Burr Brown OPA227 and OPA134, audible difference?

robbie_cro · 27th July 2007, 05:20 PM

is there any?

(>'-')> · 27th July 2007, 08:29 PM

Very big difference, the 2132/2134 has a more balanced sound while the 2227 is more bloated and has an awful midrange.

redrabbit · 31st July 2007, 11:57 AM

Don't ask subjective questions, and you won't get inflated subjective answers.

You need to try it out for yourself, and decide for yourself.
The 227 is used in a great many diy projects, so if what "whats-his-name" said above were true, he has magic ears that the rest of the diy community does not.

His blanket statement is bloated, and awful.

And neither of you included what circuit(s) said chips were being used for.

=RR=

(>'-')> · 14th June 2008, 01:01 AM

dac iv

dietcoke · 14th June 2008, 11:11 AM

Quote:

Originally posted by (>'-')>
Very big difference, the 2132/2134 has a more balanced sound while the 2227 is more bloated and has an awful midrange.

I had the opposite experience. opa2134/2 were harsh and tubby while the 2227 sounded balanced. This was in a preamp.

jcx · 14th June 2008, 04:55 PM

in a Iout DAC I/V circuit there is an engineering case for preferring a fet input op amp

fet inputs can accept the fast steps and "glitch" energy of the DAC output with less input stage distortion compared to a similar GBW op amp with a hi gm bipolar input

but circuit topolgy can make a difference too - put a discrete or CFA buffer in the I/V loop on the output of the op amp to give low impedance at high frequencies and the feedback cap implementing the 1st pole of the reconstruction filter then "soaks up" some of the DAC's switching/glitch energy at frequencies where a single "audio" op amp's output impedance is high

the 227 has lower Vnoise and could be better in analog preamp stages where the signal doesn't have the high frequency steps of the DAC output

in spite of the above reasoning many DAC data sheet reference circuits use the bjt input 5534 in the I/V circuit with excellent measured performance #, so its the hardly the case that differences have to be "obvious" to the ear either

tschrama · 14th June 2008, 11:03 PM

allthough no rigorus testing done.. I remember the opa134 as being slight harsch too.. and the opa227 has been my favortite for some time now...

27th July 2007, 05:20 PM	#1
robbie_cro diyAudio Member Join Date: Mar 2007	Burr Brown OPA227 and OPA134, audible difference? is there any?

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27th July 2007, 08:29 PM	#2
(>'-')> diyAudio Member Join Date: Jun 2007	Very big difference, the 2132/2134 has a more balanced sound while the 2227 is more bloated and has an awful midrange.

31st July 2007, 11:57 AM	#3
redrabbit diyAudio Member Join Date: Oct 2004	Don't ask subjective questions, and you won't get inflated subjective answers. You need to try it out for yourself, and decide for yourself. The 227 is used in a great many diy projects, so if what "whats-his-name" said above were true, he has magic ears that the rest of the diy community does not. His blanket statement is bloated, and awful. And neither of you included what circuit(s) said chips were being used for. =RR=

14th June 2008, 01:01 AM	#4
(>'-')> diyAudio Member Join Date: Jun 2007	dac iv

14th June 2008, 04:55 PM	#6
jcx diyAudio Member Join Date: Feb 2003 Location: ..	in a Iout DAC I/V circuit there is an engineering case for preferring a fet input op amp fet inputs can accept the fast steps and "glitch" energy of the DAC output with less input stage distortion compared to a similar GBW op amp with a hi gm bipolar input but circuit topolgy can make a difference too - put a discrete or CFA buffer in the I/V loop on the output of the op amp to give low impedance at high frequencies and the feedback cap implementing the 1st pole of the reconstruction filter then "soaks up" some of the DAC's switching/glitch energy at frequencies where a single "audio" op amp's output impedance is high the 227 has lower Vnoise and could be better in analog preamp stages where the signal doesn't have the high frequency steps of the DAC output in spite of the above reasoning many DAC data sheet reference circuits use the bjt input 5534 in the I/V circuit with excellent measured performance #, so its the hardly the case that differences have to be "obvious" to the ear either

14th June 2008, 11:03 PM	#7
tschrama diyAudio Member Join Date: Jul 2001 Location: The Netherlands	allthough no rigorus testing done.. I remember the opa134 as being slight harsch too.. and the opa227 has been my favortite for some time now...

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