Upgrading AudioNote DAC2 older version Help

I own an older AudioNote DAC2 and plan to upgrade some of its components. Could anyone provide me with any information of which part should I upgrade and using which type of components (ie. using which BlackGate?)
I currently had its tubes replace with the Amperex 6922 PQ, however, the effect was minimal. I hope by using the BlackGate, its performance would increase near/similar to the newer DAC2.1x.
Thanks so much.

make sure first and foremost it is the non oversampling dac chip that is used, if not get audionote to do that for you first. Secondly upgrade to balanced with output transformer. Only then should you really consider fine tuning.
Adinta, don't know the values, but AN should provide an upgrade path with the correct components. My dealer has offered to obtain parts and install them for me, or simply get the parts and let me install them. Kinda sounds like you are going DIY with this, yes? I think you can also contact AN directly or through triode and company if your local dealer can't.

Reading into your post, it seems you are asking if you can expect a difference. From experience swapping caps in my AN amp, I can say yes. I've swapped paper in oil, copper, and BGs and they do sound different (haven't had tried silver caps yet, $=yikes!). Also swapped resistors for tantalums and pcbs for hardwired silver. In each case, there's a noticeable increase in resolution.

One more thing, I have a 2.1x sig and a primary difference from the standard is tube rectification. If you can do this, there may be more of an improvement than just the BGs.

Please share your experiences if you decide to upgrade.

Hope this helps.
A big improvement that AN itself upgraded was to remove the filters from the DACs. Does your DAC still have a filter? It's not simply a matter of removing it; the internals have to be reconfigured slightly. IME this was a worthwhile upgrade.

Check out the Audio Note Kits forum. It's somewhere on the Audio Asylum. There may be parts info discussed.
Thanks for all.
Yes, the DAC-2 that I have is the one with oversampling.
I try to get more information from Peter of AudioNote.uk, he is very nice and helpfull. I hope it would be true that the older DAC2 could be upgraded to 2.1x or even the Sig.
Thanks so much.
Is there a big improvement when comparing the upsampling-AN DAC with the non-upsampling one? Because, actually I feel that the one I have (w/ upsmapling) is very musical (although the vocal is more laid-back).