Designing a phono preamp, in view of the current trend of making everything balanced, given my limited budget, I was forced to think a bit.

Thermal noise can be expressed in the form

e(Noise) = √ (4kTRB) ....(1)

where:

k is the Boltzmann constant

T is the absolute temperature

R is the resistance

B is the bandwidth

For n devices in series

[e(Noise)] ^ 2 = (4kTB) Σ Ri

If all n have the same R

e(Noise)s = √ n e(Noise) ....(2)

For n devices in parallel

[e(Noise)] ^ 2 = (4kTB) [Σ (1/Ri)] ^ (-1)

If all n have the same R

e(Noise)p = (1 / √ n) e(Noise) ....(3)

The stochastic nature of the noise is already covered by Eq. (1), for this reason, the thermal noise is not canceled on a balanced amp.

Conclusion: The intrinsic noise generated on a balanced amplifier is higher than on a SE amplifier by a factor √ 2

Due to I use short cables and I am very careful to shield the fields I'm happy to do my preamp SE !

Thermal noise can be expressed in the form

e(Noise) = √ (4kTRB) ....(1)

where:

k is the Boltzmann constant

T is the absolute temperature

R is the resistance

B is the bandwidth

For n devices in series

[e(Noise)] ^ 2 = (4kTB) Σ Ri

If all n have the same R

e(Noise)s = √ n e(Noise) ....(2)

For n devices in parallel

[e(Noise)] ^ 2 = (4kTB) [Σ (1/Ri)] ^ (-1)

If all n have the same R

e(Noise)p = (1 / √ n) e(Noise) ....(3)

The stochastic nature of the noise is already covered by Eq. (1), for this reason, the thermal noise is not canceled on a balanced amp.

Conclusion: The intrinsic noise generated on a balanced amplifier is higher than on a SE amplifier by a factor √ 2

Due to I use short cables and I am very careful to shield the fields I'm happy to do my preamp SE !

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