You may send the schematic by pm if you want, maybe something is overlooked?
Removing R24 would be my next step and then changing the TPS for a new one.
Removing R24 would be my next step and then changing the TPS for a new one.
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Thanks, PM sent. Just an update on my measurements. The screenshot I attached above gives the impression that /MR goes down slowly. In fact it dives instantly every ~400ms when /RESET tries to go high, and then goes up to VDD with a trace that looks like a capacitor charging.
Attachments
400ms delay is coming from the TPS3802 so there's a loop going on.
/FAULT on /MR is retriggering the the TPS Reset which then sends the TPA into shutdown. Once its coming up again, it triggers /FAULT which then pulls a reset again on /MR. 🙂 The capacitor charging is your 100n (C49).
/FAULT on /MR is retriggering the the TPS Reset which then sends the TPA into shutdown. Once its coming up again, it triggers /FAULT which then pulls a reset again on /MR. 🙂 The capacitor charging is your 100n (C49).
Problem solved thanks to doctormord. For future reference: I had connected the /MR pin on the TPS chip to /FAULT on the TPA... don't do that 🙄
The "glitch" on /FAULT is intended by TI (didn't noticed yet) as shown in TPA3255 datasheet on page 30, figure 32. It will last for about 70us.
If you're in a noisy environment, i'd recommend an RC-filter (timecontant) on the /MR pin, like 1kOhm + 1uF, as the TPA3802 is kinda sensitive to EMI pickup. (It also does not feature an internal glitch filter and will do a reset from pulses as short as 100ns)
I actually had trouble with an TPA3255 + TPS3802 in bikes soundsystem, where the TPS resets at high output levels due to EMI or ground induced noise. 1k + 1u fixed that nicely.
I actually had trouble with an TPA3255 + TPS3802 in bikes soundsystem, where the TPS resets at high output levels due to EMI or ground induced noise. 1k + 1u fixed that nicely.
Ok, thanks for the tip. I only have a series resistor to limit the current when /RESET is pulled low manually. But my build is for home use and safely stuck in a box so fingers crossed... Btw what exactly is the purpose of having both VDD and 15V connected to the TPS? The 15V is pretty straight foward with the voltage divider but I don't quite understand the 100k resistor and 1uf caps at the PVVD connection.
This capacitive divider is there to monitor both voltages but having the PVDD dominant with feed-forward character. The capacitors somewhat amplify every dip in PVDD so the SVS (system voltage supervisor) can act fast to mute the amp. I'm not a fan of this setup.
any thoughts on this latest tpa3251 finished amp that someone posted a link to in a tpa3255 thread?
AIYIMA TPA3251 Digital Audio Amplifier HIFI Power Amplifier 2.0 Home Mini Professional Amp NE5532 175W *2 Super TDA7498E/TPA3116-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Looks promising i think?, been tempted by it.
AIYIMA TPA3251 Digital Audio Amplifier HIFI Power Amplifier 2.0 Home Mini Professional Amp NE5532 175W *2 Super TDA7498E/TPA3116-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Looks promising i think?, been tempted by it.
Hi
I have EAUMT-0140-2-A by 3eaudio.
I want to add input regulator (before the input stage). When I use 100K, I got noise on the middle point. Does anybody knows why it happening? How to do it corectly?
I have EAUMT-0140-2-A by 3eaudio.
I want to add input regulator (before the input stage). When I use 100K, I got noise on the middle point. Does anybody knows why it happening? How to do it corectly?
New tpa3251 stereo finished amp:
Tilear xzd-1752 tpa3251 175Wx2 2.0 NE5532
Around £33
Buy tpa3251 175Wx2 2.0 NE5532 and get free shipping on AliExpress - 11.11_Double 11_Singles' Day
Tilear xzd-1752 tpa3251 175Wx2 2.0 NE5532
Around £33
Buy tpa3251 175Wx2 2.0 NE5532 and get free shipping on AliExpress - 11.11_Double 11_Singles' Day
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Hi amigos,
I share again on the right thread my TPA3251 DIY finished amp :
3E Audio : eaumt-0140-2-a (TPA3251)
Toroidal PSU 24VAC made in Poland 300W
Unregulated PSU module (4x 10000µF 50V, Nover capacitors) > Output 35VDC
Oxygen free wires (made in Germany)
ITX case adapted for this Amp
All the 220V has been Isolated at the top of the case
Led connected directly to the 12V / 0.5A board output
The Amplifier sounds absolutely fine ! Great dynamics, powerful and absolutely lovely to my ears =)
I share again on the right thread my TPA3251 DIY finished amp :
3E Audio : eaumt-0140-2-a (TPA3251)
Toroidal PSU 24VAC made in Poland 300W
Unregulated PSU module (4x 10000µF 50V, Nover capacitors) > Output 35VDC
Oxygen free wires (made in Germany)
ITX case adapted for this Amp
All the 220V has been Isolated at the top of the case
Led connected directly to the 12V / 0.5A board output
The Amplifier sounds absolutely fine ! Great dynamics, powerful and absolutely lovely to my ears =)
I purchased this amp through Amazon.com since the Chinese sellers on eBay can’t ship packages due to the COVID-19 virus outbreak. I am using a Mean Well LRS-200-36 switching power supply dialed down to supply 30VDC. This amp is doing a nice job of driving my KEF LS50 monitors nicely. I’ll let the amp play music for some time before I start any critical listening. So far, so good.
It is a really nice amplifier, I have the same one but in version TPA3255.
If you update the AOP and put a pair of Muse 02, you will get an incredible combo with a great improvement ! Works fine also with the OPA 1622.
An externally hosted image should be here but it was not working when we last tested it.
I wanted to purchase the Aiyima TPA3255 2.0 amp through eBay, but the seller in China could not ship the amp due to the COVID-19 virus outbreak. They were great about it and refunded my payment. That left me with the choice to purchase the Aiyima TPA3251 2.0 amp through Amazon.com who had some inventory of these amps in the US.
I connected this amp to my main system using my Audio Research LS7 tube line stage preamp and modified Klipsch Forte II speakers. This is where I started my critical music listening and discovered that the right and left channels are reversed, so I switched my right and left hand RCA interconnect connections. My reference power amplifiers are a rebuilt McIntosh MC240 vacuum tube amp and Pass DIY Sony VFET Class A solid state amp I built with the diyAudio.com store kit offered several years ago.
Both of my reference amps are excellent and I am quite pleased with the low distortion, highly musical performances of both amps in my system. I connected the Aiyima amp to the Audio Research preamp and my speakers, and I have to say this little amp is impressive. First of all, it is very quiet with no music playing through it. I held my ear close to my efficient Klipsch speakers and heard no noise. As for the sound, it is not as good as my reference amps, but it wasn’t that far off either, which is astounding considering that this amp is only $50 USD. The fact that the channels are reversed is my only real complaint about this amp.
I have my volume on the Audio Research set in my normal position, and I have the volume pot on the Aiyima amp set to 2 to 2:30 o’clock with best results at my usual listening level. I am very impressed with the frequency response from the lower registers to the treble. This amp has a smooth, neutral frequency response and tone. What is surprising is the separation and detail I hear with this little amp. The soundstage is large, but could have more depth. I am satisfied with my purchase even with the mislabeled channel connections.
I have placed an order for the OPA1622 op amps on DIP8 adapters, and I will try those. If I hear a significant improvement, I might be tempted to try the NJR MUSES02 op amps.
Thanks for the feedback. Really interesting review.
I personnally found my best sound with the combo TPA3255 + Muse 02 and as per preamp AK4497 dual with AOP 1622. I Can get a very pleasant and sweet sound with an impressive soundstage
You will get a good improvement if you also change for a linear PSU. It is what I did ��
I personnally found my best sound with the combo TPA3255 + Muse 02 and as per preamp AK4497 dual with AOP 1622. I Can get a very pleasant and sweet sound with an impressive soundstage
You will get a good improvement if you also change for a linear PSU. It is what I did ��
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