IC6 is the RIAA EQ which can be jumpered to inverse RIAA.
The board is also used as a cutting amp which is why it has inverse RIAA capability.
Phono Preamplifier Boards and Kits
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"Differential ultra low noise amplifier for low frequency noise measurements" Full citation pdf: https://aip.scitation.org/doi/pdf/10.1063/1.3605716
Looks to be about 1nV√Hz.
Looks to be about 1nV√Hz.
this here is a bit what we do but with FETs.
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Compare to post 11330 (feedback not applied).
In my design, idle is 5mA per input device.
To lower noise we can parallel some jfets.
The IF3602 is way to expensive for me...
If ever entering production I would place some large caps in the input as if one rail collapses, the cart goes to heaven.
I deliberately chose a high gain as I am not sure we can use this design for MM. Most MM have the shield connected to the left negative output so this would short one input to gnd causing bad results.
Let me know if you like it and I will further develop the sim.
To lower noise we can parallel some jfets.
The IF3602 is way to expensive for me...
If ever entering production I would place some large caps in the input as if one rail collapses, the cart goes to heaven.
I deliberately chose a high gain as I am not sure we can use this design for MM. Most MM have the shield connected to the left negative output so this would short one input to gnd causing bad results.
Let me know if you like it and I will further develop the sim.
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Hans ! I already build an MC stage with this FET and it sounded to my ears quite special. Also this FET is not easy to use. At Idss it gets so hot that I fried one. Of cause I could have used it with less voltage because the pinch off voltage of this part is very low. So for me using this FET is fun and challenging. That is all.