The best sounding audio integrated opamps

[tvrgeek]

New one on me. Just ordered an new batch of the 4562's today. I also just got several cheap MCoy kits from e-bay so I can practice on my SMT skills. Should be fun as I am old and half blind.

Originally Posted by eherdian

I've tried this relatively new opamp from Analog Device

I got the samples from them and I had to make tiny pcboard to make them fit in my DAC since the opamps are mono

my impression it is better than the plastic LM4562NA , more air, smooth and rich mid, wider sound and more open, I haven't compare it to the can LM4652HA, but right now I have this opamps in my MSB link III and LM4652HA in my highly modified Musical Fidelity A324

Anyone ever tried this opamps? I interest on your opinion

thanks

[tvrgeek]

OOOH! 45 ma.

[auddoc]

Luigi,
I found the data sheet. It is attached here.
Read page 7 of the BB data sheet for the DAC- last two paragraphs.
What you may be hearing is most likely, your transformer saturating with RF from the DAC. The data sheet suggests that the DAC be followed with a high-order filter (a very steep slope 24-36db/oct-9th to 12th order LPF around 22-25kHz)which is probably what you bypassed in the Yamaha. If you have access to a scope you will see all kinds of HF artifacts mixed with the audio signal.
What do you mean by balanced? You only have +signal and GND as outputs. To feed a balanced transformer input with an unbalanced source means you are unbalancing the input. A true balanced signal is + signal, -signal and GND. The negative (or 180 DEG phase reverse) is produced, usually by an inverting op-amp/ driver. This is a separate topic from trying to get a DAC to work without a LPF of some kind.
I get the feeling that you can't really do what you want to, in this case. Perhaps the better way to go would be to optimize the output section of the Yamaha unit with the best parts money can buy. Also, get rid of any electrolytic caps in the audio path or design a "servo"-style output which eliminates DC and the need for caps in the audio path in the first place, etc, etc. Op amps are not that evil, if done correctly.
Ciao,
Gregg

[Chris Daly]

My blog page has plenty of info about op amps and mod's
opamp - opamp construction

Supplying power supply with surface mount transistors in a emitter follower configuration all on board the Brown Dog adapter is my latest venture, See schematic and blog

Stereo separation improves immensely,

Happy listening

Cheers / Chris

[a1greatdane]

Dear Luigi,
I have to second, thats it would be a good idea with a kind of 'follower' after Your Dac.
DAC's normally delievers current out with high impedance and a form of impedance adaptor would therefore be a good idea.
I do not recommend You to Use the 4562 and derivatives however. If find them very precise and clean, but also a bit 'lifeless' - bit like most Japanese cars really... - To perfect for their own good. There's a reason a lot of these impedance adaptors/follower has previously been done with NE5534's and 5532 for economy. A good samples of these will do a very competent job here with loads of musicallity. Best is probably the old Signetics version in Cerdip, but a BB/Ti one will do the job...
You can also venture into doing something discrete here, since all You need is impedance transformation. A current generator/source and an emmitter or source follower not to mention delievering the signal from the DAC to a virtual ground point, should do just the trick. There will most probably be simplified schematic's/curcuits avaliable on this site and/or if You google around a bit You should be able to find something suitable.
Best of hunting
DocO

[Aucosticraft]

Originally Posted by Chris Daly

My blog page has plenty of info about op amps and mod's
opamp - opamp construction

Supplying power supply with surface mount transistors in a emitter follower configuration all on board the Brown Dog adapter is my latest venture, See schematic and blog

Stereo separation improves immensely,

Happy listening

Cheers / Chris

Well, went through your blog. using pass transistor makes sense.but then I have seen in old amps and preamps, that mfg used different powersupply for each channel. Also is recommended to use a pair of pass transistor stage for each channel instead of using it with every op-amp.

I got a more doubt after reading your blog. what was the selection craiteria used that made the new generation opamp sound better over the one of yesteryears. unity gain bw? noise? CMRR? PSRR? slew rate or something else?

[Chris Daly]

Hi Aucosticraft

This idea, has provided lots of discussion in the Solid State section of the Forum under Powering Opamps. It is causing a lot of comment particularly concerning " subjective- what people are hearing " vs measured what is revealed by oscilloscopes.

I am providing some scope measurements later today, from the same circuit connected to a Marantz CD80.

My thoughts on how to describe it, and you would think someone after 58 years of transistor use would have connected a transistor this way, is that its closest description is that of a transistor connected diode, however it seems to improve with resistance between the collector and base, as I have designed, and improves again with load being drawn from it.
It also follows V+ V- less transistor junction, alluding ( where there has been much heated discussion ) , where I initially described it as an emitter follower, about its correct description. I have amended website description last night, awaiting better clarification

Subjectively when involved with opamps it improves consistently the spatial stereo information, that in my experience of op amps is a very good sign of improvement.

Cheers / Chris

[SY]

Originally Posted by Chris Daly

My thoughts on how to describe it, and you would think someone after 58 years of transistor use would have connected a transistor this way...

That should tell you something.

[PaulThang]

I am a newbie in mod opamp but after several replace for opamp in few CD players ,i think that OPA 2107 and 2132 are the best dual opamp.And opa 627 and Ad797 are the best single opamp.

[luigilamarca]

Dear Gregg,
Many thanks for your last answer regarding the pcm56 cdp yamaha, but now I wanted to ask you for information instead PCM63 (denon dcd3520)
and 'can bypass this opamp dac?
or i 'can use an output transformer without opamp?
Luigi

Originally Posted by auddoc

Luigi,
I found the data sheet. It is attached here.
Read page 7 of the BB data sheet for the DAC- last two paragraphs.
What you may be hearing is most likely, your transformer saturating with RF from the DAC. The data sheet suggests that the DAC be followed with a high-order filter (a very steep slope 24-36db/oct-9th to 12th order LPF around 22-25kHz)which is probably what you bypassed in the Yamaha. If you have access to a scope you will see all kinds of HF artifacts mixed with the audio signal.
What do you mean by balanced? You only have +signal and GND as outputs. To feed a balanced transformer input with an unbalanced source means you are unbalancing the input. A true balanced signal is + signal, -signal and GND. The negative (or 180 DEG phase reverse) is produced, usually by an inverting op-amp/ driver. This is a separate topic from trying to get a DAC to work without a LPF of some kind.
I get the feeling that you can't really do what you want to, in this case. Perhaps the better way to go would be to optimize the output section of the Yamaha unit with the best parts money can buy. Also, get rid of any electrolytic caps in the audio path or design a "servo"-style output which eliminates DC and the need for caps in the audio path in the first place, etc, etc. Op amps are not that evil, if done correctly.
Ciao,
Gregg