Burr Brown OPA 2143 vs NJM2068

Amdb9, aren´t you meaning the OPA 2134? I´m not into opamps but I know that one is one of Burr Brown´s usually used ones. Another one that is better for some and not for others is the OPA 627.

Give us your feedback when you are done. I´m thinking of changing opamps in a Hafler poweramp.

I'm not sure about repair cost but he is offering very old op-amp not even half as good as OPA2134. I suspect he might have this amp handy. My advice is to replace it with LM4562 - much better amp than both. Be sure to replace it in both channels - this is dual amp but might have both amps in one channel. LM4562 can be purchased from Digi-Key for about $5. Be sure to order right suffix (DIP, SOT8 ...). OPA627 is a single amp (won't fit).

If you still want to go with NJM2068 ask this guy about supply voltage since OPA2134 starts at 5 volt minimum while NMJ2068 starts at 8V minimum.

NMJ2068 datasheet looks pretty old. They claim better performance than 4558 type amps. Nobody remembers Rayteon 4558 since it was designed/used more than 20 years ago.

Kijanki, can you please tell us about the LM4562? Which are its sonic characteristics? Is it used in any known audio product? Is it better than the OPA 627 as well? Thanks.

LM4562 is the newest audio amp from National Semiconductor (they got awards for it) intended for hi-end audio. It has excellent AC (THD=0.00003% IMD=0.00005%) and DC (0.2uV/degC) specifications. Unity Gain Bandwidth is 55MHz and slew rate is 20V/us. It work from 5V to 36V. Power supply rejection is excellent. It has pretty strong drive (600 Ohm specified). As for the known product - Benchmark DAC1 USB uses it in the output stages replacing previously (DAC1) used NE5532. Replacing all chips in Benchmark is probably too expensive for Benchmark ($5 for LM4562, $0.55 for NE5532) since there is a lot of them (about dozen packages) and NE5532 is very decent in the AC (pretty bad at DC).

It is difficult to talk about sonic character since I have never heard it (new product) and Benchmarks design objectives are very specific (promoting natural sound and avoiding warm sound). My audio experience is also very limited.

How it compares to OPA627 - I don't know. According to Benchmark's technical director John Siau they tested OPA627 and got worse results than NE5532. Mr Siau even stated in details which harmonics got worse. On the other hand Steve from Empirical Audio who moded a lot of Benchmarks says that OPA627 is better since it performs better/cleaner at low levels (microdynamics). Steve is probably the person to answer question about sonic characteristic of LM4562.

OPA627 is, as far as I know, a single package amp while LM4562 is dual amp available in DIP, Metal Can and SOIC (SMT) packages from Digi-Key for about $5. LM4562 is very good at AC and DC and having wide banwidth and wide supply range can replace any audio op-amp in the dual package. I think that National created also single packages but with different part number - I can find out.

Word about NE5532 - it was initialy designed by Signetics. Signetics became member of Philips Company and early Benchmarks used thin sounding Philips NE5532. Around year 2001 Philips factory burned down and they stopped making NE5532 selling license to Texas Instruments. TI redesigned them with larger die and the newer Benchmarks that use them have much fuller sound. Benchmark has output cap since NE5532 has pretty bad DC offset and drift.

In general audio OP-Amps are a very narrow class of all OP-amps. If you're not sure if amp belongs to this class download data sheet in pdf and check for THD vs Frequency and THD vs Output Voltage charts. Don't even bother if you don't see it.

Thanks for the info, Kijanki! My technician advised me to change the opamps of a Hafler P3000 poweramp. I think he said it had TL... and advised to change them by the OPA 2134. As I started investigating a little bit, they seemed to be not the last word in audio opamps. I don´t know anything about electric nor physical configuration of them. Any other advise? Thanks.