3e Audio SY-DAPx002 TPA3250/TPA3255 DSP Amplifier

[daftcombo]

Do I have the authorisation to open the box?

Agreed. Open Pandora's box.

 

[molexey]

I opened the box and was very "surprised".

After receiving I opened the amp and noticed the missing capacitor C136.
I texted about this to the 3e Audio store. The answer was: “it is ok, won't impact the function.there is 3 pcs 2200uF”.

Is it really Ok?

Yesterday I had free time and I realized what had happened to the SMT electrolytic capacitors. Guess what?

@3eaudio should I wait when this happens?

 

[3eaudio]

@molexey
very sorry about this there is an quality issue on these 2 small capacitor. we will ask SMT supplier improve this in further build.
regarding the BIG SMT cap is not impact function as there are 3pcs 2200uF, and in Rev1.1 design we already remove it and just keep 3x2200uF.
i suggest if you are able please swap the position of these 2 small one capacitor either remove them(cut it form the board).
or you can contact us for another replacement.

 

[zachery2006]

My SY-2002 just arrived today, it took about almost month to be delivered. But there is no custom fee, and the shipping was free when I ordered it, so I’m pretty happy. I hope there will be another free shipping events, I will buy 2 amp modules to diy.

The amp is heavy and looks solid, i really like the outlook, it‘s pretty industrial standard. But above reply makes to want to open the case first to check out any mistakes. yes, I will open the case first and take photos and let you guys help to identify any mistake.

If no issues, I will listen and compare with my other amps at hand, which are Emotiva A300, NAD M28. My current DAC is topping E30, speaker is KEF ls50.

 

[zachery2006]

Yesterday night, I was so eager to try this amp, so I didn’t open the case before listening it for the first time.

After connecting power, dac and speaker, when I turned on the amp, there is hiss noise coming from speaker, loud enough that I can hear it from 2 meters away. My other amps don’t have this hiss noise, speakers are pretty quiet, I can only hear a small amount of hiss when my ear touches to the speaker. The hiss volume is consistent and doesn’t change with volume knob turn. I bought a pair of opa1612a, hoping to alleviate this hiss problem.

Besides the hissing noise, the amp is quite good, powerful enough to drive my kef ls50. I turned the volume to the max and control the volume through e30. The sound is pretty clean, I particular the low frequency is tight than my Emotiva A300, but the sound is a little flat, a little less dynamics compared A300 and M28.

I listened only for a couple of minutes, this is my initial experience. If opa1612 will solve the hiss problem. I am super happy with this little guy.

 

[cyruz]

Yesterday night, I was so eager to try this amp, so I didn’t open the case before listening it for the first time.

After connecting power, dac and speaker, when I turned on the amp, there is hiss noise coming from speaker, loud enough that I can hear it from 2 meters away. My other amps don’t have this hiss noise, speakers are pretty quiet, I can only hear a small amount of hiss when my ear touches to the speaker. The hiss volume is consistent and doesn’t change with volume knob turn. I bought a pair of opa1612a, hoping to alleviate this hiss problem.

Besides the hissing noise, the amp is quite good, powerful enough to drive my kef ls50. I turned the volume to the max and control the volume through e30. The sound is pretty clean, I particular the low frequency is tight than my Emotiva A300, but the sound is a little flat, a little less dynamics compared A300 and M28.

I listened only for a couple of minutes, this is my initial experience. If opa1612 will solve the hiss problem. I am super happy with this little guy.

Are you sure it's a hiss and not a ground loop?

Is it still there if you disconnect the source? Can you try connecting the amplifier to a separate power socket?

 

[zachery2006]

Are you sure it's a hiss and not a ground loop?

Is it still there if you disconnect the source? Can you try connecting the amplifier to a separate power socket?

Just tested again as you suggested, I removed rca inputs, the hiss/humming is still there and doesn’t change with the volume up or down. So it’s highly likely a ground loop problem. I tried to use another power socket, no change. How do I solve this?

 

[Toku]

Just tested again as you suggested, I removed rca inputs, the hiss/humming is still there and doesn’t change with the volume up or down. So it’s highly likely a ground loop problem. I tried to use another power socket, no change. How do I solve this?

Is your speaker cable connected only to this amplifier?
Is there any wiring that connects to other amplifiers in the speaker wiring?
Are you connected to a speaker select switch?

 

[zachery2006]

Is your speaker cable connected only to this amplifier?
Is there any wiring that connects to other amplifiers in the speaker wiring?
Are you connected to a speaker select switch?

My speaker(kef ls50) only connects to SY-2002.

 

[Toku]

My speaker(kef ls50) only connects to SY-2002.

Unfortunately, my cause prediction was wrong.
It seems that there is no problem with the power supply line and speaker wiring from the situation, so a possible confirmation check is to check if the noise disappears when the power is turned on with the OP amplifier removed from the socket by opening the case cover.

 

[cyruz]

Just tested again as you suggested, I removed rca inputs, the hiss/humming is still there and doesn’t change with the volume up or down. So it’s highly likely a ground loop problem. I tried to use another power socket, no change. How do I solve this?

Actually after your tests I'm more oriented to say it's a defect because it's strange that the amplifier isn't properly grounded to the chassis. Can you check with a voltmeter if there is continuity between the rca shields and the chassis? Be sure to check on a point where the chassis painting has been scraped or on a metal screw that goes through the chassis. If there is none, you can try running a wire from one of the rca shields to the chassis and check if the hum disappears.

 

[zachery2006]

I just opened the case and took some pictures. Looks really neat.

 

[zachery2006]

Actually after your tests I'm more oriented to say it's a defect because it's strange that the amplifier isn't properly grounded to the chassis. Can you check with a voltmeter if there is continuity between the rca shields and the chassis? Be sure to check on a point where the chassis painting has been scraped or on a metal screw that goes through the chassis. If there is none, you can try running a wire from one of the rca shields to the chassis and check if the hum disappears.

I’ll try it tomorrow and report back.

 

[zachery2006]

Unfortunately, my cause prediction was wrong.
It seems that there is no problem with the power supply line and speaker wiring from the situation, so a possible confirmation check is to check if the noise disappears when the power is turned on with the OP amplifier removed from the socket by opening the case cover.

How do I remove the op amp? Just by hand pulling it out? Is it been soldered?

 

[ModDIY]

You have to remove it with your fingers, it is important to remove it gently and evenly, so as not to catch the OP's legs. Change to the new one, make sure that the OP is in the right direction, leg number 1 must be on the same side as the existing OP. But I highly doubt the hum is from an OP. Do you have another SMPS to verify that this is not the cause?

 

[Toku]

I do not suspect that the OP amplifier is defective. The reason for pulling out the OP amplifier is to disconnect the DSP from the input of TPA3255 and check the change in noise.

 

[Lorenzo74]

@molexey
very sorry about this there is an quality issue on these 2 small capacitor. we will ask SMT supplier improve this in further build.
regarding the BIG SMT cap is not impact function as there are 3pcs 2200uF, and in Rev1.1 design we already remove it and just keep 3x2200uF.
i suggest if you are able please swap the position of these 2 small one capacitor either remove them(cut it form the board).
or you can contact us for another replacement.

hi @3eaudio I'm tempted to buy one of your TPA3255 integrated Amplifiers but I realized reading specs you suggest it is for 8ohm speakers while the 3151 is for 4ohm. can you pls clarify? now I'm successfully using your TPA3255 stereo version in a DIY final Amp with 48V 17 Ampere peak with 4ohm speakers. it's very good, coils become pretty hot. ok to drive it at 48V?
thanks
L.

 

[Toku]

hi @3eaudio I'm tempted to buy one of your TPA3255 integrated Amplifiers but I realized reading specs you suggest it is for 8ohm speakers while the 3151 is for 4ohm. can you pls clarify? now I'm successfully using your TPA3255 stereo version in a DIY final Amp with 48V 17 Ampere peak with 4ohm speakers. it's very good, coils become pretty hot. ok to drive it at 48V?
thanks
L.

The voltage of 48V is not a problem electrically.
However, forced air cooling by a fan is required depending on the usage environment.
I used to use it at 48V at first, but in the summer it got so hot that the heatsink didn't touch it, and now it's down to 43V or less.

 

[Lorenzo74]

The voltage of 48V is not a problem electrically.
However, forced air cooling by a fan is required depending on the usage environment.
I used to use it at 48V at first, but in the summer it got so hot that the heatsink didn't touch it, and now it's down to 43V or less.

Thanks. I’m using tpa3255 (not 3eaudio, another board) since 3 years without issues at 48v.
I was curious to hear from manufacturer their feedback. In theory tpa3255 can run smooth at 51V, max 53.5V at 4Ohm and 53.5V max 56.5V at 8Ohm.
they should have done exebsive test up to falilurr to assess the max operating voltage of their design considering the typical ambient temperature of 25degree.

@3eaudio hope you could clarify this and the impedance of the integrated amp.
thanks

 

[zachery2006]

Unfortunately, my cause prediction was wrong.
It seems that there is no problem with the power supply line and speaker wiring from the situation, so a possible confirmation check is to check if the noise disappears when the power is turned on with the OP amplifier removed from the socket by opening the case cover.

Tested of removing OP, speakers’ noise disappeared. When I put OP back, the noise came back. So any insights?