The Opamp thread

[Mad Max]

I'm pretty sure it was mentioned in this thread that even if x IC is discontinued, the manufacturer still has orders to fulfill with its clients, so it simply isn't going to take any new orders for that part from now on.  I imagine that opportunities for other sellers to get genuine leftover stocks and what not should continue for quite some time.
It's a shame that that fine opamp is discontinued.

 

[ScottFW]

  I'm considering to change the op amps on my Xonar Essence One and I'm considering going for 4x Muses 01 or 4x LME49990 for the IV's, and 2x Muses 01 + 2x Muses 01 for Low-Pass and buffers or perhaps 2x Supreme Sound Opamp V5 + 2x Supreme Sound Opamp V5 if they would even fit inside the Xonar Essence One.
 
But how would I know if I'm actually getting genuine and legit op-amps? The easiest way to order is through E-Bay but I'm afraid I end up with fake op-amps even when the seller is rated as "Top Seller".

If it's much less expensive than official suppliers and ships from China/Hong Kong/Taiwan, it's fake. That's my default assumption until somebody else plays the role of guinea pig, lays out their own money, and confirms otherwise. If you want to see a **** show, look at ebay listings for OPA627. For other op-amps where the fakers have actually bothered to make the printing look correct with lot numbers that could possibly have existed, there may be information out there on ID'ing the fakes by other means, such as taking resistance readings between certain pin pairs and comparing against measurements from legitimate chips purchased through official suppliers.
 
It's not just op-amps that are being faked either. Capacitors are another highly suspicious category. How many people are really going to be able to tell if there's a common cheap electrolytic inside that faked Black Gate wrapper? I've seen fakes on ebay of large value electrolytic caps that were never actually made in a legitimate version by the knocked off brand name. Who's going to know there's a cheap Chinese POS inside that can't withstand the voltage printed on the label, until it BLOWS UP in their circuit? At least with op-amps the potential damage from fakes is mostly confined to your wallet and sense of pride.
 
The LME499990 sounds pretty darn good to me in CD players and DACs. With its pending discontinuation I've stocked up a few for future personal use. Mouser still has them. They'll have 100 pieces one week, then zero, then they'll get a couple hundred more, etc. Keep checking back but I'd advise anyone with even potential interest to pick up a few before production ceases, while they're still $3 apiece.

 

[zilch0md]

  I'm pretty sure it was mentioned in this thread that even if x IC is discontinued, the manufacturer still has orders to fulfill with its clients, so it simply isn't going to take any new orders for that part from now on.  I imagine that opportunities for other sellers to get genuine leftover stocks and what not should continue for quite some time.
It's a shame that that fine opamp is discontinued.

 
That makes sense, thanks.  And it's good news. Maybe I should buy spare set of LME49990 while I can.  

 

[RamGuy]

I notice that some users on various known forums have good experience purchasing from "hifiic on ebay, but I'm still rather sceptical. Ordering for Mouser.com is not that tempting as I do not plan to do any soldering myself and they seem to only sell SOIC and nothing soldered to DIP8.
 
 
When it comes to various op amps I'm tempted on going all out on the LME49990 as they are very affordable and have great reputation. The Muses are darn expensive and I hear about a lot of people that end up with not liking them too much. Everyone seems to claim that changing the IV's is the best place to start and that would mean I need to get 4x Muses and that's just ridiculously expensive. Same goes for the Burson's compared to LME49990.
 
 
From what I can gather people seem to change IV's and buffers, but no one seems to be mentioning the Low Pass Filter. According to the op amps manual for my Asus Xonar Essence One they claim that these op amps are the ones that will affect headphones;
 
2x Low Pass Filter
4x IV's
2x Buffers
 
 
Is the reason for no one mentioning the Low Pass Filter because it's a waste to change it? Is the low pass filter something unique and special so using the same op amps for low pass is not ideal?
 
 
I was thinking of trying out;
 
2x LME49990 for Low Pass Filter
4x LME49990 for IV's
2x Dual LT1057ACN8 for Buffers

 

[zilch0md]

The Muses 01 and Muses 02 are duals, so you would only need two instead of four, but they are still crazy expensive at $150/pair from Mouser.com.  I've never heard the 01's, but don't like my 02's as much as several other less expensive op-amps. The 01's seem to be more popular.
 
I would be tempted to just leave the Low Pass Filter alone.  An LPF determines the roll-off of the highs and I can't imagine how you'd go about finding an op-amp that would impact this, as they're pretty much all striving for no attenuation at 20kHz.  
 

I was thinking of trying out;
 
2x LME49990 for Low Pass Filter   
4x LME49990 for IV's
2x Dual LT1057ACN8 for Buffers

 
I like your plan except for the LPF (but for the price of two LME49990, you might as well try it).  I think that once you go to this combo, everything you try thereafter could be a let down.

 

[RamGuy]

Ended up with saying "**** it" and purchased 6x LME49990 + 2x LT1057ACN8 + 2x Dual DIP8 to DIP8 adapters from "hifiic" on Ebay.

 

[zilch0md]

^ Awesome! Have fun!

 

[zilch0md]

This looks as if the cap's negative lead is soldered to V- (Pin 4).



And this looks as if the cap's negative lead is soldered to V- (Pin 4)



So what's wrong with this next photo by Michael V? It looks the same, to me:



Isn't the cap's negative lead going to V- (Pin 4) and the positive lead to V+ (Pin 8)? Just like the caps soldered by pelopidas?

[COLOR=FF00AA]UPDATE: No. In this photo, the DIP8 extender is upside down. The cap's positive lead is going to Pin 1 and the negative lead to Pin 5, which is wrong, as pointed out by kahei036, previously. [/COLOR]

Here's another cap done by pelopidas, where the negative lead is going to V- (Pin 4):

 

[zilch0md]

Hey Mike..
Base on your second pic it seems you have connected the bypass cap to pin 1 and 5 instead of the vcc+ and vcc-..
Hope you've already figured this out got it soldered correctly..

The arc on IC socket usually indicates it's the "up" side of the IC; you probably will notice a "dot" on an IC, that usually indicates it's pin1 (datasheet would proobably the best to tell). And this dot usually is in same direction as the arc on an IC socket.

Was your correction of Michael V incorrect?

[COLOR=FF00AA]UPDATE: I've since figured out that your correction of Michael V was indeed correct. I apologize for confusing things further.[/COLOR]

 

[Michael V]

I fixed it a while ago because I had to flip around the cap. So it looks like this now
 

 
 
I used this picture as reference

 

[zilch0md]

I fixed it a while ago because I had to flip around the cap. So it looks like this now

Now, your negative lead is going to Pin 5 and your positive lead is going to Pin 4.

I think your were (unintentionally) mislead by kahei036

[COLOR=FF00AA]UPDATE: You now have it correct, as shown above. kahaei036 was right. [/COLOR]

 

[zilch0md]

I'm sorry! That's it... The diagram I'm using is a top-down view, where your photos have beem bottom-up.

Sigh...

 

[Michael V]

Oh wait! Is it because the diagram I'm using is a top-down view?

Confused!

possibly because this person would be doing it wrong too then
 

 

[zilch0md]

possibly because this person would be doing it wrong too then

You're photos match those of pelopidas - you're both doing it the same way. And I think we can trust his experience.



UPDATE: For my own sake, if no one else's.

 

[zilch0md]

It is done!  I've finally soldered some caps to something!  LOL
 
Here's the stuff nobody tells you - I had to figure it out on my own...
 

 
Within two seconds of touching the soldering iron to the pin, the pin got so hot, it melted the surrounding plastic and pushed out the far side.   Doh!
 
I had it set to 400C, so I bumped it down to 200C, but that wasn't hot enough to desolder the lead from the damaged pin.
 
So, I tried 300C - just right!  
 
That's what she said!  (Goldilocks, that is!)
 
So, here's my 3rd attempt, this time, with shorter leads:
 
  
 
 
The soldering went surprisingly well.
 
Scotch Tape is my friend!  

  (To hold stuff where I want it.)
 
You can't tell from this angle, but the pins are clear of solder - it's only wrapped around the base of the pins.
 
Maybe I can actually solder stuff after all!  LOL
 
And here they are installed underneath the Burson V5 Duals, in my iBasso PB2, with 4x LME49990 as buffers:
 

 

 

 

 
And the sound is most definitely improved!  I find this so hard to believe, given how thrilled I've already been with the Burson V5 Duals - nine days and counting.  
 
I'd say the biggest difference the caps make is in improving dynamics. Going back to having no caps sucks some life out of my most dynamic recordings. It's not subtle, but it's not night and day, either. It is readily detectable, though - especially with tracks having momentary signals that demand a lot of power, like drum hits. And the bass is more tightly controlled - as evidenced with any textured electronic bass (Daft Punk, Hans Zimmer, etc.)  But acoustic bass is better, too. My HD800 loves the Burson V5s with caps!
 
Here's a shot taken before I added the caps:
 

 
Tidal HiFi  and Onkyo HD Player > iPod Touch 6 > Zeskit rt. angle Lightning -to- USB A cable > Oppo HA-2 Line Out > Cardas HPI (Litz wire) rt. angle 3.5mm interconnect > iBasso Pelican PB2 with Burson 2x V5 Duals in I/V and 4x LME49990 as buffers, on High Gain, balanced out > Toxic Cables Silver Poison > Sennheiser HD800
 
I've been listening to music instead of finishing this post, but now I want to gush about how great this sounds. 

 
The noise-free nature of battery power has a lot to do with the success of this rig, I'm sure, but it starts with how the iPod Touch 6 is dead silent. I've been using it and, previously, an iPad 3 as my source for my desktop rig, too - pulling digital out of them has made them my favorite source - better than my laptops, for sure.  The Oppo HA-2 supports Hi-Res files from iDevices without the need for a CCK and USB receiver.  The HA-2's ES9018K2M DAC implementation is amazingly transparent and detailed.  The treble is well separated and clean, with none of the brittle edginess the HD800 so readily discerns with lesser DAC/amp combinations.  It has none of the glare I can hear with the Oppo HA-1's ESS9018 DAC - which the HD800 hates.
 
The soundstage and imaging are crazy good - definitely a benefit of using the Burson V5 Duals - much, much better than I've heard with LME49990, OPA1612, Muses 02, or anything else I've tried in the PB2 I/V stage. 
 
Detail is through the roof, but not at all sibilant or fatiguing.  Even before adding the caps, I would have said the bass is amazingly tight and deep - not what most people associate with the HD800, but now it can absolutely growl, with lots of texture and speed. It still sounds like an HD800, not something a true bass head would want, but the bass is at an energy level that I like - very natural - realistic.
 
The dynamics are stunning, with drum hits having lots of bite. This is something I can't get from my Metrum Acoustics Octave MkII and Aurix stack - which really has me scratching my head - that a portable rig could sound so good.  Vocals are natural sounding. Drums, piano, and acoustic guitar are all so "real."  (Thank you, Burson!)  Oh, and cymbals - they are so delicately and naturally defined that I've come to really enjoy them as never before. (They sound like real cymbals instead of like rubbing two blocks of Stryofoam together.)  
 
Despite the awesome resolution, this rig remains versatile - not nearly as unforgiving of less than ideal recordings as I would expect for so highly resolving and transparent a DAC and amp combo.  The more I listen to this rig, the more I cannot believe it's happening. I've had the Burson V5 Duals for nine days now, and the honeymoon is only getting more passionate!  Everything else I have to do with my time, going to work, running errands, whatever life demands, has become a distraction to getting back to the pleasure of enjoying this rig.  (I took the day off from work to get the soldering done, because I was too busy with other domestic stuff over the weekend!  LOL)
 
I've rolled many combinations of op-amps through the iBasso PB2 over the past few years, but nothing has hit me over the head like these Burson V5 Duals, in combination with all the other pieces of this rig - and adding the caps has just kicked it up even more.
 
I took it to work with me last Friday (with the caps not yet applied) and spent about twenty minutes in a quiet conference room, with each of two co-workers, pulling up their favorite tracks with Tidal HiFi, in addition to playing several of my favorites.  They were both slack-jawed with awe.  And these are guys with whom I've demo'd some of my previous portable rigs, over the years. 
 
I'm almost ready to stop asking myself that ever-present question:  Does it get any better than this?
 
Next step: Get some holes machined into the top of a spare PB2 case I ordered from iBasso, so that the Burson V5's can stick out - like a blower through the hood of a muscle car.  

 

 
OK, that's enough gushing for now.  

 
Thanks for your trailblazing efforts, pelopidas.  And thanks to Michael V, too - for getting me sorted out on which pins to solder.  

 
Joy!
 
Mike