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The Opamp thread - Page 295

post #4411 of 4693
Quote:
Originally Posted by lawrywild View Post

Just finished rolling some opamps in my Little Dot I+ Hybrid (with Mullard M8100), here are my notes

 

OPA827 (SOIC x2)

- Fast and articulate

- Severely lacking bass impact or depth

- Bright/fatiguing

- Excellent clarity

- Ultra-detailed

- Slightly artificial but relatively exciting sound



 

OPA1641 (SOIC x2)

- Good bass

- Excellent clarity

- Excellent separation

- Sparkly but very sharp top end

- Slightly sibilant

- Detailed

 

One can safely bet that these "bright" opamps were oscillating.

post #4412 of 4693

Interesting that a satisfying and acceptable signal is produced in a professional field to be sent along for processing to A/D converters and finally converted back D/A for human ear listening after all the mixing and manipulation has been accomplished. I see the chip(s) listed for mass mastering. So what headphones do these pros use? And what is inside their mixing boards? I suspect only a few even try to use this technology to its full potential. Many lack the talent to sound good and need audio technical enhancements or the clean mike signal will expose them for what they are i.e. lacking in talent or their flaws are their talent. Bob Dylan comes to mind as he could ruin any set of speaker with that scratchy voice of his, probably why a 'folk' song category was created for such performers. On the other end of the spectrum (think Alanis Morissette) there are those in-studio professionals that you never know their names except within the industry unless credited on CD inserts. The latest and greatest movie technology productions are always fun to listen to and watch because of constant improvements.

 

Being a layman I digress to rambling on but as I posted elsewhere,  graphene is the next craze so get ready to unload your current stash of headphones and speakers.
 


Edited by razzz42 - 6/6/13 at 2:28pm
post #4413 of 4693
Quote:
Originally Posted by 00940 View Post

 

One can safely bet that these "bright" opamps were oscillating.


Why is it safe to bet on that?

post #4414 of 4693
Quote:
Originally Posted by lawrywild View Post


Why is it safe to bet on that?

 

Opamps of that quality don't sound sibilant or have a sharp top end. That's a clear sign of a problem in the frequency response and those opamps should be ruler flat at audio frequencies. Or it could be a sign of high order distortions. Considering the opamps are buffered by transistors, they shouldn't be so badly loaded that the thd would rise enough for it to matter. So there must be a problem in there.

 

Especially considering how many people are reporting the opa827 to be similar in character to the opa627, which is anything but fatiguing.


Edited by 00940 - 6/5/13 at 6:11pm
post #4415 of 4693
Quote:

Originally Posted by 00940 View Post

 

Especially considering how many people are reporting the opa827 to be similar in character to the opa627, which is anything but fatiguing.

 

Have you really read many people claiming this? IME 627 sounds dark and tubey and 827 the complete opposite. There's a good reason why the latter is much cheaper than the former IMHO.

post #4416 of 4693

Yep, really. Make a search on diyaudio for a start.

post #4417 of 4693
post #4418 of 4693

Hi all,

 

I'm looking for some op amp advice for a new DIY project. My project will contain an opamp treated in a similar manner to an M^3 (i.e. class A biased 5mA driving an extremely high impedance load). I'm looking for +/-18V rail capability and sound-wise detailed but not bright, possibly mellow but overall detailed and neutral. It can be any type of input stage as I'm going to wrap it into a servo loop using either a precision or a chopper.

Current favourites look to either LME49990 or OPA1611 but please recommend anything, there are so many that I just get lost, so I thought I'd ask the folks with experience.

 

Cheers! 

post #4419 of 4693
Quote:

Originally Posted by Goobley View Post

 

I'm looking for +/-18V rail capability and sound-wise detailed but not bright, possibly mellow but overall detailed and neutral.

 

OPA2604, and the LME49860.  I'm not sure about warm and neutral going together.


Edited by holland - 6/24/13 at 8:35pm
post #4420 of 4693
Quote:
Originally Posted by Goobley View Post

Hi all,

 

I'm looking for some op amp advice for a new DIY project. My project will contain an opamp treated in a similar manner to an M^3 (i.e. class A biased 5mA driving an extremely high impedance load). I'm looking for +/-18V rail capability and sound-wise detailed but not bright, possibly mellow but overall detailed and neutral. It can be any type of input stage as I'm going to wrap it into a servo loop using either a precision or a chopper.

Current favourites look to either LME49990 or OPA1611 but please recommend anything, there are so many that I just get lost, so I thought I'd ask the folks with experience.

 

Cheers! 

LME 49990 seems to be a standard on some commercial sound adapters (cards and USB) and playback hardware like CD and DVD players. Good on clarity which helps separation, maybe favors the highs, voice range is excellent, lows good but are not going to absolutely pound. You could do a lot worse and not much better, IMHO. It's a single channel chip.

post #4421 of 4693
Quote:
Originally Posted by holland View Post

 

OPA2604, and the LME49860.  I'm not sure about warm and neutral going together.

 

Now I use OPA627 in my headphone amp, before I test some other OPA's 

http://www.head-fi.org/t/99596/new-wna-mkll-head-amp-kit/750

 

OPA604 sounds a bit muddy in this design, with LME49710 - 'It's imagination from me or not - with LME49710 and K 701 I feel the trap is littleness sharper .........'

 

This OPAs I test

 

Railsplitter
LM6171
 
AMP
LM6171
AD843
OPA602
AD847
LT1056
LT1022 
TLE2071
OPA134
OPA604
LME49710
OPA627
post #4422 of 4693

Which op-amp would you recommend for Audio-Technica A900X headphones on Asus Xonar STX out of these:

 

OPA2111

OPA2132

OPA2107

LME49720NA

LM6172

LME49860NA

 

 

I currently have two OPA2132s on I/V and one OPA2111 on buffer.

Would it better to switch out the OPA2132s with OPA2107s?

Any feedback will be appreciated!

post #4423 of 4693
Quote:
Originally Posted by razzz42 View Post

LME 49990 seems to be a standard on some commercial sound adapters (cards and USB) and playback hardware like CD and DVD players.

 

Huh?  Please advise me of a single DVD player or stereo receiver (for speakers) which uses LME49990, I'd buy it in an instant!

post #4424 of 4693
Quote:
Originally Posted by Theta Alpha 1 View Post

 

Huh?  Please advise me of a single DVD player or stereo receiver (for speakers) which uses LME49990, I'd buy it in an instant!

Even though it is a relatively a new chip still finding its way into mainstream production, it can be found in hardware today. I read it listed inside a few sound adapters (USB, stand alone, etc.) but I am not going to do all your homework for you.

 

Quote:
The quality of the CD 1 analog section is as important as its digital section. Designing an extremely accurate, stable, and linear digital section is a pointless exercise if the analog section does not have the very lowest possible noise to avoid degrading the purity of the decoded signal. It is for this reason that the CD 1 utilizes National Semiconductor LME49990 op amps exclusively in its analog section. The LME49990 is designed specifically for ultra-high end audio applications.

Parasound - Halo CD 1 - CD Player

 

That's why a $100 sound card with swappable op-amp sockets is a big plus, you can try out the latest and greatest op-amps.

post #4425 of 4693
Quote:
Originally Posted by Raito View Post

Which op-amp would you recommend for Audio-Technica A900X headphones on Asus Xonar STX out of these:

 

OPA2111

OPA2132

OPA2107

LME49720NA

LM6172

LME49860NA

 

 

I currently have two OPA2132s on I/V and one OPA2111 on buffer.

Would it better to switch out the OPA2132s with OPA2107s?

Any feedback will be appreciated!

My A900X favors the lows, not that the lows are natural but it does pound a bit, so you would want to use chips that would favor more high frequencies unless you are a complete bass freak. I'd stick LME49990MA in the I/V and then worry about fine tuning sounds to your liking with the one buffer socket.

 

On Ebay some listings from China sell (1) LME49990MA on an adapter board for cheap but you need (2) LME49990MA on a (1) adapter board being that they are single channel. So, you need (2) adapter boards for the (2) I/V  sockets which would be utilizing (4) LME 49990MA between them.

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