Hello Friends,
Do you have any suggestion for an opamp that can take my 1Vrms signal and output 2Vrms?
Main application would be as a buffer, driving another low impedance load, but driven itself by something a little bit weak (10k). Supply is either +5/0V or +/-5V.
Looking for good and cheap 😀
Thanks for your suggestions.
Do you have any suggestion for an opamp that can take my 1Vrms signal and output 2Vrms?
Main application would be as a buffer, driving another low impedance load, but driven itself by something a little bit weak (10k). Supply is either +5/0V or +/-5V.
Looking for good and cheap 😀
Thanks for your suggestions.
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What sort of quality are you looking for? A simple regulated power supply (lm317/337) and basic IC like a 5534 , 2134, etc will do the job but there are plenty of projects, pcbs, etc that'll do this okay
Have a look at Rod Elliot's website "esp" (Elliot Sound Products) for example - project 88 is High Quality Audio Preamp (Mk II) - you can just use part of that okay.
Have a look at Rod Elliot's website "esp" (Elliot Sound Products) for example - project 88 is High Quality Audio Preamp (Mk II) - you can just use part of that okay.
Thanks! I'm trying to learn the trade-offs when it comes to these decisions. My hope is to find the best solution below $0.5 though.
2V rms is 5.6 V pk to pk.
You cannot do that with 5/0 supply
With 5/-5 you are going to need a rail to rail output. Basic 4558 or TL071 type opamps need a couple of volts headroom at either rail, so 2V rms gets marginal
You cannot do that with 5/0 supply
With 5/-5 you are going to need a rail to rail output. Basic 4558 or TL071 type opamps need a couple of volts headroom at either rail, so 2V rms gets marginal
Exactly. So any tips for something low cost that still performs nicely in this situation?
@jameshillj
Thanks for the esp website tip. My issue with most of these designs (like project 88) is that even the first 6dB amplifying stage already uses opamps with +/- 15V power rails.
@jameshillj
Thanks for the esp website tip. My issue with most of these designs (like project 88) is that even the first 6dB amplifying stage already uses opamps with +/- 15V power rails.
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Thanks, good to know this is a contender. However at $2, still a bit pricey. What's the advantage of using it over something like the RC4580 ($0.17) in this scenario?
I haven't studied the 4580 but a quick look at the specs shows to to be a decent device and it may be a better choice given the low supply.
There are literally dozens to choose from, even the 5532 is OK on -/+5V rails (Sony use them like that in some CD players). Ultimately you have to draw up your own spec for what you want and see what fits the bill.
There are literally dozens to choose from, even the 5532 is OK on -/+5V rails (Sony use them like that in some CD players). Ultimately you have to draw up your own spec for what you want and see what fits the bill.
Up that PSU at least 1V both pos and neg to have a bit more headroom. Many opamps can drive outputs to 1.2V of the rails. Please try to keep to a minumum standard of quality. It makes no sense designing or building stuff that is marginal from the start.
Ah I see it was already replied :
Ah I see it was already replied :
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I dispute that many opamps that aren't billed as "true rail-to-rail" can drive to 1.2V of the rails _under load_... 2.5V is much more common ballpark.
However 2Vrms with +/-5V rails is not that problematic with a couple of volts headroom as the peak voltage is only 2.83V. Typically the power amp will clip first anyway.
If you're going to have a gain stage, why not make a Baxandall volume circuit so you set the gain appropriate to the situation, thus not wasting any headroom?
However 2Vrms with +/-5V rails is not that problematic with a couple of volts headroom as the peak voltage is only 2.83V. Typically the power amp will clip first anyway.
If you're going to have a gain stage, why not make a Baxandall volume circuit so you set the gain appropriate to the situation, thus not wasting any headroom?