So is between -20.00001dB & -20.08dB instead the -20dB calculate at the stepped attenuator, not bad at all!!!!!
and part of the reason for the very low error is that the ratio of Rin:Rs is >=1M:2k5
Instead of the more usual 10:1 or 20:1 ratio you have >=400:1
The error also becomes less as attenuation is increased (lower Rs) and conversely becomes higher as attenuation is reduced.
Watch that 1M. we have moved away from high input impedances as valve gear has become less common.
We usually find that lower input impedances result in less interference and less noise. Having a, permanently connected, very low Rs helps avoid much of any disadvantage of High Rin.
Instead of the more usual 10:1 or 20:1 ratio you have >=400:1
The error also becomes less as attenuation is increased (lower Rs) and conversely becomes higher as attenuation is reduced.
Watch that 1M. we have moved away from high input impedances as valve gear has become less common.
We usually find that lower input impedances result in less interference and less noise. Having a, permanently connected, very low Rs helps avoid much of any disadvantage of High Rin.
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The input impedance of Borbely line amp it's very easy to tweak only changing 1 resistor per channel.
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