What exactly is the difference in the various upgrade packages? I already have some opamps I plan on rolling in it but curious if there's any reason I shouldn't buy a $140 shipped one from AliExpress.
i know nothing about opamps, as low pass filter or I/V stage or buffer, but looking at the upgrades, you can notice some things:
1- every upgrade consist of a full pcb with dac + amp stage. so you replace that entire pcb with the upgrade, and reattach it to the other pcb in the player. most upgrades will also need a different case, because the number, position and type of outside connections and volume potentiometer are different from the stock. i guess part of the shell is provided with the upgrade, in this case. main differences are the low pass filter (LPF) and I/V stage opamps, but also other components.
this could be a good thing, because the other components of the pcb are supposedly designed to work best with the equipped opamps; but, in the other hand, they are expensive, because of the AK4495SEQ and the rest of components included (you get extra identical dac).
(to avoid this duplication, you could might contact with the seller, to prepare your zishan with your favorite upgrade, instead of the stock pcb, and pay only the difference, if any, plus customization fees, if any; this can't be set automatically from their site; in the case of buying overseas, you'll need an agent, and you'll need to coordinate them. it's up to you to try all this to save about $40, if you die for any upgrade and you don't want the stock one).
2- the only opamp provided in DIP-8 format (which can be put into a socket, and so be replaced with another DIP-8 -or others, with adaptor- opamp without soldering) is LME49720NA, used as low pass filter (LPF). you can find it in stock pcb, and in upgrade #2. so these ones are the unique where you can roll LPF opamp without soldering, because there is a socket in the pcb for it. but beware, space (height) is limited, because the two pcbs of the player are very close. besides, these pcbs share the volume potentiometer type and outside connectors, so the outer shell is the same. the difference between stock and upgrade #2 is the I/V opamp: OP275 in stock, AD797 in the upgrade (i don't know about other electronic components). the rest of upgrades require a new shell, and you won't be able to roll opamps without soldering.
curiously, the mini A1 amplifier uses that opamp, AD797, so many of us have purchased stock zishan together with this amp (which also has other features than differentiate from the upgrades amp stage). this way, you have a different amp flavor, and can use the amplifier, separately, with other gear (note than the zishan can't be used as a simple amplifier, because it has not inputs other than the usb dac). if we ever find we love any of the other upgrades, we are on time to order them (they are not expensive compared with the quality of their components).
kudos to
@neog007
and
@T.R.A.N.C.E.
, who had provided this info (and much more, starting with the discovering of this gem).
