Update on the FX502SPRO, the vendor didn't know about this ERROR issue and is willing to exchange my unit, but I would have to ship it to China, they even said they would reimburse shipping. I am still hesitant, as I think this is the state for this amp and I would probably get the same thing. Does that logic seem sound?
I am thinking about just keeping it, it was only $60, it is better than my TPA3116 amps, and it plays way louder than I need without error. Any reason not to?
For those of you who have this amp, please also contact the manufacturer to report this issue. I did via this page FX-Audio FX502SPro TPA3250 2 * 80W intergraded amplifier If many of us report the issue, perhaps we'll get more information or maybe they will update the amp.
I am thinking about just keeping it, it was only $60, it is better than my TPA3116 amps, and it plays way louder than I need without error. Any reason not to?
For those of you who have this amp, please also contact the manufacturer to report this issue. I did via this page FX-Audio FX502SPro TPA3250 2 * 80W intergraded amplifier If many of us report the issue, perhaps we'll get more information or maybe they will update the amp.
if you are using factory-provided PS, that is 24v @4A.
I am guessing at 24v, the highest reachable RMS is lower than say 32v, and for the same output RMS, 24v uses more current. So maybe you acrossed 4A.
However if you use 32v, it may not need 4A to the same SPL.
That is the reason, I asked not to bundled the factory-provided PS.
24 volt dc power supply powering the amp BTL equates to a maximum of 16 volts RMS. 16 volts into 8 ohm load equals 2.125 amps (32 watts).
An "8 ohm" speaker's impedance can drop to 4 ohms at lower frequencies.
16 volts into 4 ohm load equals 4.25 amps (64 watts).
That's just 1 speaker.
What speakers are you driving?
Mike
I tried this amp with KEF Q100 bookshelfs and Klipsch RF3-II towers.
On this forum and AudioKarma I have heard about a few others with this amp and I think all have been gotten the ERROR condition with the stock power supply. What I want to know is if I have a faulty unit or if they are all like this. Initial signs seem to point toward they are all like this.
As mboxler wrote, at 16V RMS max out 32Wx2 (8 ohms) or worst 64Wx2 (4 ohms) per pair. Since only 1/2 volume knob dint max-out, so worst-case consumes below those, maybe 50Wx2 (4 ohms)?
Stock DC power supply 24V 4A - comes up to about 96W.
Worst case situation if both drips into 4 ohms, 86dB sensitivity of Kef Q100 may cause you to put more volume, causing power supply protection kicks in more often then 98dB sensitivity of Klipsch RF3-II. ~~ if so, may point to borderline case. If both are just as frequent, maybe stock power supply below 96W specs, or these SMPS could not support peak transient current of Class D amp.
Stock DC power supply 24V 4A - comes up to about 96W.
Worst case situation if both drips into 4 ohms, 86dB sensitivity of Kef Q100 may cause you to put more volume, causing power supply protection kicks in more often then 98dB sensitivity of Klipsch RF3-II. ~~ if so, may point to borderline case. If both are just as frequent, maybe stock power supply below 96W specs, or these SMPS could not support peak transient current of Class D amp.
Thank you all for helping me understand, I really appreciate it!
The sound of this FX Audio TPA3250 amp is much better than my Breeze and Nobsound TPA3116 amps. I just want to know if this power issue is true for this model amp. At this point I am thinking so. It isn't a problem for me, as it has plenty of power and the sound is great, I just want to make sure I didn't get a faulty one.
The sound of this FX Audio TPA3250 amp is much better than my Breeze and Nobsound TPA3116 amps. I just want to know if this power issue is true for this model amp. At this point I am thinking so. It isn't a problem for me, as it has plenty of power and the sound is great, I just want to make sure I didn't get a faulty one.
Searched ~ do u mean this thread?
Quick Ques: if 200mV surely to high, what wld your suggestion be realistic ripple to target? 1uV?
^ You saw the PSRR (well, more like the ensemble) measurements QAMatt put on the TPA3255 thread, right? His system with the cheapo SMPS was working quite well in comparison to the well-filtered lab supply. TI TPA3255EVM
TPA3250 is liable to have a similar front-end architecture and thus not going to be dramatically different in performance.
Also it's pretty eye-rolling to suggest a 5 order of magnitude improvement in ripple when you can't even really show the need in the first place.
TPA3250 is liable to have a similar front-end architecture and thus not going to be dramatically different in performance.
Also it's pretty eye-rolling to suggest a 5 order of magnitude improvement in ripple when you can't even really show the need in the first place.
I think it's just fine, you get power with very low distortion all the way 'till power surveillance applies the brakes. If you feed the amp with a more powerful psu, you will only reach the onset of distortion quickly afterwards anyway. It is adequate for most intended uses, it is a low power design to begin with, and it plays the part it is intended for: wiping the floor with TPA3116.
I'll just repeat myself once more, need more power: get something else.
I'll just repeat myself once more, need more power: get something else.
I just wanted to say thanks to all who have contributed to this thread. I'm a big fan of some well made TA2024's (Arjen Helder) boards and have used them for several setups, including tri-amped on some high end speakers. But I needed something more powerful, yet low cost for a pair of in-the-wall JBL speakers to go in an open plan kitchen/dining/living area.
I tried some TK2050 amps several years ago but wasn't impressed with the SQ.
Hopefully the 3250 will be what I'm looking for. I've ordered one having read this thread and am looking forward to comparing it to the TA2024.
I tried some TK2050 amps several years ago but wasn't impressed with the SQ.
Hopefully the 3250 will be what I'm looking for. I've ordered one having read this thread and am looking forward to comparing it to the TA2024.
As China-made FX Audio FX502S pro (TPA3250 amp) comes with soft-power-on-off features (pcb survey shows using ST S003F3P6 8bit MCU).
It would be rather useful if somehow DIY mod it to power-on-off through detecting audio-input level on RCA line, eg:
power-on = when RCA above level of signal.
power-off = when RCA below level of signal for a duration (say 5mins)
Having auto-power-on-off, and together manually preset TPA3250 amp's volume/gain potential-meter, will remove physical need to access amp each time listening to music (even hide amp/power supply away from sight).
Just controlling source level to TPA3250 amp's RCA will be sufficient.
Anyone thought/or had some experience how to do this?
It would be rather useful if somehow DIY mod it to power-on-off through detecting audio-input level on RCA line, eg:
power-on = when RCA above level of signal.
power-off = when RCA below level of signal for a duration (say 5mins)
Having auto-power-on-off, and together manually preset TPA3250 amp's volume/gain potential-meter, will remove physical need to access amp each time listening to music (even hide amp/power supply away from sight).
Just controlling source level to TPA3250 amp's RCA will be sufficient.
Anyone thought/or had some experience how to do this?
Last edited:
I started out with TA2020-based amps a few years ago and thought they weren't bad, but then I found the TPA3116, which are worlds better. I find this TPA3250 to be significantly better than my TPA3116-based amps and recommend it.
I'm looking forward to hearing from more people about their reviews and comparisons.
I'm looking forward to hearing from more people about their reviews and comparisons.
Hi DOC
sorry my nooby question...i try my best to understand
but why 6*6 and not 6 +6???
per rail (per channel) is 6A drawn by Rload over 250mR = U= I*R = 6*0,25= 1,5Volts per rail (cchannel) drop....so for both 3Volts?
I will try to implement auto-power-on-off on TPA3250, using audio signal level sensor from New Radio Japan - NJU7181.
1 issue need some advice:
In the schematic uses a 10uf & 10pf cap to tap the RCA audio signal line say 2Vrms line, i; am not sure which type of cap, considering if causing any impact to original SQ (eg. distortion, etc). Anyone can help advice？
Attachments
Last edited:
Had the FX502SPRO in from china a few days ago, took about 3 weeks to NYC. Thanks for all the great info here, I am very very happy with it. It's a great improvement over my Wiener TPA3118 board which itself was easily the best TPA3116 board around.
I replaced the NE5532 with LME49720 and it gave a significant improvement, cleaned up the sound for sure. Not bad for 11$. I am also using my variable linear power supply at 24V/5.2A, it is sounding very good, quite a bit more bass and fuller, more balanced mids now vs the Wiener TPA3118. I had cut up the included power cable because it uses a nonstandard barrel plug however and have that to the banana terminals on the PS. Using with Ascend CBM170se speaks.
Is there any problem with running this amp at lower voltages? I'm concerned the VR circuitry might try to step it up to 24V and cause more heat, problems etc. Speaking of heat it does warm up a bit when loaded, maybe slightly warm to the touch. I wedged some stuff under the top cover of the case so it stays lifted off by 1/4 inch or so for ventilation. No issues with error light so far, for me 9 oclock is about normal listening level, 12 oclock is extremely loud (but still pretty clean). But I have sensitive speakers.
I replaced the NE5532 with LME49720 and it gave a significant improvement, cleaned up the sound for sure. Not bad for 11$. I am also using my variable linear power supply at 24V/5.2A, it is sounding very good, quite a bit more bass and fuller, more balanced mids now vs the Wiener TPA3118. I had cut up the included power cable because it uses a nonstandard barrel plug however and have that to the banana terminals on the PS. Using with Ascend CBM170se speaks.
Is there any problem with running this amp at lower voltages? I'm concerned the VR circuitry might try to step it up to 24V and cause more heat, problems etc. Speaking of heat it does warm up a bit when loaded, maybe slightly warm to the touch. I wedged some stuff under the top cover of the case so it stays lifted off by 1/4 inch or so for ventilation. No issues with error light so far, for me 9 oclock is about normal listening level, 12 oclock is extremely loud (but still pretty clean). But I have sensitive speakers.
Thanks for sharing your experience, jigglebones.
Where did you get a replacement preamp chip? If you replaced the preamp chip you got the case open. How did you do that? I couldn't see how to get the connectors in the back off without drilling them out. They look like rivets. I wanted to check temperatures and make sure the heatsinks were attached well, but didn't get the case apart.
Where did you get a replacement preamp chip? If you replaced the preamp chip you got the case open. How did you do that? I couldn't see how to get the connectors in the back off without drilling them out. They look like rivets. I wanted to check temperatures and make sure the heatsinks were attached well, but didn't get the case apart.
Probably give-up the Auto-Power-on-off mod.
Found that FX502Spro uses contact-push-release Power-on/off button (not toggle switch), it seems internal MCU manages 3 diff voltage reg. on board:
MCU power-on mode drives LM317M to provide 24V, rest of voltage reg. are always powered (LM2596HVS 12V, AMS1117 3.3V) not control by button; this means Mcu, many other components are always powered, only TPA3250's stage section & pre-amp NE5532 are power-down by button.
Without FX502Spro schematics, I faced diffcultly how to integrate NJU7181 output to control TPA3250/MCU power-on-off.
Last edited: