Comparing of different chips for opa alice circuit.

[Андрій Чубака]

Today I will start this topic of comparing different chips for this circuit. Today I got some packege of chips from post and made some test with it. So my results I will write here.

First of all chips with no good results for today.

First one is a cheap chip opa1642. I bougth 1 pc for a 0,62$ of total price with shipping from china, Architecture is unknown

Spoiler: cheap opa1642

Next one will be LM4562, I bougth this chip not because I was sure like about it is good replacing here. I made it just for my own interest because this is very different chip and I was not sure about it is working at all here.
Architecture is Voltage FB

Spoiler: lm4562

And tl072 I am also can`t use today. Maybe this chips is not enough durable or real quality is not high. I made some changes for more easy replacing chips and added some additional piece of wire so now it is won`t working at all. But I will look try one more time later mayve with chips from other manufacture. Before I used this chips and it was with good sound but not today.

Spoiler: tl072

to be continue.

 

[Андрій Чубака]

Next here will be chips with middle results wich is possible for using but real quality of sound is not best from it.

First one here will be middle price opa1642 from china with 1,45$ price with shipping from china. Today all chips for comparing from china and price I will write total with shipping. Architecture is fet.

Spoiler: 1,45$ opa1642

Next here will be opa2134 with unknown quality, maybe it is not original and not very good chip but I guess I can undestand what quality of sound possible have from this model of chip. Price 0,97$ totaly per one piece wich I bougth. Bandwidth: 8 MHz, Architecture is fet.

Spoiler: opa2134

next here will be some different kind of opa1642 which I got previously, Price was 6.45$ per 5 pieces, But they send to me very different chip then it was on photo on aliexpres and I return 3$ from this price to my self as refund.

Spoiler: opa1642 unknown quality

 

[Андрій Чубака]

And last one here will be chips with best results on my opinion

First here is good quality opa1642, with price 2.98$ per 1 piece with shipping. They send it with cute packege to me

Spoiler: opa1642 good quality

And last one chip which I used was opa1652 and to me after all comparing this chip looks like most better with full, rich and smooth sound, price is 3,89$ per 1 piece tottaly. Architecture is CMOS. Bandwidth: 18 MHz.

Spoiler: opa1652

 

[Андрій Чубака]

About problems on this test which I had. So as I wrote before I made some changes and added some pieces of additional wire for possibility replace chips without additional soldering of wires in my mic. After this on every chip I got some strange level of background noise which was visible only on graph of sound recording. I am added this image from opa1652 recording. THis is same recording as on sound sample to this chip in this topic. I won`t now thinking too many how I got this noise which I don`t hear on recording and can see only on graph. For me here impostant only how sound this chips and which is possible use in future and which I will never use again. So somehow like this. On this moment it is all but maybe later I will add some other tests but not different chips but maybe some other circuits and soution of lowcost mic building with fine or maybe not so fine results.

 

[Андрій Чубака]

Some bonus test. I bougth today in some local shop 2 new tl072 chip and I am already test it.

First one is tl072 from ti. This is very good chip with very low price and working here very good. Price is 0,27$ in local shop

Spoiler: tl072 ti

Second was tl072 from st but problem here is almost same as with tl072 from first post in this topic. It is just won`t work. Price is 0,19$ in local shop

Spoiler: tl072 st

so about all other looks like I still don`t have really good opa1642. Some how it is give too much level of background noise but I will test it more, maybe here is some other problems with mic pcb or so. but other good chips working without this noise.

 

[Khron]

Have we seen how your physical implementation looks like?

 

[Андрій Чубака]

I am still using this boards from my previous topic and regular bm-800 boddy and rk-12 capsule under 20$ price. I guess here most impostant difference between chips, so I just replacing chips in same mic.

 

[Андрій Чубака]

This is how it is working here. I am resolder this chips all time with cleaning and drying of board. Scarlett solo 3 gen is my audio interface.

 

[Khron]

Can't see much attention given to the high-impedance area of the circuit, so it's not shocking that you're having noise issues.

https://www.pcbway.com/project/shareproject/OPIC_Microphone_fce72e5c.html
See the fourth photo there - notice the opamp's pin 3 is not soldered to the board, but is bent up and goes straight to that isolation pin.

https://www.jp137.com/lts/OPIC.41.pdf
See the yellow-highlighted text on the left side of the board view, on page 6.

 

[Андрій Чубака]

THis is with dual op amp circuit. opic41 it is single op amp. there is different pin out.

About noise it is not on all chips. board was cleaned.

 

[Андрій Чубака]

I don't expect any support here at this stage. I make a comparison of chips for myself from those that are available for me to buy. And I just dump the information on this forum so that it is available to other people. I don't do anything specifically for anyone except that I write explanations and insert my files on this forum. in fact, I will need those chips that work best in this circuit. And I have only one way to find out by comparing them with each other. Because all these theoretical developments do not work in this case, and even if I had a good oscilloscope, which I do not have, I still could not be sure exactly what kind of sound I would get from this or that chip.

 

[Андрій Чубака]

I got some new opa1642 from popular shop on ali. But quality is very poor. total price is 4,19$ per 5 pc. So 0,83$ per 1 pc. And this is not possible for using in future. Also I returned 2$ as refund from this item because quality is poor.

Spoiler: poor quality chip opa1642 from ali

 

[Khron]

So the conclusion is... Don't buy specialist chips off AliExpress? Anyone with a drop of common sense could've told you that from the start

 

[Андрій Чубака]

So the conclusion is... I am still looking some best solutions for this circuit. In local shops I can`t buy any new of this opa1642 because here price is high and all chips on sale they got same way from china as me. About https://eu.mouser.com only delivery from there will cost 20 euro for me. At this moment I won`t pay this price. Maybe in some day in future but not today.

 

[Khron]

About https://eu.mouser.com only delivery from there will cost 20 euro for me. At this moment I won`t pay this price. Maybe in some day in future but not today.

At least to Europe, they have free shipping for orders of 50eu and over.

 

[Андрій Чубака]

Yesterday I found here some new shop here where is sales opa1642 and today I am decide go there and buy some chips for testing. So this is what I bought there and tested.

Opa1642, price is 2,87$ per 1 pc which I bought. So quality of chip is not good and sound is bad, chip is noisy. Just wasting time and money in this case

Spoiler: opa1642 from local shop

Second is tl072id, price is 0,41$ per 1 pc which I bought. Quality is not interesting here, chip is bit noisy and sound bit like bipolar op amps. So also is not possible use in future. No big sence in using this chip.

Spoiler: tl072id

About other things here is also sometime people won`t work propertly and they try sale to me opa1662 and opa1611 insted of opa1642 and opa1641 which I am ordered, but I carfully check this chips in shop and they replace it on correct chips for me. But anyway quality of this chips is poor and I am happy because I no need go in this shop in future.

I ordered 1 more order with opa1642 from ali and maybe some weeks later I will test it also. But for this moment I complitely done with it.

About this background noise I am also already check it one more time with most expencive chip from ali and I can say I can`t reduse this noise complitely in this mic even if I cutoff additional wires from circuit, so this noise it is problem of chips. Now I have only few chips for good mic building. So I can`t build mic with high level of self noise and after try to sale it even if this mic will sound good about quality of sound directly. THis is my conclusions about all it.

 

[user 37518]

Not entirely sure that all your chips are genuine, those 1642 look particularly fishy....

 

[Андрій Чубака]

I also think all this 1642 chips just a copies. But this is life. I want buy original 1642 and still have no possibility for it.

 

[Khron]

I want buy original 1642 and still have no possibility for it.

About https://eu.mouser.com only delivery from there will cost 20 euro for me. At this moment I won`t pay this price. Maybe in some day in future but not today.

At least to Europe, they have free shipping for orders of 50eu and over.

I guess you really don't...

 

[Андрій Чубака]

I am not in hurry about all it, also i don't have a lot of money on all it. Also i am already have some good solution with tl072 which is pretty cheap and sounds more narural i guess circuit there is more simple than in 1642 and it is can change something in sound. This is reason why i am not in hurry to pay around 35euro for a 5 pc 1642 in mouser company. But as i say before maybe in some day in future i will buy it.

I am already have here microphones for sound recording. But i no need too much use it, i don't have any popular chanel on YouTube and don't have any ability to produce song's. Now i working more like for creating some product for sale. And this is also not like my main job at this moment.

 

[Екатерина]

If your location is close to the border, you can go to Manzhouli City, where you can connect to the Chinese network, where you can order on the SZLCSC website, and from here you can go to Yanbian City, China, which is also great