MPP preamp is vastly improvable

[Teleno]

Thanks Teleno,
I will fix the legend on the board Thanks for catching that . Good thing there the same pinout.

Good thing too because you can swap them and see what works best.

[godigit1]

Thanks Teleno,
I will fix the legend on the board Thanks for catching that . Good thing there the same pinout.
I already added thru hole connection for a bat 85 as well.
I will also post a connection schem to the MPP when I can.

I have the board etched but have not had time latley to do much else.

dbanner,
I have the Gb circut working, but still have to play with the timings some more. I also have Davors timing circut etched and ready to build.
I wanted to compare both for performance. Need parts still before continuing. positive thing so far is it cancels out a bunch of magnets and will still pick up a 2 gram gold ring completly encased in magnets. Strange thing is the circut works better when connected to the scope.???

Have a good day guys.

[dbanner]

Fine, we're waiting for your brilliant contribution. A better audio doesn't help get better gold anyway.

I'm thinking about when the addition of a ground balance circuit to the MMP, whenever that may arrive, at which time the primitive audio vco would really handicap the overall performance.
It's the mods to the pcb layout to accomodate an upgraded VCO/VCA which I'm interested in. The circuits are already here on forum.

[Teleno]

Here is the Schematic.
[ATTACH]45394[/ATTACH]
[ATTACH]45395[/ATTACH]

I woudl swap U3 (LM4562) with U1 (TLC082) because the LM4562 has lower noise and higher bandwidth, which are ideal for the input stage. TLC082 has JFET inputs and low offset, ideal for integrators.

[Teleno]

Interesting. The two stage pre-amp should be an improvement.
What is the timing of the FET switches?

The timing of Q3 is the same as the timing of Q3 in the MPP (signal "c")

[waltr]

Here is the Schematic.
[ATTACH]45394[/ATTACH]
[ATTACH]45395[/ATTACH]

Interesting. The two stage pre-amp should be an improvement.
What is the timing of the FET switches?

[Teleno]

[ATTACH]45393[/ATTACH]

Hi Teleno,
Here is a pwb for your new integrator design and for anyone who wants to follow along.
I wanted to make it easier to try different amp combos.

I still have to get some parts before I can build it and test it but Ive double checked it twice and it looks good.
If anyone else could give it a eye that would be great. I will post the schematic i used in the next post I forgot to compress it.

I have not been able to find a bat 54 that is not surface mount so I placed it on the back side of the board.

Thanks again

I do not have the time to practice this hobby beyond some theoretical simulations, so I'm glad to learn that someone is picking up the tab.
Thanks and please keep us posted on your findings.

[eclipse]

You can use BAT85.

[godigit1]

Here is the Schematic.
Telano mpp integrator.zip

[godigit1]

Hi Teleno,
Here is a pwb for your new integrator design and for anyone who wants to follow along.
I wanted to make it easier to try different amp combos.

I still have to get some parts before I can build it and test it but Ive double checked it twice and it looks good.
If anyone else could give it a eye that would be great. I will post the schematic i used in the next post I forgot to compress it.

I have not been able to find a bat 54 that is not surface mount so I placed it on the back side of the board.

Thanks again

[6666]

Good work Teleno

[eclipse]

MAX412 would be great for this preamp.

[Teleno]

Hi Teleno,
Thanks for doing this it looks very good on the scope.
I was trying to put together a pwb and when drawing a schematic I found a question.
Im not that experianced but dig following along with you guys so pardon my inexpertiese and spelling.LOL
On u11 is that a second tl081 ? I cant see it on the datasheet Maybe a tlo84?
Thanks again

U11 should be a single op-amp with low noise and at least 10MHz GBP (Gain-bandwidth product in the datasheet), I had the TL081 in mind.

The trace is a simulation. Unfortunately I haven't got the time to tinker with hardware, if some of you care to try this please report your results.

[godigit1]

Hi Teleno,
Thanks for doing this it looks very good on the scope.
I was trying to put together a pwb and when drawing a schematic I found a question.
Im not that experianced but dig following along with you guys so pardon my inexpertiese and spelling.LOL
On u11 is that a second tl081 ? I cant see it on the datasheet Maybe a tlo84?
Thanks again

[Teleno]

Brilliant. So much effort for perfection of front end. Nobody care about bumblebee tick tick sound at the other end.
The best improvement for MPP would be a smooth audio.

Fine, we're waiting for your brilliant contribution. A better audio doesn't help get better gold anyway.