[ChrioN]

I need to build a couple of headphone amps for the micbooth, and I'm looking for a very stable opamp (as in no oscillation, I'm tired of that).

Any ideas?

 

[Filburt]

Try NJM4556

 

[Seaside]

Sorry, what is "micbooth"?

Anyways, A47 is not bad at all. Just make sure everything in tact and tight, set gain about 5~6 for picky OPamps in order to reduce the possibility of oscilating, or use unity gain stable OPamp that does not easily oscilate. And also, feed it enough voltage, let say 18V, to ensure its power requirement.

NJM4556 is OK chip too. Sound not as good as other expensive OPs tho, it's sound OK . It has relatively high output and less noise at cheap price. Well, you can always replace OPs later if you want.

Filburt, which do u like more soundwise, 4556 or 4580?

 

[ChrioN]

Thanks for the replies, its funny you mentioned the NJM4556...its the opamp I've had the most (infact, I've always had) troubles with in my history of DIY. In a simple c'moy circuit it got burning hot etc.

I've tried it all, bandwidth limitation, input resistor, output resistor and so on.

Any other chips to recommend?

fiy a mic booth is a (often acousticaly treated) room you record vocals and such in.

 

[IEATTEFLON]

Sounds like you should use the opa2134.

 

[Pars]

I'd agree. I've never had any trouble with OPA2132/2134 in A47s, and I've built quite a few of them.

 

[splaz]

Well according to tangent the 2132 is even more stable than the 2134...

Not that I know from personal experience, I've only got a 2134 and haven't even bothered powering up the circuit it's in yet.

 

[ChrioN]

Cool, cool. I got a couple of 2134s.

What about the AD8620 with a suitable adaptor? (I want to broaden my perspective here

)

 

[IEATTEFLON]

I think ad8620 is too pricy for studioish duties. They do sound very nice though.

 

[Clutz]

I dunno, I disagree that the AD8620 is too expensive for studio duties. Since that's the first opamp that the signal is going to pass through, I would want to use as good an opamp as possible in order to minimize colouration as much as possible during the original recording process.

 

[Seaside]

Thanks for "micbooth" explanation.

2134 is nice and stable OP yet not too expensive, something I can recommend for almost every situation. Go for it.
2227 is nice, prolly better than 2134 at some aspects, but its too laid back and fatty to my taste. I haven't got a chance to use 2107, but some people swear on it. Definitely something worth checking for. Some Ops from AD are very nice too. They usually are little hard to use though. As you already know, each OP produces sort of unique sound with different sound signature. So... you know... you keep that in mind, and choose OP that you like the most within your budget.

So... go back to cheap 4556....
Yup, its jellybean kind of cheap OP chip.
However there're several jellybean OPs that is not too bad at all. 4556 is a one of them.
I had used a handful of them at bunch of Cmoys, A47s and several other OP based amps. Used them at both gain and buffer stages, and at power rail position too. Never had any problem with them. That makes me consider this cheap OP as a descent alternative of more expensive OPs, especially when I think little thin and hollow, yet acceptable sound of 4556 is suitable for what I am making. If it gets hot in your amp, other amp may get hot too at the same circuit. That means something is not right. Could be the gain or grouding issue. I think you have to take a good look at your circuit and power.

BTW, what headphones you're connectiong to A47?

 

[ChrioN]

Quote:

Originally Posted by IEATTEFLON I think ad8620 is too pricy for studioish duties. They do sound very nice though.

Actually, we only roll with DOAs in the studio. But this is only a headphone amp for the vocalist.

Seaside: thanks for the nice read. The headphones are 55ohm AKG K271 Studio.