Hi, I ordered an HTOmega Claro Halo, and according to it I can swap the opamps. I don't know how to do that, because how am I supposed to know which opamp is supposed to sound better on it? They cost like 10 dollars each, I can't just buy a couple hundred and keep trying them out like that.

Thank you.

There are plenty of recommendations for opamps around the board here - try the search feature. What voltage is provided for the amps in your DAC? My favorite "normal" low-voltage chip is the OPA2227.

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How do I know what an opamp will sound on a board? For example, will some good build quality and technical spec amp just sound bad on the board for no reason? Because when I have tried it on the board, that means that I have already bought it.

This is my card:

HT Omega - Claro halo

I don't know what voltage it is, is voltage and pin type the only thing that matters?

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i'm sorry mate, but thats just the kind of risk you take when you diy and go into territory that you havent covered before. its part of the fun and the pain of DIY. find a few suitable Op-Amps and have a play. if there are some you dont like, as long as you dont fry them and they are decent, you shouldnt have any problem selling them on here in the F/S section

Nice that the op amps are socketed. The low distortion LM4562/LME49720 might offer an improvement, a bit cleaner and clearer. IMO, the NJM4580 is a somewhat harsh/edgy sounding chip.

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Is there any way to tell how an amp might sound? Like you said that the NJM4850 sounds "harsh/edgy". So is it going to make all boards that it is plugged in sound more harsh/edgy, or is it completely alchemical? Like you have no idea what a specific configuration is going to sound like by the individual features of the parts?

How did you find compatible amps for the board? I don't know what tells me that it's going to be compatible with my card.

Also, how is the Analoge Devices AD8620BR that they use on one of their other cards?

From my experience, I would say that, while certain op amps might have certain identifiable characteristics, those characteristics change somewhat depending upon the individual application. Many chips will sound bad if used improperly. Also, what sounds "pristine" to one person might be "boring and clinical" to another. Not everyone is interested in accuracy or low distortion. Many seek euphonious coloration.

There may be others here who can offer more assistance with the specifics of matching specifications. However, one way to start is by looking at the specs for the original parts and see which possible replacements have similar specifications. Because the NJM4580 uses a bipolar design, similar bipolar op amps may be suitable for your application. I've replaced 4580s with LM4562s in a few circuits and been happy with the improvement. FET input devices may be worth looking into as well, although most of the op amps which I have liked have been bipolar. Of the FETs that I've tried, the AD825 was my favorite, although it is only a single op amp so it would require a single-to-dual DIP adapter. It would also be a good idea to measure the voltage from ground to pin4 and pin 8 of the existing op amps. That will tell you the available operating voltage in the circuit.

No experience with the AD8620, though there are some who think it is aggressive sounding.

you need to find dual opamps in the dip-8 package (cdip and pdip should both work, being either c-eramic or p-lastic). the dip-8 duals are all pin compatible, but as someone else has already mentioned, there are some circuit specifics that will determine whether they work well or poorly in your card, and the manu is not likely to give you a schematic to help with this.

unless you are very good at soldering, i would not try to solder soic (surface mount) chips to an adaptor, but if some are available pre-made, you may want to try them.

also, opamps will give you very different sound, as you swap from one to another, and it is hard to find reliable sonic impressions on the web, weeding thru system-specifics and subjective tastes (as has already been mentioned).

i would recomend doing the unthinkable, and letting the card burn in with many hours of play and decide what improvements or changes you want, and then trying to find opamps which will give you those changes.

i've been doing this with both a prodigy hd-2 and a xonar essence, and it is worth doing, but is time-consuming and takes some warm-up and careful listening.

mouser and digikey are great resources, and you can at least compile a llist of opamps that will work as direct plug-ins to your card, and go from there.

auzentech has some they sell, and give brief descriptions of their sound as well.

do your homework, be honest with yourself, and you will get better sound without buying every opamp in creation.

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Yes, but how would I even remotely know which amp will sound like what on my card? I mean you also acknowledged that there are a lot of subjective tastes floating around the internet, and they are not reliable at all.

Objective specs only give stuff like THD% and such, they don't tell you how the thing is going to sound. And figures like the THD are useless, because the amps used today are already so pure that it's not going to make a difference to go from 0.0001 to 0.00001.

Edit:Another question, what determines what kind of chip will be compatible with my board? Which technical specs would determine that?

Does anyone know any amps that are especially known for neutrality and flatness and detail? (detail like organized and tight sound, where you can hear the finger clicks on piano keyboards clearly etc...)

This is to replace the NJM4580.

I have the LM4562 and OPA2132P recommended to me, are they good?

The 2132 is a good basic amp, very tolerant, but I find it rather flat (in a bad way). You could order a few different ones and switch them out until you find the one you like best.

awhile back I asked what op-amps would be suited for a CMoy amp, some good lists & info about the op-amps here

http://www.head-fi.org/forums/f6/bes...-other-243642/

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In my experience, the LM4562 should move in that direction. I've found it less harsh, clearer, more "analytical, and more balanced across the spectrum compared to the NJM4580. The OPA2132 tends to sound a bit warmer and rounded off in the highs, IMO, not so neutral....

There are others which are good for high resolution, but many of them can be somewhat problematic to implement without special consideration for supply bypassing.

My suggestion would be to try a couple of chips and see if it achieves the desired result, then go from there.

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Are there any response graphs for them?

Not sure that such a graph is readily available. Weird as it may sound, although there are noticeable differences in sound, the audio range frequency response of many of these op amps is likely not to appear any different on paper. Some of the technical data on the information sheets may offer some insight. But the only real way to know is to try a number of different devices for yourself.