Hi ekbrus!
I have installed Cadj like you. I have no problem with sound. Now amp input voltage is 24V (temporary from the standard power supply). I replaced the resistor R40, not noticing that the factory had already changed the value, though R41. Now I have a difference of almost 8V. It's not a problem, how do you think?
Hi All,
sorry to bring old thread back to life
This is my first post here.
Also new to class D
I am planning to buy FX-502s pro.
Had read through the whole thread.
Is it still worth to buy, or to move with 3251/3255?
Seems the package is good VFM with PSU. (even compared to tpa3116)
please note that am noob to DIY.
last time i did DIY was, to do custom made cassette player with with, Preamp, BC548 based bass-treble board and 1230/4440 based amplifer boards. (back in late 1990s till 2004).
after that moved to PC & standard 2.1 sound systems from creative for bedroom and Onkyo AV receiver for Living room.
Now buying this for listening FLAC & 320KBps Mp3s.
Changing op-amps is not a problem for me.
I still do diy pc assembly as hobby.
Advice please..
sorry to bring old thread back to life
This is my first post here.
Also new to class D
I am planning to buy FX-502s pro.
Had read through the whole thread.
Is it still worth to buy, or to move with 3251/3255?
Seems the package is good VFM with PSU. (even compared to tpa3116)
please note that am noob to DIY.
last time i did DIY was, to do custom made cassette player with with, Preamp, BC548 based bass-treble board and 1230/4440 based amplifer boards. (back in late 1990s till 2004).
after that moved to PC & standard 2.1 sound systems from creative for bedroom and Onkyo AV receiver for Living room.
Now buying this for listening FLAC & 320KBps Mp3s.
Changing op-amps is not a problem for me.
I still do diy pc assembly as hobby.
Advice please..
Cannot edit the above post, To add some points:
1. Based on the testing & results discussed, I plan to buy below Op-amps
-> LM4562NA (Chermann Favourite)
-> NE5532AP (Original from RS or Element14)
-> LME49720NA
2. Speakers: I secured a set of Pure Accoustics Junior 5.1 Speakers (used set), yet to collect, planning to use either the towers or satellite speakers to be connected to this amp.
3. Planning to use analog out for PC motherboard to input this amp.
As am going to new inventory pile on electronics (have a store room full of PC junk to put on garage sale), have to keep budget tight , to escape for family finance minister (my better half)
Kindly advice if any better options available around this price.
Any advice and guidance will be welcome.
1. Based on the testing & results discussed, I plan to buy below Op-amps
-> LM4562NA (Chermann Favourite)
-> NE5532AP (Original from RS or Element14)
-> LME49720NA
2. Speakers: I secured a set of Pure Accoustics Junior 5.1 Speakers (used set), yet to collect, planning to use either the towers or satellite speakers to be connected to this amp.
3. Planning to use analog out for PC motherboard to input this amp.
As am going to new inventory pile on electronics (have a store room full of PC junk to put on garage sale), have to keep budget tight , to escape for family finance minister (my better half)
Kindly advice if any better options available around this price.
Any advice and guidance will be welcome.
This could be another option
#Aliexpress US $79.99 | TPA3250 TPA3255 Bluetooth 5.0 with DSP Processing Integrated Power Supply All in One HiFi Amplifier
TPA3250 TPA3255 Bluetooth 5.0 with DSP Processing Integrated Power Supply All in One HiFi Amplifier|Amplifier| - AliExpress
#Aliexpress US $79.99 | TPA3250 TPA3255 Bluetooth 5.0 with DSP Processing Integrated Power Supply All in One HiFi Amplifier
TPA3250 TPA3255 Bluetooth 5.0 with DSP Processing Integrated Power Supply All in One HiFi Amplifier|Amplifier| - AliExpress
Thanks for the quick reply Kjeldsen, while searching for tpa3250/51, saw that too.
Pros:
1. Inbuilt power supply
2. Direct from 3E (not sure authentic store, started jan 4 2020 only)
3. Top quality components used.
Cons:
1. dont have option of swapping op amps, almost everything fixed (no toying/diy improvement options)
2. not a big fan of led in volume control
3. not interested in BT etc.
4. with shipping to SG, comes close to 95uS$. (almost 85% extra cost).
Actually as i am new to this and this thread is left untouched for 6 months, tot something else arrived as more VFM and SQ improvement over this. that's why checked.
Pros:
1. Inbuilt power supply
2. Direct from 3E (not sure authentic store, started jan 4 2020 only)
3. Top quality components used.
Cons:
1. dont have option of swapping op amps, almost everything fixed (no toying/diy improvement options)
2. not a big fan of led in volume control
3. not interested in BT etc.
4. with shipping to SG, comes close to 95uS$. (almost 85% extra cost).
Actually as i am new to this and this thread is left untouched for 6 months, tot something else arrived as more VFM and SQ improvement over this. that's why checked.
I just found this new TPA3221 amp.. It looks similar to TPA3250 but no UltraHD only HD.
Components looks to be better quality than most others.
Price is also really good.
TPA3221HIFI Verstarker Audio Board 100W * 2 Klasse D streo Digitale Endstufen uber TPA3116 T1444|Verstarker| - AliExpress
Only less than 36$.
What do you think about?
I think I will try.... I just ordred since a few weeks new TPA3116 amp with also looks good inside^^. Can we have to much digital amps?
Components looks to be better quality than most others.
Price is also really good.
TPA3221HIFI Verstarker Audio Board 100W * 2 Klasse D streo Digitale Endstufen uber TPA3116 T1444|Verstarker| - AliExpress
Only less than 36$.
What do you think about?
I think I will try.... I just ordred since a few weeks new TPA3116 amp with also looks good inside^^. Can we have to much digital amps?
Attachments
Bluetooth Audio Amplifier Board with 2 x 100W + 200W 2.1 Channels
@hansueli, for your consideration!
@hansueli, for your consideration!
First I like to thank all the people who put their effort and time, to share feedback and inputs in this thread regarding FX502S PRO.
Special thanks to Chermann (Chris),Irribeo, meq123,forestsgump,fauxfrench & Wiliks for being great to help with ideas of improvements with this amp.
Progress status of my FX502:
1. Amplifier: In shipping from China to Singapore
2. Purchased NE5532 from RS Components & received it on 13th June.
3. Planning to buy LM4562 & LME49720 for testing.
4. Currently have plan to only use PSU supplied along with amp.
Queries:
Pardon my noob questions, as I am mechanical engineer and have little knowledge in electronics as I mentioned. As am from factory automation field, fellow colleague who is part of electronics section(also my friend) prmoised to help in the soldering work.
1. I see the voltage regulation setup is recommended, if using supplied PSU or any 24V Psu (Still valid upgrade right?),I Saw @demonmsk's amp with R41 300ohm factory fitted (old sets with 240ohms), if i receive with 300 ohm, what will be the value to be added in R40?
2. Planning to change all caps to branded, and to greatest possible capacity to fit the size, like Bro Wiliks did, I read Chermann mentioned , it did improved SQ in 3255 board. Is it recommended?
3. I am to upgrade the 1800uF to bigger value, still needed to add capacitor in parallel for Voltage regulation?
4. Is the inductor coils need to be upgraded, saw that going above 51 C?
Special thanks to Chermann (Chris),Irribeo, meq123,forestsgump,fauxfrench & Wiliks for being great to help with ideas of improvements with this amp.
Progress status of my FX502:
1. Amplifier: In shipping from China to Singapore
2. Purchased NE5532 from RS Components & received it on 13th June.
3. Planning to buy LM4562 & LME49720 for testing.
4. Currently have plan to only use PSU supplied along with amp.
Queries:
Pardon my noob questions, as I am mechanical engineer and have little knowledge in electronics as I mentioned. As am from factory automation field, fellow colleague who is part of electronics section(also my friend) prmoised to help in the soldering work.
1. I see the voltage regulation setup is recommended, if using supplied PSU or any 24V Psu (Still valid upgrade right?),I Saw @demonmsk's amp with R41 300ohm factory fitted (old sets with 240ohms), if i receive with 300 ohm, what will be the value to be added in R40?
2. Planning to change all caps to branded, and to greatest possible capacity to fit the size, like Bro Wiliks did, I read Chermann mentioned , it did improved SQ in 3255 board. Is it recommended?
3. I am to upgrade the 1800uF to bigger value, still needed to add capacitor in parallel for Voltage regulation?
4. Is the inductor coils need to be upgraded, saw that going above 51 C?
Last edited:
Thanks for the advice & guidance Chris..
Yep.. am planning to to change opamp to original NE5532 first.
For time being it is going to be , psu supplied along with the amp only.
Later might go for 32V brick or SMPS/Linear PS.
As you mentioned, step by step.
As 4562(out of stock) & 49720 (MOQ: 5 Pcs) are not available with RS components.
So planning to buy from Element 14/mouser/digikey, along with some Caps also for upgrade to get Free shipping eligible.
That's why asked..
Yep.. am planning to to change opamp to original NE5532 first.
For time being it is going to be , psu supplied along with the amp only.
Later might go for 32V brick or SMPS/Linear PS.
As you mentioned, step by step.
As 4562(out of stock) & 49720 (MOQ: 5 Pcs) are not available with RS components.
So planning to buy from Element 14/mouser/digikey, along with some Caps also for upgrade to get Free shipping eligible.
That's why asked..
Last edited:
Received my FX502S Pro amp yesterday. Arrived in Just 7 days.
Got a different 24V-4A adapter bundled.
Connected with my retired old Denon satellite speakers from SYS5.1 package, for testing purposes.
The intended speakers (Pro Acoustics Junior F series towers)for this amp, i haven't yet collected from the selling guy.
Used my old mobile as song source. (Have regional songs in 320Kbps MP3, and MJ BAD Flac)
Through these speakers, can't define any clear SQ as of now, below are the observations made.
0. Using 24V-4A power brick as PS, Amp is still sealed, no mods done.
1. Amp power ON- Ok
2. Both Channels working-OK
3. NO hiss sound until full volume (without playing any songs).
4. For 1-2 minutes tried playing full volume, no error LED.
5. When I switch off the amp power button first all fine. But when i switch OFF the wall socket directly, have loud POP sound along with ERROR LED after 1-2 seconds from speakers.
After reading through the thread, i can't find any definitive solution for POP. even forestsgump used 32V power brick , to get POP.
Is the OFF-POP, normal, even with 24V-4A PS? anyway to eliminate?
Below are the images and short video for POP sound.
Got a different 24V-4A adapter bundled.
Connected with my retired old Denon satellite speakers from SYS5.1 package, for testing purposes.
The intended speakers (Pro Acoustics Junior F series towers)for this amp, i haven't yet collected from the selling guy.
Used my old mobile as song source. (Have regional songs in 320Kbps MP3, and MJ BAD Flac)
Through these speakers, can't define any clear SQ as of now, below are the observations made.
0. Using 24V-4A power brick as PS, Amp is still sealed, no mods done.
1. Amp power ON- Ok
2. Both Channels working-OK
3. NO hiss sound until full volume (without playing any songs).
4. For 1-2 minutes tried playing full volume, no error LED.
5. When I switch off the amp power button first all fine. But when i switch OFF the wall socket directly, have loud POP sound along with ERROR LED after 1-2 seconds from speakers.
After reading through the thread, i can't find any definitive solution for POP. even forestsgump used 32V power brick , to get POP.
Is the OFF-POP, normal, even with 24V-4A PS? anyway to eliminate?
Below are the images and short video for POP sound.
Last edited:
Hi Saran
Please measure with DMM the real voltage at the output of the regulator LM317 because some Chinese resistors are labeled wrong. so your calculation is correct but the values are not real. remember the regulator works correctly if the input voltage is about 3V more then the calculated output voltage. otherwise the regulator is not working.
caps. the big 1800µF cap fine i used it and compared with other one. mine are original and good. a small cap (100nF-220nF foil )under the pcb in parallel to the big one is for additionally decoupling- other caps like a 10µF electrolytic are too big or can touch the housing- don do that!
pop off
you wrote:
When I switch off the amp power button first all fine. But when i switch OFF the wall socket directly, have loud POP sound along with ERROR LED after 1-2 seconds from speakers.
please always switch the amp off - then switch the power plug off or pull out the wall socket connector. Why? if you switch off the wall socket first the stored energy in the caps are holding as long as possible the energy high until the power chips get loss of energy -----> this "generates" this pop off at the speakers output because the power chip is not hold in mute state.
I remember forestsgump has this topic ...finally my idea was that this small micro controller inside the amp could be the reason.
chris
Please measure with DMM the real voltage at the output of the regulator LM317 because some Chinese resistors are labeled wrong. so your calculation is correct but the values are not real
. remember the regulator works correctly if the input voltage is about 3V more then the calculated output voltage. otherwise the regulator is not working.caps. the big 1800µF cap fine i used it and compared with other one. mine are original and good. a small cap (100nF-220nF foil )under the pcb in parallel to the big one is for additionally decoupling- other caps like a 10µF electrolytic are too big or can touch the housing- don do that!
pop off
you wrote:
When I switch off the amp power button first all fine. But when i switch OFF the wall socket directly, have loud POP sound along with ERROR LED after 1-2 seconds from speakers.
please always switch the amp off - then switch the power plug off or pull out the wall socket connector. Why? if you switch off the wall socket first the stored energy in the caps are holding as long as possible the energy high until the power chips get loss of energy -----> this "generates" this pop off at the speakers output because the power chip is not hold in mute state.
I remember forestsgump has this topic ...finally my idea was that this small micro controller inside the amp could be the reason.
chris
Chris,
Thanks for the quick reply. Noted regarding Chinese resistors. Will measure later and confirm.
My amp has United Chemi-con LXZ 1800µF (not rubycon), caps near the OPAMPS are ELNA blue (Fake!?) others are United Chemi-con KY series and one Samyoung .
the 4 Pin Microcontroller is not soldered properly.
Later I will post some photos of amps internal.
Thanks for the quick reply. Noted regarding Chinese resistors. Will measure later and confirm.
My amp has United Chemi-con LXZ 1800µF (not rubycon), caps near the OPAMPS are ELNA blue (Fake!?) others are United Chemi-con KY series and one Samyoung .
the 4 Pin Microcontroller is not soldered properly.
Later I will post some photos of amps internal.
big caps are ok, blue elna as input caps could be fake -keep them in the first step.foild caps are to big here...so 10µF Elna/silmic are fine
at the regulator:
please use not more values as the datasheet suggested- there is not really a need to set the output cap of the regulator high!- if its too high it could be that you have worse voltage as needed. you will find a lot of guys with doing some test....so keep them as the datasheet suggested. i learned this after my CM6631A/9023 DAC modding.
if you want to change something then:
opamps- the delivered opamps are fake
use a psu with about 28V- then you are on the safe side of the regulators input (Vout +3V = Vin)
look at the output filter = coils and Foil caps
take time for listening after the steps adn compare with a other amp
chris