The Opamp thread

[Spacehead]

Quote:

Originally Posted by buz /img/forum/go_quote.gif I'm starting to think the LT1028C has too much bass. I even started eq'ing down the bass on my D2000 - sure as hell the first time in my life I ever did that . Heck it even brings out bass in the RE0... Maybe try a somewhat colder, analytic, very transparent opamp. Any suggestions?

bipolar ADA4898-1
jfet ADA4627-1

also pretty analytical and colder: AD8022, AD8066

 

[buz]

Forgive my ignorance, but what would the difference between JFET and bipolar be?

 

[Spacehead]

Quote:

Originally Posted by buz /img/forum/go_quote.gif Forgive my ignorance, but what would the difference between JFET and bipolar be?

Bipolar input op amps cannot tolerate differences in their input impedances so well.
If + input is 100K and - input 1K then bipolar op amp will generate DC offset due to high input bias currents.
JFET input op amps can tolerate this error very well and don't generate DC offset because their input bias currents are low.

This is my understanding about this much more complicated matter.

Bipolar op amps sound more classy to my ears. JFETs are like pop music, little compressed sounding.

 

[ROBSCIX]

Quote:

Originally Posted by buz /img/forum/go_quote.gif Forgive my ignorance, but what would the difference between JFET and bipolar be?

Different internal construction.

 

[buz]

So after listening to the LT1028C some more, I am getting used to the deeeep strong bass (always have been always will be a basshead). I think I rather need to fix the gain of the amp section than mess around with opamps much more. Should probably go get a soldering kit and a clue bat for my self

.

Or just go and buy that M-Stage, although with the bloody volcano still active, I doubt it could even be shipped to me

Edit: >< this close to buy it. Now of course I wonder what opamp I could put into the DAC to feed it LT1028C in DAC and headphone amp may be a little too much

 

[Spacehead]

I got my SMD CMOY working. Completely silent amp with gain of 3.

so easy to listen to that I cannot find too many special characteristics from this op amp:

here is what I thought:
sloppy?
good current output , can drive 32 ohm headphones
tight
bass is nice
very easy to listen
not too many details
pretty generic sounding op amp
good thing is though that it doesn't color the sound. but very boring if one wants to listen to op amps.

Maybe it was limited by my ground channel which is open loop class ab buffer with Panasonic FC output caps. closed loop buffers sound a lot better.

The performance of this amplifier is of course very good for the simplicity, I think I'll start making these for sale.

 

[ROBSCIX]

The 4556 are condsidered cheap generic opamps. I doubt you will find too many great points about those. They are usually used for their price, they are a jellybean opamp.

 

[ROBSCIX]

double post, darn site!

 

[buz]

Is there any place to get LT1028A (preferably on a DIP8 dual adapter) and LME49880 at reasonable prices (as well as DIP8 AD8022/66)? Ebay does not seem to have any... Still thinking about those AD797BR, too.

 

[12Bass]

Saw these in another thread.... though I have some skepticism due to NJR's previous devices:

-MUSES Official Website-"MUSES Series" high quality sound bipolar-input dual operational amplifier

 

[Spacehead]

I got cured! I bought worse headphones with inferior resolution, Philips SHP2500. With them on I have yet found myself wondering how would this song sound with another op amp, because, I bet I couldn't hear the difference!

But when I actually will try different op amps with those headphones, will I hear something different...?

 

[leeperry]

Quote:

Originally Posted by Spacehead /img/forum/go_quote.gif I got cured! I bought worse headphones with inferior resolution, Philips SHP2500.

you're a great problem solver

anyone tried this guy's adapters? http://shop.diyrealaudio.com/product...roducts_id=851

the guy who runs that browndog company told me that he's almost deaf, and that ebay seller says that the design of the browndog's is just terribly wrong: Dual SOIC to DIP-8 Convert PCB Adapter SMD OPA627 - eBay

I think I'll solder 2*LT1028ACN8 on the former link's adapter, and compare to its browndog counterpart

 

[12Bass]

Have considered buying some of those HK adapters, but don't need any at the moment. A comparison would be interesting.

 

[Mad Max]

Would be nice if their single soic-to-dip8 boards had the leads and pins perpendicular like that.

 

[leeperry]

oh, I didn't realize that the bottom pins were not in the center like on the browndog...so that means that the audio path of one channel is longer than the other? hummmm, very strange idea