Yay, at last a tpa3251 finished amp... I recently finished boxing up my 3e-audio tpa3251 amp board as a basic boxed amp + dc-dc boost... if i had know this was coming.... arr well. maybe i end up getting this too 
:O
I’ll wait and see if its better than other tpa325* finished amps of late...
Must resist!
:OI’ll wait and see if its better than other tpa325* finished amps of late...
Must resist!
Yay, at last a tpa3251 finished amp... I recently finished boxing up my 3e-audio tpa3251 amp board as a basic boxed amp + dc-dc boost... if i had know this was coming.... arr well. maybe i end up getting this too
I’ll wait and see if its better than other tpa325* finished amps of late...
Must resist!
did you show us your amp ???
i think the e3 boards a well made and sound like the TI
yes the amp rule is:
n= n +1
no, not published any pics. i should.... nudge me more and watch http://social.aross.me for updatesdid you show us your amp ???
i think the e3 boards a well made and sound like the TI
yes e3-audio boards seam to be good. However recent ones seam to use less fancy caps and one of mine i leant this week when i open packaging has crosion... bit like other post of mess on top of cap.... concerned :| need to test it.
I’m finding the tpa3255 heatshink get hot driving my 8ohm speakers... added a fan to latest build yesterday. next is to test.
yes the amp rule is:
n= n +1
hehe
"Better" at what wattage on what load at what volumes? I have a Fosi Audio 3116 based amp on the speakers in my bedroom(fairly efficient three way bookshelves) and the distortion is already so low I cannot imagine the 3250 improving that.
Honest question, I do plan on going through and updating things before too long, and just curious if that is a worthwhile upgrade.
Honest question, I do plan on going through and updating things before too long, and just curious if that is a worthwhile upgrade.
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no, not published any pics. i should.... nudge me more and watch http://social.aross.me for updates
yes e3-audio boards seam to be good. However recent ones seam to use less fancy caps and one of mine i leant this week when i open packaging has crosion... bit like other post of mess on top of cap.... concerned :| need to test it.
I’m finding the tpa3255 heatshink get hot driving my 8ohm speakers... added a fan to latest build yesterday. next is to test.
hehe
the heatsink getting hot? so you push really... a 4W-10W (at 90% efficiency 40-100W per channel) dissapation is a lot
but if its about 60-65°C than its ok without fan
Please tell me if it makes sense to replace the inductors in the output filter 502s pro? Having read the thread, I saw that someone changed me for coils with a core, but I thought that the 502s pro had a relatively good sound just because of the use of coils on a core in the air. Isn't air coils considered better for audio than those that are coils on an iron core? and I also noticed that those induction coils that 502s pro from the factory heat up a lot, is this normal?
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I would also like to ask the respected “chermann” if he suddenly finds time to lay out a small final post with 502s pro modifications. I saw that they had already asked for this and it was suggested to read the topic from page 30. I did this, took screenshots by choosing the right information from a variety of discussion pages, but it’s very hard for me to put together the information. Something from the modifications changed later. other modifications say what has been done, but not described for what purpose. or simply I did not quite understand. difficulties of language translation. for example, I did not fully understand why capacitors were installed on the input and output with lm317? I apologize in advance if I ask too much)
Hi Ruslan
for the coils:
the air coils are better in non class D amps because class D amps "working" with about 300kHz and above and this can emit in the coils. lot of "better" coils have ferrit enclosure to avoid this.
your coils get hot - Why its not easy to say from here. do you push hard or you forget to connect a load (speaker/resistor).
please do not use an Class D amp without load! -this can damaged / heat up the output filter = coils and caps --> brake
caps change:
the caps for the Lm317 are just to change the bad caps there. the lm317 regulator is set by me because i want to use 24V power supply and therefore i changed the setting of the lm317. so if you use about 28V you don not need to change here something.
actually i am on holiday so maybe somebody can jump in...
so for sound improvement i would start to change the fake opamp to 465
chris
for the coils:
the air coils are better in non class D amps because class D amps "working" with about 300kHz and above and this can emit in the coils. lot of "better" coils have ferrit enclosure to avoid this.
your coils get hot - Why its not easy to say from here. do you push hard or you forget to connect a load (speaker/resistor).
please do not use an Class D amp without load! -this can damaged / heat up the output filter = coils and caps --> brake
caps change:
the caps for the Lm317 are just to change the bad caps there. the lm317 regulator is set by me because i want to use 24V power supply and therefore i changed the setting of the lm317. so if you use about 28V you don not need to change here something.
actually i am on holiday so maybe somebody can jump in...
so for sound improvement i would start to change the fake opamp to 465
chris
I noticed the heating of the coils when listening music at a volume level set on 11 o'clock. My speakers is 4ohm but the average impedance is about 8 ohm in laboratory tests. heating coils goes immediately, no need to wait a long time listening to music.
Link to the review of acoustic speakers that I use where there is research data. Only in Russian, but at the end of the article there is passport data and actually measured. Возвращение хайфая. Акустические системы Vector HX300 | Аудио Hi-Fi.ru
I would be interested to know what parameters the output LC filter should have for my speakers? I have 7 10 15 uH coils and any film capacitors. I tried to power my 502s pro from a native 24v power supply and from a linear 32v laboratory power supply. I did not notice the difference in sound for some reason. maybe even with a native power supply for 24v it seemed to me that it played better, but I thinks that it should be the other way around, or I don’t know something. Of the modifications I made, it was the installation of 1uF film capacitors between the contacts of large 35v 1800uF capacitors and modified the cooling system. I ordered the operational amplifiers lm4562, waiting for them to come.
Link to the review of acoustic speakers that I use where there is research data. Only in Russian, but at the end of the article there is passport data and actually measured. Возвращение хайфая. Акустические системы Vector HX300 | Аудио Hi-Fi.ru
I would be interested to know what parameters the output LC filter should have for my speakers? I have 7 10 15 uH coils and any film capacitors. I tried to power my 502s pro from a native 24v power supply and from a linear 32v laboratory power supply. I did not notice the difference in sound for some reason. maybe even with a native power supply for 24v it seemed to me that it played better, but I thinks that it should be the other way around, or I don’t know something. Of the modifications I made, it was the installation of 1uF film capacitors between the contacts of large 35v 1800uF capacitors and modified the cooling system. I ordered the operational amplifiers lm4562, waiting for them to come.
hi
the TPA3250 datasheet say for 4R = 7µH and 0,68µF. the caps should have a minimum of 4x your power supply voltage- better 10X.... but watch out the size
excel sheet:
the red marked one are not good as doctor did some THD measurements.
hopefully it helps
chris
I wanted to ask, why are there 470 uF capacitors installed on each output line on the EVM board and in 502s pro Not installed? How do they affect sound? and I want to install them, but I can't understand what I have to use on the spot j22 j23 j24 j25 “Hi current shunt”. I can not find the information what it is. It looks like it's just a large jumper. and how should i place it on the board and why? thank you.
I replaced two coils on a coil with a core from another Chinese amplifier, which I rewound myself from 15uH to 7uH. As seen in the photo, they are generally cold. compared to those in the 502s pro. Then:1. or my coils do not work how need , the cold ones do not work at all as an inductance, or 2. something is wrong with these Chinese coils on the air core ...
and I also wanted to know why when 502s pro is turned on for me in the middle of the volume, the Music plays quite loudly, and the power consumption on the laboratory power supply shows 0.125 A (at a voltage of 32 Volts)? on 24v - 0.178-200 A ..
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If you want to use the amp as 4-channel amp, you connect the loudspeaker between the 470uF and ground. If you use it in bridged configuration, you need no 470uF cap to block the DC voltage, because it is at both outputs, summing up to zero volt.
3. way to use it is PBTL, which basicaly doubles the output transistors, for lower loads like 2 ohm. So you can have a Mono, Stereo or 4-channel amp out of the same chip with hardly identical externel parts (except the 470uF DC blocker).
Inductors have a frequency response, if they don´t match the application you might run into HF problems.
3. way to use it is PBTL, which basicaly doubles the output transistors, for lower loads like 2 ohm. So you can have a Mono, Stereo or 4-channel amp out of the same chip with hardly identical externel parts (except the 470uF DC blocker).
Inductors have a frequency response, if they don´t match the application you might run into HF problems.
Hello everyone). I Needs your help again...
1. when I measure the DC voltage between the + and - channels with a multimeter, on one of them there is a DC voltage of 25 mV, on the other 0 V. Why is that?
2. When the 502s pro is turned on, but the Music is not turned on, I connect the oscilloscope to the outputs and I see there 2.5 V 600Hz AC voltage. I understand that this is a carrier signal from TPA3250, but I do not know this signal should be at the output?
3. quietly, but still noise from twitters, even when the volume is turned down to zero. both twitter. how to deal with it?
4. When I touch the body of the amplifier with a hand, the hissing sound on Twitter changes, reacts to my touches.
Thanks in advance to everyone who can help me.
как выложить фото в интернет
1. when I measure the DC voltage between the + and - channels with a multimeter, on one of them there is a DC voltage of 25 mV, on the other 0 V. Why is that?
2. When the 502s pro is turned on, but the Music is not turned on, I connect the oscilloscope to the outputs and I see there 2.5 V 600Hz AC voltage. I understand that this is a carrier signal from TPA3250, but I do not know this signal should be at the output?
3. quietly, but still noise from twitters, even when the volume is turned down to zero. both twitter. how to deal with it?
4. When I touch the body of the amplifier with a hand, the hissing sound on Twitter changes, reacts to my touches.
Thanks in advance to everyone who can help me.
как выложить фото в интернет
Hey, just got another used fx502 from fleabay and am encountering an odd problem. When I turn on the amp it starts producing popping sounds from the speakers but no music. It is low frequency 1-2hz and I can see the drivers reaching quite high excursion. I’ve only dared to power on briefly and no idea where to start with troubleshooting. Any ideas welcome!
Well, it could be the voltage supervisor on the 3250 board which trips due to undervoltage or it may be the supply that is in hickup mode due to a short on the amp board. If there's a heatsink attached, their might be a problem.
Either way, you should measure supply +/- on the board without the supply attached. Also the outputs of the amp. Each +/- out to GND and supply ++ to see if anything shortens out.
Either way, you should measure supply +/- on the board without the supply attached. Also the outputs of the amp. Each +/- out to GND and supply ++ to see if anything shortens out.