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-   -   Burr-Brown OPA1611/1612 are here (http://www.diyaudio.com/forums/solid-state/149222-burr-brown-opa1611-1612-here.html)

BrianL 22nd August 2009 04:40 AM

Burr-Brown OPA1611/1612 are here
 
I just noticed today on the TI web site that the OPA1611 (single) and OPA1612 are finally reality. I've seen mention of these on various threads in this and other forums. Maybe it's too soon for anyone to have obtained and evaluated samples, but -- well -- has anyone yet? They are supposed to be great audio op-amps. The datasheet looks pretty impressive -- good 'objective' specs. I would hope they sound as good as they measure. That would be most excellent.

eplpwr 23rd August 2009 11:50 AM

Suspiciously similar to OPA211/2211
 
Quote:

Originally Posted by BrianL (Post 1904684)
I just noticed today on the TI web site that the OPA1611 (single) and OPA1612 are finally reality. I've seen mention of these on various threads in this and other forums. Maybe it's too soon for anyone to have obtained and evaluated samples, but -- well -- has anyone yet? They are supposed to be great audio op-amps. The datasheet looks pretty impressive -- good 'objective' specs. I would hope they sound as good as they measure. That would be most excellent.

If you compare the OPA1611 to OPA211 you notice that they are essentially the same chip, only that OPA1611 has lousier specs for DC offset and drift. A clever way to make money of the rejects. The same "sorting" is done for OPA132 / OPA134, pitching the chips with more offset and lousier CMRR (OPA134) as suitable for audio.

From the hype surrounding the OPA1611 I had hoped for an output stage with a higher standing current (bias), but comparing the OPA211 and OPA1611 datasheets it's definitely the same chip - 3,6 mA idle current for both.

Oh well, marketing at it's best again ...

Edit: BTW i think OPA211 is great sounding op-amp!

scott wurcer 23rd August 2009 02:56 PM

Quote:

Originally Posted by eplpwr (Post 1905293)
I had hoped for an output stage with a higher standing current

The OS looks borrowed from the xDSL drivers, low distortion on min possible standing current.

BrianL 24th August 2009 01:45 AM

Pelle,

Are you sure your comment is correct? From what I've heard/read, the "audio" parts (1611 / x134) are not trimmed for lowest DC offset (relative to their siblings) as that's not an important audio parameter. That doesn't make them "rejects". Is a Toyota Highlander a "reject" Lexus RX since they share many common components and general design?
I believe I read somewhere (AES report on this forum?) that the 1611' AC response has been tweaked for lower distortion compared to the '211. I've not listened to anything with the 211, though I hear good reports; I guess I'll have to go straight to the 1611...

If only they were in PDIP. Sigh...

syn08 24th August 2009 02:23 AM

Quote:

Originally Posted by BrianL (Post 1905670)
Pelle,

Are you sure your comment is correct? From what I've heard/read, the "audio" parts (1611 / x134) are not trimmed for lowest DC offset (relative to their siblings) as that's not an important audio parameter. That doesn't make them "rejects".

It is very likely he's correct. OPA211 is a SiGe part, and as in every new technology it is likely the parameters dispersion is still pretty large, so there's lot of room for "rejects". Usually, manufacturers choose to split the production in classes. Apparently TI decided to take advantage of the BB reputation in the hifi world and re-baptize lower class parts with the "audio" tag.

I don't think there's anything wrong in doing this, as you said, DC performance is not really critical in audio and OPAA1611/12 are actually 25% cheaper. OPA211 is an excellent opamp for audio, at par to the AD ADA4898 and the National LME4562.

eplpwr 24th August 2009 05:59 PM

BrianL,

I guess "reject" is a too strong word indicating a completely defective component (my bad - not native in english), maybe I should have written not-quite-up-to-spec or something like that.

I also wish they made them in DIP packages. NS definitely got good packagings for their new amps; both DIP and also TO-99 (at a premium).

BrianL 25th August 2009 01:48 AM

I talked to a TI/B-B applications engineer today. My statements were verified:

- OPA1611/1612 are optimized for better distortion than the OPA211 (already pretty good). So, it is a different design and chip.

- high levels of DC precision are generally not required by audio customers (audio equipment makers). So, parts are not spec'ed for or tested for the same levels of DC precision as a part, i.e., OPA211, designed, spec'ed and sold for DC precision. (my note: 'customers' generally exclude us hobby types as we're not the guys who buy the quantities that keep vendors in business! So even if 'we' think extreme DC precision is important, we're in the minority as far as the market is concerned. And if the big customers don't want/need something that adds expense, then a company is not going to provide it in the product.)

So, as a user, Pelle or Syn08, I guess you (and I) get to decide which is best for our application. I hear the '1611 is the best sounding ever, so I'm willing to give it a try. With all this talk of DC specs, it's interesting to note that the OPA1611 equals or exceeds the LM4562 in everything except bias current.

The bottom line is that different markets need different specs and companies optimize products to match the market. Even if the base designs are similar or one is based on the other (as in the Highlander vs. Lexus RX comparison), doesn't make one necessarily 'superior' and the other 'inferior'

syn08 25th August 2009 02:30 AM

Quote:

Originally Posted by BrianL (Post 1906426)
I talked to a TI/B-B applications engineer today. My statements were verified:

- OPA1611/1612 are optimized for better distortion than the OPA211 (already pretty good). So, it is a different design and chip.

Unlikely. Even the distortion spec is identical for OPA211 and OPA1611: -136dB @ 1KHz and 3V out.

But then OPA1611 is cheaper and, as you said, the DC performance is not critical in audio. Otherwise, I'm 99.9999% sure there is no difference between the objective performances of these two chips. Can't wait though to read about how much better OPA1611 sounds :)

Wavebourn 25th August 2009 03:22 AM

I'm still waiting for samples they promised last October...
A first, they promised DIP for prototyping.
Then they said that there are no DIP doubles anymore, singles only...
Then they answered that there will be no DIPs at all, but they will start shipping SMD version soon, and I am in their list...
Now, almost an year later, I hear they have samples available, but no message from them...

May be it is a Fortune telling that I should not use them at all? :spin:

BrianL 25th August 2009 05:27 AM

syn08: yes likely; in fact, true. Compare gain/phase curves (fig 11 OPA211; fig 5 OPA1611); they're not the same. Carefully compare comparable distortion plots at high frequencies. Yes, probably no noticable change at 1kHz, but definitely in the high frequencies. All of these show the effects of changing open loop response.

Reminds me of one of my favorite phrases from an equipment review in The Absolute Sound years ago:
"subtle, yet dramatic differences".

;-)

I, too, await samples. From the datasheet, it looks as if any hopes of PDIPs have vanished, again I'd guess that the large customers don't do PDIPs anymore. I love PDIPs -- you can see them; you can read the marking on the package...


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