[ecohifi]

Quote:

no warnings to the newbe that AD797 is not strictly speaking "unity gain stable"??
 
not exactly helpful - the chip needs extra external components to be stable at low gains - can't be "dropped in" to most op amp circuits, even with adapter
 
some here might benefit form this thread:
 
http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
 
I may not share the belief system that op amp rolling is a great idea but I don't see an excuse to set people up to fail by not giving them necessary engineering information

Jcx,
 
good point, in the unity gain experimental pre I have, the AD 797 do not work!!!  In this unity gain circuit I have strickly used unity gain opamps and even some begin to sound thin and decided to distort.  An example is the LME 49990 that requires proper psu decoupling caps.  Another is the limited voltage supply requirements.  I had the AD 8066 in mind but thats limited to +-12V.  The circuit I am using has a +/-15V. 
Without a scope it is hard to tell, some say that when an opamp oscillate the temp increases and becomes hot to touch.  I have noticed that some opamps are inherently hot anyway thats why a scope is required.  I use to have access to one but not any more.
 
It is also good practice to google the device data sheet and download it and decide whether the device will suit your circuit.  The other tip is to find a device that is similar in requirements to the device you plan to replace or roll. 


 
 

 

[Mad Max]

Yes, opamps do become too hot to the touch when they are oscillating.  They're supposed to be lukewarm, even with 30V across the power pins as far as I know (excluding things like class-A biasing and what not).
 
Most people would be confused by your post and jcx's and know absolutely nothing about opamps other than that socketed ones can be swapped out with others.  How would you help them?  They seem to just want to go with whatever others are raving about.  For example, people are rolling LME49720 into the M-Stage and raving about the sound, but one head-fier has found that it is not suited for that particular circuit at all to begin with:
 
Quote:  thread

... LME has offest that goes up within volume band raises slowly with gain (8mV to 18mV). This means that LME does not like changes in input resistance and needs steady resistance, OR FEEDBACK (that LC [or M-Stage] does not have). Furthermore, AD797 (the best, the fastest, etc...) opamp starts with 10mV and in high gain has huge amount of DC offset (100mV and more) which means that is not good for this kind of setup, at all...

 
 
There's guides to equalizing your headphones around here but none on general opamp-rolling.  There's the occasional thread for a specific component, and mostly people's impressions from "blind-rolling" at that.  We should probably put together a concise thread for others to read and help reduce "setting up people to fail".

 

[SpudHarris]

Quote:

Yes, opamps do become too hot to the touch when they are oscillating.  They're supposed to be lukewarm, even with 30V across the power pins as far as I know (excluding things like class-A biasing and what not).
 
Most people would be confused by your post and jcx's and know absolutely nothing about opamps other than that socketed ones can be swapped out with others.  How would you help them?  They seem to just want to go with whatever others are raving about.  For example, people are rolling LME49720 into the M-Stage and raving about the sound, but one head-fier has found that it is not suited for that particular circuit at all to begin with:
 
There's guides to equalizing your headphones around here but none on general opamp-rolling.  There's the occasional thread for a specific component, and mostly people's impressions from "blind-rolling" at that.  We should probably put together a concise thread for others to read and help reduce "setting up people to fail".

Nicely said and thanks!
 
I'm one of the guilty ones blind (ishly) rolling as I do not know how to work through an opamp data sheet. i.e. whats good, whats bad, what will work, what may cause issues etc...etc... I've picked up a few tweaks here and there and can probably ''talk a good shag'' but I'd really value a more concise guide.
 

 

[tomb]

Quote:

 
There's guides to equalizing your headphones around here but none on general opamp-rolling.  There's the occasional thread for a specific component, and mostly people's impressions from "blind-rolling" at that.  We should probably put together a concise thread for others to read and help reduce "setting up people to fail".

This has been done - and it was at least 6 years ago, maybe longer.  There have been a few other opamps created that might belong in this list, but not many.  Nevertheless, it gives numerous good pointers about what to select, how to employ them, and what you might expect in terms of sound differences.  This thread is so long, I'm sure it's been posted before, but it's probably a good idea to do it again:
 
Tangent's Notes on Audio Op-Amps
 
 

 

[genclaymore]

I been trying a-lot of different op-amp combos, I liked most of them, Others I didn't. I had to stop my self because I kept wanting to try another combo.   Right now I trying out 2x LME49860NA In the I/V , 2x LT1028ACN8's in the buffer of my X-Fi HD, With OPA2107AP in the Headphone Buffer socket in my Fiio E9.  I liking this combo so far, I had a OPA2111AM in my Fiio E9, but with the 2x 1028ACN8, the bass was punchy and the bass was uncontrolled.  But with 2xLME49710NA in the X-Fi HD buffer with the OPA2111AM in the Fiio E9, its bass sound good to me.
 
Planning on getting a Matrix M-Stage, its more roomy inside so I can use my dual to single op-amp adapter  as well as being able to access it insides much much easier. While being able to see what I doing.
 
With the Fiio E9, I have to put a small flash light in my mouth angled into the front opening, while I pull up the op-amp with one of those small pointy tools with a  grooved hook, I cant think of their name. Since the motherboard bios chip puller I have isn't angled. While holding the Fiio E9 steady in my hand. When you swap op-amp a-lot, it makes you wish the amp was in a bigger casing and easier to access.

 

[Mad Max]

 
Quote:

This has been done - and it was at least 6 years ago, maybe longer.  There have been a few other opamps created that might belong in this list, but not many.  Nevertheless, it gives numerous good pointers about what to select, how to employ them, and what you might expect in terms of sound differences.  This thread is so long, I'm sure it's been posted before, but it's probably a good idea to do it again:
 
Tangent's Notes on Audio Op-Amps
 
 

 
While I've seen that page before, it is hardly linked or mentioned outside of the DIY forum within Head-fi.  We should come up with something like "An Idiot's Guide to Opamp-rolling".  That link should be part of the guide or at least have mention of that page, along with this one, this one, and others, maybe link to some of the threads that I've seen on diyaudio.com.
 
I'm not quite sure how to fully express what I'm thinking.

 

[tomb]

Quote:

 
 
While I've seen that page before, it is hardly linked or mentioned outside of the DIY forum within Head-fi.  We should come up with something like "An Idiot's Guide to Opamp-rolling".  That link should be part of the guide or at least have mention of that page, along with this one, this one, and others, maybe link to some of the threads that I've seen on diyaudio.com.
 
I'm not quite sure how to fully express what I'm thinking.

Then maybe you should do it?
 
 

 

[genclaymore]

I put the LME 49720NAs and LME49710NA back into my sound card. Went back to rolling the op-amps just in my fiio E9 instead of both sound card and amp. I like the mid range and mid bass of the LT1057CN8 On my DT880 pro-250. The way It makes the mids sound fuller or more of it. I cant explain it.  Tho when I first Tried the LT1057CN8, I tried it with the AKG 702s I had before these headphones, didn't like it with those.  While with the AKG 702s I liked the LT1057ACN8s, Where the same LT1057ACN8s i didn't like with these DT880 pro250.
 
Now i can stop rolling op-amps for a while Til I get this new amp that I saving for.

 

[SpudHarris]

Yeah, I'm afraid it get's ya like that....
 
Some days everything sounds sweet and other days I yearn for a little bit more or something a little different (depending on what I'm listening to). It's a very specific type of OCD I'm afraid and if you are visiting this thread? I'm afraid there ia a good chance you may be suffering the same affliction, so sad

 but true....

 

[leeperry]

 

Yeah, I'm afraid it get's ya like that....
 
Some days everything sounds sweet and other days I yearn for a little bit more or something a little different (depending on what I'm listening to). It's a very specific type of OCD I'm afraid and if you are visiting this thread? I'm afraid there ia a good chance you may be suffering the same affliction, so sad

 but true....

Sadly, I think that's because opamps will never match discrete designs...there's a long thread on diyaudio on that matter: http://www.diyaudio.com/forums/everything-else/88894-discrete-components-better-than-opamps.html
 
And I'm not talking about discrete DAC's based on a voltage output DAC chip(that has a crappy I/V stage embedded) or cheapo discrete opamps, I'm talking about fully discrete designs. Opamps are just a cheap shortcut I'm afraid...and dual opamps are even worse than singles.
 
"to me a well-designed discrete circuit sounds better, and i've rolled a lot of op amps. they all sound different from each other, so i couldn't imagine how they don't degrade the sound. to me the difference between various op amps even within the same manufacterer is like night and day. people with half-decent ears (like myself) should do a blind test comparing a cascade of op amps to straight wire. that will effectively demonstrate that op amps suck."
 
Amen

 

[genclaymore]

I even thinking about grabing a Audio-GD NFB - 12 and calling it a day. Other then it being more affordable over the Matrix M-stage. So I can stop doing all of this op-amp rolling madness, that I cant stop from doing.

 

[leeperry]

I've opened a thread on that matter: http://www.head-fi.org/t/588070/opamps-thd-n-imd-snr-measurements-dont-mean-jack-irl-so-let-it-go-hummkay

 

[DefQon]

Anyone know a good cheap source for the AD8599 and AD744? My previous luck was on fleabay where the AD8588/AD744 were only $8 shipped, now there is only 2 sources that has the AD8599/AD744 for almost $20.

 

[ROBSCIX]

Quote:

I even thinking about grabing a Audio-GD NFB - 12 and calling it a day. Other then it being more affordable over the Matrix M-stage. So I can stop doing all of this op-amp rolling madness, that I cant stop from doing.

Opamp rolling is just a sign of wanting to get more out of what you have..IMO.  If you move to a device without opamps for instance, you will just find something else to change and mod.  To me the quest for better audio is a part of the fun.  Trying to tweak, tune and choke more sound quality out of the devices I have.  You can go with a new device, but it might not stop you from tweaking..just from changing opamps in that device.

 

[SpudHarris]

Quote:

Opamp rolling is just a sign of wanting to get more out of what you have..IMO.  If you move to a device without opamps for instance, you will just find something else to change and mod.  To me the quest for better audio is a part of the fun.  Trying to tweak, tune and choke more sound quality out of the devices I have.  You can go with a new device, but it might not stop you from tweaking..just from changing opamps in that device.

Agreed 100% Rob. I have owned amps/dacs with no capacity for rolling opamps and once you know the limitations of what they are capable of where else can you go. I get very exited at the thought of new opamps coming through from the likes of TI, National and Analogue Devices etc. I've been testing the OPA1611/1641 family of late to good effect and looking forward to more new stuff.
 
My favourite opamp of the moment, just so you know is the LME49990. In the right circuit it is tube like, nice warm full sound yet retaining those beautiful micro details and transients we so love. I have been swapping these into most of my amps the last few months....