[citral23]

There are consistent reports about the screen of T1 being extremely outdated and a bummer to use (resistive), some reports about screen not responding or outright broken, pressing it admittedly "too hard" (shouldn't happen tho, ideally). Pretty much everyone agrees that the firmware is horrible, and that only the sound of this device makes it worthwhile, everything else sucks. Personally, I'd take a DSD pro (which I already own) any day over the T1, it has its quirks, but it's robust at least. I've given up on the idea of getting a T1 with all the meh to bad reports, and just purchased a Cayin N3 instead as a pocketable, more versatile and IEMs friendly device than the DSD, now that it sells for 123€ on Ali it's hard to beat imo (was more debatable when it was selling for 160-170).

T1 with the same AK4490, but inferior implementation imo (Cayin has < 1ohm output Z and really good lpf and amp section) sells for around 60€ but if the screen or USB-C ports give up within 2 weeks it's wasted money. Cayin is a mature product with reliable dac function, line out, remote control from smartphone etc. etc.

 

[Draknodd]

Anyone knows at what voltage opamps are fed?

 

[Ivan TT]

Anyone knows at what voltage opamps are fed?

+/- 9volts

 

[Draknodd]

+/- 9volts

Thanks then ... correct me If i'm wrong:

ak4497 outputs 2.8v pp, so 1.4v rms.
If I put ad8620 to gain = 3 I would have 4.2v
then 2x lme 49600 as current buffers
then 2.5socket.

Could it work ?

 

[therealbene]

Thanks then ... correct me If i'm wrong:

ak4497 outputs 2.8v pp, so 1.4v rms.
If I put ad8620 to gain = 3 I would have 4.2v
then 2x lme 49600 as current buffers
then 2.5socket.

Could it work ?

I think it's not that way. AK4497 is current output, where the Vrms is created in I/V stage. On LPF stage, you can adjust gain before being fed to your added current buffer, which might be possible assuming you can fit it inside the player.

 

[Draknodd]

I think it's not that way. AK4497 is current output, where the Vrms is created in I/V stage. On LPF stage, you can adjust gain before being fed to your added current buffer, which might be possible assuming you can fit it inside the player.

Ak4490 Is current output, ak4497 Is voltage output, no I/V stage only LPF in zishan

 

[gazzington]

I notice on a group on Facebook that people make huge mods to these daps from op amps to see through body etc. Where do they get these see through body parts from?

 

[DBaldock9]

Thanks then ... correct me If i'm wrong:

ak4497 outputs 2.8v pp, so 1.4v rms.
If I put ad8620 to gain = 3 I would have 4.2v
then 2x lme 49600 as current buffers
then 2.5socket.

Could it work ?

Just realized that your math might be off.
From - https://www.allaboutcircuits.com/tools/rms-voltage-calculator/ - I see that 2.8V (p-p) = 1.9798V (RMS)

 

[DBaldock9]

I notice on a group on Facebook that people make huge mods to these daps from op amps to see through body etc. Where do they get these see through body parts from?

Many craft stores have acrylic plastic, in multiple colors, and the clear glue to attach pieces together.
I'm not sure what technique they're using for making smooth, straight bends in the plastic.

 

[Draknodd]

Just realized that your math might be off.
From - https://www.allaboutcircuits.com/tools/rms-voltage-calculator/ - I see that 2.8V (p-p) = 1.9798V (RMS)

Rookie mistake, thanks.
Still better, I've checked a similar mod with lme49600 on the SE output. With +-9 v at max volume there's clipping. Raising to +-12 Is easy (just change a resistor and the 10v rated caps), the step up Is a mp1542d so It should not be a bottleneck.
The mod is pretty easy but atm my main concern Is to find a comfortable Place where to take lpf signals. Taking the signal at output resistor could be and idea but I would need very small cables and to be very precise. This mod won't need a custom pcb at all

 

[Themilkman46290]

The smooth strait bends on plastic are made using a bender, if your good at making things it can be home made, a power supply (9v) and a hight temp wire held at 2 points with good tension with a piano hinge on a wood table with a piece of wood on the end for the folding, you let it warm and slightly melt the plastic and use the hinge to do the work

 

[Themilkman46290]

Thin metal like aluminium is good, in leather makes it feel nice, adds grip and won't Crack

 

[Merlin-PT]

@Draknodd
I think you need 4 buffers for the balanced output, there are 4 signals to buffer L+L-R+R-.

If I understood it right, here @Ivan TT said he used 2 dual channel opamps configured has buffers for the BO:
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-98#post-14703801
That looks like another option.

 

[Draknodd]

@Draknodd
I think you need 4 buffers for the balanced output, there are 4 signals to buffer L+L-R+R-.

If I understood it right, here @Ivan TT said he used 2 dual channel opamps configured has buffers for the BO:
https://www.head-fi.org/threads/the-zishan-dsds-corner.826185/page-98#post-14703801
That looks like another option.

I was thinking about this yesterday night: I thought "wait, lme49600 is 5 pin how the f is it possible to use only 2 of them". A solution could be 2x ad8397 with gain =1, they can output 310mA so they should be perfect as buffer

 

[Merlin-PT]

Google if ad8397 is unity gain stable (gain=1), I've read it can oscillate, if so it's not a good candidate for buffer, but I never tried it.