Recently, the number of op-amps in packages that are not friendly to DIYers, such as SOT-23 and WSON, has increased.
The OPA1688 also has a different pinout from the standard.
I couldn't find a conversion board on the market, so I made a conversion board by exposing and etching myself.
Incidentally, there is a correction to jean-paul.
Distortion of OPA1641
THD is emphasized by 60dB. So the -22.878 dBc measurement is -82.878 dBc = 0.00718%.
It has doubled! Farting in my brain.
It’s great that your findings are in line with mine.
It also helps as a confirmation that what I hear is not some bias or delusion, which are both very common when audio is in question.
I have a line-up of different opamps I have been comparing. So far I have not tried the 1642, but I'll get some.
Attachments
Okay, so I took your advise and ordered a pair of OPA1642. I have now listened to them for about half a day...
I agree they are great! Slightly less transparent when compared to the OPA2828, but they offer a bit more punch in the lower region, so they don't sound thin-ish like the 828.
I need to listen more, but overall they seem to strike a very nice balance. I don't have a clear winner, pros and cons. Time will tell....
Sometimes measurements and real life impressions differ a little. I think it is a very good all rounder and a bit better than many older opamps (regardless of the also not bad measured performance). Its low power consumption is a real benefit.
Suppose having a stellar measuring opamp but you don't like the sound. I stopped worrying about such matters. For all fast(er) opamps counts that adequate decoupling is a must. This might not always be done properly in a device.
Suppose having a stellar measuring opamp but you don't like the sound. I stopped worrying about such matters. For all fast(er) opamps counts that adequate decoupling is a must. This might not always be done properly in a device.
After switching back and forth a few times...
The warmth that the OPA1642 adds in the low end is enticing, but I quickly came to my senses when I listened to the OPA2828 again. The amount of detail it retreives in the I/V stage is simply unbelievable. Yes, depending on the recording it can be thin-ish, but the detail and transparency just can't be beat. Everything simply sounds 'real'. After another switch, back to the OPA1642, it sounded 'muddy' in comparison. No doubt the OPA1642 is a fine opamp and I can imagine people like it's warmth and punch, but the OPA2828 is simply on a different level.
Naturally it's all a matter of taste and also depends on the neutrality of other components in the chain. I can imagine that if your entire setup is rather (or overly) analytical, that the OPA1642 might balance things out. For me it's a no go, as my focus at the moment is to get a sound reproduction that is as clean and transparent as possible. Just love that micro-detail!
Therefore sticking to the OPA2828 for now.
The warmth that the OPA1642 adds in the low end is enticing, but I quickly came to my senses when I listened to the OPA2828 again. The amount of detail it retreives in the I/V stage is simply unbelievable. Yes, depending on the recording it can be thin-ish, but the detail and transparency just can't be beat. Everything simply sounds 'real'. After another switch, back to the OPA1642, it sounded 'muddy' in comparison. No doubt the OPA1642 is a fine opamp and I can imagine people like it's warmth and punch, but the OPA2828 is simply on a different level.
Naturally it's all a matter of taste and also depends on the neutrality of other components in the chain. I can imagine that if your entire setup is rather (or overly) analytical, that the OPA1642 might balance things out. For me it's a no go, as my focus at the moment is to get a sound reproduction that is as clean and transparent as possible. Just love that micro-detail!
Therefore sticking to the OPA2828 for now.
Yes, the opamps on the PCB are surrounded by 10n and 100n quality SMD caps as close to the device as possible. Think I'm okay on that front.
It's really not hard to tell them apart. The I/V is a pretty critical point in the chain. Judging if you can hear the room around a specific instrument is not hard to do and easy to remember if the difference is sufficiently significant. At the moment that difference is huge and stands out, but as said... will try again after 5 days of noise processing. The whole chain is pretty analytical, otherwise i would not be able to hear. I always wonder if people that argue that amps and chips sound the same actually brought the chain as a whole to a sufficient level to tell ..
So I let both OPAMP play for a week and this is my impression;
After burn-in, the 2828 can't be called 'thin' anymore. I suspect that people that mentioned this made their comments before burn-in, as I did. Shame on me. Everything else I wrote about the OPA 2828 is still equally true, so very transparant, very neutral, retrieves lot's of detail from the signal. It is however a little timid when it comes to dynamics. Still.... Absolute bliss and the best in an I/V stage I've heard to date.
The OPA 1642 after burn-in did gain some points. It became a bit more transparent and airy. Still consider the OPA 2828 to be in a different league.
Naturally I say this in the context of looking for the most transparant and neutral opamp out there. This may not be the preference of others, so naturally it remains a matter of taste.
For just something like 16 EUR I recommend to give the OPA 2828 a try. Expensive for an opamp, insignificant for audio bliss
Are you referring to the term 'decoupling'? If so, this is related to the powerlines of the opamp, not the output circuit.
For just something like 16 EUR I recommend to give the OPA 2828 a try. Expensive for an opamp, insignificant for audio bliss
Okay, so if you are using a very high bandwidth opamp, as in the case of the 8282 some 200 MHz, than it becomes harder to keep it stable and prevent it from association. To that end adding capacitors between V+ and V- helps. Just read this...
https://www.google.com/url?sa=t&sou...oQFnoECA0QAQ&usg=AOvVaw1ak1euGrRP6jjlLu-NmW8x
8282 —> 2828
Association-> oscillation
Stop the time!
BTW 16 Euro versus 3 Euro is a considerable difference.
I think its high bandwidth makes input filtering a must for audio use. Same goes for correct decoupling. Probably not an easy drop in for many audio devices. Chances are that laymen will be creating RF transmitters without knowing. Just saying.
Association-> oscillation
Stop the time!
BTW 16 Euro versus 3 Euro is a considerable difference.
I think its high bandwidth makes input filtering a must for audio use. Same goes for correct decoupling. Probably not an easy drop in for many audio devices. Chances are that laymen will be creating RF transmitters without knowing. Just saying.
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Indeed a somewhat dislectic spelling error. So a goog read by TI on decoupling.
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