[00940]

Quote:

Originally Posted by majkel /img/forum/go_quote.gif Another expensive but not inteded for audio is OPA627 which sounds a bit thin and laid back, like a living dead. It's good for analysing music, not listening for pleasure.

According to TI, the OPA627 is good for :

# PRECISION INSTRUMENTATION
# FAST DATA ACQUISITION
# DAC OUTPUT AMPLIFIER
# OPTOELECTRONICS
# SONAR, ULTRASOUND
# HIGH-IMPEDANCE SENSOR AMPS
# HIGH-PERFORMANCE AUDIO CIRCUITRY
# ACTIVE FILTERS

And IME the OPA627 sounds nothing like thin, quite the contrary. Unless you don't operate properly : it needs highish voltage rails (certainly higher than +/-10VDC) and a current buffer (don't drive headphones directly). ClassA bias helps a bit.

 

[Mulo]

Quote:

Originally Posted by 00940 /img/forum/go_quote.gif And IME the OPA627 sounds nothing like thin, quite the contrary. Unless you don't operate properly : it needs highish voltage rails (certainly higher than +/-10VDC) and a current buffer (don't drive headphones directly). ClassA bias helps a bit.

Agree. Even unbuffered and powered with just +/-6V it (OPA627 x2) sounded more meaty in the mids than the OPA2134, OPA2227, and AD823 (all unbuffered). It is a little dull in sonic color, though, but still much more colorful than things like the LM6172 or AD8066. So I guess it is well suited for audio, though perhaps not the most well suited opamp

 

[aych]

from what i've heard, its not all about the opamp itself, a couple engineering buddies told me that the technical specs of the opamp will be altered with the transitor circuit in the XO. whether its true or not, im not sure, but the wave on the oscilliscope changes quite drastically with the rest of the goodies inside the XO

 

[majkel]

It's quite possible OPA627 sounds better when supplied with higher voltages. However, I would still recommend AD825 instead - much cheaper, sounding... better.

Regarding the TI recommendations - recently NI has added "low distortion" remark to their LM6172 description when they realized high demand for this chip in the audio market. Primarily, the LM6172 was intended as a xDSL driver and related.

 

[gritzcolin]

I am bringing this back to life. I want to see if there is an opamp which I can drop in to the XO and get better bass than the existing AD823, all around detail is good too. My biggest problem is I read the 823 is crap from most people on the boards but I also see alot of talk of voltage and other fancy words, meaning to me that if I pick the wrong amp it wont sound right with the supplied power or maybe mess up the amp.