Whites PI3000 Modification Release

[Anonymous]

Luca,
Have you tryed a LM6365 IC in place of 5534.
I am looking for a better CI to replace 5534 in my
PI detectot.one that will plug into same socket.
Hows your mod comeing on white PI-3000.
Frank Serra. in US.

 

[Anonymous]

Hello Frank,
I did try a AD797 opamp in place of the NE5534.
Unfortunately it is unstable.
I learned that I need to connect it correctly (compensation and decoupling) otherwise it oscillates.
My mod to the PI3000 works really well.
Recently I got water inside the coil so I'm waiting for a replacement one from Whites UK.
I had then the chance to open my old coil and count the windings : 36 windings. It looks a lot for a 11" coil.
Anyway I'm now sure that the long RX recovery time (25uS)my PI3000 takes after TX pulse is due to the NE5534 overload and NOT to coil inductance or lack of shielding.
The problem is that if you want the NE5534 to recover faster you need to reduce gain (1000 in the case of PI3000), also good power supply decoupling is advisable as I understand by studing theory.
I got all the components to build part of the PI3000 schematic and try different combinations of Opamps. When I'll have news , I'll post it!
Cheers
Luca

 

[Anonymous]

What do you think of LM6365 is it a waist of time.
Try winding your own coil, make it light-er.Mono coils are easy to make.wind it on a non-metal template so that you can test it and re-use wire.
36 turns of wire might not be to much.I went much higher with my PI-1000, Dont go lower 24 turns,This is from memory. Experment and be safe.
Frank.

 

[Anonymous]

Hello,
the LM6365 is one of the OpAmps I would have tried. It should recover very fast.
Anyway I still belive that we can obtain a very fast amplification by using two NE5534 instead of one by making amplification the square root of required one.
For example, I want to try to replace the NE5534 pre amp of the PI3000 working at a gain of 1000, with two NE5534 working at gain 33 each. Lowering amplification means grater bandwidth and faster recovery time!
Cheers

 

[Anonymous]

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