The best sounding audio integrated opamps

[theAnonymous1]

Originally Posted by abraxalito

Yet you're using the (expensive) metal can versions of the NS CFB opamps -that to me suggests you really want to get the best sound. Although I've not used these particular parts, my experience with various other amp chips is that attention to grounding is important for ultimate sound quality and that ground planes don't cut it, in general.

Yeah, proper grounding eludes me so I just throw a ground plane at everything. I call it the "I have no clue what I'm doing" approach.

I'll try a RC filter off 500R/220pF and change the servo op-amp to OPA2211 and report back.

BTW, trying to stay a little on topic here, the LME49713 does sound excellent.

[theAnonymous1]

Originally Posted by theAnonymous1

I'll try a RC filter off 500R/220pF and change the servo op-amp to OPA2211 and report back.

Success!

I decided to keep with the NI theme and put in a LME49860 for the servo and I installed the input RC filters.

Output offset is now ~9mV for both channels and the board sounds amazing. I can already tell I like it better than the LME49710/LME49600 amp I built.

And about the previous mention of my not-so-great grounding method; the board is as silent as silent gets. No hum, hiss, noise whatsoever.

Thanks for the help fellas.

[bmoraru]

Originally Posted by Andrea:

Now I'm considering the possibility of biasing the LT1028's to class A with a pair of 4.7K resistors (would result in a 1.2 mA bias). It was said to work well with this opamp.

hi Andrea, please explain how to bias to class A, i don't quite understand this - TIA!

[fastvideo]

Originally Posted by bmoraru

hi Andrea, please explain how to bias to class A, i don't quite understand this - TIA!

Biasing Op-Amps into Class A

[Bonsai]

I am surprised annonymous1 that you are reporting offsets at this level. Something does not sound right here. Are you willing to post up your circuit?

[leeperry]

I'm seriously amazed by how good OPA1641 sounds..I don't like OPA1611 or OPA827, but darn 1641 is unbelievable as PCM1793 LPF

[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

[luigilamarca]

please, i have need the help for BB pcm56 P , I would like to connect this dac direcly a my premplifier without opamps ,

I have read data sheet and the pin 9 have volt output and pin 2 ground
but How ?
Thanks luigi

[auddoc]

Buongiorno Luigi,

Generally it's not good design practice to have a DAC directly drive cables of any length, or another separate stage- it will perform poorly, even if it's a voltage type output. Either select a very good sounding op-amp as a driver/follower, that will have low noise, wide bandwidth, high slew rate, low output Z, and low input current, or build a discrete design with FETs or bipolars- more difficult. The BB family of op-amps like OP27 and similar are really nice sounding, quietand you can run the supplies up to (+/-)18 or 20 volts, which gives lots of headroom. What is the preamp and what is the first device the signal hits when arriving at the pre-amp input? Input impedance? Nominal line level expected is -10dBv or +4dBM? ( home & garden vs professional audio levels) Some of the big recording consoles use video op-amps as buss drivers because of these qualities plus the ability to drive low Z such as 50 Ohms. Please send the data sheet for the DAC- that would help for further advice.
Ciao,
Gregg

[luigilamarca]

thanks for your reply .
i give you more information :
i have yamaha cdx 10000 with pcm56p
but i would like to direcly the dac to input transformer of my preamplifier


this is data sheet of pcm56p
and my preamplifier is push pull transformer circuit
imput transformer is 30k-30K

i have connected pin 9 of dac to +plugs cable
and 2 pin to - plugs cable

the volume gain is good
but the sound goes up and down as if there was anyone that lowers and raises the volume

Originally Posted by auddoc

Buongiorno Luigi,

Generally it's not good design practice to have a DAC directly drive cables of any length, or another separate stage- it will perform poorly, even if it's a voltage type output. Either select a very good sounding op-amp as a driver/follower, that will have low noise, wide bandwidth, high slew rate, low output Z, and low input current, or build a discrete design with FETs or bipolars- more difficult. The BB family of op-amps like OP27 and similar are really nice sounding, quietand you can run the supplies up to (+/-)18 or 20 volts, which gives lots of headroom. What is the preamp and what is the first device the signal hits when arriving at the pre-amp input? Input impedance? Nominal line level expected is -10dBv or +4dBM? ( home & garden vs professional audio levels) Some of the big recording consoles use video op-amps as buss drivers because of these qualities plus the ability to drive low Z such as 50 Ohms. Please send the data sheet for the DAC- that would help for further advice.
Ciao,
Gregg