Opamp Rolling
May 20, 2005 at 4:26 AM Thread Starter Post #1 of 17

aseltzer144

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What are some of your favorite opamps usable in a Go-Vibe or similarly architected Cmoy? I know the OPA2227 is popular in DiY Cmoys and the Go-Vibes are commonly used with the AD8066 and AD8620. Are there any others worth considering that will work well in a 9V powered amp?
 
May 20, 2005 at 4:44 AM Post #2 of 17

crazyfrenchman27

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You're probably going to need two 9V for something like OPA627, so AD8610/AD8620 is probably the way to go for best sound and best battery life.

OPA2107/OPA2111 would be an interesting choice, as well.

AD797, AD744, LM6171, AD843 are probably unusable in a cmoy setup, too.

-Matt
 
May 20, 2005 at 7:35 AM Post #5 of 17

amb

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Quote:

Originally Posted by crazyfrenchman27
I really don't understand why you'd prefer OPA2132 over OPA2227, though.
The OPA2227 is just objectively better, IMHO.



Perhaps you mean subjectively? Spec-wise the OPA2132 is superior to the OPA2227 in many important areas except noise.
 
May 20, 2005 at 2:38 PM Post #6 of 17

crazyfrenchman27

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Quote:

Originally Posted by amb
Perhaps you mean subjectively? Spec-wise the OPA2132 is superior to the OPA2227 in many important areas except noise.



But specs don't matter. I don't think anyone has demonstrated a correlation between specs and sound quality for IC.

I think you can say that it objectively presents a better sound...unless everything is preference?

I would look into OPA2604 as well...
 
May 20, 2005 at 4:09 PM Post #7 of 17

bg4533

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Quote:

Originally Posted by crazyfrenchman27
But specs don't matter. I don't think anyone has demonstrated a correlation between specs and sound quality for IC.

I think you can say that it objectively presents a better sound...unless everything is preference?

I would look into OPA2604 as well...



Nothing is objective in our audio world, except maybe the specs. There is no way to objectively define "what sounds better".

I prefer the OPA2132 over the OPA2227 in most cases.

Headroom chose to use the OPA2134 (esentially the same as the OPA2132) in their amps.

The OPA2132 also seems more popular over at DIYAudio.

I think that is plenty
 
May 20, 2005 at 4:29 PM Post #8 of 17

aseltzer144

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The AD8620 is a logical choice since it is widely well regarded and can be bought premounted on a Browndog adapter.

With the OPA2132, there seem to be two variants that would work in a Go-Vibe. I assume I would want the 8-Dip package. That leaves an OPA2132P-ND and an OPA2132PA-ND. Which one is more appropriate?
 
May 20, 2005 at 5:21 PM Post #9 of 17

skyskraper

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in simple low power amps its the 134/132's that i find myself coming back to consistently. i like the fact that theyre a bit more relaxed then the 227's. they also seem to be more umm, hard to articulate myself, "compatible"? with most headphones ive used. may not present the best synergy with any one single can but seem to provide the best average to my ears when used in portable battery powered amps, hell they perform well even in something like the m3. other portable favourite (from pimeta experience mainly) is the lm6171/2. with the right resistor installed i had no audible oscillation (couldnt tell you if there was any non audible oscillation, don't have a scope), tight and punchy sound, might not be for everyone though, and might not be workable in all amps.
 
May 20, 2005 at 7:13 PM Post #10 of 17

bg4533

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Quote:

Originally Posted by aseltzer144
The AD8620 is a logical choice since it is widely well regarded and can be bought premounted on a Browndog adapter.

With the OPA2132, there seem to be two variants that would work in a Go-Vibe. I assume I would want the 8-Dip package. That leaves an OPA2132P-ND and an OPA2132PA-ND. Which one is more appropriate?



The difference between the OPA2132P and PA will be DC offset. The P should have slightly lower offset, but both chips should work fine.
 
May 20, 2005 at 7:53 PM Post #11 of 17

dwchin

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OPA2107 is definitely my favorite opamp for the Go-Vibe, followed closely by the AD823. The OPA2107 gives good detail with great bass/lows, and they say the sound signature is similar to the OPA637 (though not quite as good) but at a fraction of the cost. It's a fantastic all-around opamp, even more so than the OPA2227.

From Analog Devices, I actually prefer the AD823 with my HD600s over the AD8620. I find that the AD823 gives slightly more detailed highs than the OPA2107, but without the occasionally harsher nature of the AD8620. I switch from my Senns to Etys, and I find Etys + AD8620 is a bit much, but the AD823 is a perfect compromise.

I have tried the OPA2132, as well as several others, but they were not as engaging as the OPA2107 or the AD823.

Edit: I thought I'd also mention that the OPA2107 does an excellent job on battery life. I could squeeze in a few more hours it seems with the OPA2107 than with some of the other opamps I've tried. It's a fine opamp, and I definitely recommend you to check it out.
 
May 20, 2005 at 7:56 PM Post #12 of 17

NiceCans

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May 20, 2005 at 9:10 PM Post #14 of 17

bg4533

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Quote:

Originally Posted by Sinbios
Would the 8620 be OK with a 9V pimeta? Tangent's clipping points at 2V into 330ohm is 7.6V, and I'm wondering if a single 9V will suffice.


It will do alright, but 2 batteries would be better. Tangents tests used an unbuffered amp. The addition of the buffer should make the minimum operating voltages a little lower. Battery life probably won't be that great though.
 
May 20, 2005 at 11:53 PM Post #15 of 17

aseltzer144

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You all have come through with some outstanding alternatives for opamp rolling in the Go-Vibe (or other Cmoy derivatives). To further narrow the universe of possibilities, I suppose I should offer that my primary 'phone is the Ety ER6, followed by the Shure E2 "for fun". I therefore appreciate all the descriptions with regard to high end harshness, etcetera. On the other hand, I don't want to be too specific as there is a likelihood I may change 'phones over time.
 

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