Adjusting screw tightness on Esoteric K1X helps a lot!

[Windows X]

A bit tiring but worth it. Readjusting screw's tightness on all possible areas without removing screw except outer chassis. System sounds more relaxing after stress on PCB and enclosure are reduced. Now Esoteric K1X is singing with fuller dynamics and richer harmonics. Happy listening.

P.S. Do not unscrew all 4 pieces around transport block area. Loosen up a bit and rescrew each one at time to make sure position won't be changed.

P.S. 2 I recommend to adjust only around safe area like mounting area on chassis and PCB block. Proceeding further may pose some risks on your unit being disassembled. If you are daredevil and can accept the risks, it's up to you to go deeper than my recommendation with caution and safety in mind.

 

[AMR / iFi audio]

A bit tiring but worth it. Readjusting screw's tightness on all possible areas without removing screw except outer chassis. System sounds more relaxing after stress on PCB and enclosure are reduced. Now Esoteric K1X is singing with fuller dynamics and richer harmonics. Happy listening.

P.S. Do not unscrew all 4 pieces around transport block area. Loosen up a bit and rescrew each one at time to make sure position won't be changed.

P.S. 2 I recommend to adjust only around safe area like mounting area on chassis and PCB block. Proceeding further may pose some risks on your unit being disassembled. If you are daredevil and can accept the risks, it's up to you to go deeper than my recommendation with caution and safety in mind.

Interesting experience. Two factors come to my mind in this case. Either the screws were just a bit too loose, or the PCBs were having some thermal expansion induced stress. Just food for thought.

 

[Windows X]

Interesting experience. Two factors come to my mind in this case. Either the screws were just a bit too loose, or the PCBs were having some thermal expansion induced stress. Just food for thought.

Screws are a bit too tight in some areas. I unscrew a little and re-apply with smaller screwdriver so it'll have smaller torque causing less stress. The screws on regulators play pretty huge role also. Well, I'm not making screws a bit too loose here. Just not too tight.

 

[AMR / iFi audio]

Screws are a bit too tight in some areas. I unscrew a little and re-apply with smaller screwdriver so it'll have smaller torque causing less stress. The screws on regulators play pretty huge role also. Well, I'm not making screws a bit too loose here. Just not too tight.

Please, always use the correct sized screwdriver. Torque is in your hand, not in the tool. Using the wrong sized one can destroy the screw heads and will for sure be grounds for rejecting your warranty.

 

[thedudeabides]

You would think that the smart techs at Esoteric would / should know how tight the screws should be.

 

[AMR / iFi audio]

You would think that the smart techs at Esoteric would / should know how tight the screws should be.

I hope ours are tight enough

 

[dandylinpsst]

Does anyone know what the 2 lines marked in red do?
DC power ?or clock signal?

 

[AMR / iFi audio]

View attachment 94732
Does anyone know what the 2 lines marked in red do?
DC power ?or clock signal?

Probably the power supply doesn't look too important. Simple shielded wires, so no clocks or digital for sure.

 

[Windows X]

Please, always use the correct sized screwdriver. Torque is in your hand, not in the tool. Using the wrong sized one can destroy the screw heads and will for sure be grounds for rejecting your warranty.

Esoteric staff has done professional job in making sure all corners around PCB have evenly matched tightness. Some DACs I did this before have some corner being too tight while some being easily loose.

However, the screw is a bit too tight and make harmonics feel stressed and not flowing naturally. After adjusting screw tightness to be just right, it flows with more organic and full sound without compression or feeling stressed out.

And of course I use the right tool to unscrew properly without damaging screw knot or circuit. I reapplied screw again with screwdriver that won't eat away screw's head. And I didn't force my hand to make screw putting extra pressure on PCB or chassis more than needed.

Well, it's understandable that they need to keep screw tight as shipping out across countries can cause screw to loosen up. I also need to keep screw on my products being tight enough to make sure it won't get loose after shipment too as shock impact can be fatal during shipment.

As for warranty, yeah it's probably not good idea to perform this. I'm doing this at my own risks and share my experience for the risk of getting warranty voided. I still do only at parts where it's 100% safe and won't risk causing problem to device.

To be honest, I'd rather get my warranty voided than listening to strained sound that some people consider Esoteric being house sound. I considered changing opamp from MUSES03 to something else also but adjusting tightness seems to keep me satisfied enough so it's not yet time to physically void warranty of my product.

Regards,
Keetakawee

 

[dandylinpsst]

Probably the power supply doesn't look too important. Simple shielded wires, so no clocks or digital for sure.

My engineer friend said this is the signal line that transmits the clock.
And I found out that these 2 lines are coaxial cables. He explained that these two coaxial cables are very important for L/R clock signal. Does the esoteric hold back a trick for next model or only consider cost ??
It means that whatever you feed the K1X a better 10M clock signal
will be discounted here.
He also shown me the pic that has the same function coaxial cable in esoteric D1x.
Does anyone have another opinion?

 

[AMR / iFi audio]

My engineer friend said this is the signal line that transmits the clock.
And I found out that these 2 lines are coaxial cables. He explained that these two coaxial cables are very important for L/R clock signal. Does the esoteric hold back a trick for next model or only consider cost ??
It means that whatever you feed the K1X a better 10M clock signal
will be discounted here.
He also shown me the pic that has the same function coaxial cable in esoteric D1x. View attachment 94767
Does anyone have another opinion?

What you show on a photo is the best way (or you can use U.FL) to connect the clock, if you need to go boar to board. Clock signals are dependent on a continuous impedance to maintain their integrity. When routed on PCB we calculate the track width with the properties of the laminate to create a proper transmission line for a signal like this. The higher the frequency, the more crucial it is. In electronics, 10M is quite slow, but many DACs use clocks around 50M, or even 100M and it really needs attention with PCB layout.

 

[diaZ]

The clock signal is on both DAC PCBs further divided by small integrated amps into four branches leading to the outer line of the 8 transistor switches outside of the resistor array to syncronise the inner line of transistors, switching the 8 resistors which are in the middle connected and lead to the Muses 03 inputs.
So every of the 64 resistors is perfectly and separately synchronized with the clock signal.
It makes no sense to exchange the muses 03 to other single OP amps, the only one to discuss would be the OPA627BP.
Soundwise both are very very similar, spec wise the OPA627 is a bit better.
For Owners of the K-03XD: after the resistor array there is a very cheap and suboptimal sounding OP NE5534.
Only here it is a good idea to exchange to Muses03 or OPA627. The K-01XD owns in this position the Muses03.

 

[AMR / iFi audio]

The clock signal is on both DAC PCBs further divided by small integrated amps into four branches leading to the outer line of the 8 transistor switches outside of the resistor array to syncronise the inner line of transistors, switching the 8 resistors which are in the middle connected and lead to the Muses 03 inputs.
So every of the 64 resistors is perfectly and separately synchronized with the clock signal.
It makes no sense to exchange the muses 03 to other single OP amps, the only one to discuss would be the OPA627BP.
Soundwise both are very very similar, spec wise the OPA627 is a bit better.
For Owners of the K-03XD: after the resistor array there is a very cheap and suboptimal sounding OP NE5534.
Only here it is a good idea to exchange to Muses03 or OPA627. The K-01XD owns in this position the Muses03.

I can't imagine people buying a fresh Esoteric to mod it Madness!

 

[diaZ]

I do

 

[AMR / iFi audio]

I do

Wow, that's impressive. How did you start doing this? Have any photos? Are you doing it yourself?

 

[bryans]

This is without a doubt next level stuff here.

 

[diaZ]

It began last century with the Esoteric VRDS 25X and his output stage. OP amp rolling was very popular theese days in Germany.

Actual pictures are from K-03XD, I changed (myself) the NE5534 to OPA627BP.
An incredible huge difference to my ears.
I own the N-01XD with P-02X and made the comparison before and after the OP amp exchange in the K-03XD.
My personal opinion: Its a shame for Esoteric to use in such a great player in the output stage such a cheap and lowsounding OPamp.
Of course to keep the distance to the K-01XD.

 

[AMR / iFi audio]

It began last century with the Esoteric VRDS 25X and his output stage. OP amp rolling was very popular theese days in Germany.

Actual pictures are from K-03XD, I changed (myself) the NE5534 to OPA627BP.
An incredible huge difference to my ears.
I own the N-01XD with P-02X and made the comparison before and after the OP amp exchange in the K-03XD.
My personal opinion: Its a shame for Esoteric to use in such a great player in the output stage such a cheap and lowsounding OPamp.
Of course to keep the distance to the K-01XD.

Nice job! Have you considered putting a socket in there, so you can roll some other opamps? Maybe some discrete ones like Sparkos, Burson, or Muzg?

 

[diaZ]

Thank you! Sockets for OP amp rolling is an effective way if you want to try out and find out what matches best your favorite musical taste. And for my taste BB OPA627 fits the best.
And also OPA 627BP sounds worse in a socket. (worse input guarding). And in this filter application the input bias current with typical one pA (!) is a benefit no discrete OP amp can reach. For this reason I prefer the BP version with lowest Ibc over the AP version.
The second best sounding OP amp in this position is the Muses03. But this is very much a matter of personal taste.
In any case, to kick out he NE 5534 is the best you can do, if you are an Esoteric K-03XD owner. No other actual Esoteric output stage is using this low priced IC.
All the newer and the most expensive Esoteric DACs ( including D1X) are equipped with the Muses 03 in the filter section.The last time I saw an Esoteric DAC with OPA627 was the D-03.

 

[AMR / iFi audio]

Thank you! Sockets for OP amp rolling is an effective way if you want to try out and find out what matches best your favorite musical taste. And for my taste BB OPA627 fits the best.
And also OPA 627BP sounds worse in a socket. (worse input guarding). And in this filter application the input bias current with typical one pA (!) is a benefit no discrete OP amp can reach. For this reason I prefer the BP version with lowest Ibc over the AP version.
The second best sounding OP amp in this position is the Muses03. But this is very much a matter of personal taste.
In any case, to kick out he NE 5534 is the best you can do, if you are an Esoteric K-03XD owner. No other actual Esoteric output stage is using this low priced IC.
All the newer and the most expensive Esoteric DACs ( including D1X) are equipped with the Muses 03 in the filter section.The last time I saw an Esoteric DAC with OPA627 was the D-03.

OPA627 is an excellent FET input device, thus it has a very low input current. How are you seeing it as a benefit in this application? Is the DAC output or feedback resistors high impedance?
The biggest pro of discrete opamps is a two-pole compensation, which is impossible to do in an IC. Two-pole compensation allows the opamp to have much more feedback at high frequencies (say 10k+), offering better distortion reduction. Sparkos has an excellent blog post about it, I believe, you'll love it: https://sparkoslabs.com/discrete-op-amps/audio-op-amps-gain-seek-bandwidth/
He makes excellent opamps too.

As for sockets, you are absolutely right. They add inductance and physical distance to the decoupling capacitors. It has the biggest effect on power supplies. Most discrete opamps have their own decoupling on board, so it's not that big of an issue.

I'm very curious to hear from you about that. It's a very interesting discussion!