Threshold Pot doesn't work

[h9361]

That looks OK to me.

Thank you for your replying.
I have a fundamental question about preamp PI.
I read your ITMD2 book, you told that we use a 1000 Gain for preamp of normal PI (without GB).
But you and other are using a lower Gain for preamp gain on PI+GB.
Sorry for my amatory question, because i am learning more about PI machine.

[Carl-NC]

Many basic PI designs have a 500-1000 preamp gain. I often use a lower gain to improve settling speed for earlier sampling.

[h9361]

Many basic PI designs have a 500-1000 preamp gain. I often use a lower gain to improve settling speed for earlier sampling.

Please forgive me, Dear Carl.
Please see the following, it is my Power and TX part.
I used TX part from HHD. As you remember HHD ground is positive pole of VB.
But i am using negative pole as Ground. My doubt is about TX part components, specially C1, R19, Q12 and etc.
Is it possible check it and tell me how to change it based on negative pole ( ground)?
Thank you.

[Carl-NC]

Probably something like this:

[h9361]

Probably something like this:

thank you.
Voltage level of my pulse is exactly like HHD, 0/-5V. Do you think it works over the schematic?

[Carl-NC]

No, for this to work you need positive logic. You need to post the whole schematic so I can see what you are trying to do.

[h9361]

No, for this to work you need positive logic. You need to post the whole schematic so I can see what you are trying to do.

Please see attached, S0 is from my micro and Q5 adjust its voltage level to -5 (N1 is my final TX pulse exactly like HHD).
Can you guide me how to change it so that my pulse voltage level convert to +5?

[Carl-NC]

Why are you running the micro from -5V if the circuit runs on +12V? Seems like you would want to run the micro from +5V.

Here is a basic level translator:

[h9361]

No, for this to work you need positive logic. You need to post the whole schematic so I can see what you are trying to do.

I had a trying for converting its voltage level.
Do you think it is true?

I added your new TX part to my schematic, do you think L2 must be connected to +VB ( red line)?

[h9361]

Why are you running the micro from -5V if the circuit runs on +12V? Seems like you would want to run the micro from +5V.

Here is a basic level translator:

Thank you.
see the schematic from my micro. S0 is for TX pulse generation.

[h9361]

Why are you running the micro from -5V if the circuit runs on +12V? Seems like you would want to run the micro from +5V.

Here is a basic level translator:

In my previous version of HHD+GB, i used a micro.
The micro produces TX pulse (with two pots for controlling frequency and pulse width (off timing like HHD)), 4 sampling pulses with two pots for each pulse in order to controlling both sampling width and delaying. Voltage level of 4 sampling pulses is exactly like HHD, +5/-5V.
Now, i want to change my pervious version GB to your Bipolar version.
Regarding to the explanation, do you think the whole schematic is true, specially voltage level of sampling (+5/-5V) to 4066 and connection of L2 to +VB (red line)?

[h9361]

Why are you running the micro from -5V if the circuit runs on +12V? Seems like you would want to run the micro from +5V.

Here is a basic level translator:

Thank you for your helping.
please forgive me for my requests.
Is it possible to see attached, do you think L2 must be connected to +VB (with your new TX part)?
Is the red line true?

[Carl-NC]

You cannot connect L2 to +12V, it needs to be connected to ground. You also cannot short J6 for a mono coil, it won't work. The switches will work with +5/-5 logic but how will you get that from a micro?

[h9361]

You cannot connect L2 to +12V, it needs to be connected to ground. You also cannot short J6 for a mono coil, it won't work. The switches will work with +5/-5 logic but how will you get that from a micro?

Thank you dear Carl.
Please see the edit, is it ok for both DD and mono?

About switches, i already did on my HHD. A friend guided me as follow for +-5V:

[Carl-NC]

No, it still won't work for a mono coil. You can't apply 12v to an opamp that is running on +/-5V.

I still don't understand why you want to run the micro from -5V. If you run it from +5V you can rid of all the level translators.