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Review and Measurements of Topping TP60 and FX Audio FX502SPro Amps

villason

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To be honest, with a little bit of perspective the FX502S PRO is great for its price. I am getting one.
 

sajunky

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To be honest, with a little bit of perspective the FX502S PRO is great for its price. I am getting one.
For a price a good choice. Just don't get it with power supply. It seem to be underpowered, mine turned into a half brick after 5 hours. I didn't push it hard for long, only during the first few minutes of testing in which I noticed, it was overloaded at times. After that it was driven @steady load @10-15 Watts peak. When died, I replaced it with the old Meanwell S100-24, it never do activate protection, my bookshelf speakers do complain before it happen. You should get 150W version to have a margin.

There is a lot of clean power from this amp. There is no jaw dropping on the beginning, but it sounds really good, natural, bass is very tight and fast. Female vocals, guitars, drums sound perfect. Everything I do throw in sounds good. However I generally do agree with comments @vert. It is not about sibilants though, I have it well controlled on Polk Audio Rt3, but a long listening experience. When listening to the complex material like choir, I am sensitive to the specific distortions in the 5-7kHz range, it cause a fatigue. To be clear, young people I asked for the opinion don't see a problem.

There is a design fault which makes the amp sound the best at the volume set to 9 to 11 a' clock. It is something like the impedance matching problem with TPA. Turning the volume up beyond 2'a clock can trigger protection as Amir has indicated. It is not what would turn me off from purchasing this amp, many other attributes speak for.

The amp seem to be sensitive to speakers. It works well on polks, but Wharfedale EVO2-8 dominate with high frequency. The other amp (read below) control speakers much more even.

So, now there is other thing as promised. For a price below $120 from Aliexpress you can have a complete stereo amp with built-in PSU that is performing a class higher than FX audio. It it is now placed on my desk, disregarding any safety standards, no enclosure, just a PC-board, driven by the Topping D30 directly (there is no pot, as the amp input impedance strongly changes vs. frequency). Any pot would reduce high frequencies.

I planned to purchase two IcePower 50AX2 BTL, but the seller didn't know which version they sell and SE stereo version is not convertible to BTL, so I settled on the 125AX2 that can work either in SE or BTL mode. I do encourage Amir to test these amp modules. I am very happy from the IcePower. Still I hear distortion in 5-7kHz like in other D-Class, but to the much lesser degree. However it is a topic for another thread.
D30-125ASX2.jpg
FX502SPRO is behind.
 
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villason

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For a price a good choice. Just don't get it with power supply. It seem to be underpowered, mine turned into a half brick after 5 hours. I didn't push it hard for long, only during the first few minutes of testing in which I noticed, it was overloaded at times. After that it was driven @steady load @10-15 Watts peak. When died, I replaced it with the old Meanwell S100-24, it never do activate protection, my bookshelf speakers do complain before it happen. You should get 150W version to have a margin.

There is a lot of clean power from this amp. There is no jaw dropping on the beginning, but it sounds really good, natural, bass is very tight and fast. Female vocals, guitars, drums sound perfect. Everything I do throw in sounds good. However I generally do agree with comments @vert. It is not about sibilants though, I have it well controlled on Polk Audio Rt3, but a long listening experience. When listening to the complex material like choir, I am sensitive to the specific distortions in the 5-7kHz range, it cause a fatigue. To be clear, young people I asked for the opinion don't see a problem.

There is a design fault which makes the amp sound the best at the volume set to 9 to 11 a' clock. It is something like the impedance matching problem with TPA. Turning the volume up beyond 2'a clock can trigger protection as Amir has indicated. It is not what would turn me off from purchasing this amp, many other attributes speak for.

The amp seem to be sensitive to speakers. It works well on polks, but Wharfedale EVO2-8 dominate with high frequency. The other amp (read below) control speakers much more even.

So, now there is other thing as promised. For a price below $120 from Aliexpress you can have a complete stereo amp with built-in PSU that is performing a class higher than FX audio. It it is now placed on my desk, disregarding any safety standards, no enclosure, just a PC-board, driven by the Topping D30 directly (there is no pot, as the amp input impedance strongly changes vs. frequency). Any pot would reduce high frequencies.

I planned to purchase two IcePower 50AX2 BTL, but the seller didn't know which version they sell and SE stereo version is not convertible to BTL, so I settled on the 125AX2 that can work either in SE or BTL mode. I do encourage Amir to test these amp modules. I am very happy from the IcePower. Still I hear distortion in 5-7kHz like in other D-Class, but to the much lesser degree. However it is a topic for another thread.
View attachment 29504
FX502SPRO is behind.

You have now my attention. How do you control the volume then?

By the way, Amir already reviewed the Yamaha WAX50 (or something) with the 125ASX2.
 

sajunky

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You have now my attention. How do you control the volume then?

By the way, Amir already reviewed the Yamaha WAX50 (or something) with the 125ASX2.
Thanks, I saw it. It would be interesting to see measurements of the amp module alone. There is also Amir's review of PS Audio Sprout 100 which use in my opinion the same module and results are different.

As for the volume adjustment, I do it on the Foobar2000. It has a direct access to the volume control of the DAC chip. Windoze just makes bit-perfect connection using WASPI Exclusive mode or ASIO XMOS driver. The only problem is when playing DSD, as there is no volume control on the D30 for DSD stream. A workaround is to convert DSD to PCM in the Foobar's SACD module.
 
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Deleted member 9685

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If I buy FX502S Pro with MEAN WELL GST90A24-P1M 24V 3.75A instead of the bundled power supply and never turn the volume dial beyond 11, would I get good sound?
 
D

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According to comments in this thread, a better power supply reportedly makes it pump out more power before clipping happens.
I just want an amp that can pump 10W comfortably into each of my Eltax Monitor 1 stereo speakers. 2 speakers * 10W = 20W
For vast majority of the time, each speaker would consume substantially less than 10W. More like 2~3W.
I don't have much money. Considering that it performs better than Topping MX3 and SMSL AD18, I am willing to settle with it and a good power supply and call it a day.
 
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Is FX502S Pro going to benefit from an external DAC like SMSL M100? It seems even an onboard soundcard(Realtek ALC887-VD) can have higher SINAD than 77dB.
 
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It seems FX502S Pro is being sold at 34.95 USD without power supply with shipping fee of 7.32 USD on aliexpress.com.
34.95+7.32 = 42.27 usd
If I add GST90A24-P1M(Mean Well's 24V 3.75A adaptor)(22.31 + 8.71 = 31.02 USD) on top of that, I pay 73.29 USD.

2019-09-20_Fri_12:21:47.png

I'd like to give FX502S Pro a benefit of doubt. The unit that amirm received could have been a defective unit with distortion issues.
But then, you get to question quality control.
 
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Allo Volt+ and Allo Volt+ D are TPA3118 amps that might be able to outperform FX502S Pro.
When Allo.com releases TPA3255 amps, I will buy one.
 
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sychan

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Allo Volt+ and Allo Volt+ D are TPA3118 amps that might be able to outperform FX502S Pro.
When Allo.com releases TPA3255 amps, I will buy one.

It seems that you really want to buy the FX502S Pro, but suffering from doubt due to the poor measurements Amir posted and keep hoping you can get some conditional validation of the FX502S.
Many people are perfectly happy with their FX502S amps - despite the objective metrics. So many people love to put tubes in their signal path, despite all the measurements showing that tubes just add relatively high amounts of distortion - yet it makes people happier with the sound they get. This just shows that Amir's instruments measure electrical signals, not human satisfaction. Human hearing is objectively unable to detect the levels of distortion that Amir's instrumentation are able to detect, so unless you are somehow a cyborg (or you play your music at ear bleeding levels) below a certain level, the distortion is an abstract problem. Apparently "high fidelity" is below 0.1% distortion, which -60dB. The FX audio unit easily surpasses that requirement.
I guess that since we are well fed, safe, comfortable and healthy, we have the luxury of worrying about abstract problems like how many dB of distortion below our hearing threshold we are getting for $35. Bear in mind that with the Allo Volt+D selling for $125, any Allo TPA325x amp is going to be a lot more expensive than $35.
I suggest you just buy the FX502S - honestly, at $42 delivered, its about the price of a pizza dinner. Whatever its objective faults, it will bring you much longer lasting pleasure than a pizza pie and a pitcher of beer.
 
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Many people are perfectly happy with their FX502S amps - despite the objective metrics. So many people love to put tubes in their signal path, despite all the measurements showing that tubes just add relatively high amounts of distortion

I'm not worried about its objective metrics when it is working well. He reported that it tended to randomly produce extreme amounts of distortion that he could hear with his ears. Maybe, he received a defective unit. Maybe, the model itself is faulty.

Plus, the fact that protection circuit kicks in beyond 2'o clock due to design error makes me question its quality.

I also question lifespan of condensers on FX502S Pro. Allo uses high quality components including high quality condensers on its amplifier boards.
It's possible that Allo Volt+ which costs 40 USD on amazon.com surpasses or matches FX502S Pro because Allo squeezed more performance out of TPA3118 through tuning than TI engineers did.

I also suspect that TPA3255 version of Allo Volt+ may not cost more than 70 USD which is still pretty cheap. No-name chinese TPA3255 amps are being sold at about 45~46 USD on aliexpress.com. I think that since TPA3255 can pump up to 150W to each channel at 8 ohm, it can drive my speakers comfortably. I read that an amp that can pump 1.5 times the maximum allowable power of a speaker sounds substantially better than an amp that can't.

That said, I am willing to buy FX502S Pro if the model itself doesn't have audible defects that amirm heard. He wrote he had to turn it on and off several times to make extreme distortions go away. I'm just worried about three things. 1. extreme distortions 2. protection circuit 3. lifespan of condenser

Apparently "high fidelity" is below 0.1% distortion, which -60dB. The FX audio unit easily surpasses that requirement.

I never really thought about how much SINAD is required to not hear noise or distortion. I didn't know -60dB was good enough for humans.
Is the equation X=20*log10(0.001)=-60dB?

Perhaps, I can be satisfied with TPA3116/TPA3118 amps that do not have any defects in design as long as they provide my speakers with enough power.
 
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sychan

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I'm not worried about its objective metrics when it is working well. He reported that it tended to randomly produce extreme amounts of distortion that he could hear with his ears. Maybe, he received a defective unit. Maybe, the model itself is faulty.

Plus, the fact that protection circuit kicks in beyond 2'o clock due to design error makes me question its quality.
I also question lifespan of condensers on FX502S Pro. Allo uses high quality components including high quality condensers on its amplifier boards.

I don't understand how people complain about QA when they are paying bottom dollar. That is part of why it costs less! When you spend so little money, you have to expect that you may have to invest your own time dealing with returns on possibly faulty unit. Holding onto both your time and your money is very, very hard. Also bear in mind that in terms of testing, Amir's sample size is 1, which is not a sound basis for extrapolation. You can check on DIYAudio or AudioKarma which seem to have enough of fans of the unit so that there is a larger sample size.

It's possible that Allo Volt+ which costs 40 USD on amazon.com surpasses or matches FX502S Pro because Allo squeezed more performance out of TPA3118 through tuning than TI engineers did.

The first part of this is misleading, because the $40 item on Amazon is not a turnkey, usable amp. Its a bare board, no enclosure, no power supply, screw in speaker terminals, not even a knob on the volume control. The price for the Volt+ as a turnkey amp is $70. Twice the cost of the fx502s pro.
The second is subjective because I haven't seen any 3rd party, objective testing of both units (maybe I missed it?). You are mixing anecdotal accounts and objective measurements. I'd love to see Amir review the Allo Volt+(D) (there's probably one gathering dust in his To Do pile). But he hasn't reviewed it, nor the TI EVM - so you can't compare them to the the fx502s review.

I also suspect that TPA3255 version of Allo Volt+ may not cost more than 70 USD which is still pretty cheap. No-name chinese TPA3255 amps are being sold at about 45~46 USD on aliexpress.com.

I don't see why you can believe this. The 3E Audio TPA325x boards are all at least $70 for a bare board, and they, like the expected Allo amp, are based on the TI reference design. If Allo puts all their tricks into the board and specs good parts, how are they going to sell it for that much cheaper than another Chinese manufacturer who is also building a clone of the TI reference design? Allo has a few guys getting French and Canadian salaries that 3E Audio doesn't seem to have. Plus, if you want something beyond a bare board, Allo charges an extra $30.


Perhaps, I can be satisfied with TPA3116/TPA3118 amps that do not have any defects in design as long as they provide my speakers with enough power.

You have a lot of doubts about the FX502s pro, but don't expect Amir to make them go away. He thinks its a piece of junk, but many people feel that for the price, its quite reasonable. If you want a TPA3118 design with good specs, buy the Allo Volt+. But you will be paying $70 + shipping + power supply, not $40. All in, expect about $100 for the Volt+ option. That is about 2x the cost of the fx502s pro, but you will have piece of mind - which is really what you seem to be after. But realize that Amir hasn't tested the Allo Volt+ series, so you're still operating on the recommendations on forums that are much more subjective, so Amir can't provide piece of mind on that option either.

https://chicagodist.com/products/volt-amp-1?variant=12336618995791
 
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The first part of this is misleading, because the $40 item on Amazon is not a turnkey, usable amp. Its a bare board, no enclosure, no power supply, screw in speaker terminals, not even a knob on the volume control

Allo Volt+ is still useable. I already use HiFiBerry Amp2 which is a bare board.
I already have a reliable 18V 3.33A power supply which can work with Allo Volt+ and HiFiBerry Amp2.
You can screw the speaker terminals. It has a volume dial. I'm going to leave the volume at a fixed position after some initial fiddling.
It is just not convenient. It doesn't have binding posts into which I can plug banana plugs. Banana plugs are convenient.

The 3E Audio TPA325x boards are all at least $70 for a bare board, and they, like the expected Allo amp, are based on the TI reference design. If Allo puts all their tricks into the board and specs good parts, how are they going to sell it for that much cheaper than another Chinese manufacturer who is also building a clone of the TI reference design?

If 3E audio sells a TPA3255 amp board at 70~75 USD, so can Allo potentially because Allo has economy of scale in its favor.
Engineer costs can be amortized through economy of scale. What 3E audio sells is more like a prototype that doesn't expect a lot of sales.

That is about 2x the cost of the fx502s pro

The price of FX502S Pro also doesn't include power supply.
 
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sychan

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Which power supply do you recommend for FX502S Pro?

You'll have more luck on AudioKarma for this kind of question. This guy seemed happy with his nobsound PSU on the fx502s:
https://audiokarma.org/forums/index...ss-d-tripath-amps.881496/page-3#post-13008229

The poster is using the German Amazon, but the same Nobsound psu is available on US Amazon. Some people also like units from "Alitove" - I have no experience with any of them, so cannot offer any guidance aside from suggesting you read through that thread.
 

Toku

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I purchased and tested two FX-502S Pros and two Topping TP60s.
FX-502S Pro is completely a design error as pointed out in this forum, and as soon as the volume is increased, the protection circuit operates, an error display appears, and the operation stops. In addition, when the power is interrupted, a large pop noise is generated and the speaker is adversely affected.

The sound quality is narrow and does not satisfy the performance of the TPA3250 chip. I am particularly dissatisfied with the low-end drive.
I tested several types of OP amps, but I couldn't change this product to something attractive. I use a 24V-10A power supply.

Topping TP60 is a product of the past and will not be attractive to purchase now.

If you are going to buy a TI TPA3250 TPA3251 TPA3255 series amplifier, I would recommend the following products.
Currently I have purchased these products with good results.
So FX-502S Pro and TP60 have already left from me.

https://en.aliexpress.com/item/3303...go_expid=af393baa-eac9-4192-b13f-09d8e1ce16-3 22df-4cfe-badc-f95a91d28f29 & ws_ab_test = searchweb0_0, searchweb201602_8, searchweb201603_53

https://en.aliexpress.com/item/3304...xpid=6cd4c297-95bc-4931-837e-97749btfdaf-0946 f622-43ec-987e-d01dcc0f222e & ws_ab_test = searchweb0_0, searchweb201602_8, searchweb201603_53

https://www.ebay.com/itm/TPA3255-1x...h=item4d7b2cf3b2:g:9dsAAOSwRtNbgR7p:rk:5:pf:0
 
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If you are going to buy a TI TPA3250 TPA3251 TPA3255 series amplifier, I would recommend the following products.

I'm attracted to ABGN Hot-Tpa3255 because it is more powerful and uses a more recent amp chipset. What kinds of power supply do you recommend for this? The seller recommends 30V 6A although I may want more power to create headroom for Eltax Monitor 1.
 
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Toku

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I'm attracted to ABGN Hot-Tpa3255 because it is more powerful and uses a more recent amp chipset. What kinds of power supply do you recommend for this? I want to drive Eltax Monitor 1. The seller recommends 30V 6A although I may want more power.
The higher the power supply voltage, the better the sound quality.

In the product description
Current: 4A or more
Working voltage: DC30V-48V (inside + outside-5.5 * 2.5MM) recommend to use DC30V 6A (Max DC48V 8A)
It has become.
But MAX48V is impossible.

Because a 1000uF / 50V capacitor is used for the power supply, the power supply should be used below 35V for safe operation.
The maximum input voltage of the TI LM317 chip used in the internal 12V Reg circuit is 40V, and we want to keep it below 35V for safe use.
So "recommend to use DC30V 6A" Is correct.
I'm using 32V / 5A or 30V / 10A.
 
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