Newbie opamp question
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violeta88

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I'm currently using a OPA2228P in my Cmoy with a gain of 10 and I'm having a little problem with the sound. With my Minidisc player as the source (I don't have the pot set up yet so I can only use it as a source) and my AKG K240S headphones the sound is bright and metallic. I don't know if my headphones are simply too bright or if they are just too revealing but whatever the case I need a darker/warmer DIP-8 opamp that will work well with a 9V power supply. I've used the OPA2134 and wasn't quite satisfied in it bass-wise. So any suggestions would be greatly appreciated. Thanks in advance.
 
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tangent

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The OPA2227 won't be as harsh, and since it's the same basic circuit, it has the same voltage characteristics. That etched sound you're hearing could be oscillation or it could just be the speed of this chip showing through. I know I was less than thrilled with the 228, but the 227 is a fine chip IMHO.

If the 227 doesn't do it for you, I'm not sure you have any options left, other than going to a higher power supply so that you can run the OPA627.
 
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aos

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I found that OPA2228 does it for me, especially as a standalone chip (like in CMOY or to replace generic opamps in CD players and such). It seems capable of driving more things than your average opamp but it can oscillate, so you might take up tangent's suggestion and use OPA2227. I can't say that I am able to hear the difference between these two, and they should have the same sonic signature.

There are several Linear opamps that you might try in addition to what is generally talked about - e.g. LT1358, LT1360 and LT1361 among others. I've used them before in older versions of portable DAC that run on 5V and they worked fine.
 
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violeta88

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Thanks guys for the suggestions. I think I'm going to give a fresh OPA2134/2 a shot I think one of the problems was the chip I was using was semi fried from the second-generation amp that I was working on (it had a lot of problems with it including a backwards PS) so I think the bass problems are from that. But I will keep those chips in mind if the 2132 is underwhelming. I also found that adding a pot helps the brightness, but I inadvertently broke my pot, so I have to buy a new one. Thanks again for the help. It is greatly appreciated. It's refreshing to find one friendly forum left on Head-Fi.
 
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Gariver

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I use the OPA2228P in my X-Cans V1, and I love it! I tried all sorts of dual opamps, including the OPA2134, until I found the OPA2228. That's the one I'll keep in the X-Cans.
 
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