Out of curiosity bought some op-amps from aliexpress and the results were expected and unexpected. Current amp is the Douk U3 Mini(waiting for parts to build the sapphire4).
Only 2 functioning and 1 doa out of 25. The 3 that made it is Muses8920, LME49720, DEAD OPA1612 with adapter . The focus and the camera is not the best in my phone.
The stock Douk U3 came with a NE5532P, the audio was fine, but the massive pops at startup or when suddenly switching song was annoying so the curious me went to aliepxress and ordered the best in class op-amps.
NE5532P: Good sound, nothing to emphasize, maybe the top end was veiled a little bit and suffered when a lot of sound was playing at once.The DC at the output was 3V but it went down to 34mV after a 30 seconds. When turning it off, the offset jumped back to 3V to give me that nice pop. At startup the pop happened instantly then disappeared.
MUSES8920: Low end died a little bit and the top end felt more alive "aka" harsher and it became a guitar amp. The amp started to distort a lot when a loud sound happened, at first i thought it was my dac(cheapo usb c dongle) so thought nothing of it. After getting a cheapo es9018k2m dac the distortion remained so it wasn't the issue. The DC voltage at the output was 3.3V at startup and slowly went down to 50mV after 25min of idle. I could hear the "pop" slowly rise up the drivers then go away. 100% sure it was a fake MUSES chip.
LME49720NA: Low end returned with the high end becoming even harsher. I'm noticing more details in general and warmer tone, could be placebo or some "unwanted" harmonic distortion.
It doesn't distort at all and i need less volume knob turn to reach my listening volume compared to the NE and FAKE MUSES.
Oh boi the dc on this one. At startup its 18V then it dies down to 1mV in 20 seconds. I'm confident that this one is genuine. Not doing the pop sound test on this one.
OPA1612: Dead on arrival, nothing more to say about it.
In a 30min heat test. Case temp: NE 33°C, MUSES 31°C, LME 34°C, they all within 10%.
This "test" was done over 6 months.
Sidenote. HP is DT-990 250ohm. The amp is dead silent when nothing is playing and i don't have any issues others have reported with it. Its being powered by a phone charger 5V 2A.
Only 2 functioning and 1 doa out of 25. The 3 that made it is Muses8920, LME49720, DEAD OPA1612 with adapter . The focus and the camera is not the best in my phone.
The stock Douk U3 came with a NE5532P, the audio was fine, but the massive pops at startup or when suddenly switching song was annoying so the curious me went to aliepxress and ordered the best in class op-amps.
NE5532P: Good sound, nothing to emphasize, maybe the top end was veiled a little bit and suffered when a lot of sound was playing at once.The DC at the output was 3V but it went down to 34mV after a 30 seconds. When turning it off, the offset jumped back to 3V to give me that nice pop. At startup the pop happened instantly then disappeared.
MUSES8920: Low end died a little bit and the top end felt more alive "aka" harsher and it became a guitar amp. The amp started to distort a lot when a loud sound happened, at first i thought it was my dac(cheapo usb c dongle) so thought nothing of it. After getting a cheapo es9018k2m dac the distortion remained so it wasn't the issue. The DC voltage at the output was 3.3V at startup and slowly went down to 50mV after 25min of idle. I could hear the "pop" slowly rise up the drivers then go away. 100% sure it was a fake MUSES chip.
LME49720NA: Low end returned with the high end becoming even harsher. I'm noticing more details in general and warmer tone, could be placebo or some "unwanted" harmonic distortion.
It doesn't distort at all and i need less volume knob turn to reach my listening volume compared to the NE and FAKE MUSES.
Oh boi the dc on this one. At startup its 18V then it dies down to 1mV in 20 seconds. I'm confident that this one is genuine. Not doing the pop sound test on this one.
OPA1612: Dead on arrival, nothing more to say about it.
In a 30min heat test. Case temp: NE 33°C, MUSES 31°C, LME 34°C, they all within 10%.
This "test" was done over 6 months.
Sidenote. HP is DT-990 250ohm. The amp is dead silent when nothing is playing and i don't have any issues others have reported with it. Its being powered by a phone charger 5V 2A.
The lottery of cheapness by own desire for those that like to loose valuable time and prefer parts that will have a question mark tattooed on them.
This makes zero sense as the gain structure of the circuit should be dictated by the components and not the opamps. If the gain is genuinely changing with the opamp then something is really wrong with the opamp.
Could be the control is changing the supply voltage, then it makes sense.
JRC 5532 are about 50 cents here.
TI 072 a little less.
Lot of trouble taken for small amount.
JRC 5532 are about 50 cents here.
TI 072 a little less.
Lot of trouble taken for small amount.
Where did you pull that from?
Hope you realize that´s an oxymoron.
What else did you expect from a relabelled LM358?
What else did you expect from a relabelled LM358?
Next tests will how the same so I´ll stop here.
Bonus points for the DOA one and the
That the Op Amps worked at all with meager 5V prove they are LM358
Op amp output swing (signal amplitude) is proportional to the power supply voltage.
If the pot is controlling the supply voltage (adequate watts here in rating), then it could be A cause for the issue. Not the only cause, but a possible cause.
It is Chinese, I believe.
There was a police officer telling a reporter that the maximum items purchased with stolen credit cards were Rolex and Nikon.
'Must be the advertising', he said.
In this case, it is applicable, I think...
If the pot is controlling the supply voltage (adequate watts here in rating), then it could be A cause for the issue. Not the only cause, but a possible cause.
It is Chinese, I believe.
There was a police officer telling a reporter that the maximum items purchased with stolen credit cards were Rolex and Nikon.
'Must be the advertising', he said.
In this case, it is applicable, I think...
The MUSES one is amusing (pun intended). I think I would do a better job of marking one up with a sharpie than that.
These exotic opamps are presumably the 'best' for faking - such a high markup.
I have quite a few NE5532s that have come from China - normally as an unwanted 'gift' on preamplifier boards that I want for the boards rather than the inserted opamp. However ... I tested them (to the limited degree I can) against known genuine NE5532s and have to say most of them seem fine. They are typically branded JRC. The one that failed testing (implausibly low DC offset and noisy) was branded TI and on inspection was obviously a fake (screen printed not engraved and poorly printed at that). I am not even sure that was a bipolar opamp - might have been an LF353 or similar.
So my current experience is JRC 'branded' NE5532 seem OK. But NE5532 is now so generic there is no reason not to go for a known good source. Anything exotic and you are almost certainly wasting time and money buying from dubious sources.
These exotic opamps are presumably the 'best' for faking - such a high markup.
I have quite a few NE5532s that have come from China - normally as an unwanted 'gift' on preamplifier boards that I want for the boards rather than the inserted opamp. However ... I tested them (to the limited degree I can) against known genuine NE5532s and have to say most of them seem fine. They are typically branded JRC. The one that failed testing (implausibly low DC offset and noisy) was branded TI and on inspection was obviously a fake (screen printed not engraved and poorly printed at that). I am not even sure that was a bipolar opamp - might have been an LF353 or similar.
So my current experience is JRC 'branded' NE5532 seem OK. But NE5532 is now so generic there is no reason not to go for a known good source. Anything exotic and you are almost certainly wasting time and money buying from dubious sources.
The amp internally runs at 25V so low voltage is not the problem. Then they went a mile to laser re-etch the NE because i rubbed hard with Isopropyl alcohol and the text stayed. On the fake muses the text just disappeared and left a blank chip. Did the same with the LME and text stayed. Dont have a oscilloscope to measure the slew rate so i'm limited to very basic tests.
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My bad, only realized today that i accidentally added a +3db boost. Its my bad for not checking beforehand.
@jean-paul Thanks for the offer but ill decline your offering and suffer more with aliexpress parts. I would order genuine chips from mouser but the shipping cost is just too insane for me.
Yes I realized that you like to torture yourself and retracted my offer. It would have been a time saving experience with quality original parts at very low cost and that is so not 2022.
@jean-paul My amp and dac is from ali so it would be fitting to use only those parts for the "true" experience.
If that floats your boat then things are OK. However to many time is a more valuable asset than money.
The only time this approaches being true is if the opamp is hard clipping but that's a situation you never want to be in with audio reproduction.
One OPA1612 costs $8.12
One LME49720NA $3.43
One NE5532 $1-2 depending on variant.
If they had the muses too you'd be up to about $20.
I figured you could add in a couple of other opamps/parts for your rolling and you'd be up to the limit.
One LME49720NA $3.43
One NE5532 $1-2 depending on variant.
If they had the muses too you'd be up to about $20.
I figured you could add in a couple of other opamps/parts for your rolling and you'd be up to the limit.