LM4562
Hello,
I have contact with the LM4562 about 3 weeks ago! I use OPA2134 for a long since 1998!Its a good sounding opamp,and is "price wise".
It start with the tweaking of a Philips CD850II cd player in 1996.I got the service manual first, the elna caps audio series second and a pair of OPA2604. The OPA2604 give a run to the LM833 and NE5532!Wider soundstage and better defenition and "tone"! Then came the OPA2134, which are better,more detailed, in my opinion, than the OPA2604!
My amp is an Advance Acoustic MAP-407.It have decent power amps, and a pre-amp stage based on 2XOPA2134 and a phono stage based on a NE5532 with a Rin about 22KOhms, which kill the treble extension of my Shure M97xE!
I dont like the sound of NE5532, but i reckon its a great performer in the noise and distortion domain, so i get the iron and put the Rin of the phono amp about 47K2Ohms and a socket! I try a OPA2134 of my stock!In terms of audible noise is about the same in MM and a little bit more in MC, but the sound is full and with decent soundstage and extension!Then i bought 4 LM4562, and i try one in the phono amp (Socket), and when i start to listen it after the system warm up for 15 minutes, i notice a more relaxed and detailed sound with wider soundstage and better depth!Now the Shure M97xE get the image out of the speakers fisical limits! Its an improvement...by the way the deck is a Project Xpression II with a speedbox 1!
After this i change the first stage of the pre-amp section with a LM4562 and... it sounds great, wider soundstage much better depth and sweet, but only after a burn period of about 20 hours, before that it tend to sound a bit excessive in mid to high band!
Its a very good piece for audio, but in terms of noise in my phono amp the OPA2134 still seems less intrusive to my ears!
The second stage of the pre-amp section (After volume pot) have the original OPA2134, but i suspect this series are more flat sound than the stock parts i have!
I wondering if a second LM4562 on the second stage of the pre amp could became a bit stress, since the OPA2134 tend to tamed the sound a bit!
Now i ask to Mr. Audioman54, if its worth and possible to bias the LM4562 in to class A, and what Voltage value and polarity should be applied to the output pin, since i have +/- 15V and +/- 12V in various devices which use dip 8 opamps?!
Thank you and
Regards
Paulo
Hello,
I have contact with the LM4562 about 3 weeks ago! I use OPA2134 for a long since 1998!Its a good sounding opamp,and is "price wise".
It start with the tweaking of a Philips CD850II cd player in 1996.I got the service manual first, the elna caps audio series second and a pair of OPA2604. The OPA2604 give a run to the LM833 and NE5532!Wider soundstage and better defenition and "tone"! Then came the OPA2134, which are better,more detailed, in my opinion, than the OPA2604!
My amp is an Advance Acoustic MAP-407.It have decent power amps, and a pre-amp stage based on 2XOPA2134 and a phono stage based on a NE5532 with a Rin about 22KOhms, which kill the treble extension of my Shure M97xE!
I dont like the sound of NE5532, but i reckon its a great performer in the noise and distortion domain, so i get the iron and put the Rin of the phono amp about 47K2Ohms and a socket! I try a OPA2134 of my stock!In terms of audible noise is about the same in MM and a little bit more in MC, but the sound is full and with decent soundstage and extension!Then i bought 4 LM4562, and i try one in the phono amp (Socket), and when i start to listen it after the system warm up for 15 minutes, i notice a more relaxed and detailed sound with wider soundstage and better depth!Now the Shure M97xE get the image out of the speakers fisical limits! Its an improvement...by the way the deck is a Project Xpression II with a speedbox 1!
After this i change the first stage of the pre-amp section with a LM4562 and... it sounds great, wider soundstage much better depth and sweet, but only after a burn period of about 20 hours, before that it tend to sound a bit excessive in mid to high band!
Its a very good piece for audio, but in terms of noise in my phono amp the OPA2134 still seems less intrusive to my ears!
The second stage of the pre-amp section (After volume pot) have the original OPA2134, but i suspect this series are more flat sound than the stock parts i have!
I wondering if a second LM4562 on the second stage of the pre amp could became a bit stress, since the OPA2134 tend to tamed the sound a bit!
Now i ask to Mr. Audioman54, if its worth and possible to bias the LM4562 in to class A, and what Voltage value and polarity should be applied to the output pin, since i have +/- 15V and +/- 12V in various devices which use dip 8 opamps?!
Thank you and
Regards
Paulo
Audioman,
Is it possible to short circuit sink and source inLME49811, and so, to use it as a super opamp.
Is it possible to short circuit sink and source inLME49811, and so, to use it as a super opamp.
49722 gain section 49600 buffer
Audioman54,
I'm still messing with a preamp and after reading your comments, was thinking about using the 49722 as the gain section of a preamp then the volume control pot, feeding the 49600 as the buffer. I've looked at the 49600 page - is there anything special I need to do to incorporate the 49722 in lieu of the 49710 they show? Is this a good combination?
Regards,
Ken
Audioman54,
I'm still messing with a preamp and after reading your comments, was thinking about using the 49722 as the gain section of a preamp then the volume control pot, feeding the 49600 as the buffer. I've looked at the 49600 page - is there anything special I need to do to incorporate the 49722 in lieu of the 49710 they show? Is this a good combination?
Regards,
Ken
Attachments
Re: revised schematic
"One of the things to watch for in low noise bipolar amps is the input noise current density. That can easily swamp input noise voltage in moderate to high impedance circuitry. The LME49713 data sheet lists a whopping 16 pA per root Hz at 1KHz. The 49713 also shows a typical input bias current of 1.8 uA, which means that the input bias resistor can create a significant IR drop at some settings, the effect of which will cause a varying offset ranging from a few millivolts to around 50 mV (which will be amplified by the DC gain of your circuit) as the volume is changed. The choice of 50K for the “volume” pot may not be the best choice given those facts. Something closer to 5K may yield somewhat better results. I don’t know how much of an improvement the LME49610 would be in this regard, given similar input bias currents and a mislabeled input noise current graph in the data sheet. [/B]
I got this reply on another thread on the same subject. I'm planning on building it this week. Is there a better way than the schematic I've posted?klewis said:
"One of the things to watch for in low noise bipolar amps is the input noise current density. That can easily swamp input noise voltage in moderate to high impedance circuitry. The LME49713 data sheet lists a whopping 16 pA per root Hz at 1KHz. The 49713 also shows a typical input bias current of 1.8 uA, which means that the input bias resistor can create a significant IR drop at some settings, the effect of which will cause a varying offset ranging from a few millivolts to around 50 mV (which will be amplified by the DC gain of your circuit) as the volume is changed. The choice of 50K for the “volume” pot may not be the best choice given those facts. Something closer to 5K may yield somewhat better results. I don’t know how much of an improvement the LME49610 would be in this regard, given similar input bias currents and a mislabeled input noise current graph in the data sheet. [/B]
The 49713 is a current feedback op amp -- it will drive a low impedance load with enormous bandwidth -- start with a feedback resistor of 820 ohms as suggested in the data sheet -- i would use a much lower value potentiometer ahead of the buffer.
the LME49713 is surface mount -- you can get an aries adapter if you want to go DIP-- DK carries both.
the LME49713 is surface mount -- you can get an aries adapter if you want to go DIP-- DK carries both.
Hi Klewis,
i am very interested to see what you develop. I have plans to implement the same opamp as a buffer but have not had time to begin the project. i am still working on the power supply.
i saw that jackinnj said that the data sheet recommends starting with 820R. It seems to me that it recommends 1.2K as you originally implemented. With a 800R resistor the gain goes up by a couple of dB in the higher frequencies. jackinnj knows a lot more than me so i would trust him but i would be curious to understand his suggestion better.
also, this is what the data sheet says about changing the value of Rf
"In addition to reducing bandwidth, increasing the feedback resistor value also reduces overshoot in the time domain response."
can someone explain what they mean by "time domain response"?
i guess that for the purposes of audio we may not care about gain changes at frequencies several orders of magnitude higher than 20khz, but we do care about overshoot in the time domain response.
i am very interested to see what you develop. I have plans to implement the same opamp as a buffer but have not had time to begin the project. i am still working on the power supply.
i saw that jackinnj said that the data sheet recommends starting with 820R. It seems to me that it recommends 1.2K as you originally implemented. With a 800R resistor the gain goes up by a couple of dB in the higher frequencies. jackinnj knows a lot more than me so i would trust him but i would be curious to understand his suggestion better.
also, this is what the data sheet says about changing the value of Rf
"In addition to reducing bandwidth, increasing the feedback resistor value also reduces overshoot in the time domain response."
can someone explain what they mean by "time domain response"?
i guess that for the purposes of audio we may not care about gain changes at frequencies several orders of magnitude higher than 20khz, but we do care about overshoot in the time domain response.
Okapi,
I've ordered the parts and hope to have it running this weekend. Wish me luck.
I also saw the reference to 1.2k, but, if you look in the graphs, they also show the response with .8k Rf resistor.
Ken
I've ordered the parts and hope to have it running this weekend. Wish me luck.
I also saw the reference to 1.2k, but, if you look in the graphs, they also show the response with .8k Rf resistor.
Ken
okapi said:
I was reading from the 2007 preliminary datasheet -- my error -- since that time the device is also available in the HA (metal can) package.
Here's the first data-sheet:
An externally hosted image should be here but it was not working when we last tested it.
Jack,
Did the preliminary data sheet provide a suggested schematic? The final one doesn't...
Ken
Did the preliminary data sheet provide a suggested schematic? The final one doesn't...
Ken
Hi Mark, I'm sorry you are laid off.
Hope You get another job soon.
I'm curious about the lme49719 with metal can.
I have some lme49710HA and LM4562HA.
Their metal can seem not to be connected to any point.
It's floating.
Some other OPAMP with metal can typically connect it to -V or suggest the user to connect it to the virtual ground point.
Why is the lme Floating? Any benefit?
Is the dies of the HAs specially picked?
Or they perfom better simply because the case is better?
If we want a better die, we just go for the higher voltage rated version?
Can we make some homemade metal cans for regular DIP8 OPAMP to achieve as good result?
Hope You get another job soon.
I'm curious about the lme49719 with metal can.
I have some lme49710HA and LM4562HA.
Their metal can seem not to be connected to any point.
It's floating.
Some other OPAMP with metal can typically connect it to -V or suggest the user to connect it to the virtual ground point.
Why is the lme Floating? Any benefit?
Is the dies of the HAs specially picked?
Or they perfom better simply because the case is better?
If we want a better die, we just go for the higher voltage rated version?
Can we make some homemade metal cans for regular DIP8 OPAMP to achieve as good result?
BTW, I have some LME49830 in hand.
Just curious about why is there so few people playing with this part.
I think this part gives a very easy way to produce good result without the need of a drive stage.
How do you think about lme49830?
And any suggestion about this?
I tried a conventional comensation with 10pf CC1 at gain of 11 driving a pair of 2sk1058 2sj162.
It works well.
Just curious about how high a bandwidth it can go.
The specified 26db minimum gain seems to be very conservative compared both to my experiment and the Bode plot in the datasheet.
Just curious about why is there so few people playing with this part.
I think this part gives a very easy way to produce good result without the need of a drive stage.
How do you think about lme49830?
And any suggestion about this?
I tried a conventional comensation with 10pf CC1 at gain of 11 driving a pair of 2sk1058 2sj162.
It works well.
Just curious about how high a bandwidth it can go.
The specified 26db minimum gain seems to be very conservative compared both to my experiment and the Bode plot in the datasheet.
There are some threads in the ChipAmp forum for the LME49830 and its cousins, LM4702, LME49810, LME49811. They are pretty easy to work with. The only trouble I ever had was with setting the compensation for full stability and good PCB design. But these are the same type of problems all discrete amps have too.
-TH
-TH
Sorry to have not check in for awhile everyone
Sorry to have not checked into DIY for a while everyone but this job search has been taking all of my time. I have a couple of interviews next week so we will see how it goes. One makes parts for the professional audio community and the other makes audio parts for cell phones.
Klewis as far as using the LME49600 after the LME49713 only do that if you need more than 100 ma of output current. The 49600 will do 250 ma and the 49600 100ma. Both parts are built on the same process but the sonic qualities of two 49713's in series will be slightly better than a 49713 and a 49600 in series.
OKAPI As far as the feedback resistor goes for the LME49713 we found that for audio a 1.2k to 1.5k resistor works quite well. The apps engineer on that part did quite a bit of testing checking HF peaking with different feedback resistors (gain vs frequency on page 8 of the data sheet-top left) and that range of values was what we ended up using in our audio designs. That is also the same value suggested for the AD811/AD9610 CFB opamps that I previously used in all my audio designs. By the way if anyone wants to buy any of those I have 800 never used AD811 dips in my parts cabinet. Even have some of the metal can AD9610's (dual die hybrid F16 low lever radar mil spec part) that have been out of production for a long time. Those were $300 each when I bought 100 of them over 20 years ago when I owned my own audio business and use them in my highest end designs only. That was the metal can part we went after with the LME49713 metal can.
FOO you asked about the metal can LME49719? I assume you meant the 49713? I was told that the can on all these parts is supposed to be connected to the neg rail. I never actually checked it though so now you have me curious. I will go out to the lab (garage now) and check my D/A preamps parts to see if the cans are floating?... On my D/A preamp I read the neg 18VDC rail on the cans but the ohm meter shows 3 meg to the cans from both rails. I will do some more investigation on this question.
Also FOO, Spittinllama is the best person to ask about the LM4702/LME49810/811/830 stuff. All I will say about those parts is that for a bipolar amplifier the 811 is my favorite part to listen to. And Please everyone buy a bunch of those 811's and LME49713's before the "National Solar Magic/Power Wise" folks that are in charge of National stop making some of our awesome LME parts. I heard some nasty rumors about the future of those parts that I have not be able to verify.
Lastly Foo the die are the same in the plastic and metal can parts. So the sound quality difference has to be because of the various aspects of the metal can packages. Bob Pease and I never got the chance to try and figure out exactly what it was about the metal cans that made the difference though. (That is because I was laid off in Nov and Bob was laid off a few weeks ago. I still am in contact with him though.) Some possibilities are...Shielding properties of the can? Thermal Stress of the plastic in contact with the die? Bigger bond wires in the metal can? Dieletric properties of the plastic being in driect in contact with the die? Heat dissipation properties of the can? Any of these/all of these/none of these? Don't know for sure. The higher voltage rated parts are tested at the higher voltages to assure those ratings.
Best Audio Regards Everyone from a still out of work audio engineer,
Audioman54 / Mark
Sorry to have not checked into DIY for a while everyone but this job search has been taking all of my time. I have a couple of interviews next week so we will see how it goes. One makes parts for the professional audio community and the other makes audio parts for cell phones.
Klewis as far as using the LME49600 after the LME49713 only do that if you need more than 100 ma of output current. The 49600 will do 250 ma and the 49600 100ma. Both parts are built on the same process but the sonic qualities of two 49713's in series will be slightly better than a 49713 and a 49600 in series.
OKAPI As far as the feedback resistor goes for the LME49713 we found that for audio a 1.2k to 1.5k resistor works quite well. The apps engineer on that part did quite a bit of testing checking HF peaking with different feedback resistors (gain vs frequency on page 8 of the data sheet-top left) and that range of values was what we ended up using in our audio designs. That is also the same value suggested for the AD811/AD9610 CFB opamps that I previously used in all my audio designs. By the way if anyone wants to buy any of those I have 800 never used AD811 dips in my parts cabinet. Even have some of the metal can AD9610's (dual die hybrid F16 low lever radar mil spec part) that have been out of production for a long time. Those were $300 each when I bought 100 of them over 20 years ago when I owned my own audio business and use them in my highest end designs only. That was the metal can part we went after with the LME49713 metal can.
FOO you asked about the metal can LME49719? I assume you meant the 49713? I was told that the can on all these parts is supposed to be connected to the neg rail. I never actually checked it though so now you have me curious. I will go out to the lab (garage now) and check my D/A preamps parts to see if the cans are floating?... On my D/A preamp I read the neg 18VDC rail on the cans but the ohm meter shows 3 meg to the cans from both rails. I will do some more investigation on this question.
Also FOO, Spittinllama is the best person to ask about the LM4702/LME49810/811/830 stuff. All I will say about those parts is that for a bipolar amplifier the 811 is my favorite part to listen to. And Please everyone buy a bunch of those 811's and LME49713's before the "National Solar Magic/Power Wise" folks that are in charge of National stop making some of our awesome LME parts. I heard some nasty rumors about the future of those parts that I have not be able to verify.
Lastly Foo the die are the same in the plastic and metal can parts. So the sound quality difference has to be because of the various aspects of the metal can packages. Bob Pease and I never got the chance to try and figure out exactly what it was about the metal cans that made the difference though. (That is because I was laid off in Nov and Bob was laid off a few weeks ago. I still am in contact with him though.) Some possibilities are...Shielding properties of the can? Thermal Stress of the plastic in contact with the die? Bigger bond wires in the metal can? Dieletric properties of the plastic being in driect in contact with the die? Heat dissipation properties of the can? Any of these/all of these/none of these? Don't know for sure. The higher voltage rated parts are tested at the higher voltages to assure those ratings.
Best Audio Regards Everyone from a still out of work audio engineer,
Audioman54 / Mark
Hi Mark! It's good to see you back on the threads - even if it might be just a short visit due to your situation. Everyone here is pulling for you and Bob and wish you all the best with your search! 😉
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