Help with LTSpice simulation

[dbanner]

I am trying for first time to do LTSpice simulation of Rx preamp of gold bug circuit. I cannot seem to get it to work properly. Assuming the original circuit is correctly drawn. Am I doing something wrong? Maybe I will try to do CZ5 Rx preamp just to see. Here is the file.

[drninja]

I think the "original" circuit is a pile of errors. It resembles the internals of a classic opamp, but for example the current mirror does not function at all (Q4 Q5 in your file) its output should be q5's collector not its emitter. And the rest is the same, i cannot imagine how the vas or the buffer stage would work...

[dbanner]

Well ok then. Doesn't matter. I'm fed up with it anyways. I'll try modelling cz5 preamp. Yes I noticed that on Q5. What I wanted to know was if I'm running the simulation right with respect to the input signal.

[green]

Well ok then. Doesn't matter. I'm fed up with it anyways. I'll try modelling cz5 preamp. Yes I noticed that on Q5. What I wanted to know was if I'm running the simulation right with respect to the input signal.

I am trying for first time to do LTSpice simulation of Rx preamp of gold bug circuit.

Is it the first time to do spice simulation or the gold bug circuit?

I would suggest starting with a signal driving an op amp. When that makes sense replace the op amp with your transistor circuit. Fewer places to make an error.

[dbanner]

Thanks. I knew there were several errors in gold bug preamp circuit drawn by W.L which I was trying to sort out, I simulated the CZ6 preamp circuit which works, so I wanted to get the gold bug circuitry sorted out. I am new to spice so just learning all the tricks and techniques of software. There are plenty tutorials on how to use LTspice so I be doing a lot of reading to get up to speed where I can run basic stuff without too many problems.
Here is the CZ6 preamp
I know I have long way to travel to learn but every journey begins with the first few steps.

[dbanner]

SUCCESS! I have found and corrected the mistakes on W.L schematic for gold bug for Rx preamp circuit. The Rx preamp circuit now works beautifully as it supposed to. Here is the Ltspice file with the corrected preamp circuit.
Can anyone tell me how to take screenshots of the simulations, do I need special screenshot software or can I take screenshot from ltspice software itself. I'm using old xp, I know but for some reason having trouble downloading and installing ltspice in Ubuntu so I reverted back to the only windows software I still have.
I am now closer to building the darn thing.

[6666]

You get full points for perseverance ! I cannot be bothered with so many transistors these days,
in windows it depends on the key board you have but on a laptop its just FN and PRTSC which copies the page to memory then paste into picture program

[dbanner]

Thanks, will try to do as you say. I've been curious to know why Fisher used transistors for preamp instead of op amp. Must be some hidden benefit that my little knowledge does not yet understand.

[drninja]

I think they went discrete for noise performance, i mean there are no other reasons paralleling input transistors in a differential pair. Imo modern opamps run circles around the circuit, eg. a cheap LMP7731 or the AD797.

[KingJL]

... Can anyone tell me how to take screenshots of the simulations, do I need special screenshot software or can I take screenshot from ltspice software itself. I'm using old xp, ...

Don, you can take snapshots of the simulation circuit and simulated scope windows separately within LtSpice. Highlight the correct window then Tools->Copy bitmap to Clipboard. Then use whatever graphics editing software (photoshop, libre office draw, etc.) and paste into an image.