[blipblop]

Hmm...

 

[Tomo]

Hi,

I am a total weirdo and used THS4022 to drive my K240M. ... It's NOT for any low-impedance headphones since it has to have minimum gain on 11. You can probably drive HD580 but I have never done that.

I also have OPA627, but in buffer-opamp configuration.

Tomo

 

[blipblop]

Is it safe to plop in an OPA627 without a buffer configuration?

 

[jeffreyj]

The best op-amp I've found for driving cans directly (down to 32R!) is the TS922 by STMicroelectronics. It has low current drain but plenty of oomph, and good to excellent specs otherwise (very low noise and distortion, somewhat sluggish slew rate - but this means no pole compensation is required). It's available from Mouser for something like $1.15 apiece and it is a dual op-amp.

Here's the listing for the DIP version at Mouser .

 

[blipblop]

and this can plopped in a cmoy?

 

[jeffreyj]

Uh... I did write that it will drive headphones directly, so, yes, it can be "plopped" into a CMoy.

 

[blipblop]

No need for the attitude. Some of us are very new to this and don't sit behing a soldering station for a living.

 

[jeffreyj]

[deleted my original snappily sarcastic response]

You're right - there's no need for any attitude on my part. Conversely, when you do receive help from other forum members, the least you can do is read what was written. After all, I did say the TS922 will drive headphones directly, and what is popularly called a "CMoy" around here is just that: an op-amp driving headphones directly.

 

[superjohnny]

Quote:

Originally posted by jeffreyj ...and what is popularly called a "CMoy" around here is just that: an op-amp driving headphones directly.

I'm going to show my ignorance and say in my best Johnny Carson voice, "I did not know that."

I've used the OPA2132PA in a CMOY...

rofl, I'm funny

 

[Demolition]

Quote:

Originally posted by jeffreyj [deleted my original snappily sarcastic response]

That's too bad, Jeffrey. I thought that it was quite a relevant statement.

D.

 

[blipblop]

Quote:

After all, I did say the TS922 will drive headphones directly, and what is popularly called a "CMoy" around here is just that: an op-amp driving headphones directly.

Again, I didn't know that - I only now realize that directd-driving had to do with buffers, and even that may be wrong. Apparently you didn't read what I wrote.



Quote:

Conversely, when you do receive help from other forum members, the least you can do is read what was written.

I read what was written, but didn't understand, and therefore tried to seek clarification. Now is the logic clear? I, along with many other people here, ask what may be deemed to be stupid questions all the time. I try my best to read and learn before asking, although sometimes the answer itself is a bit too complicated for a newbie like me. Fortunately, everyone else here has been kind enough to answer politely, knowing that they, at some point, may have done the same.

 

[Pars]

Dunno... I think given Jeffrey's experience and willingness to help people here, I would have just let it go, and after rereading my own post, said "Yeah, he's right". But that's just me...

Oh yeah, back to the topic. I have tried an LM6172 and an NE5532 as well as the OPA2132PA. The NE5532 had somewhat marginal offset with a std. CMoy set for a gain of 5.5 with the default resistor combos, so I never actually listened to it. The LM6172 had offset of about 0.5V on both channels, so I did not listen to that either.

I did build one on a breadboard with resistors such as Tangent suggests in his working with cranky op-amps writeup (R2/3/4 of 100K/475K/121K I think). The offset was semi-acceptable (10-20mV) so I did listen to this. It had a promising sound, but was edgy and broke up on transients (crappy mobile Sony ear-buds). I wasn't sure whether this was due to being built on a breadboard with long wiring/lead inductances (I left the resistors, etc. uncut). I checked the outputs of all with a scope and did not see any oscillation that I could detect (I assume that it appears on the outputs and not on the power pins). This one might be worth tossing together on a real board (if the RS board can be considered real.. hehe), but I am done with CMoys and off looking for something better (doing a MINT now, then a Gilmore). Nothing in any of these got hot.

 

[jeffreyj]

Demolition and Pars, in my best James Brown imitation I say, "uh thanks for your support."

blipblop, I don't know why you think that being a member of a forum such as head-fi *entitles* you to receive help from the more knowledgeable persons who contribute here, but you need to disabuse yourself of that notion because receiving said help is a gift, not a right.

Furthermore, you did not state in your opening post that you are a total newbie that doesn't even know what a CMoy is - namely, a headphone amplifier circuit in which the op-amp drives the headphones directly - but the title of your thread *implies* that you do. I mean, we all know (or should, anyway) that it is dangerous to make wild assumptions, but few would think twice about assuming that any op-amps suggested in a thread titled, "what opamps have you tried in a CMOY," would be usable in a CMoy...

Now the big irony here is that you asked me to tone down on the attitude but then you went slinging it around in your next response. At some point I will quit finding this amusing and start finding it annoying, at which point I'll simply ignore you. Ball's in your court, blipblop.

 

[blipblop]

Listen, this bickering is ridiculous. I'm not going to continue this. And although I don't think I'm entirely at fault, I apologize for catching an attitude, when I objected to you doing so. I guess I was a bit sensitive to what I percieved as condescension. I do appreciate your willingness to help, and seeing as you are obviously a respected member here, I'll defer to you.

We cool?

 

[Demolition]

blipblop,

Getting back on topic again...

I guess you've probably tried the 2132, but have you tried any of the other op-amps listed in Tangent's Notes On Audio Op-Amps? If I recall correctly, Tangent initally tested them on unbuffered CMoys, which is what you appear to be testing your chips with. I'm not sure if all of his notes relate to the op-amps' performances without buffers, though. But, in any case, have a look at the list and see what might interest you.

Perhaps the Analog AD823 might be worthwhile to test. I've never tried one personally, but I've heard (both here and on Headwize) that it's an excellent chip. (Note that it's a low-current chip, though, and may sound crappy with low-impedance cans. It wants an amp with buffers.)

D.