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
Last edited:
"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.
I think the Noise Limit here are the 10 Ohm source resistors and the idle current. I would make them as los as 2.2 Ohm and set the Kyle for the pair at 50mA or something. Other then that the circuit Workshop well.
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.
Last edited:
Yes, I like the FET Version and I have some IF3602. If you further develop the circuit for this FET ( lower value Source resistors, 50mA idle per pair ) i am able to build a prototype.
This is for MC cartridges of cause.
This is for MC cartridges of cause.
Joachim,
I wonder what reason, apart from having a few, could justify a very expensive dual Fet instead of two super low noise trannies, costing almost nothing, to be used in a MC preamp?
Or do you want to use this amp also in someway for MM ?
Hans
I wonder what reason, apart from having a few, could justify a very expensive dual Fet instead of two super low noise trannies, costing almost nothing, to be used in a MC preamp?
Or do you want to use this amp also in someway for MM ?
Hans
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.