The DigiKey No.: 296-43972-5-ND, costs 2,59€ +VAT (<10 pieces).
LME49720NA/NOPB Texas Instruments | Integrierte Schaltungen (ICs) | DigiKey
Theoretically the manufacturing place shouldn't affect the quality. Can type is another case, because the can shields the circuit.
It is anyway very intresting, the LM4562 is still to buy...🙂
LME49720NA/NOPB Texas Instruments | Integrierte Schaltungen (ICs) | DigiKey
Theoretically the manufacturing place shouldn't affect the quality. Can type is another case, because the can shields the circuit.
It is anyway very intresting, the LM4562 is still to buy...🙂
TI wanted to cancel the LM a few years ago. Probably due to the great demand it is still in production. According to the docs at digikey the fab has moved from Scotland to Dallas. America first!
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I've put the LM4562s back.... and wow... day and night... all details are there again...🙂 The LME49720 ICs are flat, dull, without details, no bass, no sparkling highs, weak midrange.... Perhaps needs some more bypass filtering or I don't know. But for me definitive a bad choice.
I have some LME49710 that come from digikey (so i hope they are original) and still sound different. Not sure why, perhaps its simply variance in manufacturing, but they sound different in the high frequencies. Its 6 ICs, 5 sound exactly the same and one has a less detailed HF.
I use to assemble with those chips a LOT, my solid choice. IMHO LME49710, LME49720 and LM4562 performs identical, as long as identical employed..in some line level circuitry. With Phono Preamps…LME49710 /LME49720 TO-99, metal can.. are clearly better, quieter. They are of course all much surpassed by LME49713 CF amp.. if you can employ it properly.
If they were exactly the same they would sound identical, but they do NOT. Something must be different, other manufacturing process, fake ICs........
Audio circuits are not evaluated by listening tests, they are completely unscientific and unsuitable. Physics and mathematics have been well known in this area for 30 to 40 years. There are excellent measuring instruments available.
In "guitar world" it's very common to pinpoint a "golden" batch of the "best" manufacturer from the "best production year" of a certain type opamp (f.e a 4558) that works, feels and sounds best in a certain guitar fx. (note "batch", "year", "manufacturer").
Hmmmm..... Unless you consider the OPA1612, LT1028, LT1115, 1N A217, or the THAT 1580---which are ALL quieter in a phono stage. And all but the 1NA217 have less distortion, some by an order of magnitude; and all are faster than the NE5534.
The amplifiers you mention have lower input voltage noise, but when their input current noise is taken into account, when working into typical moving magnet cartridge source impedances, the total noise of the phono amp circuit is not necessarily lower.
Any amplifier has a combination of input voltage noise and input current noise, and both affect the total noise that the circuit will produce. The typical tradeoff with a bipolar input stage design is that to get less input voltage noise, you need to increase the standing current of the input pair, which increases the amplifier's input current noise.
So, while the 5534 has higher voltage noise, it also has lower input current noise, and the RMS sum of the voltage noise of the input stage, the input current noise interacting with the source impedance of the phono cartridge, and the Johnson noise of the source resistances is what's important. The input voltage noise performance alone is not the whole story - you can't just ignore the resulting high input current noise.
It is the combination of these three noise sources that matter, and an amplifier with a higher input voltage noise can very well result in less total noise than an amplifier having much less input voltage noise and higher input current noise, because that input current noise interacts with the decidedly nonzero source impedance of the phono cartridge.
Yes, that is true. I compared the above mentioned products with a Shure V-15 phono cartridge (3.5mV nominal output, 1.35KΩ source impedance). All had lower noise than an NE5534 with that source, counting both voltage AND current noise. Current noise generally becomes dominant in source impedances ABOVE ~3KΩ; below that voltage noise is more of a contributor. That is precisely why high impedance sources (guitar pickup) will be quieter with a FET-type opamp than the bi-polar ones mentioned.
Yes. When talking about op-amp usage in Phono preamps…there is of course big difference when interfacing MM or MC cartridges. There is a lot of good op-amps for output and source impedances of MM cartridges..and they do not need to be exactly “ultralow noise” variety. But for something like MC with 0.2mV output and source impedance well below 100 Ohms..? Majority of nowadays High-end cartridges are something like that.