[thedtecter]

Looking for forum advice on what opamp will provide the cleanest bass. This is not for audio listening but rather to use with some field equipment. Units are coupled with Bose QC-15's set on low, believe impedance is rated at 73 ohms +/- 10% at 1khz. My needs are quite low end - top end is < 4000 hz and I need very clean, smooth sound < 1500 hz. Would consider 2x 9v as power supply in the cMoy if that offers better chip options. Thanks!

 

[Bill-P]

I haven't heard any other op amp that does bass as well as the OPA627.
 
Save for maybe the OPA637, but you need massive gain for the OPA637 to not oscillate.

 

[yifu]

I know it is a contentious subject around here but to my ears, opamp rolling produces no audible effect at all.
 
Any difference you find with opamps would be likely due to distortion by driving them out of spec. Few opamps measure objectively better than the old NE5532 or JRC4556, which is why you'll find hundreds of them should you open up any professional sound equipment. There is just no need to shell out for a 15 dollars opamp when a 1 dollar one works just as great in audio applications, the 'upgrades' in terms of slew rate etc are not relevant for audio applications and are more for other electronic applications.

 

[Bill-P]

If you read his post carefully, he's claiming that op amps only "sound the same" given the right circuits. Otherwise, there really IS a difference in sound, and even if he claims it's because the op amp is overloaded, unhappy, etc...

It is still a difference.

If you can't hear it, then something is definitely wrong.

 

[thedtecter]

Is there a dual equivalent to the OPA627 (or similar) to use in a cMoy?
 

 

[kramer5150]

OPA2107 running at 18V is a good candidate for that.  Its biggest drawback is peak current, so with power hungry cans it cant get as loud as others.  But still its loud enough to cause hearing damage with most high efficiency  cans.

 

[kramer5150]

Quote:

 
Agree, I have noticed very noticeable differences between AD2227 and AD8620 for eg,.

x2.. two different sounding chips, on a blind AB.
 
x2 also on OPA637 gain.  I cooked my Yuin PK1 when mine went into oscillation, at a gain of 3.5- 4.  Others warned me but I was stupid.

 

[Bill-P]

Highest resolution to me so far has been the OPA209 in the Leckerton UHA-6S Mk.II.
 
In fact, it's just a bit too high in resolution. It brutally butchers just about anything, and since some of my sources aren't as high in resolution (old recordings), I ultimately resorted to the smoother and less brutal OPA627.