I wouldn't go changing 220uf capacitors that are close to the opamp at random - they are often specced at 220uf for ESR reasons both in terms of power delivery to the opamp(s) themselves and if applicable the regulators feeding them will sometimes have an ESR range needed for stability - without...

Mostly my impressions have been from various DIY amps so mentioning the device itself is somewhat meaningless to most people :s (generally loosely of similar principles to the O2 and PBA amps but also fairly different from the stock version of those designs). DAC wise fairly varied - including a...

I'm generally not a fan of Cirrus Logic DACs myself - most of their mainstream lines sound a bit dulling and muddy to my ears and while the higher tier parts are a little better I still find it hard to get excited by them. ESS DACs do tend to have quite a "power punchy" sound as someone said...

Aslong as you don't connect their outputs directly together and instead each has a low value resistor on the output they shouldn't fight each other - though you'd be best off scoping to be sure.

If you have an amp that is designed with a different opamp for left and right (it is normally the case for 2x single channel opamps amps) not a problem to do that at all - people have done it in the past to do testing.

Do you mean something like having one opamp handle bass and another mid-range and treble on the same channel or having completely separate opamps on opposite left and right channels? The first would probably have some pretty funky issues around the frequency cut-off of the filter but might...

Yes compared to other opamps of a similar quality - there are other opamps that have lower current but not necessarily a good choice for audio - the OPA1692 is designed for portable audio (and USB).

Yeah I've used the 1692 in a couple of amps. I like - it just sounds "right" - no problem areas/concerns I've noticed, neutral with good articulation, good separation but not "open and airy" - it won't blow you away with its "musicality" or tonality or anything as some ascribe to some opamps but...

On a lot of more recent ICs "Burr-Brown" seems to be used more as a marketing term for having a certain minimum audio standard - TI seems to want to keep the name alive in respect for its pioneering work. On older chips (including the 213x and 222x, etc.) it was usually synonymous with a certain...

That is the supposed Burr-Brown sound - a touch warm and fairly relaxed but tends to make the bass a little bloated. Some like it some don't. Personally I consider the OPA2227 a better 2132 and the OPA2228 better again as it has a certain "something" the 213x/2227 lacks.

I have a hard time liking the OPA2132 or 2134 - they are decently transparent and easy to work with but somehow there is for want of a better way to put it a lack of passion when they are prominent in the audio chain - what I've said before it is like someone playing the same tune after the...

EDIT: Ignore.

Which is always going to depend on a degree of subjective and objective assessment factors. In no particular order - though the AD8066 tends to take top place for me the ones I use the most which would be favoured over others: AD8066 OPA2228 OPA2209 OPA1612/2211 OPA1692 I also use OPA2227...

Also depends what you use to rank the opamps - impressions by ear are always going to be subjective and the impression highly varied by the design they are used in as CoiL says. There have been various attempts to rank them by on paper parameters like voltage noise (such as...

On paper, whether it is noticeable to the ear or not is another matter, the 2210 is much improved for things like noise, though the 2111 still has some tricks up its sleeve in that context. There are a fair few differences in "architecture" approach as well. I've never sat down and tested them...

Analog Devices have recently pushed out some new opamps in the LTC range I think that are designed with driving headphones in mind but I've not kept upto date on developments like that.

Some of the JRC/NJM opamps are designed with audio use including driving headphones in mind, same for the TI variant of the RC4580. AD8397 and a couple more like that are designed for the kind of loads that you'd get from headphones as part of their audio considerations. There are 2-3 more that...

Another one I had a play with was the LM6172 - I think I was having problems getting it stable maybe - didn't get around to scoping it - but for audio it was quite grainy and coloured. I might be getting a bit mixed up between which of the LM and LMH ones are in the same series and/or I've...

My intention isn't to be negative of the 1622 - it is very good at what it is intended to do and if you have the knowledge to get the best out of it in a DIP-8 context as you obviously do then another story but I don't recommend people just buy them pre-mounted on a breakout board and stick them...

I've used the LMH6643 quite a bit as it can deliver reasonable current reasonably linearly but it is a lower voltage range part more suited to USB applications, etc. and it is slightly coloured but nothing terrible - however I don't recommend the 6000 and 7000 series for audio use - they are...

There is a whole load of information about the IC from johnc124 around the web about it - he actually works for the company that developed and manufactures the chip I assume you aren't getting him mixed up with a modder? there are all kinds of potential problems with DC offset, etc. if you just...

The 1622 is a 10 pin propitiatory IC that isn't drop in pin compatible with the generic 8 pin opamp - I don't really recommend using it on a breakout board as a drop in replacement for an 8 pin opamp as that will degrade its performance and potentially run into some of the same kind of issues...

At a basic level you can feed various test frequencies and patterns through an opamp while monitoring the output with an oscilloscope to check the behaviour is as expected. That very quickly identifies things like clipping and ringing even with test equipment in the $/£/€100 kind of price range.

Good catch on that one! yes the 4556's advantage is its ability to deliver current with low distortion when you actually need a decent buffer. One of my concerns here - though he is right in what he says - the 4556's slew rate and other relevant specifications are quoted as typical rather than...

4556 is good (very good) for driving actual current demanding headphones but personally, despite having seen all the measurements, I don't rate them for stuff like the Sennheiser HD600 which like a reasonable amount of voltage and voltage "response" - while it does happen rarely I definitely...