Which TPA3255 amp do you recommend?

[datrumole]

Sure sounds like it. Check whether there is anything installed in this position right now.

If step A gets you a doubled input sensitivity already, chances are you may not have to do anything more. 12.8 V x 2 = 25.6 V > 21 V, so you should be able to drive the amp into clipping from 2 Vrms.

I deleted my post since I wasn't able to read the Step B part. Looks like Step A is messing/disabling the PFFB and Step B is changing feedback resistors to increase gain. Agree that you don't need step B.

awesome, thanks guys!

the resistor locations in stepB currently have resistors

in looking at stepA vs stepB, is one a better idea than the other? @jlesterp you mention PFFB being bypassed by stepA, should i leave that in and do stepB instead? (asking for clarity from aiyima on what resistor values would go there)

i know one of these will get this back to usable, but what about all the poor people who are stuck buying this thing and having no idea. i feel like @AIYIMA should reconsider their design

 

[datrumole]

is it possible to set the input sensitivity of the A07 in a similar way to 1.0V or 2.0V and retire the volume knob?

I don't use my volume knob at all (volume control upstream) and right now i'm using tea leaf reading to decide on which position on the dial is best for me.

my Dac's max output is 1 Vrms and my power supply is 48V 4.6A.

i'm sure there is a way to mess with the circuitry, but smarter people would need to comment and is probably not recommended

the easiest way to figure out where to put the dial is to get a meter or cheap scope to check where clipping occurs to find the balance between the two

EDIT
@abdo123 check out FNIRSI-1C15, got it from aliexpress for like 60bucks, great reviews, accurate readings, great price for a hobbyist scope

 

[SylphAudio]

awesome, thanks guys!

the resistor locations in stepB currently have resistors

in looking at stepA vs stepB, is one a better idea than the other? @jlesterp you mention PFFB being bypassed by stepA, should i leave that in and do stepB instead? (asking for clarity from aiyima on what resistor values would go there)

i know one of these will get this back to usable, but what about all the poor people who are stuck buying this thing and having no idea. i feel like @AIYIMA should reconsider their design

The buffer opamps in that configuration is using a single supply so changing the gain might make the opamps go unstable. (Any DC offset will be fed to the second opamp stage) So it's not recommended, it might be stable with NE5532 but not with others. The gain should be adjusted before the buffer opamps. Confirm with AIYIMA if the sandpapered SMT IC is an opamp preamp, you can change the gain there.

 

[datrumole]

The buffer opamps in that configuration is using a single supply so changing the gain might make the opamps go unstable. (Any DC offset will be fed to the second opamp stage) So it's not recommended, it might be stable with NE5532 but not with others. The gain should be adjusted before the buffer opamps. Confirm with AIYIMA if the sandpapered SMT IC is an opamp preamp, you can change the gain there.

sorry, for the smooth brained individuals, is changing the gain is what stepB would be doing? since there are already resistors in there, and they didnt supply any resistor values anyway, it's the step that has the least amount of guidance and direction

so you are recommending stepA?

edit: i've also posed your question to @AIYIMA

 

[SylphAudio]

I think you should ask AIYIMA since they have the schematic of the board. I'm just guessing here and assumes that their buffer stage is similar to EVM

 

[Tangband]

Im not sure that the original Aiyima a04 and the one with green colour has an active pre amp stage that is a no-name IC.

In this thread linked below, where they modify the a04, they came to the conclusion that the two replacebly IC 5532 has :

A : first stage in 5532 = gain 6 dB
B: second stage in 5532 = - makes the signal balanced to the four inputs on 3251 , that runs in BTL mode.

https://www.diyaudio.com/forums/class-d/362341-aiyima-tpa3251-modification-build-thread.html

 

[SylphAudio]

Im not sure that the original Aiyima a04 and the one with green colour has an active pre amp stage that is a no-name IC.

In this thread linked below, where they modify the a04, they came to the conclusion that the two replacebly IC 5532 has :

A : first stage in 5532 = gain 6 dB
B: second stage in 5532 = - makes the signal balanced to the four inputs on 3251 , that runs in BTL mode.

https://www.diyaudio.com/forums/class-d/362341-aiyima-tpa3251-modification-build-thread.html

Yup it can be, only 2 input coupling cap is needed for SE input (and 4 coupling caps for TPA3251 balanced inputs). So those extra caps might be DC blockers from 1st stage to 2nd stage so that the gain can be increased even when single supply is used. You can verify by checking resistor values if the replaceable ICs do have a gain.

 

[nhatkhang]

Should be interesting to understand why Aiyima has stopped the first and best version of the A04 with those Elna 2x3000uf caps and Red robe caps.
it would be really great to re-edit this version and send it to Amir!

Own both two (but the best version of A04) and sounds really better than the A07, I agree.

Dear Daniboun,

Is this the version you mention to?
At this time should I buy this version? (I found it still on taobao).

 

[datrumole]

Dear Daniboun,

Is this the version you mention to?
At this time should I buy this version? (I found it still on taobao).

View attachment 145945

that looks like the rev 3.1 board since it has the extended heatsink

the one i believe in question from @daniboun is the tilear rev 2.1 black board from early 2020

 

[datrumole]

@jlesterp


i went ahead and removed the 4 resistors as indicated by aiyimas first suggestion

i'm now getting 16.1-17Vrms of CLEAN output (depending on how nit pity you want to get)

from 17 to 20.4Vrms the top of the waveform gets a little wiggly as we hit clipping right about 20.8Vrms (identical to the rev 2.1 board)

personally, i think all the way up to 18.3Vrms looks pretty good

so a nice improvement

so we went from 12.8Vrms with 2Vrms input (unable to clip with most DACs) ~20W@8ohm

to

17Vrms ~36W@8ohm of clean power, only requiring 1.1Vrms input, which most if not all DACs can achieve!

pushing it, you can go to 20.4Vrms ~55W@8ohm with 1.35Vrms input, which again, is achievable by most if not all DACs before things head to clipping

now, the rev 2.1 board stays clean the entire way to clipping to 20.8Vrms, so the rev 2.1 board is still superior for sure

provided some pics of the upper end of each of them

 

[SylphAudio]

Is the chip still TPA3251 or they've replaced it with TPA3255?

What are the connections of these 5 output caps? If these are connected to each opamp stage, then there will be degradation of sound. Though the electros will mask the high frequencies and hide imperfections.

 

[robertospeed]

Aiyima has created another good amplifier, for me better than aiyima a07 that I have previously owned with a power supply at 48v 7.3a, this is the new Aiyima d03, made it play with my q acoustic 3050i and sounds really very well, I don't scream like A07, the D03 has a clean and full-bodied sound, full of low and medium sharp and clean. The strange thing I noticed is that it has a 32V 5A power supply and sounds with more power of Aiyima A07 with feeder 48V 7.3A, the features you can see them on the Aliexpress site: https://www.aliexpress.com/item/1005002841621855.html

 

[Toku]

Aiyima has created another good amplifier, for me better than aiyima a07 that I have previously owned with a power supply at 48v 7.3a, this is the new Aiyima d03, made it play with my q acoustic 3050i and sounds really very well, I don't scream like A07, the D03 has a clean and full-bodied sound, full of low and medium sharp and clean. The strange thing I noticed is that it has a 32V 5A power supply and sounds with more power of Aiyima A07 with feeder 48V 7.3A, the features you can see them on the Aliexpress site: https://www.aliexpress.com/item/1005002841621855.htmlView attachment 146227View attachment 146228

I also purchased D03 at the same time as the release.
Until now, I have considered a full digital amplifier like the D03 to be a bad idea. However, since full digital amplifiers have recently been adopted in high-end products, I got the newly released AIYIMA D03 and tried using it. And I fell in love with this product, which has higher sound quality and power than I had imagined.
The first thing I felt when I heard the sound of D03 was that it had higher sound quality and power than A07 of the same AIYIMA. I realized the performance of the latest full digital amplifier.

There is no pop noise associated with turning the power on and off, which I care most about. There is no pop noise even if you unplug the AC adapter while playing. This is ideal for applications such as turning the entire system on and off with a master power switch.
White noise when there is no sound is less than A07 and is excellent.
It's not the perfect product, but I was able to meet a very good amp.

 

[robertospeed]

I also purchased D03 at the same time as the release.
Until now, I have considered a full digital amplifier like the D03 to be a bad idea. However, since full digital amplifiers have recently been adopted in high-end products, I got the newly released AIYIMA D03 and tried using it. And I fell in love with this product, which has higher sound quality and power than I had imagined.
The first thing I felt when I heard the sound of D03 was that it had higher sound quality and power than A07 of the same AIYIMA. I realized the performance of the latest full digital amplifier.

There is no pop noise associated with turning the power on and off, which I care most about. There is no pop noise even if you unplug the AC adapter while playing. This is ideal for applications such as turning the entire system on and off with a master power switch.
White noise when there is no sound is less than A07 and is excellent.
It's not the perfect product, but I was able to meet a very good amp.

Thanks for your comment, can you help me make a nice review of this aiyima d03?

 

[datrumole]

Is the chip still TPA3251 or they've replaced it with TPA3255?

i didnt want to wipe the paste off while i had it disassembled since i wasn't sure if i had any in the house, so i wasn't able to tell

however i did find some mx4 paste that i can replace it with, so i'll disassemble and confirm today if they kept the same chipset

What are the connections of these 5 output caps? If these are connected to each opamp stage, then there will be degradation of sound. Though the electros will mask the high frequencies and hide imperfections.

View attachment 146218

happy to let you know, just need a bit more detail on how best to provide. should i put the meter between the caps and each of the opamp pins and see if i hit continuity?

 

[Toku]

Thanks for your comment, can you help me make a nice review of this aiyima d03?

Yes, that's fine.
I disassembled D03 because it made a loud rattling noise when I held the main unit in my hand and shook it, so I had to disassemble and examine it. The cause seems to be that the case was not assembled properly, and when I reassembled it, the sound disappeared. At that time, I took a lot of pictures of the inside.

 

[datrumole]

Is the chip still TPA3251 or they've replaced it with TPA3255?

yes, confirmed the A04 rev 3.1 still uses the 3251 chip

however after all this nonsense, i think it might just be easier to get the A07 and not have to deal with modding it unless there is any real benefit the A04 has over the A07

 

[robertospeed]

Yes, that's fine.
I disassembled D03 because it made a loud rattling noise when I held the main unit in my hand and shook it, so I had to disassemble and examine it. The cause seems to be that the case was not assembled properly, and when I reassembled it, the sound disappeared. At that time, I took a lot of pictures of the inside.

Excuse me a lot, I'm Italian and I don't understand the English language, I use a translator, what kind of noise felt? When did you light up? Actually I feel a noise when I put the electric plug at the current, but then it does not emit any noise. Can you write to me in private? And send photos of the interior? I should make a nice review of the D03 on this site, but I can't write well in English, so I need a little help from you if it's possible.

 

[Joe Smith]

yes, confirmed the A04 rev 3.1 still uses the 3251 chip

however after all this nonsense, i think it might just be easier to get the A07 and not have to deal with modding it unless there is any real benefit the A04 has over the A07

This is what I would recommend! I have both and the A07 is superior in my view in both SQ and power, and gets very loud with the 32v/5a supply using efficient 6 ohm speakers.

 

[Deleted member 9685]

I also purchased D03 at the same time as the release.
Until now, I have considered a full digital amplifier like the D03 to be a bad idea. However, since full digital amplifiers have recently been adopted in high-end products, I got the newly released AIYIMA D03 and tried using it. And I fell in love with this product, which has higher sound quality and power than I had imagined.
The first thing I felt when I heard the sound of D03 was that it had higher sound quality and power than A07 of the same AIYIMA. I realized the performance of the latest full digital amplifier.

There is no pop noise associated with turning the power on and off, which I care most about. There is no pop noise even if you unplug the AC adapter while playing. This is ideal for applications such as turning the entire system on and off with a master power switch.
White noise when there is no sound is less than A07 and is excellent.
It's not the perfect product, but I was able to meet a very good amp.

How can D03 sound better than A07? Do you have any theory? Is A07 connected to mainboard sound card?