3e Audio SY-DAPx002 TPA3250/TPA3255 DSP Amplifier

[NEO Dan]

UPDATE: SORRY, my response was about the standalone DSP from 3E Audio, and not the AMP+DSP combo.

I am not an expert, but I've messed a bit with this DSP.

The 3E Audio DSP has all the I2S exposed, and you can run external DACS and ADC but it's limited by the internal clocks of the DSP.

I've tried the 3E audio DSP with USB to I2S input (running OK), with external I2S DAC (Running OK) and even running 2 DSP in tandem (Runnning OK). What I can not do Is run 2 DSP in tandem with USB input or one DSP with USB input and additional I2S DAC.

So, I am limited by USB input and 4 outputs, bluetooth input and 4 outputs or analog input and 8 outputs.

In any case, the ADC is the real problem. The DACs are not THAT bad. Even now, the price of this DSP is quite good, when it was USD$30 was a steal.

Hi mga2009,
I don't have any of the equipment yet so I am speculating from memory here on what I've read so far.
The second DSP needs to have its clock crystal oscillator removed and I believe there are master and slave settings to be set.

Surprised to hear about troubles adding a DAC to a spare I2S output, I do know the HiFi Berry DAC+ DSP uses the PCM5102 as its main DAC so you might grab one and give that a go. There are also plenty of settings to trip you up. IIRC the Wondom videos cover adding a second connected DSP.
I ordered the HiFi Berry DAC+ DSP to get my feet wet as the whole thing seemed like a better place for me to start since I want to use a Raspberry Pi as one of my streaming sources.

 

[mga2009]

Hi mga2009,
I don't have any of the equipment yet so I am speculating from memory here on what I've read so far.
The second DSP needs to have its clock crystal oscillator removed and I believe there are master and slave settings to be set.

Surprised to hear about troubles adding a DAC to a spare I2S output, I do know the HiFi Berry DAC+ DSP uses the PCM5102 as its main DAC so you might grab one and give that a go. There are also plenty of settings to trip you up. IIRC the Wondom videos cover adding a second connected DSP.
I ordered the HiFi Berry DAC+ DSP to get my feet wet as the whole thing seemed like a better place for me to start since I want to use a Raspberry Pi as one of my streaming sources.

Yes, I've been told that the crystal on the second DSP must be removed (and wire it to the first DSP`s crystal) If I am to use digital input on the 1st DSP.

Adding an external I2S DAC is no problem at all when using analog input (ADC), but I did not have success while using digital input (I2S to USB or I2S to bluetooth). Notice again, that I am no expert at all, but had a ton of help in diyaudio forum.

Anyways, I am open to any recommendation or if you need test of any kind.

 

[dtn666]

With the latest firmware, at low volume, the sound is constantly turned off. very uncomfortable at night.

 

[dream]

With the latest firmware, at low volume, the sound is constantly turned off. very uncomfortable at night.

I just got 3e audio TPA3250 amp last weekend.
Happy to find there is a thread here.

I have similar problem as dtn666 does. When the audio signal is off for a few minutes, the amp goes standby.

It's very annoying because I have to turn the amp on again every time CD playing is over.

@3eaudio
1. Is it possible to turn the auto-standby function off?
2. If I change the resistors for 3V input sensitivity, will the performance degrade in terms of SNR or THD+N or etc?
3. The volume knob is linear type. Can we change to A type logarithmic?

Thank you

 

[3eaudio]

I just got 3e audio TPA3250 amp last weekend.
Happy to find there is a thread here.

I have similar problem as dtn666 does. When the audio signal is off for a few minutes, the amp goes standby.

It's very annoying because I have to turn the amp on again every time CD playing is over.

@3eaudio
1. Is it possible to turn the auto-standby function off?
2. If I change the resistors for 3V input sensitivity, will the performance degrade in terms of SNR or THD+N or etc?
3. The volume knob is linear type. Can we change to A type logarithmic?

Thank you

1. there is a project that remove auto-standby,please visit www.3e-audio.com
2. the performance should be the same
3. no log type so far,i guess you should do step 2 first as i guess your input may too high now.

 

[dream]

1. there is a project that remove auto-standby,please visit www.3e-audio.com

@3eaudio thank you for your reply

Please give the project link. I go through www.3e-audio.com but cannot find any.

1. there is a project that remove auto-standby,please visit www.3e-audio.com
3. no log type so far,i guess you should do step 2 first as i guess your input may too high now.

Yes. My DAC output is quite high ~2V. I'll try step 2.

 

[thulle]

Please give the project link. I go through www.3e-audio.com but cannot find any.

The only thing i found was this note in the amplifier guide:

Auto Entry Standby Mode When No Audio or Act unit after 20 Minutes, User Can disable by Update DSP F/W

The DSP has source files here: https://www.3e-audio.com/dsp/adau1701-2in4out/
I guess the user can modify it to preferred behaviour.

edit: Wonder if that might be the -65dB threshold at the top in this pic?

3e Audio SY-DAPx002 TPA3250/TPA3255 DSP Amplifier

no, it from transformer, i check it by spl meter, and it can't be fixed To be fair, try touching the capacitor with something non-conductive, such as a plastic pen. If this noise is coming form the cap you will notice a change in intensity.

www.audiosciencereview.com

 

[daunbailo]

This noise from the capacitor in a snubber. Noise intensity varies with temperature. As the amplifier (the capacitor) warms up, the noise decreases. This noise also disappears when the power supply goes from active burst mode to normal mode.
You can check it, just load the amp around 2w.

Glad I've found this message, my unit just went POP because of that snubber, the ICE2QS03G seems not to enable the amplifier to turn on anymore, the cap went nuts and the fuse blew with a nice smoke, I've barely used the amp in the last months and it was disconnected, now I just have a nice bricked amplifier.
Does anyone have advices on this? I'm probably going to order the cap and the fuse (this one is expensive) and see if anything helps, but the amp before the magic smoke was not even turning on.

 

[VasiliSk]

Disable auto shutdown + make a better power down mode
Once again i find out that anything bought from china needs to be polished on your own. So!
What we gonna do here is disable annoying auto shutdown, add automatic low power mode and upload all of that to IC. I hope you bought amplifier with USB stick right? This simple mod on SY-DAP1002 halves idle power usage from 5W to 2-3W and auto enables power stage immediately.

First we need to do some soldering! Completely disconnect your amplifier. I did discharged power capacitors with resistor too.
Add and replace resistors that shown here:

Spoiler: Picture

100R is new resistor added here to disable TPA3250. After you finished soldering there will be no sound. Now we need to upload new fw.

Get Sigma Studio from Analog devices website and install it, open attached project in zip file. Attach usb probe to connector on the board. From ESD side i would do connector first, USB plug last.

1. compile project
2. select hardware
3. upload project to EEPROM so it will work after power reset
Done!

This is my diagram for GPIO8 (open collector) pin that disables power stage, you can do same for other amplifier:

 

[mathiasb]

• Built-in 15 Segment LEDs Ring for volume indicating and other UI etc.

Unfortunately, this is useless for now. Because the volume potentiometer uses a linear (not log) curve.
Another cool feature if the LED ring could indicate as a dynamic VU meter.

I have re-created output block with the interpolation linear to log curve. If anyone is interested, I'll share a dspproj file for Sigma Studio.

Apologies for necro bumping - do you / someone have the dspproj file to share with a logarithmic volume control? Thanks

 

[r-36m2]

1.

Hello, 3eAudio!

Please. Please tell the truth.
Are the original Japanese Elna Silmic 2 capacitors installed in the amplifier?
This is very important because I am ready to buy the original ones.

There are 10 electrolytic capacitors in the sound transmission circuit. If they are not original, it will have a fatal effect on the sound.
I will add 0.22 uf of Epcos 32652 polypropylene capacitor in parallel to each of them. But I have to be sure that Elna is a real Japanese Elna.

I have no complaints if the capacitors are not original.
On the contrary, I will be grateful for the truth and will be able to change them to the original ones.

Thanks!

 

[3eaudio]

Hello, 3eAudio!

Please. Please tell the truth.
Are the original Japanese Elna Silmic 2 capacitors installed in the amplifier?
This is very important because I am ready to buy the original ones.

There are 10 electrolytic capacitors in the sound transmission circuit. If they are not original, it will have a fatal effect on the sound.
I will add 0.22 uf of Epcos 32652 polypropylene capacitor in parallel to each of them. But I have to be sure that Elna is a real Japanese Elna.

I have no complaints if the capacitors are not original.
On the contrary, I will be grateful for the truth and will be able to change them to the original ones.

Thanks!

sure they are original Japanese cap.
you are welcome to do any test to verify it.

 

[mathiasb]

Hello,

I have programmed my unit with the auto stand by function disabled. However when there is little to no signal after just a couple of seconds - the unit goes into some sort of standby. I have to crank the volume quite high to make it wake up again. This means during movies when there is no talking, the amplifier goes into standby, and the movie goes quiet until I crank the volume up again.
I am using this to power a set of tweeters.
Any idea how I can fix this?

 

[r-36m2]

sure they are original Japanese cap.
you are welcome to do any test to verify it.

Thank you very much!

1. I added 2 low ESR electrolytes of Panasonic FM 1200 uf next to the TPA3250 and another 6800 uf next to the transformer.
2. I added X7R 4.7 uf caps in parallel to each TPA3250 electrolyte. A total capacity of TPA caps 15828 uf.
3. I replaced the 100 uf electrolyte cap after the 12 Volt stabilizer with a Panasonic FK 330 uf.
4. I added Epcos 32652 0.22 uf polypropylene capacitors in parallel to each Elna electrolyte before and after the op-amps (8 pcs).
5. I removed 2 Elna caps at the input to the amplifier.
6. I added 0.01 uf NP0 Murata caps in parallel with 1 uf caps after output chokes (Epcos MKT).
7. I replaced the original NE5532 with the Philips NE5532, which I bought 10 years ago.

What did I get? I got a clearer and faster bass. I got a little more legibility at high frequencies around 8-10 kHz and above. The sound has become a little clearer and more lively.

8. I ordered 4 Panasonic ECWF 1 uf polypropylene capacitors instead of Epcos MKT.
9. I ordered MC33272 op-amps instead of NE5532.
10. I want to install PFFB elements for TPA 3250 (feedback) and in this regard I have a few questions.

Dear 3e-audio, could you send me the amplifier input circuit (before ADAU) and the circuit around the operational amplifiers (between ADAU and TPA) so that I can understand the input impedance (I need it for my DAC op-amps circuit), as well as which op-amps I can use in this circuit (opa1656 and more) and which elements I will have to add or replace to organize TPA feedback.
I have read the TI datasheets and the description of the PFFB and I see that not all elements match.
In addition to this (if it's not a secret), I would be grateful to you for specifying the models of output chokes so that I can understand their characteristics.

I will be grateful to you for any answer! With best wishes!

 

[3eaudio]

Thank you very much!

1. I added 2 low ESR electrolytes of Panasonic FM 1200 uf next to the TPA3250 and another 6800 uf next to the transformer.
2. I added X7R 4.7 uf caps in parallel to each TPA3250 electrolyte. A total capacity of TPA caps 15828 uf.
3. I replaced the 100 uf electrolyte cap after the 12 Volt stabilizer with a Panasonic FK 330 uf.
4. I added Epcos 32652 0.22 uf polypropylene capacitors in parallel to each Elna electrolyte before and after the op-amps (8 pcs).
5. I removed 2 Elna caps at the input to the amplifier.
6. I added 0.01 uf NP0 Murata caps in parallel with 1 uf caps after output chokes (Epcos MKT).
7. I replaced the original NE5532 with the Philips NE5532, which I bought 10 years ago.

What did I get? I got a clearer and faster bass. I got a little more legibility at high frequencies around 8-10 kHz and above. The sound has become a little clearer and more lively.

8. I ordered 4 Panasonic ECWF 1 uf polypropylene capacitors instead of Epcos MKT.
9. I ordered MC33272 op-amps instead of NE5532.
10. I want to install PFFB elements for TPA 3250 (feedback) and in this regard I have a few questions.

Dear 3e-audio, could you send me the amplifier input circuit (before ADAU) and the circuit around the operational amplifiers (between ADAU and TPA) so that I can understand the input impedance (I need it for my DAC op-amps circuit), as well as which op-amps I can use in this circuit (opa1656 and more) and which elements I will have to add or replace to organize TPA feedback.
I have read the TI datasheets and the description of the PFFB and I see that not all elements match.
In addition to this (if it's not a secret), I would be grateful to you for specifying the models of output chokes so that I can understand their characteristics.

I will be grateful to you for any answer! With best wishes!

that is not a simple (a huge) modification and looks you are skilled on electronics, anyway,well done for DIY
for PFFB,this amp not include in design at the beginning. the performance is limited by DSP DAC output,not tpa3250 itself,so we don't suggest you try to do that.

 

[mathiasb]

Hello,

I have programmed my unit with the auto stand by function disabled. However when there is little to no signal after just a couple of seconds - the unit goes into some sort of standby. I have to crank the volume quite high to make it wake up again. This means during movies when there is no talking, the amplifier goes into standby, and the movie goes quiet until I crank the volume up again.
I am using this to power a set of tweeters.
Any idea how I can fix this?

@3eaudio any idea, or link to firmware I could flash to have constant on?

 

[r-36m2]

for PFFB,this amp not include in design at the beginning. the performance is limited by DSP DAC output,not tpa3250 itself,so we don't suggest you try to do that.

Thanks for the answer!
I will be assembling the PFFB on a separate board so that it can be easily connected and disconnected.
I think if there is an R_in of about 2.7 K after the op-amps, then the PFFB should not have any effect on the DSP operation.
In any case, information about the nominal values of the elements around the op-amp, as well as at the input of the amplifier, would help me a lot, since the SMD elements are very small and it is quite difficult to measure their nominal values at home.

 

[3eaudio]

@3eaudio any idea, or link to firmware I could flash to have constant on?

use No ASB file to try

 

[3eaudio]

Thanks for the answer!
I will be assembling the PFFB on a separate board so that it can be easily connected and disconnected.
I think if there is an R_in of about 2.7 K after the op-amps, then the PFFB should not have any effect on the DSP operation.
In any case, information about the nominal values of the elements around the op-amp, as well as at the input of the amplifier, would help me a lot, since the SMD elements are very small and it is quite difficult to measure their nominal values at home.

the op-amp is configured as instrument op-amp, a little bit different with Ti App one.
you may add extra one as Ti show.

 

[mathiasb]

use No ASB file to try

Can you please link the exact file? I want to make sure I flash the correct FW. Thank you