Audio OPAMP
Francis Li
I just played with different model of OPAMP available in my home. I
replaced them in the NAD 3240 amp and listen to some testing tracks
and round-robin several times. The result is interesting.
The IC's includes: (price in HK$)
NE5532 (most popular in products - about $15)
NE5535 ($40)
LT1057 (most expensive - $150)
UL-02 (advertised as most advanced, but only $20)
TL072 (released almost 20 years ago and the cheapest - $5)
C4570C (the NAD original one)
I found the worst is LT1057! It has no attack.
UL-02 and NE5532 is alike - still very soft but a little better.
C4570C is too shine and sound field too front.
NE5535 has the best attack and thickest piano image and quite shine.
To my surprise, TL072 give me the best result. It has enough attack
and detail. And it give the deepest sound field and the most stable
voice focus.
I feel quite disappointing to the audio shops. They cheat!!!
Do you have experience on these things?
Francis.
-------------------------------------------
Francis Li ⊙自在居士
email: km...@glink.net.hk
homepage: http://www.glink.net.hk/~kmli
-------------------------------------------
Bill Thompson
km...@glink.net.hk (Francis Li) wrote:
> I just played with different model of OPAMP available in my home. I
> replaced them in the NAD 3240 amp and listen to some testing tracks
> and round-robin several times. The result is interesting.
> To my surprise, TL072 give me the best result. It has enough attack
> and detail. And it give the deepest sound field and the most stable
> voice focus.
> I feel quite disappointing to the audio shops. They cheat!!!
> Do you have experience on these things?
Yes, but I must admit not the same experience. In many circuits,
the TL072 will exhibit truly measurable even order harmonic
distortion due to its poor common-mode performance. This often
adds an extra illusion of detail but it's not true to the
recording. Different op-amps have different capacitance,
bandwidth, slew rate etc. and often must be trimmed differently
in a given circuit to operate properly. Sometimes a circuit
that's perfectly stable with one op-amp will oscillate when you
substitute another one. Its not a good idea to just plug in a
bunch of chips and jump to a conclusion based on the results
without really looking at the circuit, seeing what type of
amplifier would be best applied there, and then trimming for good
frequency and transient response and for stability.
--
<- Bill Thompson - Ashly Audio Inc. Rochester, NY - b...@frontiernet.net ->
<- http://www.ashly.com bi...@ashly.com ->