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The Opamp thread

Dec 14, 2020 at 12:54 PM Post #7,023 of 7,456
Setmagic said:
Hello I just bought my first opa from AliExpress with good reviews. But I'm not 100% sure if it's original. OPA1612
Click to expand...

I bought 2 from 2 different Aliexpress sellers and also would like to know what they are.
Outside they look like yours, with exception of having different numbers bellow 1612A.
I removed the die from both of them and they had the same die.

I only have a 3eur toy microscope, so I can't zoom more and couldn't find any identification:
1.jpg


2.jpg

EDIT:
https://www.diyaudio.com/community/...press-no-counterfeit-but-why-so-cheap.399994/
 
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Dec 14, 2020 at 7:57 PM Post #7,027 of 7,456
The markings look identical, this is good, but imo not conclusive.
I prefer to always buy from official distributors. I got these from AliEx to open them.
The die photos look pretty and my idea was to look inside to see what was there, but I have nothing to compare this one. :)
It was easy to open the IC and remove the die, I tried this recently.
If anyone wondering, I followed this process with hot air station (do use safety glasses):
 
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Dec 23, 2020 at 10:05 PM Post #7,028 of 7,456
Hi
I have an Objective 2 ( O2). Op amp Stock is 1X NJM2068 input and 2X NJM4556 output . Sound is full Natural and Transparent
I am Replaced NJM2068 to OPA2134 . The sound is a very little warmer and very little more bass but Soundstage is narrow than stock NJM2068 and And the mids looks in the face Compared to NJM2068 . I do not like the sound. Sound stage is important to me. NJM2068 not any colored and very balance but less Fun and No signature

I want to buy a OPA2107 and a LM4562 for output op amp. Can two different models be used for op amp output? Or do I just have to replace the same model (x2) for output stage? If not. Is there a logical reason?
Does buying 2x new Op amp (output stage) have a good audible effect? My expectations of the stock sound: Warmer sound (More bass. fuller Mids . Warm treble) and bigger sound stage than stock. ( Complete positive changes Without any sound worse than stock Objective 2 AMP)

Which has the most impact on the sound ( Output stage or Input stage?? )
I live in Iran. OPA2134. OPA2107. LM4562. AD8620. Available. At a very high price: $30 to $40. Also available NE5532 very cheap $1
Op amp Models with higher numbers but less known and popular. Very cheap to buy.( For example LM4562 and AD8620 $30 to $40 and LM4890 and AD8692 only $2). Are they worth buying? Higher model numbers and drastically lower prices. Good sound or not for Audiofile HIFI?
I will be grateful. If you know the answers to these questions, please help
 
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Dec 24, 2020 at 7:19 AM Post #7,029 of 7,456
saeid72 said:
Hi
I have an Objective 2 ( O2). Op amp Stock is 1X NJM2068 input and 2X NJM4556 output . Sound is full Natural and Transparent
I am Replaced NJM2068 to OPA2134 . The sound is a very little warmer and very little more bass but Soundstage is narrow than stock NJM2068 and And the mids looks in the face Compared to NJM2068 . I do not like the sound. Sound stage is important to me. NJM2068 not any colored and very balance but less Fun and No signature

I want to buy a OPA2107 and a LM4562 for output op amp. Can two different models be used for op amp output? Or do I just have to replace the same model (x2) for output stage? If not. Is there a logical reason?
Does buying 2x new Op amp (output stage) have a good audible effect? My expectations of the stock sound: Warmer sound (More bass. fuller Mids . Warm treble) and bigger sound stage than stock. ( Complete positive changes Without any sound worse than stock Objective 2 AMP)

Which has the most impact on the sound ( Output stage or Input stage?? )
I live in Iran. OPA2134. OPA2107. LM4562. AD8620. Available. At a very high price: $30 to $40. Also available NE5532 very cheap $1
Op amp Models with higher numbers but less known and popular. Very cheap to buy.( For example LM4562 and AD8620 $30 to $40 and LM4890 and AD8692 only $2). Are they worth buying? Higher model numbers and drastically lower prices. Good sound or not for Audiofile HIFI?
I will be grateful. If you know the answers to these questions, please help
Click to expand...
I'm back to NJM2068 stock objective 2 . WOW. Wide Soundstage very bigger than OPA2134. Less bass. Mids Transparent and very deep. no like OPA2134 Sticking to the ear hole. Treble Transparent without warm like OPA2134. Sound Overall not cold but Absolutely superior OPA2134
OPA2134 Like garbage. With these conditions, I probably do not like OPA2107? OPA2107 Is it close to 2134? Maybe I should be completely carefree. How about LM4562? Any suggestions?
Someone answer faster. Thanks
 
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Dec 26, 2020 at 3:58 AM Post #7,030 of 7,456
saeid72 said:
I'm back to NJM2068 stock objective 2 . WOW. Wide Soundstage very bigger than OPA2134. Less bass. Mids Transparent and very deep. no like OPA2134 Sticking to the ear hole. Treble Transparent without warm like OPA2134. Sound Overall not cold but Absolutely superior OPA2134
OPA2134 Like garbage. With these conditions, I probably do not like OPA2107? OPA2107 Is it close to 2134? Maybe I should be completely carefree. How about LM4562? Any suggestions?
Someone answer faster. Thanks
Click to expand...
I bought a LM4562. I will get it tomorrow. Now I'm in stock (1x NJM2068 input and 2x NJM4556 output)
But today I replaced 1 of NjM4556 output with OPA2134 . Yes! 2 different amps at the output stage. No one has ever done this before. it works. It is possible. it's interesting
Now I have a better sound. The OPA2134 has completely left its mark.
Strong bass. Warm Treble. Forward midrange (but not as bad when OPA2134 on input stage) Less soundstage (but not as narrow as when OPA2134 in input stage)
The sound is completely mixed. Two different op amp affect the output stage 50/50 each. Maybe this OPA2134 will replace one of NJM4556 forever. But it still has a really negative impact on the sound stage. soundstage OPA2134 It is a complete disaster. When OPA2134 in the input stage. Tragedy. Absolutely no sound stage
 
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Dec 26, 2020 at 4:00 AM Post #7,031 of 7,456
saeid72 said:
I bought a LM4562. I will get it tomorrow
But today I replaced 1 of NjM4556 output with OPA2134 . Yes! 2 different amps at the output stage. No one has ever done this before. it works. It is possible. it's interesting
Now I have a better sound. The OPA2134 has completely left its mark.
Strong bass. Warm Treble. Forward midrange (but not as bad when OPA2134 on input stage) Less soundstage (but not as narrow as when OPA2134 in input stage)
The sound is completely mixed. Two different op amp affect the output stage 50/50 each. Maybe this OPA2134 will replace one of NJM4556 forever. But it still has a really negative impact on the sound stage. soundstage OPA2134 It is a complete disaster. When OPA2134 in the input stage. Tragedy. Absolutely no sound stage
Click to expand...
Those 2 op amps arent on different channels are they?
 
Dec 26, 2020 at 4:12 AM Post #7,032 of 7,456
Dec 26, 2020 at 5:48 AM Post #7,033 of 7,456
saeid72 said:
No, I do not think they are separate. Both amps of the output stage phase work in parallel. They are not separate. My amp is objective 2. As far as I know. x2 op amp on output stage phase work together. Not separated
According to the manufacturer :
http://nwavguy.blogspot.com/2011/08/o2-details.html
Click to expand...
Okay just asking a dumb question. In my burson C3X ref i have 4 op amps. Two pairs, one pair in the IV stage and one pair in the LP stage. In each pair there is one per channel. Burson say it's fine to have different op amps in each stage but the pairs of R+L should be the same. If they were different it would still work i think but you wouldn't want to have different sounding channels.

What device are you modding?
 
Dec 26, 2020 at 6:33 AM Post #7,035 of 7,456
Sam Spade said:
Okay just asking a dumb question. In my burson C3X ref i have 4 op amps. Two pairs, one pair in the IV stage and one pair in the LP stage. In each pair there is one per channel. Burson say it's fine to have different op amps in each stage but the pairs of R+L should be the same. If they were different it would still work i think but you wouldn't want to have different sounding channels.

What device are you modding?
Click to expand...
Exactly right. This makes perfect sense. An amp with 1 output channel. Logically, the same amp should be used. But I used two different models. I wanted to test and I was fascinated. I wondered why no one tried it. But the results were great for me. There really is no disharmony or distortion or delay or distance. Problems may appear with accurate measurements and on paper. But there is nothing wrong with listening to my precise ears. Only the color and mood of the OPA2134 added. I'm thinking of doing a triple combination(LM4562 OPA2134 AD8620) Three kinds of sound and three companies. It seems like a dream
my device: Objective 2 amp (Amp discussed) + Schiit modi dac + Akg Q701 Headphone


Sam Spade said:
Oh i looked at your link. Thats really cool 😄
Click to expand...
Grand Master nwavguy. Only on paper and measure . No belief in Listen:ksc75smile:
 
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