The Opamp thread

[Avro_Arrow]

Better for what?
 
Quote:

I'm looking at some Opamps are there anything that is better than the OPA128? I know they are expensive, but from what I've read they are supposed to be one of the best.

 

[riktw]

Some stuff i learned today:
 
S THS3001 is a mean mean evil opamp, oscillates like a madman unless your PCB is really well designed.
But when you got it to stop oscillating it sounds really nice and clear
Well, at school the best thing i had to compare it against was a NE5532
Designed and ordered a small PCB to test them with, hope they sound nice after listening a while to.
 
http://focus.ti.com/docs/prod/folders/print/ths3001.html

 

[Mad Max]

THS4081 is really nice, but needs very clean power.

 

[Armaegis]

Can someone recommend some opamps to use for taking in a line level signal, then outputting the sums or differences of those signals into another amp? It boils down to what I'm trying to accomplish in this thread: http://www.head-fi.org/forum/thread/530374/building-an-active-balanced-ground
 
I'm planning on building the circuit into either a 3 channel b22 or a 3 channel a20 (maybe both) and would like to simply tap power off the s22 without having to rig someting up for lower voltages.
 
Preference for single channel opamps (but I'm open to suggestions), and I would like to try to keep costs down. I need a minimum of three opamps for the circuit, possibly five if I'm using input buffers (though the buffers would not necessarily have to be the same as the operational ones, and I don't mind using dual channel here either). I would be happier buying several sets of midrange opamps and being able to experiment rather than spend a ton of money on just a single high end set. I will also being going no higher than x2 or x3 for gain, so they will need to be stable in that range.
 
That's about all the info I can think of off-hand.
 
edit: and prefererably in DIP-8 so I can change them out easily with sockets
 
Thanks.

 

[Avro_Arrow]

OPA1641 sounds decent and is pretty easy to use.

 

[Armaegis]

Quote:

OPA1641 sounds decent and is pretty easy to use.

Is there a DIP8 version?

 

[Avro_Arrow]

No, you have to use a Brown Dog to get DIP8
 
OPA132 would give you a native DIP8 chip with reasonable quality
and low price. Not as good as the OPA1641 though...
 
If you can use a BiPolar op amp in your design, LT1363 is quite good
and available in DIP8. You have to take care to design the input properly
to avoid DC offset but otherwise it is a pretty forgiving chip.
 
Quote:

Is there a DIP8 version?

 

[Armaegis]

Thanks.
 
Hmm, I don't think I've got a steady enough hand to solder anything onto a browndog (though I guess it doesn't hurt to try... it only costs money right?

)
 
Unfortunately, the OPA132 is not in stock at Digikey.
 
Here are a few I've been looking at (mostly just gleaned from reading or looking at AMB)
AD797
OP27GP (biased to class A?)
OPA228PA or 228P
OPA134
OPA227
more expensive ones...
OPA211
LT1028
OPA627
 
I've got a few others scrawled on some pieces of paper somewhere, but I'll dig those up later.
 
Are some opamps better at driving high impedance loads (such as an amp input) vs driving relatively low headphone loads?

 

[Mad Max]

Quote:

...  
Are some opamps better at driving high impedance loads (such as an amp input) vs driving relatively low headphone loads?

That's what BUF634 is for. 

 

[Avro_Arrow]

Or it's little brother, the OPA633 buffer....
 
Quote:

That's what BUF634 is for. 

 

[Mad Max]

ADA4610
 
I can't wait to audition this one versus 4627.  =o

 

[Theodore]

I have the Asus Essence ST card,together with its daughter card H6.Have you any idea about the opamps of this H6 card and the possibility of changing them to something else?

 

[SpudHarris]

 
Quote:

ADA4610
 
I can't wait to audition this one versus 4627.  =o

Yeah, looks interesting.
 
Is the 4627 your favourite? I like that chip also but am rolling OPA602BP,[font= 'ms pgothic'] OPA209 and OPA121 at present in my Ibasso P4. Have you tried any of those?[/font]

 

[Mad Max]

I am awaiting a pair of 209 just out of curiosity.
 
OPA121?  Its datasheet dates back to the eighties, is it any good? 

 
I don't have OPA602 on the way, maybe next time.
 
Yup, 4627-1B is still my favorite for being uber precise and a little lively.  Its soundstage is my favorite as well.
Like my headphones don't already have unrealistic, ultra-sharp imaging.

 

[Mad Max]

So OPA209 is here, but I am out of spare adapters.
 
Also, I hadn't tried out OPA827 out in my portable amp for some reason, and now that I have: 

 

 

 

 

It shines very differently than when in my desktop gear.  I love it a lot more now.

 
It brings out the best in the Minibox-E+, even more than 4627-1B could!