Circuit simulation software

[dhodgeh]

I know a bit about electronics and would like to improve my working knowledge of circuits.

Wondering if anyone can recommend software for constructing virtual circuits in order to be able to run through some of the experiments you see in the tutorials and such.

My goal here is to work towards a good understanding of tube amp circuitry.

Thanks in advance.

Don

[km6xz]

The most common are derivatives of SPICE(Simulated Program with Integrated Circuit Emphasis) one of the very first, in 1973 written by a UC Berkeley grad student in Fortran. There are some simplified versions with graphical interfaces that are easier to use. PSpice was a version written for personal computers that was intended for the first floppy disk based IBM PC, before the XT that had a hard drive back in the early 1980s. It has changed hands a few times and is now a discontinued OrCAD product but they offer a free download limited version: OrCAD Downloads | OrCAD
There are a few free versions such as Linear Technologies LTSpice Linear Technology - Design Simulation and Device Models .

The most popular commercial version is MuiltiSim by National Laboratories. Some like MultiSim have full design schematic capture and pc board layout and autorouting as a complete design suite. It can be expensive for a hobbyist but a real cost savings for a design pro.
There is one that has become popular due to lower price that does most of much MultiSim does called TINA and they have a free download version with more limited capability.
Analog Devices has a free version of MultiSim http://www.analog.com/en/content/adisimpe/fca.html
All these from chip companies are optimized for their own chips but can be used if you find spice models for tubes you are interested in. Duncan Amplifiers has some tube PSpice models for popular tubes: Spice Models
CoolCAD has a free student version of CoolSPICE CoolSpice | CoolCAD Electronics
SPICE is confusing for many beginners because you need to know how the circuit works and what to expect or else results might be misleading so it is better as a learning tool supplement. It provides more information than you will need as a non-engineer so the data it displays or shows in graphical versions. Good luck

[Jazz P Bass]

Kind of hard to beat actually building a circuit.

The Hand/ Eye/ Brain thingy will go a long way to learning how the circuits operate.
As opposed to simply moving items around on a screen.

[km6xz]

Yes, Jazz P Bass is right, I mentioned in the earlier reply how you must know how the circuit works before simulation makes sense or is useful. Get into simulation AFTER you have designed a circuit where you are confident that the basic concept is solid and only need tweaking of final values. For that, simulation can be a real time saver and a confirmation that what you already designed will work as expected.
Build up a Bread board system, a general purpose power supply, a signal source, oscilloscope, and an easy interconnection system. For tube circuits an actual slab of wood 1/2 in thick with stand off insulators and barrier strips mounted. Mount the tube sockets on the board with wires from each pin to a terminal on a barrier strip. Mount some barrier strips in parallel about 2.5 inches apart so you can run resistors and capacitors between the strip lugs for connections without soldering.. The voltages are potentially lethal so make sure the high voltage leads and connections are safely away from contact with you and color coded. Say all the HT wires would be red, heaters low voltage green, signal blue and any common ground connections black so you can see at a glance what should be on those wires..
It is best to wire up and test only one stage at a time. Get is working exactly as you intend or experiment with it. When ready to add another stage, put a magic marker line or colored tape out line around the stage that is completed and star with the second stage in isolation, not connected to the first. after the second is doing what you intend inconnect them as they would normally be in a finished circuit.
If starting with solid state, your safety and work are easier to maintain. There are connector strips at any electronics supply store with hundreds of tiny holes 0.1 of an inch apart in a grid. The holes allow directly inserting ICs, transistors capacitors and wires into the holes and under each row of holes is a metal strip that connects any wires or leads that are plugged into that row. You can also buy pre-cut wire kits of various colors and lengths that are sold core so perfectly fit the holes to make connections between rows. My suggestion is to do all your initial experiments with ohms law, reactance, and other fundamentals on one of these low voltage easy to use plastic bread boards instead of starting with tubes. It will be much safer. After you learn the fundamentals of current voltage, resistance and reactance and can throw together basic circuits with ease that does exactly what you intended them to do before bread boarding it. Only then would it be advised to shift to the tube circuits and their high voltage.
Good luck

[foxking]

I know a bit about electronics and would like to improve my working knowledge of circuits.

Wondering if anyone can recommend software for constructing virtual circuits in order to be able to run through some of the experiments you see in the tutorials and such.

My goal here is to work towards a good understanding of tube amp circuitry.

Thanks in advance.

Don

I know this thread is bit older and I should respect the age (2 year old ).
I recommend you to use circuit wizard, a free version is available and is very very wasy to use compared to other Simulaters.