Hi I am in the middle of doing a college project at the moment trying to design a marshall JMT50. I am a bit lost and confused as to whether I am doing it correctly. I was hoping someone could tell me if I'm doing it correctly. I have attached a compressed folder of the schematic and asc file. Thanks
Hmm, please try a bit harder, you need to learn to use the program first and copy the schematic exactly as shown before even trying to run the simulations, please read the manual and follow some online tutorials (see under Software Tools forum for example) and elseswhere for starters - especially if this is for your coursework.
When you say "design" , what exactly do you mean? This amp has already been designed, laid out, built and copied. What is it that you are "designing"?
How much understanding do you have of layout, basic circuit function, power supplies, lead dress, grounding schemes,etc?
There's a lot to learn before you pick up a soldering iron.
How much understanding do you have of layout, basic circuit function, power supplies, lead dress, grounding schemes,etc?
There's a lot to learn before you pick up a soldering iron.
You need to compare what you have to the original very carefully.
Then check it at least 3 times to be sure.
Valve amplifier layout is a minefield.
They are very prone to hum unless careful layout and proper grounding is used.
Also be aware that valve amplifiers can kill you.
Read up on safety before you even consider working on one.
On mine I had a LED and resistor connected to B+ so I could see if there was any charge on the power supply capacitors.
Then check it at least 3 times to be sure.
Valve amplifier layout is a minefield.
They are very prone to hum unless careful layout and proper grounding is used.
Also be aware that valve amplifiers can kill you.
Read up on safety before you even consider working on one.
On mine I had a LED and resistor connected to B+ so I could see if there was any charge on the power supply capacitors.
That is a good idea! I was thinking that there should be some more ''safety'' designed into tube amps, like a ''service'' switch and maybe something like your indicator.
That is why there are labels stating that "There are no user serviceable parts inside". An Engineer gets access to service information direct, from the manufacturer, if they have been on courses and are up to the required standard.
So no need for "safety" devices.
Yes in the ideal world where service techs and engineers never make mistakes, a label should be enough protection. I have done work on high voltage industrial equipment, and even when someone is always careful, faulty equipment or distraction or someone else's actions can put someone in hospital or worse. Panel lockouts and safety switches on panels are standard, but I've seen people bypass those..that's usually where troubles begin.
Boob, Nigel, etc. 🙂
I don't think the actual amp will be physically built, doubly so if it's a college project where lately stuff is limited to less than 30 to 50V between any two points of the circuit.
I guess tiernan has to fully draw and simulate the schematic, probably showing voltages and waveforms at different points, all of which can be simulated.
Actual breadboarding is not exactly encouraged, unless it's "safe" projects such as the microprocessor-of-the-day-application and similar stuff.
Short ago somebody posted about actually building a guitar tube amp as school project, very similar to this, but he fancied scaling voltages down, say +40V for the power tubes, +25V for preamp, and so on, but unfortunately that won't work or at best be so crummy that result would be useless.
In that case I suggested building a good SS amp, and posted a couple 15W Peavey and Marshall amps he could use as a guide.
Now, in simulation, even thousands of volts are "safe" 😉
I don't think the actual amp will be physically built, doubly so if it's a college project where lately stuff is limited to less than 30 to 50V between any two points of the circuit.
I guess tiernan has to fully draw and simulate the schematic, probably showing voltages and waveforms at different points, all of which can be simulated.
Actual breadboarding is not exactly encouraged, unless it's "safe" projects such as the microprocessor-of-the-day-application and similar stuff.
Short ago somebody posted about actually building a guitar tube amp as school project, very similar to this, but he fancied scaling voltages down, say +40V for the power tubes, +25V for preamp, and so on, but unfortunately that won't work or at best be so crummy that result would be useless.
In that case I suggested building a good SS amp, and posted a couple 15W Peavey and Marshall amps he could use as a guide.
Now, in simulation, even thousands of volts are "safe" 😉
Appreciate the insight, JM. I didn't think this was the intent after reading the OP. I can't open all the files so I can't know what else is in there. I suppose the only way we will ever know for sure is if tiernan weighs in on the discussion and allows us to help him.
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