Audiotrak Prodigy HD2 Modifications - Page 2

The components under the left socket are not at the same location at all...it's not just a matter of components values. Now maybe one version is "better" than the other, that B stock model is newer production apparently.

The red caps on the DE version are Wima capatitors, 1nF and 33pF.

I managed to replace the stock headphone output opamps with SOIC LM4562's. Since it is my line of work and have access to magnifying system with soldering capabilities, I modified the leads to fit the pads on the PCB. As you can see, all other opamps have been subbed with LM4562's.

Sounds fantastic. No abnormalities with the substitution.

I managed to replace the stock headphone output opamps with SOIC LM4562's. Since it is my line of work and have access to magnifying system with soldering capabilities, I modified the leads to fit the pads on the PCB.

Sounds fantastic. No abnormalities with the substitution.

Are You ready for some shematics?

Please note I'm just an HD2 owner, diyer, not working to any electronics company.

If there is against any rule or law to post things like this, then please contact me. (PM in my profile)

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It would be great to make a list of needs, that and why to modify on the HD2.

In my case i bought this card as my music collection is on a computer and I needed a good DAC to play music and movies. I couldn't afford an USB DAC this good, ... lets say the HD2 is half price of those.

I'm happy with my choice.

But there is some point where it can be enhanced. These are:

-Sound quality (can easily do with op-amp that fits out of the box)

-Volume control of the headphone output (I think it's a must, because I must unplug the headphones every time I use the HiFi amplifier.

These are my aims.

Opamp rolling is an easy choice, but I found a need to re-set the buffer opamp gain to fit LT1028. I heard this and heard nothing better or equally good, so I am doing it anyway.

There is always an option to use Burson opamps but if I had the cash for those I would buy a K702 instead...

The volume control of HP output has some options.

I could use an ALPS potmeter, it could be drilled to the back plate but it is down there under my desk... there is a choice to adjust the HP volume to the HiFi output and leave it there.

Another way is to do this with a pair of resistors. This is more balanced and better quality (and much cheaper), but can't adjust to different headphones . Can use a high - low switch drilled to the back plate.

I haven't decided yet. Any thoughts?

about the LM4562 soics on SOP pads 

when paralleled they output about 50 mA , that is barely enough for headphones

and nice work!! 

I could do that with own eyes 

Just a follow-up on the "LM4562 soics on SOP pads". I did not measure the resulting output after the 4562's were installed. I can say that I can drive a pair of Senn. HD580's to ear splitting levels (clear and clean) and indistinguishable from my other stock HD2. Bottom line... I don't know if it was a vast improvement, definitely  not a detriment.

as far as I know there's two NJM4580V on the stock card, but one is used for the line-in and one for the HP out.

a 4562 can/will  be loud enough to drive phones...but the low end bass will be inexistent and 26mA is not enough to do this kind of work IMHO.

The caps that have been replaced, are they the same value's as the originals?