As I shared before the only tantalum I used intentionally was in a side chain time constant. Because Tantalum has poor DA (dielectric absorption) they can behave slightly differently in such timing circuits.
Warning: this is about to get a little esoteric. DA or soakage is a characteristic of capacitors related how the energy storage is distributed within the physical capacitor structure. The typical model for DA is bunch or RCs in parallel. The typical example showing DA in action is taking a charged up capacitor, short it out momentarily, and then when you release the short, the capacitor recovers to a fraction of the initial charged voltage state. This is caused by residual charge inside the capacitor equalizing or normalizing over time.
In practice for most typical audio applications, like DC blocking where the capacitor is loaded with a resistive termination the DA does not show much evidence (while the audiophools tried to make a big deal about it back in the 70s/80s). However if loaded with a nonlinear termination that charges and discharges with different impedances, DA can express it's ugly head. The obvious example of this bad behavior is in a sample and hold circuit. We can easily imagine the high DA capacitor after being quickly charged by a low impedance sample circuit, followed by the high impedance unloaded hold circuit, where like the un-shorted capacitor seeks out its longer term equilibrium. We rarely see electrolytic capacitors used in sample and hold circuits. In side-chain time constants, and that meter example being asked about, the high DA capacitor being charged with low impedance fast attack time constant, then released to decay with higher impedance termination can see some influence caused by DA.
I expect this DA caused error to be small, but substituting a low DA capacitor for the tantalum "could" introduce a subtle tracking difference. If you want the meter behavior to be the same use the same dielectric capacitor.
JR
PS; I'm glad to see I am not the only one overthinking capacitor dielectrics.
Warning: this is about to get a little esoteric. DA or soakage is a characteristic of capacitors related how the energy storage is distributed within the physical capacitor structure. The typical model for DA is bunch or RCs in parallel. The typical example showing DA in action is taking a charged up capacitor, short it out momentarily, and then when you release the short, the capacitor recovers to a fraction of the initial charged voltage state. This is caused by residual charge inside the capacitor equalizing or normalizing over time.
In practice for most typical audio applications, like DC blocking where the capacitor is loaded with a resistive termination the DA does not show much evidence (while the audiophools tried to make a big deal about it back in the 70s/80s). However if loaded with a nonlinear termination that charges and discharges with different impedances, DA can express it's ugly head. The obvious example of this bad behavior is in a sample and hold circuit. We can easily imagine the high DA capacitor after being quickly charged by a low impedance sample circuit, followed by the high impedance unloaded hold circuit, where like the un-shorted capacitor seeks out its longer term equilibrium. We rarely see electrolytic capacitors used in sample and hold circuits. In side-chain time constants, and that meter example being asked about, the high DA capacitor being charged with low impedance fast attack time constant, then released to decay with higher impedance termination can see some influence caused by DA.
I expect this DA caused error to be small, but substituting a low DA capacitor for the tantalum "could" introduce a subtle tracking difference. If you want the meter behavior to be the same use the same dielectric capacitor.
JR
PS; I'm glad to see I am not the only one overthinking capacitor dielectrics.
