Yes, that was the FX502 thingy.
Bottom line: Excellent value for money! Very good sound quality on low-mid-and a little bit loud levels. My wife also (completely unprovoked) commented on an apparent upgrade in sonic qualities, though she has a problem expressing the specific differences compared to some quite good TPA3116's, when prodded further she said "it's just better". I assume a big part of it is lower noise floor, but it seems to be just a little bit better in every way, bass is more defined, mids sound pretty good, treble is pretty good. Though I have heard better in a completely different price league. It compares favorably to some low priced but decent quality, new off the shelf class ab amps with good specs.
If you want/need more power go for the TPA3255 instead.
Bottom line: Excellent value for money! Very good sound quality on low-mid-and a little bit loud levels. My wife also (completely unprovoked) commented on an apparent upgrade in sonic qualities, though she has a problem expressing the specific differences compared to some quite good TPA3116's, when prodded further she said "it's just better". I assume a big part of it is lower noise floor, but it seems to be just a little bit better in every way, bass is more defined, mids sound pretty good, treble is pretty good. Though I have heard better in a completely different price league. It compares favorably to some low priced but decent quality, new off the shelf class ab amps with good specs.
If you want/need more power go for the TPA3255 instead.
Actually, am not needing more power, but only have use of 1 channel of TPA3250 (FX502S Pro)
- So if can config to PBTL - it would be ideal.
- OR keep to existing BTL, any danger/risk if leave the unused channel audio input shorted, audio output not connected?
Yes i can agree on this. i looked for a lot of commercial amps to get some nice deal...but i always stopped because of housing and thermal issues..... for me.
so a good amp board 30 - 60 Euro - housing 40 -100 euro...PSU 40-100$
this offer cost about 68 $...with delivery and tax about 100euro ..............for me
thats the reason why i am looking for old defect amps to get PSU and housing...not nice ...but...
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A 20 year old transformer performs as well as a new transformer. I often refurbish them a bit with a new layer of lacquer.
Sometimes I bother putting the amplifier construction in a cabinet, sometimes not. If I do, I construct something simple but suited in size from what I can buy in a Baumarkt. To the outside of the box, I only need a volume control, power ON/OFF and inputs/outputs (keep it simple).
The Asian constructions are really value for money (most of them). A problem seems sometimes to be that, while their skills in producing mechanics and PCBs at very competitive price is difficult to compete with, sometimes the circuit designs are less worked through. There are some very good engineers out there but much less than needed. So, the really good engineers can get a well paid job elsewhere in a split second and many manufacturers (of smaller size it seems) have to rely on what they find in datasheets and circuits disclosed on the Internet. Therefore, some engineering issues may have been less well considered.
Sometimes I bother putting the amplifier construction in a cabinet, sometimes not. If I do, I construct something simple but suited in size from what I can buy in a Baumarkt. To the outside of the box, I only need a volume control, power ON/OFF and inputs/outputs (keep it simple).
The Asian constructions are really value for money (most of them). A problem seems sometimes to be that, while their skills in producing mechanics and PCBs at very competitive price is difficult to compete with, sometimes the circuit designs are less worked through. There are some very good engineers out there but much less than needed. So, the really good engineers can get a well paid job elsewhere in a split second and many manufacturers (of smaller size it seems) have to rely on what they find in datasheets and circuits disclosed on the Internet. Therefore, some engineering issues may have been less well considered.
HI
i understand your point. I am in a small city
so i want to avoid producing waste with buying a housing and then you have to throug it away. but for my excuse i just starting now with diy.....so i see it now that my lab is getting full with devices...e.g. yes the offer is very good and for sure for this price. for small room listening its fine but i have to have something for my open baffle (1 TB8" and 2x 12" woofers each side
....my Q100 KEF are not so critical)so bigger PSU and greater and cooling cases.
Actually it seems that this specific implementation there has been some engineering and quite possibly inspiration from the DIY crowd going on. There is "smoothing stuff" happening, regulating the PSU input. The NE5532 seems well implemented as a pre-stage. Then you have the output filter coils that are actually quite decent.
It is cheap, but it is also well thought out and not poorly made. Seems like they made mostly sane compromises during the engineering phase.
A no-holds-barred DIY version of this would not be enormously much better, we are talking about a relatively low power design to begin with.
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forestsgump: are you using it for only 1 channel in mono? Why not use the other channel for a sub, you can do filters from the output of your PC or make a simple passive xo between the source and amp if you have no other option.
It is cheap, but it is also well thought out and not poorly made. Seems like they made mostly sane compromises during the engineering phase.
A no-holds-barred DIY version of this would not be enormously much better, we are talking about a relatively low power design to begin with.
Edit:
forestsgump: are you using it for only 1 channel in mono? Why not use the other channel for a sub, you can do filters from the output of your PC or make a simple passive xo between the source and amp if you have no other option.
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Thanks for the review @KaffiMann!
I too recently got the FX502SPRO. I agree, it seems to have better sound than the TPA3116 units I have (single-chip Breeze and dual-chip Nobsound). It has a much better noise floor than the un-modified Breeze/Nobsound (although I was able to improve them with the gain mod).
I too got the error twice. If I play music above 1/2 volume I have gotten that to kick in. The ERROR light flashes and you have to power cycle the amp, then it works right away again. Granted 1/2 volume is very loud, I am just driving 8-ohm speakers, so that surprised me. Some on the Audio Karma boards thought this might be a sign that the power supply brick can't keep up with the amp. I am not sure what is causing the error, but it would be sad if the factory-provided PS can't fully power it. That said, I don't need those very high volumes in practice.
Any other thoughts on the cause or things I could test? So far this amp is very promising.
I too recently got the FX502SPRO. I agree, it seems to have better sound than the TPA3116 units I have (single-chip Breeze and dual-chip Nobsound). It has a much better noise floor than the un-modified Breeze/Nobsound (although I was able to improve them with the gain mod).
I too got the error twice. If I play music above 1/2 volume I have gotten that to kick in. The ERROR light flashes and you have to power cycle the amp, then it works right away again. Granted 1/2 volume is very loud, I am just driving 8-ohm speakers, so that surprised me. Some on the Audio Karma boards thought this might be a sign that the power supply brick can't keep up with the amp. I am not sure what is causing the error, but it would be sad if the factory-provided PS can't fully power it. That said, I don't need those very high volumes in practice.
Any other thoughts on the cause or things I could test? So far this amp is very promising.
Well, sort-of:
Using as a typical stereo amplifier to wharfedale diamonds, and also ...
The other use-case “only 1 channel in mono” is for wireless multi-room network music streaming, which run the Wharfedale seperately as 2 x mono speakers systems.
(mimic Sonos
:- gotten 2 x of Chromecast Audio, 2 x FX502S-pro, 2 x Meanwell SMPS). No intention to get a sub, as I just need it musical.
If somehow, I can mod FX502SPRO to PBTL like TPA3250 EVM, it would be very ideal more powerful outcome, otherwise i would compromise on it being a BTL.
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FX502SPRO bundled SMPS @24v,96w (Amp PCB uses some 25v Alu-caps, but mainly 35v), while TPA3250 EVM implements at 32v (EVM PCB uses mainly 50v Alu-caps, i think run at 38v shld be fine)
I opted-out on the bundled, instead use Meanwell SMPS set @31v,150w.
Crossing my-fingers get supply voltage close but not blowing those 35v cap of FX502SPRO
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It happens immediately if the chip runs out of current, have not run the chip near limit for any length of time, it is quite loud, it is just before "party where people fondle the volume after excessive drinking" loud. It has not managed to produce any significant heat yet.
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forestsgump: What about bi-amping then?
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forestsgump: What about bi-amping then?
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Bi-amp: let's say same input is given to both FX502SPRO's Left & Right RCA, so that left channel of FX502SPRO output to the woofer, Right channel of FX502SPRO output to Tweeter.
Am i right?:
Both woofer & tweeter would receive the same music power output.
If certain acceptable volume at woofer, the same power maybe damaging to tweeter (or vice versa), since Bi-amp bypass the internal speaker crossover distribution circulatory. (unless separately manage power-level of left/right output)
So, KaffiMann, you think the ERROR is due to under-voltage/current at loud volumes? Is there anything we can do about that? Is that a concern?
Gallium Nitride!
Allow me to quote form an article:
"But what if there were a Class D transistor technology with switching so precise that it could generate a near perfect power representation of the small audio signal produced by the PWM Modulator, thus reducing (or fully eliminating) the need for these large amounts of feedback? What if the technology were so disruptive that the bandwidth of the output filter could be doubled for High-Definition Audio without fear of increased EMI/EMC problems? And, what if the switching technology of a Class D audio amplifier could boast an "On" resistance with switching losses that were so low that power dissipation became negligible, thereby enabling the world to enjoy the benefits of Class D, at or above the quality of Class A?"
"This transistor technology is called Gallium Nitride (GaN) and is poised to uproot the high-end audio world. In fact, GaN-based Class D is much more power-efficient than traditional, MOSFET-based Class D and offers orders of magnitude better performance. Performance that to many listeners, even surpasses the quality of Class A. At any given product price point, these new Class D solutions can meet, or surpass the quality of today's linear amplifier solutions. As an example, the eGaN FET-based Class D amplifiers can easily achieve a mid-band THD performance of 0.005%, where a comparable linear amplifier Class would achieve around 0.05%."
Reference: Why We'll Soon Be Living In A Class D World - Audiophile Review
forestsgump:
If you sum in mono before input I doubt you would notice any difference. It would be Output L feed into filter and driver 1, and Output R feed into filter and driver 2. Just a load for each output, signal difference related to f would be negligible.
chermann:
For this amp, in it's intended power band; no issue whatsoever with heat.
swank42:
Not a concern at all, the amp provides really good sound quality in the intended power band, it just happens to completely cut off on one channel if attempted to use at high power. Probably because of the SMPS, but most likely the "smoothing stuff" would give upo quickly after so I did not bother pursue the issue.
If you need "loud enough" (ca 9.5) then get the TPA3250, If your applications require "goes to 11" get the TPA3255. If you are arranging a block party for the closest 4-5-6 blocks, get creative (and start studyin')
If you sum in mono before input I doubt you would notice any difference. It would be Output L feed into filter and driver 1, and Output R feed into filter and driver 2. Just a load for each output, signal difference related to f would be negligible.
chermann:
For this amp, in it's intended power band; no issue whatsoever with heat.
swank42:
Not a concern at all, the amp provides really good sound quality in the intended power band, it just happens to completely cut off on one channel if attempted to use at high power. Probably because of the SMPS, but most likely the "smoothing stuff" would give upo quickly after so I did not bother pursue the issue.
If you need "loud enough" (ca 9.5) then get the TPA3250, If your applications require "goes to 11" get the TPA3255. If you are arranging a block party for the closest 4-5-6 blocks, get creative (and start studyin')
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I think you should look for a more stable PSU.
During my test with a class D board i found out that a strong PSU with 180Watts and 5-10mV ripple(Rigol DP832) is not good enough if you push this on its limit.
Seriously? At full power a 5-10mV ripple isn't nothing to think about if your voltage isn't sagging with audio amplitude. 10mV at switching frequency (psu) is damped by 60dB. If your voltage is sagging at the bulk caps, your wiring and or psu has to much impedance/resistance. (Binding posts, wiring, cables) This can clearly be seen with a scope.
sorry i am not the expert...i just starting now with diy and electronic (its sooooo long time ago
)i mentioned espacially for low frequencies
yes that is all right. I test my 7498e board (other treat) and i keep the level below my psu is on its max. e.g total output about 120W.
if i change the frequence from 4khz to 40Hz and then to 20Hz... i see that the psu is taggling around and lower the output voltage from 30V to 29.5 and the current (CP) is starting to get dancing around (both outputs 30V (CH1 + CH2) in parallel to get max 6A)
....... it looks like that my PSU is to weak ?
is that correct or normal...?
thx
Tag along: then at full power does 200mVpp ripple switching frequency (psu) is damped by 60dB? or how much damping is needed?
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