Change OpAmp for SABAJ D4

[Xavinho]

Hello,

I have opened the case of my Sabaj D4 to change the OpAmp for a Burson Audio (V5I OPAMPS). However, it seems that the current OpAmp (NJM4556A) is already welded in...
Do you know if I can take that out?

Thank you!

 

[Fluffy]

Why are you making the change? It's measurements point to a pretty competent amp.

 

[DonH56]

Hello,

I have opened the case of my Sabaj D4 to change the OpAmp for a Burson Audio (V5I OPAMPS). However, it seems that the current OpAmp (NJM4556A) is already welded in...
Do you know if I can take that out?

Thank you!

The fact that you are asking implies you should not touch it... It is soldered in and any electronics tech can probably swap it out for you. But if you've never soldered before, or done any sort of electronics rework, it'd be better to learn on something that isn't important. I'd advise finding a techie friend or local electronics service place.

 

[FrantzM]

The fact that you are asking implies you should not touch it... It is soldered in and any electronics tech can probably swap it out for you. But if you've never soldered before, or done any sort of electronics rework, it'd be better to learn on something that isn't important. I'd advise finding a techie friend or local electronics service place.

+1
I will add this:

You will gain nothing from the swapping while voiding the warranty and running the (very real and high) risk of destroying your component...

 

[Xavinho]

Why are you making the change? It's measurements point to a pretty competent amp.

Hi! The simple answer is because the Burson Audio OpAmp is better than the provided one (as per my research/please indicate to me otherwise with details if it is not the case). However, I am asking for support, as I was not aware the OpAmp is attached...

In any case, as a general question, is it safe to change the current one with this OpAmp?

I will truly thank anyone who can help me in this little, but amazing journey!

Cheers

 

[Xavinho]

+1
I will add this:

You will gain nothing from the swapping while voiding the warranty and running the (very real and high) risk of destroying your component...

Hey there

Can you please specify why exactly you think the current OpAmp is better (sonically speaking particularly)?

I will appreciate any help on this matter, and thank you for your time.

Yours truly,

 

[solderdude]

Best way to remove the opamp is to cut of the legs near the plastic dip.
Then heat each pin till it is 'loose' in the solder and gently pull it out.
Repeat for each pin.
Use a de-solder gun or de-solder wick to clean out the holes.
Remove the residue from the PCB and inspect if the through holes are still O.K.
Solder in a turned-pin IC socket.
Clean the residue of the PCB again.
Push in the v5i.
Do a subjective listening tests and enjoy the wonderful musical experience and then close the device and enjoy till the next upgrade comes along.

The reason I recommend to put in an IC socket are for reasons below.
Consider the opamp is ONLY in the headphone path and the chosen IC is because it is capable of delivering more current than most opamps so it can drive lower impedance headphones.
As the 'data sheet' of the v5i is not elaborate and leaves out its output current plots/numbers but only speaks of some numbers in 600 Ohm makes me wonder if it is a wise decision to change the opamp in THIS particular design at all.
So if I were you, which I can't be as I won't ever swap out the 4556 with an opamp I know jack sh!t about and is ill documented, without doing proper testing with a GHz scope and various loads.
So along with the IC socket order along a 4556 so you can put it back when results aren't what you expected from the many, many glowing reviews that are solely subjectively done.

This is all the help I can offer.
Note that this is a dual layer PCB and you are exchanging the headphone out buffer with an opamp that does not appear to be designed for the job based on people claiming they can hear a gnat fart a mile away and have superior sonic hearing capabilities that exceed any measurement gear.

If you really want to do some improvement for the headphone output I recommend to buy a decent headphone amplifier and connect that to the line-out of the Sabaj D4.

 

[March Audio]

Looking at its spec sheet I really wouldnt bother.

Thats about 86dB. Thats appalling for a modern op amp. From the measurement links above the existing amp is an order of magnitude better!

 

[Fluffy]

Hi! The simple answer is because the Burson Audio OpAmp is better than the provided one (as per my research/please indicate to me otherwise with details if it is not the case).

Can you elaborate on the research you did? What exactly are the proposed benefits?

 

[RayDunzl]

Ok, you made me look:

I thought the Burson would be a discrete device, but nooooo...

 

[Xavinho]

Looking at its spec sheet I really wouldnt bother.

View attachment 37620

Thats about 86dB. Thats appalling for a modern op amp. From the measurement links above the existing amp is an order of magnitude better!

View attachment 37623

Hi. Thank you for laying it out like this!

I am baffled. I think I miss red the info on the Burson OpAmp regarding the technicalities. I will re check asap and let you know

Nonetheless, I wanted to try the Burson OpAmp, as I am curios how it could sound, specially with a great device such as the Sabaj D4.

I am ever grateful for all your help.

Cheers

 

[Xavinho]

Ok, you made me look:

I thought the Burson would be a discrete device, but nooooo...

View attachment 37626

Hehehe...

Can you be more specific?

 

[RayDunzl]

Can you be more specific?

I expected to see something more like this - https://www.diyrecordingequipment.com/products/ml2520-discrete-opamp-kit

A little board with discrete components...

 

[LTig]

I am baffled. I think I miss red the info on the Burson OpAmp regarding the technicalities. I will re check asap and let you know

I've downloaded the datasheets of both the NJM4556A (NJM) and the Burson Audio V5i (BA, see posting #8) and the Burson is no match:

• The NJM can deliver up to 70 mA output current into a 150 Ohm load at 10.5 V. There is no maximum output current specified at all for the BA. The only specification for a load is 600 Ohms, 4 times higher than NJM and at least 2 times higher than common high impedance headphones.
• Looking at the mechanical construction of the BA I would never use it for driving headphones since the shield prevents dissipation of heat of the SMD chip underneath (no exchange of air required for cooling). Since BA also does not specify whether it has thermal protection it is possible that listening at higher SPL may destroy it.
  Agreed, NJM does not specify this either but you can rely on Sabaj to have taken this in account. Otherwise they would get a lot of complaints and warranty repairs.
• The NJM has THD of below 0.0003% at ~4 V output (the sweet spot, at lower voltages noise dominates) to a load of 200 Ohm, and this at 30 dB gain (which means you can expect lower THD for lower gain). The BA specified 0.005% (~ 15 times higher!) at a lower voltage and a lower load, and the gain is not specified so you should expect any lower THD than this.
• The NJM specifies a voltage noise of less than 10nV/sqrt(Hz) between 20 Hz and 1 kHz. The BA does not specify noise at all which usually is a hint that this spec is bad (yes, you have to read between the lines, even in data sheets of respected manufacturers). The existance of FETs in the input stage is another hint.
• Even BA does not list the NJM4556 as a possible candidate for replacement.

Conclusion: Don't do it, you won't improve the sound, especially not with the Burson.

Nonetheless, I wanted to try the Burson OpAmp, as I am curios how it could sound, ...

You can't. To compare its sound you need a second unmodified D4 to be able to perform a reliable double blind test (DBT). Otherwise you may hear a lot of differences due to expectation bias and the inability of us humans to remember sound. It's the way we are wired, all of us. See my failures below.

...specially with a great device such as the Sabaj D4.

The Sabaj D4 may be great because its designers used the best matching components they could think of. Why do you think anybody else would be able to do better than them without insight into their development documentation or their minds?

I know what I'm talking about. Although I am an EE I fell myself victim to op-amp rolling in an Arcam Black Box 3 DAC and thought it sounded much better than before, until I did a blind test against an unmodified model where I failed miserably. Recent measurements opf this DAC showed that the performance of the modded model was not better although I used an op-amp which was very much hyped by audiophiles and the press at that time. You can read about it here and here.

 

[pozz]

Hi @Xavinho

Please check out these reviews before doing any swaps:

• https://www.audiosciencereview.com/...ng-replacing-op-amps-in-topping-d10-dac.4576/
• https://www.audiosciencereview.com/...amps-in-gustard-h20-headphone-amplifier.7407/

 

[Sintek]

Apologies for bumping an old thread, but I have a related question. What is the trick in disassembling the Sabaj D4? With the back panel off the PCB can be pulled out only slightly before a ribbon connector at the front stops it. I can find no information anywhere.

Thanks for any help.