grounding. Well it'll have to do for now but I'm going to try to make the best out of the device with some modifications.

The device was delivered with a complete parts list. Some of these parts are:

50VA custom torodial transformer 8V+15V
4 big power caps are NOVER 5600uf 63V (Panasonic made). I will probably upgrade them for some Nichicon KG Type II 6800uf 63V unless people think very highly of these caps.
The regulator output caps are Nichicon Muse KZ 470uf 25V caps. Quite big. Their direct competition could be the Elna Silmics II which I have really great experience with in the signal path.. But since this is still the PSU I am wondering if it would not be a better choice to use some caps here that are designed to work in the PSU.. like the Panasonic FR caps or FMs with really low ESR.
The other electorlytes are Nichicon FG 47uf 50V caps
A lot of red Wima caps arround the opamps
3x OPA 1612A which I've never heard of
ST LM317 and Fairchild LM337 voltage regulators which I already replaced for ON version
A JYEC TCXO crystal.. never heard of them, but they seem to be used a lot by respectable Chinese brands like Gustard and Audio-GD. So I guess it's not to bad.
A Sanyo cap near the ES9018 chip
And some other parts


Feel free to comment on the project. I haven't made up my mind yet about all the part choices. If you have suggestions and also for mods to improve the circuit than I am happy to hear about them. If you have a suggestion please explain why to me. I'm trying to learn. That's the most important thing. I'm not trying to put something together quickly to just copy some other's work and race to the end goal. I want to learn more about audio circuitry.

 

[Cidious]

I'm still studying the circuit and I've decided to first build the devices as it is supposed to be build according to the seller. My new 'town mate' Richard, here called abraxalito helped me identifying some weak spots in the device and he made a few good suggestions to modify some thing after I'm done building up. I will do it step by step to evaluate the changes just like I did with my Lehmann clone.

Here are the schematics for the device. The schematics show LM4562 opamps. I've got some OPA1612A that came with the device but I also have some OPA2604APs ready to take their places with some class A adapters (the same i've used in my lehmann).

http://www.diyaudio.com/forums/attachment.php?attachmentid=532020&stc=1&d=1455814207

I've noticed that the parts mentioned in the schematics are not 100% matched in value looking at the parts delivered with the device. For example all 10uf/16v caps from the schematics are replaced with 47uf/50V caps that came with the package. I am not sure yet what I will do. I have to figure some stuff out. I'm still learning about all the functions of the components.

 

[Cidious]

A LOT of wima caps.. not really happy about it.. better alternatives are quite expensive. At least I swapped the MKS2 0.1 caps out here for MKP2 0.1 caps. Will do more swapping after I've finished the build near standard.

Replaced MKS2 0.1 caps here with MKS4 0.1 caps

These puppies went with the package. Brittish brand from Anglia parts. They only give the ripple current spec in the specsheet. 3.3A if I am not mistaken. I have space for 30x50mm. Not sure if I should increase the size to 6800uf and maybe Nichicon KGs or Elna's for Audio.

Would and Elna for Audio 6800uf 35V be better than these 5600uf 63V caps? Or maybe KG Gold Tune 6800uf 50V. Both fit I think. I am not willing to put Mundorfs in it haha. Badshit expensive here in China!

I will be populating the reg output positions with Elna Silmic 470uf 25V caps instead of the Muse KZ caps. The other small electrolyte cap positions I will populate with Silmic 47uf 25V caps instead of the Nichicon Fine Gold 47uf 50V caps. This will be my starting point.

Probably after that I will start looking into cleaning up the power supply section with some mods.
After that I will try higher electrolyte cap values for the reg ADJ positions. and maybe near opamp.

Would it also matter if I used something better than the Wima MKP2 near the DAC chip itself below the Sanyo cap?


I guess nobody gives a **** about this project. Doesn't really matter. I will keep logging my findings.

 

[Cidious]

Ok, So i've finished my build.

I did the smoke test and at first it seemed ok and all light were going on and the display responded. But after a brief heat check.. my fingers almost got fried on the LM317 voltage regulator above the opamps. It's going into the analog circuit. I've checked the 470uf Elna cap behind it and resoldered and cleaned the surroundings. Something is pulling a lot of current through it.. It stinks and it's WAY hotter than the other ones. The seller of the parts and the board agrees that it's not normal. I can not put my finger on the heatsink. Not even for a second.

If some one has any idea where to start looking I would be really grateful.

DC offset is already adjusted to 0 volt with the trimpots.

Oh and BTW, can someone say something about the WEIRD ELNA for Audio caps I've got in there? They are not gold but orange and have black cap instead of metal with the sword.. they look fake to me..

 

[Stixx]

The board itself is looking well made so it's a pity that something's not right.
The current has to go somewhere so there should be a part generating a lot of heat except the LM317 of course.
Or is it the supposedly fake Elna caps? Check the resistance across them, maybe you have close to a short there...

 

[Cidious]

I pulled the 'fake' Elna for Audio PSU caps out. They are fake for sure. Not even going to bother with their performance.

For now I put the Nover 5600uf caps in.. which are probably fake too haha. I've got some genuine Nichicon KG type 2 4700uf 35V caps on the way for the time being until I've found some good Elna's or something else nice and genuine.

The other Elna Silmic caps must be real.. even though their gold color is a bit more towards the Nichicon gold color than the somewat greenish gold of the silmics I'm used to. The silmics I have come from 2012.. I also have some 2015 caps. One of these Silmics was showing shorting. So I pulled it out and it wasn't the cap. The cap is exactly 470uf and works fine. It's the circuit..

After some looking around I've found that the heatsink of the LM317 that was overheating big time was making contact with the ground... Yeah.. no wonder so much current went through it. All looks fine now. But I think I'm going to replace the Voltage regulator anyway.. I think it's toasted..

It's late here now. so I won't test tonight but tomorrow will be a fresh day with fresh courage!

Thanks for your response. I found the Elna cap shorting and then I read your post and it confirmed my thoughts and after that I was able to find the real problem

 

[Stixx]

Excellent.

 

[Cidious]

I can confirm that all measures well now. I haven't listened to it yet. I am waiting for some new signal wire tomorrow.

My impressions so far:

• The board is REALLY of amazing quality. I've soldered multiple parts in and out and all the holes are rock solid! Even with a shitload of heat they don't bend or break for a bit.
• The case is als a really well build and finished housing. Great materials, well designed in terms of use and design. The display has a nice color and is not intrusive and gives just the right amount of information.
• I also really like the transformer. It is a big well build transformer and the wiring is well done.
• Overal the seller chose great high quality parts. Very heavy quality coax input connector and good XLR connectors. Nichicon Muse KZ caps are very good caps but I just prefer Silmics myself. The wima caps are allright since the alternatives are more expensive. The voltage regulators are ST and Fairchild models. I've replaced them with ON regulators which have proven themselves to me in the Lehmann builds. I did replace the RCA connectors.. They felt really flimsy. I've replaced them with some generic 24K gold plated copper ones of better quality. I don't believe in connectors made by elves by moonlight.. But I do believe in more weight in copper
• The PSU NOVER caps would not be my first choice since I think they are fake too, all coming from the same Chinese counterfeit factory. I will replace them with Nichicon KGs or Elna for Audios.
• The Amanero USB board is supposed to be better than the XMOS board. We'll see about that.
• I can not say anything yet about the opamps that came with it (OPA1612A) since I haven't listened to the machine yet. I have some OPA2604APs ready to roll

I also have some questions. The DAC uses a JYEC TCXO 100mhz crystal.. I could get my hands on a Crystek 100mhz crystal.. which is supposedly a good crystal.. what would the benefit be of a better crystal? I am totally not invested yet in these kind of things.

Next to some minor parts changes, I will mod the device further. Since I've found a buddy in this boring Chinese city that is also invested into audio (a LOT) in a rather interesting way (he's also a member here with a looooong blog), I am willing to go a few steps further. I've been discussing changes with Richard (Abraxolito if my mind serves me well) that make sense to me and are easy to implement.

Since I still have another Lehmann board including case and transformer I can first do these mods there since it's using about the same power supply as my DAC with a big groundfill.

• I will cut the big PSU caps ground from the groundfill (sewers) and give them dedicated wires to a new sewers to reduce noise from these big puppies.
• I am also interested into lowering capacitor sizes around the opamps and increasing resistor values accordingly. These mods are fairly easy to implement.
• Then I want to take it a step further and look into a CM choke and inductors before the powersupply and cleaning up the power before it goes into the voltage regulators to reduce noise even further.

I will do my mods step by step and keep a log here.

 

[Cidious]

So the first test run completed. With only about 20 powered hours the burn in of the Silmic caps is not complete yet.

After a brief listening session I conclude the following:

Very musical sound with the OPA1612A opamps
Soundstage depth is good
Sound is warm and comfortable. No sibilance
Details are there but can be better
The sound can be cleaner

Haven't done much listening because.. since I live in China there was a KTV evening organized by my friends here.. So screaming my lungs out was more important this night. Hehe!

Tomorrow I will start with rolling opamps (OPA2604) and adding some UFEEL dip8 upgrade adapters to the opamps to clear them up a bit and give the device a bit more control. I will order some more opamps to roll. Thinking about dual opamps in the beginning of the output and 2x discrete opamps at the end. This will fit best with the wima caps around it.

If people have suggestions on what opamps could be useful within this circuit, I'm open to suggestions. I want it to be transparent but it shouldn't loose it's depth.

 

[Cidious]

OK

I've done some more serious listening test and from what I can tell nog after a approximately 30 hour burn in is that I am really fond of the sound signature which is very warm, the soundstage is deep and instrument seperation is ok. The DAC is not yet near it's full potential.


A/B comparison with Sanskrit 6 (Wolfson 8740) DAC (€80)

The Sanskrit 6 is a really good DAC for it's price. Very transparant and good dynamics and detail. But the shitty noisy chip transformer ruins it a bit. Also PRAT could be a bit better and the bass is very extended but a tat loose.

The L.K.S ES9018 performs very well out of the box with only Silmic II instead of Muse KZs and a few other higher grade Wima caps used here and there. Standard it's using OPA1612A opamps. When I did a first serious listening session I noticed how warm and musical this DAC is, but that its missing a bit of the airyness the Sanskrit has. The sound is really thick and dark and the highs are a bit rolled off. The sound is very bodied and thick. Sound stage is more deep than wide.
Then I rolled in the trusted OPA2604APs. Right on the spot. Highs extended a bit more. The soundstage got wider and the instrument separation just got a tat better. But the bass got a bit bloated which was a bit annoying after a while.
But I had another trick up my sleeve. These UFEEL upgrade adapters. They cost about €8,50 each, but are definitely resulting in better sound than biasing with resistors. This solved most of the audio signature problems. The bass got REALLY tight. On Plastikman - Explore I could just raise the volume on my QMS Q5 speakers (which are REALLY good at bass too) and every kick was just so tight and controlled. Much better than with the Sanskrit! The sanskrit is a bit loose in this department on the Low end. Voices got cleaner and more forward and all the instruments in the high range just got more separated.


After these small modifications the sound really changed to the way of my liking. I'm not there yet. I still think the sound can be a bit more airy and cleaner but, so far I'm really impressed.

I will replace the PSU caps with Nichicon KG type 2 4700uf 35V caps. I figured 4700uf will be more than enough. Maybe I even try some blue Vishay BCs which really pleased me in the Lehmann.
And then I will start tuning the PSU for a cleaner sound.

 

[Cidious]

For people that are interested in what adapters I've used for the for the opamps:

It's quite a unique product I think. Can not find a lot of products alike on Taobao at least. The maker of these adapters speaks English really well and is invested in High-End audio like very expensive CD players.

For me.. the adapters work. They have a very positive effect on the sound and make everything less noisy and more in control. So good effect on PRAT and noise

 

[Cidious]

I can be totally sure now that all the parts had proper burn in time. My conclusion so far combined with the Lehmann which is running with 2x OPA604AP.

A lot of depth in the soundstage
Very warm (a bit to warm for me combined with the already warm lehmann)
Good microdetail with smaller instruments
Tight deep bass
Loose upper bass which is bleeding into mid range a lot
Voices are laid back due to overwhelming and bloated upper bass

Due to upper flaws the sound is intrusive, because I need to turn up the volume to properly hear voices and other mid tones. This way the upper bass gets really annoying.

Don't get me wrong! The DAC is not bad at all. It's the best thing I have here but it needs to be better. The sound needs to be pleasing non intrusive so I forget it's there

So there is some work left to do. I think the OPA2604AP are a bit to much in the I/V stage. Not very well suited for this circuit here. I have ordered myself some AD797 and AD843 single opamps to play around with. I will also put them in class A with a CCS to see if that helps.

I will rework the analog section around the opamps with smaller caps and bigger resistors.

Also finally ordered myself some Nichicon KG Type 2 4700uf 35V caps. I am pretty sure the 5600uf 63V Novers are fake as ****.. I've have ordered a couple of Elna for audio and BHC caps.. which I all found to be fake and coming from the same factory.. exact same size, shape and materials.. Not original. So I ordered some 100% genuine Nichicon 4700uf 35V and some Vishay BC 4700uf 40V caps which I need for some other project too. Can try both but the Nichicons are intended for the DAC if it doesn't make a big difference. When I'm at it replacing them, I will cut their shared ground and give them dedicated ground wires.

 

[Cidious]

Replaced the 4x NOVER 5600uf 63V caps with 4x Nichicon 4700uf 35V in the PSU. I can almost not explain in words how this improved the sound! These Novers caps (which I already thought to be fakes) were bloating the bass, recessing the mids and putting a lot of noise and distortion in the signal.. placing the Nichicons solved all this. I will also test the Vishay BC 4700uf 40V caps which performed even better in my Lehmann than the KGs by being more musically pleasing and warmer. Curious how they will do in this DAC.

NEVER buy these Nover LA counterfeit c(r)aps!

After that placed some AD797ANZ mono opamps in the I/V stage which are a bit more clinical than the OPA204AP but give back more airyness and open sound. Also placed OPA627BPs in the filter to differential stage.

Combined with OPA111VMs or OPA604APs in my Lehmann this creates a nice dynamic sound.


Next incoming are AD843AR, AD843SQ AD828AR and AD828AN. But these probably need some adjustment on the voltage rails to not burn out to quickly.

So far I like the AD797ANZs but they are a bit clinical and missing some dynamics as is. Going to try to tune the surrounding circuit better to let them open up more.

A lot of good test work ahead.

 

[Cidious]

I'm experiencing a lot of white noise on the background of tracks.. The song 'Private Investigations' by the 'Dire Straits' for example is loaded with noise.. I have the SACD, Normal CD and some Vinyl rip in 96Khz. All are very noisy just like some most other High-res albums I have like 'Wish you were here' from 'Pink Floyd'. One of the only near silent albums is '2001' from 'Dr Dre'..

So something is going wrong. Don't know where to start looking. Any clues?

Update: I've found out my Sanskrit 6 does the same on the tracks.. I can not recall 'Private Investigations' being this noisy.. Maybe some one here can clear up?

 

[Cidious]

Update2: I've tested all equipment, cables, wall sockets etc to find out where the problem comes from.. Well it's just the tracks.. Love over gold is just NOISY as SH*T!. It's considered an audiophile recording.. just like Wish you were here from Pink Floyd.. Well they SUCK. I put Audacity over it to denoise them (also losing some details, but only for testing) and the noise is almost gone. It's mostly the recording. Private investigations is such a lovely track with the contrast between soft and loud parts.. Well it's in the garbage bin since it annoys me to much.

 

[Cidious]

Canged the R80 and R82 resistors on the voltage regulators for the analog section from 2.55k to 1.5k to lower the voltage rail from 15V to somewhere up in the 8V range.

This so I could pop in some AD843SQ (ceramic package) opamps and bias them to class A with 2 jfets. The class A bias really made a a big improvement for sound quality.

Everything got very open and tight. Loads of space and detail.

There are only a few mods left I want to try since I already really LOVE the sound.