The Opamp thread
Mar 9, 2014 at 10:14 PM Post #4,681 of 7,383
  Don't worry...
 
I can sort you out dependant on how many you are after. I still have a few left over, both adapters and OpAmps so let me know what you need and we can work something out.
 
Cheers
 
Nigel

Actually sorted it out in the end. Local company bringing the bits in for me. Bit more expensive but what the heck...I'm a mad gamer that likes to immerse myself in the sound of the game.
 
Mar 17, 2014 at 10:59 AM Post #4,682 of 7,383
Well the good news is that these OPA2111AM's are the real deal gold plated legs and all. The little adapters that come with are good when you need a quick way to use a TO99 in a DIP socket, no soldering or Brown Dog required.

Anyone interested in getting one of these? I already have two on Brown Dogs as spares but can order more. You can have them for same price as me (£6) + shipping. These retail for £39.00 + VAT each
eek.gif
If you want them on Brown dogs ready to roll it will be an extra £2.50 (£8.50 total).


Pic:

OPA2111AM.jpg

 
I ordered a OPA2111KP (PDIP) test sample now. I will test them in my GSP Audio Solo headphone amp.
 
Gives a single channel version of the OPA2111 too  - PDIP or TO99?
 
From where you get the white adapter socket - TO99 to PDIP?
 
Mar 17, 2014 at 12:01 PM Post #4,683 of 7,383
I ordered a OPA2111KP (PDIP) test sample now. I will test them in my GSP Audio Solo headphone amp.


[COLOR=525252]Gives a single channel version of the 
[/COLOR]OPA2111 too  - PDIP or TO99?


From where you get the white adapter socket - TO99 to PDIP?


They came with the TO99's. You just push and the legs just split into a DIP footprint (with a little help)...
 
Mar 20, 2014 at 11:42 AM Post #4,685 of 7,383
I get an OPA2111 (KP - Dual LN DIFET, 8 DIP) sample and put them into my headphone amp GSP-Audio Solo DIP socket.
Before I had tuned them with an LME49720HA OPA (original are an AD823AN)
 
In my second headphone amp WNA MKII I use two OPA627  now.
The OPA627 is an Precision High-Speed Difet® Operational Amplifier and have an slewrate from 55V/usec
The OPA2111 is an Dual Low-Noise Difet® Operational Amplifier and have only an slewrate from 2V/usec
 
I wonder thats the OPA2111 sounds so good too, despite its low slew rate.
It seemed to be the better choice that the modern high end LME49720HA
 
Modifications are my passion 
normal_smile .gif

 
In all the time I had done this, mostly I preferred FET input OPAs before BJT input OPAs.
 
TI offers other high fidelity JFET input audio dual op amps like OPA2134, OPA1642 and OPA1652, or bipolar input audio duals like OPA1602, OPA1612 and OPA1662.
 
What are your experience between OPA2111 and OPA2134 - the others from TI are only SOIC packages. Another way is to use an adapter - two 8 DIP to one.
 
Mar 20, 2014 at 3:59 PM Post #4,686 of 7,383
  I get an OPA2111 (KP - Dual LN DIFET, 8 DIP) sample and put them into my headphone amp GSP-Audio Solo DIP socket.
Before I had tuned them with an LME49720HA OPA (original are an AD823AN)
 
In my second headphone amp WNA MKII I use two OPA627  now.
The OPA627 is an Precision High-Speed Difet® Operational Amplifier and have an slewrate from 55V/usec
The OPA2111 is an Dual Low-Noise Difet® Operational Amplifier and have only an slewrate from 2V/usec
 
I wonder thats the OPA2111 sounds so good too, despite its low slew rate.
It seemed to be the better choice that the modern high end LME49720HA
 
Modifications are my passion 
normal_smile .gif

 
In all the time I had done this, mostly I preferred FET input OPAs before BJT input OPAs.
 
TI offers other high fidelity JFET input audio dual op amps like OPA2134, OPA1642 and OPA1652, or bipolar input audio duals like OPA1602, OPA1612 and OPA1662.
 
What are your experience between OPA2111 and OPA2134 - the others from TI are only SOIC packages. Another way is to use an adapter - two 8 DIP to one.
 
 
To my ears the OPA2111KP sounds very bright and clean, almost harsh...The OPA2134 sounds warmer and less clear, almost fuzzy...

 
Mar 21, 2014 at 5:38 PM Post #4,687 of 7,383
Just checking I have these amps in the right way.
 
The pin that sticks out is pin 8 which based on the DIP8's that were in the slots should be in the right place...
 
Any pointers before I flick the switch and fry the board :)
 
Cheers
 
motorwayne
 

 
Mar 21, 2014 at 11:02 PM Post #4,689 of 7,383
Yeah, didn't see that but ended up just matching up to the diagram from farnell. Booted up all good...sounds a lot better, richer.
 
That being said, with these babies in, I can have the plastic shield piece over that area...wonder if it makes a difference to interference?
 
Any ideas from other Tit HD owners?
 
Mar 31, 2014 at 11:11 PM Post #4,690 of 7,383
I'm designing a Gainclone for Headphones, just as a simple fame, since it's my first time designing. I am going to use a gain of 6, but I can't seam to select my Opamp. I'm not going to use the LM3875 since it's so high powered. I was thinking maybe LME49990 or OPA827. Any other ideas? 8 pin DIP preferred, but not necessary. I really have no idea what Opamp to use, so any help would be great, Thanks!

Here is my schematic for the simplest gainclone around

I'm assuming this will work for SE use, I'll just share the ground between the two amp boards.
 
Apr 1, 2014 at 1:34 PM Post #4,692 of 7,383
I suppose it's a CMOY. I didn't really think about that lol. I might add a MOSFET follower on later. I'm planning on running it from +-15V supply rails. I have never designed an amp before, so I figured I would start with the simplest design possible; the standard non-inverting Opamp. I plan to share the ground between the two channels
 
Apr 29, 2014 at 10:40 PM Post #4,694 of 7,383
So...I was working replacing the stock front channel JRC5532D opamp in a Klipsch 4.1 preamp after already finding and upgrading the stock sub output ST TL082CN opamp with an AD 8066AR and all replacing all 6 resistors on the little board with Nichicon 10uf 25 volt (aluminum audio grade, mainly due to height restriction when closing it back up).
 
After searching for a replacement for the 5532D that would make it worth my while to bother with it, I decided on a dip 8 LME 49860NA. I don't know if it is the dual channel version of the single channel LME49990 or something close but reviews were okay with it. Remove some cement and then desoldered the 5532D and its accompanying (2) resistors soldered to the backside legs (inputs?), apparently helps eliminate oscillations. Hoping the new 49860NA  opamp would not need them. Went well, installed a DIP 8 socket. Left the other stock rear channel 5532D in place until the results are in. Defluxed everything and recoated with spray silicone. I figure I can do as good a job as any Chinese 10 year old slave laborer. Went to my mess of opamps and thought I picked out one of the two new 49860NA  but no by mistake had a LM 4562NA (didn't even know I owned one) what are the chances?
 
Install it, turned it on and I go, "What a waste of time and money this was." Lows were missing, highs were clear to the point of being shrill, mids nowhere to be found. If it needed breaking in, I doubted it would ever recover. Having the DIP 8 socket installed, I begin digging for some old standby opamps to checkout and discover I have two 49860NA in the mix. Go check the occupied DIP socket and confirm it is a 4562NA sitting in it and grab the eBay $5 special yellow handled opamp tweezer/removers and install the 49860NA and turn the system back on.
 
The difference is between night and day. Clarity with clean highs and lows and mids mixed right in between, nothing really stands out unless there is a flute playing or bass drum hit. Vocals are clear and true. If I am missing warmth or am hearing sibilance, hard to tell, may be the recording(s) but the great detail adds to the separation (staging).
 
After a year or two, I am still getting use to the clarity in lows. No longer am I hearing thuds and booms but musical bass notes by using decent opamps plus at low power points (don't have to turn it up for lows). Also I find movies or audio tracks that use AAC audio are the most compact and best at reproducing sounds. I have to use Foobar for playing AAC back (added the plugin? Can't remember) but can't edit the properties i.e names, dates, tracks but there is absolutely no degradation when I rip an audio track from a movie or off You Tube now (mp4 files). I can still convert to other formats via Foobar with some warning message that the new music file won't be any better except a larger file which it always is compared to the original AAC file.
 
Testing mostly with a CD album, Title : Morph The Cat (2006) Donald Fagen. Has good ranges and some tight bass, well recorded. Ripped:  Baby, It's Cold Outside from the ending movie soundtrack ELF (2003), kept it in its AAC format, sounds better than the CD movie sound track album.
 

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