Thanks for the in depth reply. I went through most of the pages here but probably missed yours about the power measurements.
How is it regarding the cooling of the chip? was it not stable to 4R load due to weak power supply or because of chip temperature instability no able to dissipate heat effectively to the heatsink? have you tried to load only one channel, just for the curiosity how the TPA holds?
I very liked the cooling mod that made meq123. I was thinking about something very similar but attached with screws, not glued on pcb. Just a piece of 5,5mm aluminium with milled sides for the original screws to hold it in place which holds top heatsink as well, than this one attached to the main case with one crew similar as meq123 did.
Apart that I have found this adapter:
32V 5A High Power Switching Power Supply Adapter 200W for TDA7498 FX1002A FX1602 | eBay
that could be huge improvement, at least I hope so. Will change all the caps for 50V rating ofc and more tuning when i get the amp in hands
btw what is the package of the LM317 regulator is it TO252 or which one? thinking of replacing it for some better LDO but dont know the package yet.
How is it regarding the cooling of the chip? was it not stable to 4R load due to weak power supply or because of chip temperature instability no able to dissipate heat effectively to the heatsink? have you tried to load only one channel, just for the curiosity how the TPA holds?
I very liked the cooling mod that made meq123. I was thinking about something very similar but attached with screws, not glued on pcb. Just a piece of 5,5mm aluminium with milled sides for the original screws to hold it in place which holds top heatsink as well, than this one attached to the main case with one crew similar as meq123 did.
Apart that I have found this adapter:
32V 5A High Power Switching Power Supply Adapter 200W for TDA7498 FX1002A FX1602 | eBay
that could be huge improvement, at least I hope so. Will change all the caps for 50V rating ofc and more tuning when i get the amp in hands
btw what is the package of the LM317 regulator is it TO252 or which one? thinking of replacing it for some better LDO but dont know the package yet.
Look fwd to your working on LDO, consider that LM2596(150khz buck) is a "better" buck version, but 150khz freq is still too low, generates noise.
that LM317 seems to be TO252, changing it to low noise LDO seems to be a simple yet effective solution to address whatever comes out of the 150khz buck.
Last edited:
Hi wiliks
yes meq123 did i very nice cooling. i did it before with a ceramic resistor.
the cooling of the chip is - according to the datasheet under the chip! so the chip should have a big mass of pcb layer to cool best. this is not really happened in the fx implementation. but for listening session now in my oben baffle (8R sub and more then 12ohms tweeter) with rally loud volume is not a problem.
@power
i did a lot of time measurements with my differential scope probe during listening at 4R and 8R speakers. i got 2W - 10Watt - i have a 26m2 (225cm high) living room in my cellar and its loud enough!
@psu
21 euro for 150W and more s enough...the LRS150-24 can be set about 28V and you get around 192 W
LDO
maybe some expert can give us an advice.
chris
yes meq123 did i very nice cooling. i did it before with a ceramic resistor.
the cooling of the chip is - according to the datasheet under the chip! so the chip should have a big mass of pcb layer to cool best. this is not really happened in the fx implementation. but for listening session now in my oben baffle (8R sub and more then 12ohms tweeter) with rally loud volume is not a problem.
@power
i did a lot of time measurements with my differential scope probe during listening at 4R and 8R speakers. i got 2W - 10Watt - i have a 26m2 (225cm high) living room in my cellar and its loud enough!
@psu
21 euro for 150W and more s enough...the LRS150-24 can be set about 28V and you get around 192 W
LDO
maybe some expert can give us an advice.
chris
Last edited:
the buck regulator lm5008- lm5010.... like on the EVM boards and like voltwide and doctor use it in there development?
at the YJ TPA3255 board i had to change the buck regulator 2575T-12 but its is not possible with my 40W soldering iron to fix the thermal pad on the board..
i do not want to use my 100W solder hammer....
the buck regulator lm5008- lm5010.... like on the EVM boards and like voltwide and doctor use it in there development?
at the YJ TPA3255 board i had to change the buck regulator 2575T-12 but its is not possible with my 40W soldering iron to fix the thermal pad on the board..
i do not want to use my 100W solder hammer....
thks fr the suggest on buck, will chk them out. I was thinking of low noise LDO LT1963 to rep. LM317.
Chris btw, you done tons of work on Fx502spro ~ cld be most well-versed abt it among many of us. Did you spot any fake component used?
~ i wld hope replace any of these components, bef they cause trouble & kill the amp!
hi
i am a listener- that means i use the amps very often for sound and relax session afterworks or for compare sessions.
no the fx502spro is a well done amp - > buck for the money!! no damaged so far
month ago i just changed the value of the lm317 setup and the opamp nothing more and its works fine without doing strange things.
now
the original implemented opamps are fake. and the 4562 are relay good.
changed the input caps to elna silmic 2
i changed the output filter
chris
from post 738....
now i sitting and listening ....
i did the 4th compare between the amp1 and amp2. as always i pick 4-5 titles of tidal (note the volume) and choose some music types and compare several times.
what i did not expect is that the bigger coils are sounding better. its more darkness and more dynamic and the middle of the sound stage is more details . the smaller coils seams more smoother and the interprets and instruments are near to the listener = not so deep sound stage.
especially at this title this amps sound great:
la sicilia - album I visionari - stefano bollani
Burundanga album duets - marialy pacheco
the look of love- album her´s the ben - Jacintha (did i wrote i like saxophones
)chris
chris
if i remember you did an estimation of all power consumption for the fx502spro?
because i do not think its needed to have a regulator with 1A. ....
yes it is pin 15. datasheet 10.2.1.2.4..do you want to change the working frequency? i remember the setup at the fx is about 450khz.
if you want to change look at table 12 and table 13.
Last edited:
luckly I planed to use this for my tpa3255 YJ boards...
its really tight !
SQ compare between both amps not done. same opamp (4562) same input caps (elna silmic 2) but now different coils
chris
Questions to the experts here...
should i solder the 3rd pad of the coils (würht 7443631000) together and connected to ground?
what happend? Better SQ?
thanks you in advance
chris
yes I was thinking about more ways of improvement and this one looks interesting. Its just about changing one resistor to get it working at 600kHz (oscilating at 3,6MHz according to datasheet) I am surprised that noone tried it yet, and i would be very curious if that brings further sound improvements or just more heat, dont know...
I am still waiting to get my amp, so once it will arrive i will definitely test that
I am still waiting to get my amp, so once it will arrive i will definitely test that
Sound check with different opamps
Good evening
After changing the the fat coils in both amps i did the SQ check for my DIL opamp i bought:
LM4562, LM49720, BB2134
at post 440 and 575 i did some compare tests.
https://www.diyaudio.com/forums/class-d/315681-tpa3250-listening-58.html#post5443600
the distance get closer but its the same as i have described. all opamps made the job better than the fake opamps which come with the fx502spro.
slightly difference:
4562 is my favorite , this amps is darker and give me all natural sound i like, deep stage and no real mistakes.
lm49720 is closed to the 4562 but is not so dynamic and dark.
BB2134 is not as bad as i described. he is very present in the middle of the speaker, analytic and is concentrating his force in the middle of the speakers...it feels like the sound comes through a big 3m magnifier glass, less sound from the back ground--> ideal for headphones
pic shows my listening examples
chris
Good evening
After changing the the fat coils in both amps i did the SQ check for my DIL opamp i bought:
LM4562, LM49720, BB2134
at post 440 and 575 i did some compare tests.
https://www.diyaudio.com/forums/class-d/315681-tpa3250-listening-58.html#post5443600
the distance get closer but its the same as i have described. all opamps made the job better than the fake opamps which come with the fx502spro.
slightly difference:
4562 is my favorite , this amps is darker and give me all natural sound i like, deep stage and no real mistakes.
lm49720 is closed to the 4562 but is not so dynamic and dark.
BB2134 is not as bad as i described. he is very present in the middle of the speaker, analytic and is concentrating his force in the middle of the speakers...it feels like the sound comes through a big 3m magnifier glass, less sound from the back ground--> ideal for headphones
pic shows my listening examples
chris
Attachments
Last edited:
to test my soic opamps to dil8 i bought this
10 PCS SOP8 SO8 SOIC8 SMD to DIP8 Adapter PCB Board Convertor Double Sides: Amazon.de: Beleuchtung
any idea where i get some correct pins to solder in that fits into the DIl-8 socket of the fx502spro???
thank you in advance
chris
10 PCS SOP8 SO8 SOIC8 SMD to DIP8 Adapter PCB Board Convertor Double Sides: Amazon.de: Beleuchtung
any idea where i get some correct pins to solder in that fits into the DIl-8 socket of the fx502spro???
thank you in advance
chris
I wonder when you came to the conclusion that the original opamps are/where fake? Am i getting old?
because of:
post 333
TPA3250 somebody is listening?
maybe thats the reason why the LM49720 and LM4562 are sounding different
http://www.waynekirkwood.com/images/pdf/US_Patent_7649417_Bias_Current_Cancellation_Audip_Amp.pdf
http://www.waynekirkwood.com/images/pdf/US_Patent_7649417_Bias_Current_Cancellation_Audi
p_Amp.pdfSo I just swapped out the (fake?) opamps from my FX502spro and put in LME49720NA.
The problem now is that I have a significant crackling sound in my right channel that I'm fairly certain wasn't there before
Is there any chance that I broke something when I opened the amp, maybe by pressing too hard on the board when inserting the opamps?
Or what else is it likely to be?
The problem now is that I have a significant crackling sound in my right channel that I'm fairly certain wasn't there before
Is there any chance that I broke something when I opened the amp, maybe by pressing too hard on the board when inserting the opamps?
Or what else is it likely to be?