[kookaudio]

Rude question here: is there a general consensus on what opams make a better job instead of the two 275 ones...?

 

[HeyManslowdown97]

Rude question here: is there a general consensus on what opams make a better job instead of the two 275 ones...?

There is a cross reference list I found and went from there. There are “favorites” like common swaps like AD8599, AD8620 or AD8066?? (I think that’s number). I’d say these are the three most common I’ve seen in mods.

Here’s the link to cross reference the Opa275 and there more options with every options link, ad infinite.

FYI: the 470ufs Audio Notes were too big. I managed to fit them in but it’s not necessary and was a headache . The 220ufs are fine and a better choice!

http://www.hotenda.com/reference/cross/part/OP275.html

 

[kookaudio]

There is a cross reference list I found and went from there. There are “favorites” like common swaps like AD8599, AD8620 or AD8066?? (I think that’s number). I’d say these are the three most common I’ve seen in mods.

Here’s the link to cross reference the Opa275 and there more options with every options link, ad infinite.

FYI: the 470ufs Audio Notes were too big. I managed to fit them in but it’s not necessary and was a headache . The 220ufs are fine and a better choice!

http://www.hotenda.com/reference/cross/part/OP275.html

Thanks, but I was asking about this specific use, with the 4497...

 

[kookaudio]

There is a cross reference list I found and went from there. There are “favorites” like common swaps like AD8599, AD8620 or AD8066?? (I think that’s number). I’d say these are the three most common I’ve seen in mods.

Here’s the link to cross reference the Opa275 and there more options with every options link, ad infinite.

FYI: the 470ufs Audio Notes were too big. I managed to fit them in but it’s not necessary and was a headache . The 220ufs are fine and a better choice!

http://www.hotenda.com/reference/cross/part/OP275.html

Sorry for double posting.

 

[HeyManslowdown97]

Sorry for double posting.

No problem but those are the most common mods I’ve see for the 4497 in lieu of the Opa 275 I have seen in the Zishan scheme.

I’m not sure there’s a specific Op amp designed ak4497 unless it’s made by Akm specifically??

I believe that you have to with cross reference and specs datasheets that closely matches the Opa275.

 

[Merlin-PT]

Rude question here: is there a general consensus on what opams make a better job instead of the two 275 ones...?

I don't know, but in my unit the first think I did was to replace the "op275" and I got sibilance (with sibilante songs) with a lot of opamps that never gave me sibilance in other circuits. If I went for less detailed, less bright opamps, the sibilance was gone, but the sound was also less detailed. Beside those sibilance songs, these opamps sounded very good to me.

I temporary bypassed the op275 LPF, had to lift some resistors near the socket opamp and soldered 4 wires from the 4x100uF caps to the socket inputs, then I tried all the opamps I had in the socket (I also bypassed the the discrete transistors).
This way I could use a socket and only 1 opamp to chose what I was going to use in LPF.
In the end, my personal taste, was the same I already had tried in LPF: 2x ad8066 or 2x op2209 these are very detailed but give me a bit of sibilance in 1 or 2 songs, but beside that the detail is very good...if I went to muse8920 or some others that also sounded good, there was much less detail and less sibilance in those 2 songs. I also bought 2x op275 genuine opamps and they were the worst sounding opamp here, I don't know why, because I've used it before and like the sound of it.
I'm not 100% happy with the sound, so my player is still open.

 

[kookaudio]

I don't know, but in my unit the first think I did was to replace the "op275" and I got sibilance (with sibilante songs) with a lot of opamps that never gave me sibilance in other circuits. If I went for less detailed, less bright opamps, the sibilance was gone, but the sound was also less detailed. Beside those sibilance songs, these opamps sounded very good to me.

I temporary bypassed the op275 LPF, had to lift some resistors near the socket opamp and soldered 4 wires from the 4x100uF caps to the socket inputs, then I tried all the opamps I had in the socket (I also bypassed the the discrete transistors).
This way I could use a socket and only 1 opamp to chose what I was going to use in LPF.
In the end, my personal taste, was the same I already had tried in LPF: 2x ad8066 or 2x op2209 these are very detailed but give me a bit of sibilance in 1 or 2 songs, but beside that the detail is very good...if I went to muse8920 or some others that also sounded good, there was much less detail and less sibilance in those 2 songs. I also bought 2x op275 genuine opamps and they were the worst sounding opamp here, I don't know why, because I've used it before and like the sound of it.
I'm not 100% happy with the sound, so my player is still open.

So you mean you are with the op275, right?

 

[Merlin-PT]

No, I'm with the ones I liked the most: 2x ad8066 or 2x op2209.
I would say taste/preference, music type and phones also play a role in tuning this.
Right now I have 2x op2209 and like the sound.
Maybe is not possible to be 100% satisfied, perfection is not possible in this price and portability and I'm being too demanding.
Let's say my player is still a work in progress, because there are some more things I want to try.

 

[NymPHONOmaniac]

Yeah,,,,another reference list but now for sub500$ dap!

not just chinese, even if I think they are the one offerng best sound value!

Any suggestions welcome, as well as comparaison. Zishan DSD AK4497 is on the list.

Will surely buy the new Z3 ak4493 version once its on aliexpress too!

https://www.head-fi.org/threads/bes...ressions-reference-list.900875/#post-14799972

 

[Ivan TT]

Latest round of mods for your amusement

Changelog:
1. DC to DC convertor now has adjustable voltage, around 9 to up to 14 Volts using trimmer, currently at 12V. This required caps replacement (both electrolytics and all across OPA1622 DIP8 boards)
2. Tried AD1613 DC to DC convertor, could not get it to work (not sure why), returned to LT1946, accommodating difference in pin 7 (currently grounded)
3. Due to catastrophic failure (human error, human is me) currently have stock 5V LDO and reduced capaictance on VFREF. Bass took a hit (in a bad way), TPS73250 rocks (ordered, awaiting delivery)
4. 2x OPA1622 are configured as buffers in parallel, using 1Ohm balancing resistors. DC is about 0.5mV, sound is a bit fuller. Paralleling reduces output impedance further, from 5Ohm to 3Ohm.
5. Third OPA1622 configured as low impedance ground buffer, separately for L- and R- on the balanced out. Picks up buzz from the screen when it's active.
6. Broke plastic screen (on the case, not on the board) Patched up using UV resin. My DSD looks like a car crash even on the outside now. Sounds great though

Listening to this Mikkas remix on my DIY IEMs, not bad.

 

[kookaudio]

Is it what it seems, that you double-grounded the 2.5mm-3.5mm jacks...?

 

[HeyManslowdown97]

Latest round of mods for your amusement

Changelog:
1. DC to DC convertor now has adjustable voltage, around 9 to up to 14 Volts using trimmer, currently at 12V. This required caps replacement (both electrolytics and all across OPA1622 DIP8 boards)
2. Tried AD1613 DC to DC convertor, could not get it to work (not sure why), returned to LT1946, accommodating difference in pin 7 (currently grounded)
3. Due to catastrophic failure (human error, human is me) currently have stock 5V LDO and reduced capaictance on VFREF. Bass took a hit (in a bad way), TPS73250 rocks (ordered, awaiting delivery)
4. 2x OPA1622 are configured as buffers in parallel, using 1Ohm balancing resistors. DC is about 0.5mV, sound is a bit fuller. Paralleling reduces output impedance further, from 5Ohm to 3Ohm.
5. Third OPA1622 configured as low impedance ground buffer, separately for L- and R- on the balanced out. Picks up buzz from the screen when it's active.
6. Broke plastic screen (on the case, not on the board) Patched up using UV resin. My DSD looks like a car crash even on the outside now. Sounds great though

Listening to this Mikkas remix on my DIY IEMs, not bad.

Yea I was look at Dc to DC converters last night after reading this article.

The thin that makes them great is straight and consistent current because Zishan power supply blows!

They have external Dc to Dc converters that I wanted to try before committing to putting it on the boards but I wasn’t sure I’d notice a difference since the board itself may not be generating constant rate of current.

Personally looking at your mod I don’t think I’d prefer the sound since we are into different quality of sound outputs but I can say that thing pushes a lot of power and probably sounds very clean on the insane electric mixes which is really hard to do on crazy bass tracks.

I can appreciate your achievement though and the fact that you have an approach!

https://www.digitaltrends.com/mobile/how-does-fast-charging-work/

 

[Ivan TT]

Is it what it seems, that you double-grounded the 2.5mm-3.5mm jacks...?

Nope, SE ground is stock (normal ground), balanced out has 2x separate active buffered grounds, using yet another OPA1622 (there's a bit of discussion about this arrangement here in other threads and on the banned guy's site).
To be honest SE out sounds better, go figure.

crazy bass tracks

Drop the bass!
I kind of appreciate how modern music reclaimed extremes of spectrum, especially low end.
DIYing earphones that dig deep enough is a challenge, but it's a different story (and different thread).

 

[HeyManslowdown97]

What are the ohms range per channel in the amps of the 2.5mm and for the 3.5mm??

Can a impedance transformer be used in the Zishan???

Here’s something also confused about if you have an the an amp that voltage rate is 9v-36v how does it achieve that range when the input is at lower voltage. I get the whole relays and the output being higher but how do you increase-decrease the DC going into the amps on the Zishan???

I believe that how you can improve the overall performance of a selected amp but I have no way of understanding how-to find out how the measure the power supply to the amp and how it works. (I don't mean ”Measuring” as in using a multimeter. I mean calculating how the voltage source powering the amp works or how to alter it with DC of course)

 

[HeyManslowdown97]

What are the ohms range per channel in the 2.5mm and for the 3.5mm??

Can a impedance transformer be used in the Zishan???

Nope, SE ground is stock (normal ground), balanced out has 2x separate active buffered grounds, using yet another OPA1622 (there's a bit of discussion about this arrangement here in other threads and on the banned guy's site).
To be honest SE out sounds better, go figure.

Drop the bass!
I kind of appreciate how modern music reclaimed extremes of spectrum, especially low end.
DIYing earphones that dig deep enough is a challenge, but it's a different story (and different thread).

So true about the extreme spectrums because it’s now possible! Also Moore’s Law is really no more and now software can just about get the full polential from components. It’s like that with everything sensors are better so cars run more efficient, etc

Yea and I've also noticed that recorded music has gotten better! Like wayyy better with digital. I listen to older recordings on the Zishan compared to the music that's come out in recent years its noticeably better.

Even the crappiest Katy Perry song is mixed amazing because of the sound enigeers. It’s the same with “Mumble Rap” they may repeat the same phrase 25x in a song and aren’t “lyricists” but the tracks by the producers are very textual with lots of depth and also newer digital sounds not heard of. Like who knew Bass had so much nuances to it?? It all started with Drum Machines in the late 70s to here we are now!

I appreciate it for inspiration but just not for enjoyment- like it’s not my go-to preference (You-know-what-I-mean).