It's a bit like looking for a partner in life; you want to find the balance of compromises that you can live with. As far as capacitors go it depends on the application.
Let's guess (because you are using DATs and the DOT is 3.3µF capacitor) a high pass capacitor for a tweeter, you want ESR at 10kHz to be near zero (0.0* is not unreasonable), DF should be low, Q should be high, ∂ should be low. Values shouldn't change much with frequency (yours vary quite a bit). Measure a high quality audio grade film capacitor and compare the measurements with an 'ordinary' electrolytic of the same value. Audio grade electrolytics will typically be somewhere in between.
Let's guess (because you are using DATs and the DOT is 3.3µF capacitor) a high pass capacitor for a tweeter, you want ESR at 10kHz to be near zero (0.0* is not unreasonable), DF should be low, Q should be high, ∂ should be low. Values shouldn't change much with frequency (yours vary quite a bit). Measure a high quality audio grade film capacitor and compare the measurements with an 'ordinary' electrolytic of the same value. Audio grade electrolytics will typically be somewhere in between.
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Looking at the data I have comparing electrolytic vrs film, The electro's have lower ESR @ 120hz. Should electro's be used at low frequency?
I have two different capacitor analysers, but I am not sure I trust their measurements. Sometimes I think the algorithms used by these analysers are tricked and give a dubious result. I also have DATs (V2) but I don't use that for capacitance measurement.
Whether the capacitor will be a better choice because of lower ESR (say 0.1Ω instead of 0.4Ω) depends on where it is used. If the capacitor is used as a high pass filter for a tweeter for example, the 'high' ESR isn't a negative (as long as it doesn't change dramatically with frequency above 500Hz or so to above 20kHz). The higher ESR will mean a slightly smaller value of R in the tweeter attenuator normally needed to balance the output of the tweeter with the other drivers.
As a low pass for a mid driver, that 0.4Ω may be undesirable because of the drop 1dB or so of drop in output of the mid driver. Also any series resistance (as opposed to reactance) will reduce the amplifier's ability to damp motion in the driver that is not coherent with the driving signal. That's not so important for high frequency drivers as they generally don't rely on damping from the amplifier so much to behave properly.
For a simple power supply, any ESR in a filter capacitor is normally effectively in series with the output of the supply. For big power amplifier suppliers, I look for ESRs below 0.01 ohms at ripple frequencies, and 'audio grade' filter capacitors will maintain that low ESR throughout the audio band.
To answer your question, should electro's be used at low frequency, yes and/or no. More information needed about the circuit it is in and what it is doing in that circuit. Generally I would not use an electrolytic in an audio circuit where a film capacitor will fit (as in cost and/or size).
It goes without saying that audio signal coupling capacitors should be carefully selected for audio quality, but for bypass capacitors in audio circuits it is often overlooked that those components are also passing audio signals correlated with the signal that the circuit is processing, so they should be audio grade as well. Filter capacitors are somewhat decoupled from the audio signal by the PSRR of the circuitry so perhaps less important. I use low ESR Cs for filtering and audio grade Cs for local supply bypassing near the amplifier circuitry.
Audio grade capacitors not only have properties that are more consistent with frequency, they are also less affected by mechanical vibration AKA microphonics. This is particularly important for low level circuits such as phono RIAA and head amp stages. Electrolytics are typically far worse than film caps in this regard. One of my tests when restoring an amplifier is to tap all of the capacitors while the amplifier is at full volume control position with no signal; any capacitors that are sensitive to tapping are binned and replaced with WIMA film, or electros such as Elna Tonerex or Nichicon Fine Gold, depending on what will fit.
Whether the capacitor will be a better choice because of lower ESR (say 0.1Ω instead of 0.4Ω) depends on where it is used. If the capacitor is used as a high pass filter for a tweeter for example, the 'high' ESR isn't a negative (as long as it doesn't change dramatically with frequency above 500Hz or so to above 20kHz). The higher ESR will mean a slightly smaller value of R in the tweeter attenuator normally needed to balance the output of the tweeter with the other drivers.
As a low pass for a mid driver, that 0.4Ω may be undesirable because of the drop 1dB or so of drop in output of the mid driver. Also any series resistance (as opposed to reactance) will reduce the amplifier's ability to damp motion in the driver that is not coherent with the driving signal. That's not so important for high frequency drivers as they generally don't rely on damping from the amplifier so much to behave properly.
For a simple power supply, any ESR in a filter capacitor is normally effectively in series with the output of the supply. For big power amplifier suppliers, I look for ESRs below 0.01 ohms at ripple frequencies, and 'audio grade' filter capacitors will maintain that low ESR throughout the audio band.
To answer your question, should electro's be used at low frequency, yes and/or no. More information needed about the circuit it is in and what it is doing in that circuit. Generally I would not use an electrolytic in an audio circuit where a film capacitor will fit (as in cost and/or size).
It goes without saying that audio signal coupling capacitors should be carefully selected for audio quality, but for bypass capacitors in audio circuits it is often overlooked that those components are also passing audio signals correlated with the signal that the circuit is processing, so they should be audio grade as well. Filter capacitors are somewhat decoupled from the audio signal by the PSRR of the circuitry so perhaps less important. I use low ESR Cs for filtering and audio grade Cs for local supply bypassing near the amplifier circuitry.
Audio grade capacitors not only have properties that are more consistent with frequency, they are also less affected by mechanical vibration AKA microphonics. This is particularly important for low level circuits such as phono RIAA and head amp stages. Electrolytics are typically far worse than film caps in this regard. One of my tests when restoring an amplifier is to tap all of the capacitors while the amplifier is at full volume control position with no signal; any capacitors that are sensitive to tapping are binned and replaced with WIMA film, or electros such as Elna Tonerex or Nichicon Fine Gold, depending on what will fit.
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