Laserscrape,
AD811 opamps (CFB) are very good sounding Older Opamps (I still have 600 or so from 20 years ago in my parts cabinet). They were the inspiration for the LME49713's.
And Nigelwright7557,
There is no question (100's and 100's of hours of listening at NSM in the sound room many years ago) that just about anyone can hear differences between various low noise/low THD opamps used in identical circuits/boards/equipment. I demo'ed this to Bob Pease using LME49713's in plastic dips and metal cans and even though he was in his 60's (like I am now!) Bob picked the cans (double blind testing with levels matched to .5db or so) over the plastic dips "100%" on various types of music.
Have not posted in years but someone asked me about "audio stuff" at work today and I ended up here.
Lastly FauxFrench,
TI to acquired Burr-Brown in $7.6B stock deal in 6/21/2000 and that is why they eliminated our audio group when they bought National Semiconductor many years later for $6.5 billion because they already owned an audio group from BurrBrown that made good parts and did not need another audio group...but our National semi group made some better "LME" parts that are unobtainium now. Also Analog Devices is still it's own company and it even bought Linear Technology in March 2017.
I miss my audio engineering buds from National!
audioman54 / Mark
AD811 opamps (CFB) are very good sounding Older Opamps (I still have 600 or so from 20 years ago in my parts cabinet). They were the inspiration for the LME49713's.
And Nigelwright7557,
There is no question (100's and 100's of hours of listening at NSM in the sound room many years ago) that just about anyone can hear differences between various low noise/low THD opamps used in identical circuits/boards/equipment. I demo'ed this to Bob Pease using LME49713's in plastic dips and metal cans and even though he was in his 60's (like I am now!) Bob picked the cans (double blind testing with levels matched to .5db or so) over the plastic dips "100%" on various types of music.
Have not posted in years but someone asked me about "audio stuff" at work today and I ended up here.
Lastly FauxFrench,
TI to acquired Burr-Brown in $7.6B stock deal in 6/21/2000 and that is why they eliminated our audio group when they bought National Semiconductor many years later for $6.5 billion because they already owned an audio group from BurrBrown that made good parts and did not need another audio group...but our National semi group made some better "LME" parts that are unobtainium now. Also Analog Devices is still it's own company and it even bought Linear Technology in March 2017.
I miss my audio engineering buds from National!
audioman54 / Mark
Anyone has experiences with AD811 in line level preamp? It's a fast opamp more suitable for DAC output.
Both of 744 and 811 are expensive, and real world implementations are known to be bad. This is understandable as the opamp is very fast and wide bandwidth. Even lm4562 implementations are not good enough for me and i think 811 implementations are worse than 4562 implementations.
I don't know about the 744+811 in line level, whether it is good enough or not. But I have had a prejudice that opamp based line level can never be special
With the price of 744+811 i think better opamps can be had for better result?
Which real world implementations are bad ones?
I would agree that opamp line level circuits are going to struggle when put up against good implementations of discrete circuits. Opamps have their place though for DIYers who value convenience.
Where I live neither AD811 nor AD744 is expensive. Unless you want mil-spec variants that is, in which case you do have to pay handsomely - AD811SQ/883B ??? ??? AD811SQ ???? ??8????-???
I would agree that opamp line level circuits are going to struggle when put up against good implementations of discrete circuits. Opamps have their place though for DIYers who value convenience.
Where I live neither AD811 nor AD744 is expensive. Unless you want mil-spec variants that is, in which case you do have to pay handsomely - AD811SQ/883B ??? ??? AD811SQ ???? ??8????-???
Well, from circuits circulating around here. In their implementation, many people are even not aware if it is a CFA not VFA. I have never heard a CFA that can compete with VFA BTW.
It is Audioman64 who favors the 811. He knows his things and when he said it is good then it should be good. But we can guess that he uses ground plane and the like in his implementation. What I have heard was the opposite. Sound was inferior.
Thanks a lot for the clarification.
TI+BB+NS one group and AD+LT another.
When I was young.... (many years ago), AD and BB were known to be top performance (and expensive) but NS was attractive due to a much better performance/cost factor. TI had little analog at that time.
The number of companies seemed much larger than today. Even Siemens and Philips were huge in those days. ST seems to remain, probably with a base in French and Italian car industry, Alstom and Airbus.
I guess, today Asian chip manufacturers eat into the market. As the production is anyway out there, why not also the design.
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the AD744 +AD811 combo by Walt Jung works very well as a line stage.
i built and used one heavily years ago and still use it occasionally between experiments with other line stage designs i play with.
Thanks to a rare/unique feature of the pinout of the AD744, Walt's design does not use the AD744's output stage to drive the AD811.
The Audio Amateur did have a project and sold boards for someone's version of this.
mlloyd1
i built and used one heavily years ago and still use it occasionally between experiments with other line stage designs i play with.
Thanks to a rare/unique feature of the pinout of the AD744, Walt's design does not use the AD744's output stage to drive the AD811.
The Audio Amateur did have a project and sold boards for someone's version of this.
mlloyd1
I still couldn't find the 744+811 circuit.
I studied the 811 and checked if there is something better. I think I found one from AD, the 844. But 811 is special in that the output current is 100 mA. Based on this I purchased the 811 in case I will need this property in the future.
I also read mlloyd1 comment regarding 744+811 in audio asylum (i think). There was someone who mentioned that his discrete opamp is better and it happens that my discrete opamp is based on the same circuit as his.
I studied the 811 and checked if there is something better. I think I found one from AD, the 844. But 811 is special in that the output current is 100 mA. Based on this I purchased the 811 in case I will need this property in the future.
I also read mlloyd1 comment regarding 744+811 in audio asylum (i think). There was someone who mentioned that his discrete opamp is better and it happens that my discrete opamp is based on the same circuit as his.
Below is the schematic for the Jung 744/811 preamp.
Other JFET op-amps can be used if you connect pin 6 to the input of the 811.
Even some bipolars can be used, but watch out for high DC offset at the outputs!
The sound is okay, but I find most op-amps(including the 744 when using pin 6 instead of pin 5) actually sound better when used by themselves and forgetting about the AD811s.
Other JFET op-amps can be used if you connect pin 6 to the input of the 811.
Even some bipolars can be used, but watch out for high DC offset at the outputs!
The sound is okay, but I find most op-amps(including the 744 when using pin 6 instead of pin 5) actually sound better when used by themselves and forgetting about the AD811s.
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Thanks Mercedese63!
Honestly, I'm not convinced that 811 can sound good. It is ultra fast/wide bandwidth and high output current, but as long as we don't need those two properties, it looks hopeless to me.
744 OTOH can be special. I own 746, which is the dual version of 744. It is slightly inferior than the 744 (from spec) but it has potential that I have been tempted to buy the 744. Now that I know it has the COMP pin that can be used to bypass the output, I'm more tempted.
But if we take the output from COMP, the signal is inverted. It seems that we can take the output from the output pin but running it in class-A (with resistor bypass)?
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Nope - the COMP pin (pin5) is coming from the input to the OPS. Looking at the output stage, its the standard complementary/push-pull pair of EFs. EFs are non-inverting.
I thought the +in was the left JFET while actually it is the right hand side JFET.
Have never played with such comp/output pin. Will keep an eye for the CA3130
I checked my database for the possibly best CMOS: From AD it is LTC6090. From TI it is OPA1652. Not something we meet everyday.
You're welcome!
Since you have the AD746, why don't you try it by itself and forget about the AD811, BUF634, LM6171 or any other high output op-amp that can only totally ruin the sound quality?
I have tried almost every op-amp out there from all the top companies over the years and I can tell you without a shadow of doubt that adding some type of buffer after most op-amps whether a IC(like the BUF634 or the infamous but sh_tty sounding LME49600) or a discrete buffer like the wildly popular BD139/140 output stage used in the Lehmann Cube and some other headphone amps, only totally ruins the sound of a otherwise good-sounding and simple op-amp circuit.