[393699]

   
"The bass has better extension...it is much less loose sounding than the default OPA2134." (now you have my complete attention).
 
I appreciate the ear-friendliness of the stock HPA-1. It's the opposite of bright, also a compact & effective system pre-amp, once the woeful volume knob is replaced w/one that can easily be seen. But it was easy to tell that the stock bass is somewhat loose & "boomy." One of my favorite inexpensive Chinese closed back headphones, the Yenona Adapter Free DJ model, sounded distinctly boomy on the HPA-1, but not on 2 other SS amps (Burson Soloist amp/preamp; and Lake People G109-A).
 
Your description of the LME49990 intrigues me. I may have to try this. But how exactly do you buy this opamp in such a way that it installs properly in the HPA-1? Does the stock opamp come configured properly for the HPA-1, or do you have to buy 2 set onto an adapter, as I did for the OPA627?
 
And where did you buy yours? Obviously I want to avoid fakes, which are very common, as @leeperry pointed out.

 
You can purchase from this guy on EBAY. They are definitely authentic. Yes, it comes with two on the adapter. I think you will be impressed. The LME49990 is a far better sounding opamp than the OPA2134. There is no question about it. It is so much more refined, articulate, accurate, and detailed. I will be shocked if you come away unimpressed.
 
http://www.ebay.com/itm/1PC-DUAL-SOIC-LME49990-OP-AMP-MODULE-DIP8-/201562948955?hash=item2eee16855b:g:A9QAAOSw6oBXEnVs

 

[Pharmaboy]

   
You can purchase from this guy on EBAY. They are definitely authentic. Yes, it comes with two on the adapter. I think you will be impressed. The LME49990 is a far better sounding opamp than the OPA2134. There is no question about it. It is so much more refined, articulate, accurate, and detailed. I will be shocked if you come away unimpressed.
 
http://www.ebay.com/itm/1PC-DUAL-SOIC-LME49990-OP-AMP-MODULE-DIP8-/201562948955?hash=item2eee16855b:g:A9QAAOSw6oBXEnVs

 
Just purchased it. Went from "I never heard of this" to "I gotta have it!" in ~3 minutes (a personal best).
 
Seriously, checked comments on this opamp, and you have lots of company in liking it. Others said things relatively similar to what you did here, leading me to believe this could actually do some sonic good for my beloved HPA-1.
 
And it's cheap!
 
Thanks very much for your help.

 

[393699]

   
Just purchased it. Went from "I never heard of this" to "I gotta have it!" in ~3 minutes (a personal best).
 
Seriously, checked comments on this opamp, and you have lots of company in liking it. Others said things relatively similar to what you did here, leading me to believe this could actually do some sonic good for my beloved HPA-1.
 
And it's cheap!
 
Thanks very much for your help.

 
Hey, no problem, dude. You will be impressed. The first thing you will notice is the soundstage improvements, and the tighter bass. It really brings out the details in the music and gives you that head bobbing and foot tapping feel. I was immediately impressed with the instrument separation in various CDs I listened to yesterday. It is a rather revealing opamp. The bass on the opamp is very fast, accurate, and tight. There is no boomyness to it at all. The treble is very clean and articulate. The treble extends far better than the OPA2134, but it is so much cleaner sounding. As I mentioned before, male vocals really get pushed forward in the mix and are more pronounced. Everything sounds very realistic. Post back when you get it installed.

 

[Pharmaboy]

   
Hey, no problem, dude. You will be impressed. The first thing you will notice is the soundstage improvements, and the tighter bass. It really brings out the details in the music and gives you that head bobbing and foot tapping feel. I was immediately impressed with the instrument separation in various CDs I listened to yesterday. It is a rather revealing opamp. The bass on the opamp is very fast, accurate, and tight. There is no boomyness to it at all. The treble is very clean and articulate. The treble extends far better than the OPA2134, but it is so much cleaner sounding. As I mentioned before, male vocals really get pushed forward in the mix and are more pronounced. Everything sounds very realistic. Post back when you get it installed.

 
OK, the LME49990 arrived this morning. A very nice looking little device, too...surface mounted, if I'm not mistaken. Very neat & clean.
 
I've installed it in the HPA-1, hopefully correctly. In that regard, I have a lame/newbie question:
 
-- Given that the OPA2134, as installed, has a physical notch in the end of the mount, which faces backwards (toward the back panel w/RCA ins & outs)
-- And given that the LME49990 has no physical notch in the mount, but does have an outlined notch on one end (ie, outlined w/a silver line that runs the top mounted device)
 
Was it correct for me to install this w/the outlined end facing backwards?
 
There are only 2 ways to plug this into the HPA-1: w/that outlined notch facing backwards; or w/it facing forward.
 
Does this even matter? I'm a little reluctant to turn this on w/o an answer to this (lame) question first.
 
Thanks!

 

[393699]

   
OK, the LME49990 arrived this morning. A very nice looking little device, too...surface mounted, if I'm not mistaken. Very neat & clean.
 
I've installed it in the HPA-1, hopefully correctly. In that regard, I have a lame/newbie question:
 
-- Given that the OPA2134, as installed, has a physical notch in the end of the mount, which faces backwards (toward the back panel w/RCA ins & outs)
-- And given that the LME49990 has no physical notch in the mount, but does have an outlined notch on one end (ie, outlined w/a silver line that runs the top mounted device)
 
Was it correct for me to install this w/the outlined end facing backwards?
 
There are only 2 ways to plug this into the HPA-1: w/that outlined notch facing backwards; or w/it facing forward.
 
Does this even matter? I'm a little reluctant to turn this on w/o an answer to this (lame) question first.
 
Thanks!

Yes, you have installed it correctly. If you installed it backwards, you would not damage anything. You would just have no sound. How do you like it ?

 

[Pharmaboy]

 
Yes, you have installed it correctly. If you installed it backwards, you would not damage anything. You would just have no sound. How do you like it ?

 
I'm relieved to hear I did this correctly!
 
Now I'll put the HPA-1 in the system to burn in for several hours, then will listen to it tonight.
 
More to follow!

 

[Pharmaboy]

 
Yes, you have installed it correctly. If you installed it backwards, you would not damage anything. You would just have no sound. How do you like it ?

 
I hear music through it, so all is apparently well.
 
I'm lucky to have a lot of flexibility in this system. My NOS 19 DAC has 2 RCA outputs, both live all the time, so I typically run 1 headphone amp as preamp/main (for past week that's been a new/used Audio GD SA-31SE, very interesting unit), w/the Lake People G109-A as 2nd HP amp.
 
Just replaced the G109-A with the HPA-1 + connected sub + speakers to its outputs. So now the HPA-1 is powering the speakers & actually sounds pretty good (at least at low volume).
 
In 3-4 hours I'll give it a listen on headphones.
 
(life is good)

 

[393699]

   
I hear music through it, so all is apparently well.
 
I'm lucky to have a lot of flexibility in this system. My NOS 19 DAC has 2 RCA outputs, both live all the time, so I typically run 1 headphone amp as preamp/main (for past week that's been a new/used Audio GD SA-31SE, very interesting unit), w/the Lake People G109-A as 2nd HP amp.
 
Just replaced the G109-A with the HPA-1 + connected sub + speakers to its outputs. So now the HPA-1 is powering the speakers & actually sounds pretty good (at least at low volume).
 
In 3-4 hours I'll give it a listen on headphones.
 
(life is good)

It is an amazing sounding opamp. The difference when compared to the stock OPA2134 is night and day. It is detailed, transparent, and very accurate. You will be impressed.

 

[Pharmaboy]

   
Hey, no problem, dude. You will be impressed. The first thing you will notice is the soundstage improvements, and the tighter bass. It really brings out the details in the music and gives you that head bobbing and foot tapping feel. I was immediately impressed with the instrument separation in various CDs I listened to yesterday. It is a rather revealing opamp. The bass on the opamp is very fast, accurate, and tight. There is no boomyness to it at all. The treble is very clean and articulate. The treble extends far better than the OPA2134, but it is so much cleaner sounding. As I mentioned before, male vocals really get pushed forward in the mix and are more pronounced. Everything sounds very realistic. Post back when you get it installed.

 
I just listened to a wide assortment of familiar cuts (classical, jazz, top studio work by Donald Fagen, reggae, AfroPop), using headphones I'm intimately familiar with on the HPA-1, the Marantz MPH-2's.*
 
Damn--I am VERY impressed! Had no idea that swapping opamps to the LME49990 could improve an amp so much (an amp I liked a lot to begin with).
 
Everything you say is true: the treble is more extended and definitely more clear; the soundstaging is almost dramatically expanded and improved; and the bass is obviously tighter, less "boomy." I would add that the midrange is pulled forward a little and greatly expanded in detail (which also feeds into the greatly improved soundstaging & channel separation). I'm hearing all sorts of midrange details (things like drumming, the little percussive sound of guitar strings, and vocal timbre) that were buried pretty far down previously. Overall, the sound is more balanced, even across the frequency range, and flatter/less scooped in the midrange.
 
But perhaps the best thing is that this opamp isn't really altering or degrading the basic sound profile of the HPA-1 (warm, euphonic, listenable--not a detail- or treble-cannon, just a very pleasurable listening experience); instead, it extends it & refines that sound. Same HP amp, but evolved, clarified, solidified. Different, but the same.
 
These improvements are not minor. They're easy to hear. I find myself listening at a somewhat lower volume and hearing more...w/o realizing it, I was using the volume knob to "goose" more sound & clarity from the HPA-1 (something my tinnitus does not appreciate).
 
@DW75, I am in your debt for turning me onto this opamp!
 
* highly recommended, relatively inexpensive, solid closed back design (1 of the 5+ rebrands of the ISK MDH9000; Marantz is my favorite)

 

[393699]

Great to hear it worked out. Of all the opamps I have heard, my two favorites to date are the LME49990 and the AD8620. The LME49990 just offers an accurate presentation of the music. Detailed and neutral, with nice extension at both ends. I do not experience any fatigue at all with my HPA-2 paired with my DT880 Premium 250 Ohm using that opamp.

 

[Thenewguy007]

OK, the LME49990 arrived this morning. A very nice looking little device, too...surface mounted, if I'm not mistaken. Very neat & clean.

I've installed it in the HPA-1

How do you install it? Just pull out the old one & insert the new one?
Is it that simple?

 

[Pharmaboy]

How do you install it? Just pull out the old one & insert the new one?
Is it that simple?

 
Yes and no. It really is that simple in practice (unplug the stock opamp; plug in the LME49990). However, these opamps are tiny (fingers look like trucks next to them) and not easy to grasp. I had the benefit of certain tools that made it much easier:
 
-- Jeweler's lamp: it's a ring-shaped flourescent lamp w/a magnifying lens in the center (covered by a plastic flap/cover that can be left open, or closed). It's incredibly handy for small electronics tasks, also watch stuff like taking links out of stainless steel watch bracelets; swapping leather bands, etc.
 
http://www.lampsplus.com/products/magnifying-clamp-on-desk-lamp__15330.html
 
-- Watchmaker's tweezers (set of 3): 1 of this set opens to ~5/8" inch & has lightly serrated inner edges, also is a little sturdier on the business ends. This is what I used to carefully pry out the stock opamp and replace w/the new one.
 
The LME49990 opamp is well made, a sturdy little thing. It perfectly plugs into the 8 holes in the circuit board (2 parallel rows of 4 holes each). BUT...you have to be certain that each tiny little prong is actually seated in its assigned hole, before pushing it securely in. That's where the magnifying lamp came in handy.
 
You could do the same exact things using your fingers + a 3-4" wide magnifying glass--depending on how small your fingers are, and how good your vision is.

 

[leeperry]

pull out the old one

 
http://www.ebay.com/itm/190998454958 

 

[Pharmaboy]

   
http://www.ebay.com/itm/190998454958 

 
Sweet!
 
Didn't even know such a thing existed.

 

[leeperry]

Been in here for a while 

 
Anyway yes, 49990 brings mstage to a whole new level and next step would apparently be to bypass its DC decoupling input caps FWIR.....anyway, I got a spare mstage for crazy experiments that'll soon see some action goin'