crossover
I made the crossover and its operation is excellent.
the analyzer tells me that the sine waves are as described by elektor, the sound reproduced with my system is qualitatively superior to commercial products that exceed 500 euros.
Comparative tests have shown its quality.
you know some scheme with superior reproduction quality, to indicate me to be able to realize it.
thank you.
guido bullo
I made the crossover and its operation is excellent.
the analyzer tells me that the sine waves are as described by elektor, the sound reproduced with my system is qualitatively superior to commercial products that exceed 500 euros.
Comparative tests have shown its quality.
you know some scheme with superior reproduction quality, to indicate me to be able to realize it.
thank you.
guido bullo
As you have it, you can easily test effective phase linearity with square waves.
Sum the outputs with a few resisitors an scope its wave form.
No longer square.
OP27/LME49710
Hi everyone
I have replaced in the OP27 AD buffer with a LME49710 and inexplicably there is an intense buzz on the woofer, I re-set OP27 and the buzz disappears.
To adapt the impedance of the Sony player I changed the value of the cermet bringing it to 100K, and the value of the capacitor to 1uf
With OP 27 and LME49720 everything works perfectly, while with 49710 no!
Can anyone tell me what the problem is and how to solve it?
If I had to replace the OP 27 with an AD817, can I get a better sound quality?
An OPA132P could be a better solution than the LME49710?
Thank you all
Hi everyone
I have replaced in the OP27 AD buffer with a LME49710 and inexplicably there is an intense buzz on the woofer, I re-set OP27 and the buzz disappears.
To adapt the impedance of the Sony player I changed the value of the cermet bringing it to 100K, and the value of the capacitor to 1uf
With OP 27 and LME49720 everything works perfectly, while with 49710 no!
Can anyone tell me what the problem is and how to solve it?
If I had to replace the OP 27 with an AD817, can I get a better sound quality?
An OPA132P could be a better solution than the LME49710?
Thank you all
The OP27 and the LME49710 are single opamp chips, the LME49720 is a dual opamp chip which is a totally different pin-out, they are not directly interchangeable. The LME49710 also lacks the voltage offset trim function the OP27 has. These chips are not directly compatible, and unless the chip manufacturer specifically states compatibility, it's never safe to assume they are.
Mike
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I am perfectly aware of the differences.
I do not care about LME49720 because it works perfectly in the filter.
What interests me to know is the reason for the buzz that voluntarily or involuntarily produces LME49710 to replace the OP27 in the circuit, I also want to clarify that the difference between the two chips and in favor of the 49710 that divinely sounds is significantly higher than the OP27. But it produces a buzz.
There is a zip file that you could open to understand the wiring diagram, located on page 1.
Hello
Hi everyone
I can only say that the pair LME49710 / 49720 does not work as it should, and Texas does not correct the production defect.
to get some working chips what I have to do, who has to give me back the money and the time spent unnecessarily.
a pair of NE5532 / 5534 Signetic, let's talk about a product purchased in 1990 works better than LME, why call it ultra?
buttateli a mare
Guido
The chip may be oscillating, and that may be the "buzz" that you hear. This may be due to circuit layout and bypassing at the chip supply pins needing attention. Some of these higher performance opamps require special attention to work correctly so my by their nature. I've encountered oscillation with them myself on poor Chinese DAC PCBs.
Also, are these chips from a licensed retailer/supplier? Often ebay chips are rebranded and will not behave correctly.
Also, are these chips from a licensed retailer/supplier? Often ebay chips are rebranded and will not behave correctly.
LME49710/49720
Hi everyone
As I imagined the LME49720 purchased by Digikey do not present the noise defect of those purchased from other suppliers.
The LM4562 have no defects and also give me a superior sound performance even to the OPA2134.
I forgot, to say that OP249 remains the best ever (compared to those tested by me on this circuit)
Basically I own No. 52 LME49720 / 49710 that I will have to throw to the paper, of course now I know that all the faulty components are not covered by any kind of guarantee, even if in Europe it is two years.
In the Chinese markets that are in my city, if you find defects, the goods are changed without any problem!
Remember that faulty LMEs run and if you encounter problems throw them out the window.
Sorry for the outburst but I have unnecessarily changed components of the power supplies as a result also the printed and toroidal, and I assure you that the damage is considerable.
Guido Bullo
Hi everyone
As I imagined the LME49720 purchased by Digikey do not present the noise defect of those purchased from other suppliers.
The LM4562 have no defects and also give me a superior sound performance even to the OPA2134.
I forgot, to say that OP249 remains the best ever (compared to those tested by me on this circuit)
Basically I own No. 52 LME49720 / 49710 that I will have to throw to the paper, of course now I know that all the faulty components are not covered by any kind of guarantee, even if in Europe it is two years.
In the Chinese markets that are in my city, if you find defects, the goods are changed without any problem!
Remember that faulty LMEs run and if you encounter problems throw them out the window.
Sorry for the outburst but I have unnecessarily changed components of the power supplies as a result also the printed and toroidal, and I assure you that the damage is considerable.
Guido Bullo
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