Head-Fi.org › Forums › Equipment Forums › Portable Source Gear › Teclast T51
New Posts  All Forums:Forum Nav:

Teclast T51 - Page 88  

post #1306 of 1468
Quote:
Originally Posted by lee730 View Post



iphone4/itouch does wonders there as well :) Just I hate itunes with a passion. The ibasso also seems to be quite good on its own right (more so after the bugs have been worked out). The Studio V is just stupidly easy to navigate, it has some minor quirks in its navigation which I'm sure Jack could easily rectify with a firmware update. I consider the Studio to be as easy to use as my Sansa Fuze which is saying something good.



Our hate for itunes unite us, I just hate its guts, what does a music application got to do with books or apps, or copying .......triportsad.gif

post #1307 of 1468

Teclast T51 (blue-screen, 2011) RMAA results 

 

(Update: LM6172 + new invertors MOD done)

 

post #1308 of 1468

Battery usage test.

 

Teclast T51 (blue-screen, 2011, LM6172 + invertor mod)   

 

 

Measurement details :

  • 1. Battery Fully charged.
  • 2. VSonic GR07 earphones connected. Volume adjusted louder then normal usage, wheel position adjusted – right in the middle
  • 3. Normal EQ .
  • 4. Music used – Lossless hard-rock (FLAC)
  • 5. During testing i had turned the screen on about 5 times, so that it could emulate «daily usage» conditions.

 

 

Measure Results -  10 hours .  


Edited by AlexRoma - 2/19/12 at 6:00am
post #1309 of 1468
Quote:
Originally Posted by AlexRoma View Post

Teclast T51 (blue-screen, 2011) RMAA results 

 

(Update: LM6172 + new invertors MOD done)

 


...so just just the invertors replacement cleared the distortion in HO. nice. thx for inspiration alex :P

 

post #1310 of 1468

First of all, I've to declare that I'm just a newbie in DIY.  I follow what the datasheets say, so I'm sort of secured of not getting wrong, at least in paper.  I've a few questions regarding the component selections.  I just want to know more, instead of starting a fight with sb who is so open to share how we can mod T51.  many of you should know that there're mods around on T51, but not until now, there're people're finally willing to share.

 

pt1. In power regulating DACs, the datasheet suggests using a 0.1uF and 10uF cap combo.  Is it worth stacking a 10uF X7R cap on top of your suggested 0.1uF C0G cap?

pt3. In output of the dual DACs, the caps employed are: 2x3.9nF, 2x1.0nF, 2x6.8nF, 2.2nF.  In the datasheet, the 6.8nF pairs should be a pair of 7.2nF.  I'm guessing these are served as high-pass filters.  Unfortunately, there're no 7.2nF and 3.9nF caps exist in the FKS2 series.  Which do you suggest for 3.9nF replacement: 3.3nF or 4.7nF?

pt6. The supply voltage for the DACs are 3.3V and 5.0V.  Shouldn't we choose LP2985AIM5-3.3 instead?

 

Thanks in advance for answering the questions.

 

P.S.  BTW, I wonder what capacitors in pt3.  I read in some Chinese forums, they're said to be CBB caps.  What is CBB caps?  PP caps?  I'm very confused.

 

Quote:
Originally Posted by w357 View Post

 

All that is circled with colored frames:

1. red - shunts power DACs and operational amplifiers.

2. blue - the amplifier low-pass filter and amplifier for headphones.

3. Green - capacitors of low-pass filter

4. Orange - kit of headphone amplifier (two resistors and two capacitors in pairs for each channel)

5. Purple - 5V voltage regulators for DAC and LPF (of 3 stub - one in the same place, but on the back of side of the board)

6. Pink - 3V voltage regulators of headphone amplifier

7. Yellow - power inverters of operational amplifiers

Nothing else to touch it, unless Y want to become a non-working player!

stabilizers, inverters, and operational amplifiers unsolder it's best flat-tip type "cutter" or "paddle". It allows you to warm up once all the legs on one side of the chip and lift it.

low-pass filter replacement stabilizer placed on the reverse side of the board will have to unscrew the two screws and remove the motherboard from the case. in this case you should try to not bend it to cracked lead-free soldering processor! better once bend the edge of the case.

after removal of the components should be removed excess solder .

REPLACEMENT PARTS

Look above and change in strict compliance:

1. change it for quality ceramic NP0 0,1 uF. I set the capacitors of the firm Murata. here it should be noted that shunts are a pair of DACs capacities of 10uF and 0,1 uF. Unsolder  it all and put in place Murat 10uF (space for smaller capacity are empty).This replacement will clear some power DACs and the opers of noise.

2. still skip this point ...

3. Change at the highest quality film capacitors, which will be found. I put WIMA FKS2. Ideally would put sulfide Panasonic, but only if it is available soldering hair-dryer, infrared  station, or a stove. Soldering iron sulfide capacity would be killed instantly. This is replacement capacitors once and for all fix the problem Player’s bright sound.

  4. just unsolder and forget. No replacement necessary ...

  5. change in LP2985AIM5-5.0

  6. change in LP2985AIM5-3.0

  7. change to TPS60403.

Now we choose the op-amp for low pass

  that is, return to step 2, missed earlier ...

 

  here we have some leeway to set the desired character of the future sound mod.

  from what I've tried it myself, I offer the following options:

LM6172 - dynamic sound, quite smooth, melodious. slightly rounded attack (because of the smoothed small parts), good depth, punch in midbase.

LM4562 - on analyticity and the level of distortion is comparable to the previous version, but has a slightly more melodic sound. cleanest RF, isolated middle and dry, but tight bass. the overall sound is extremely detailed, accurate midrange-oriented, fast. I myself stopped on this amplifier.

[review of amps translated partly]

WARNING! installing low-pass filter amplifier to its outputs (1 and 2 in the photo) to the level above the board! they should not be soldered to the board (in air)! In this case, the line out audio player goes straight to the DAC on the negative feedback loops of op-amp low-pass filter. Of course don’t uselow impedance load to LO  if you do not want to kill inadvertently DACs.

After all these steps, wash board using CRAMOLIN FLUX-OFF (can be in two or three times with a toothbrush, for better removal of flux), giving dry.

 

Headphone amplifier

    currently there are several options Amplifier:

 

  1. well-known "Storb modes" based on the AD8397. it will not consider

РИС1.JPG

 

  2. Storb analogue-mode PCB authorship Symmcat

storbmodeagle.png



 


Edited by dumbears - 3/12/12 at 7:08pm
post #1311 of 1468

add another to the list of people willing to pay for these mods to be applied.

post #1312 of 1468

Mod done. However, bad news. I think i screwed up my touchscreen. It dosen't work anymore. T.T Will make a few last attempts to revive it.

 

Is the touchscreen powered by one of the voltage regulators? Anybody have any idea what could have gone wrong?

 

Note to anybody else who does this mod. Please be careful when you desolder the ceramic capacitors, op-amp and voltage regulators. Do not break the pads below.


Edited by Cryok95 - 3/20/12 at 6:12am
post #1313 of 1468
To get the touchscreen work again, you may solder the flat cable soldered to the pcb. I today had the same issue, and I resoldered the 5 exposed threads, it works again.

Hope it helps.
post #1314 of 1468

Hi all! In the short time I finish an advanced "Ultimate mod" (ear amplifiertpa6120, etc) and is ready to make a mod for others. I live in Russia (as the author of "Ultimate mod"), can offer such a scheme - I buy the player in China,doing fashion and send to you. There are people interested? If there are enough students - declared a further details.
PS about my competence can be read - my nickname burnway


Edited by burnwaygta4 - 4/11/12 at 1:44am
post #1315 of 1468


 

Quote:
Originally Posted by burnwaygta4 View Post

Hi all! In the short time I finish an advanced "Ultimate mod" (ear amplifiertpa6120, etc) and is ready to make a mod for others. I live in Russia (as the author of "Ultimate mod"), can offer such a scheme - I buy the player in China,doing fashion and send to you. There are people interested? If there are enough students - declared a further details.
PS about my competence can be read - my nickname burnway



 

Any Pics, I am interested.

post #1316 of 1468
 
 
 


Quote:
Originally Posted by turokrocks View Post


 



 

Any Pics, I am interested.



I placed an order for modification of components in the Farnell - when they come, I will make pictures

 

I think there will be 2 versions of the mod. The first low-cost ceramic x7r with shunts, the second film with the use of expensive Panasonic PPS as a shunt power.

 

111111111.png  - a PCM headphones amplifier, which I'll embed the player

 

Edited by burnwaygta4 - 4/11/12 at 2:05am
post #1317 of 1468

 

Wow this thread is looking good.

 

 

What's a PCM headphone amplifier?

 

post #1318 of 1468
Quote:
Originally Posted by kiteki View Post

 

Wow this thread is looking good.

 

 

What's a PCM headphone amplifier?

 



 

Yeah, I would also like to know, and might send mine for the 2nd/expensive update.

And why are you surprised, as until now there is no real update from Teclast!


Edited by turokrocks - 4/11/12 at 4:45am
post #1319 of 1468
Quote:
Originally Posted by turokrocks View Post



 

Yeah, I would also like to know, and might send mine for the 2nd/expensive update.

And why are you surprised, as until now there is no real update from Teclast!

Yes, this PCB for headphones amplifier - one of the parts of my mod teclast t51.

post #1320 of 1468

I'm also interested to send you my T51 for the 2nd mod :)

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Portable Source Gear
This thread is locked  
Head-Fi.org › Forums › Equipment Forums › Portable Source Gear › Teclast T51