I made a mistake on my Post # 217:
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The tradeoffs are:
0-500VAC and 4 diodes: less turns, but 2X the wire cross section Area.
500-0-500VAC and 2 diodes: More turns and lower wire cross section Area.
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Of course, just like TonyTecson said, you have to account for all the series resistances in the circuit; primary DCR, secondary DCR, diode drop, etc.
But when it comes to Simulation Software, I say . . .
So much for the art of calculating it by hand.
How did Western Electric ever put sound in the Movie Theater, before PCs and Windows?
___________________________________________________________
The tradeoffs are:
0-500VAC and 4 diodes: less turns, but 2X the wire cross section Area.
500-0-500VAC and 2 diodes: More turns and lower wire cross section Area.
_____________________________________________________________
Of course, just like TonyTecson said, you have to account for all the series resistances in the circuit; primary DCR, secondary DCR, diode drop, etc.
But when it comes to Simulation Software, I say . . .
So much for the art of calculating it by hand.
How did Western Electric ever put sound in the Movie Theater, before PCs and Windows?
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6A3sUMMER That software has done nothing but confuse me anyway.
I have no idea how it works and the instructions are few and far between on the website.
Maybe it's good for people with a little more technical knowledge but I am not there yet.
I tried asking my brother inlaw (Electrical Gingerbeer) about the project and he said he has no idea at all about valves and tubes. Then came the "Why do you want to waste your time building one of them. Just buy a decent amp from the HiFi shop"
Turns out as an Electrical Engineer he only programs stuff and writes computer code.
I have no idea how it works and the instructions are few and far between on the website.
Maybe it's good for people with a little more technical knowledge but I am not there yet.
I tried asking my brother inlaw (Electrical Gingerbeer) about the project and he said he has no idea at all about valves and tubes. Then came the "Why do you want to waste your time building one of them. Just buy a decent amp from the HiFi shop"
Turns out as an Electrical Engineer he only programs stuff and writes computer code.
PSUD2 is ideal for tuning your power supply to deliver the power requirements of the amplifier, i.e. you have to have a good idea of what you are shooting for, and in that case you have to define the operating points of the tubes so you know their HT and current requirements.
And that will probably not correspond to the transformer you have, so you have to iterate to find a solution that works.
The alternative is to fix your outcome at the start, choosing a schematic that is tried and tested, then order the bits you need. To do justice to your tubes you are going to have to throw some money at OPTs anyway, why spoil the boat for a ha'pe'th of tar? Ordering what is used in the schematic saves the pain of learning the modelling software.
And that will probably not correspond to the transformer you have, so you have to iterate to find a solution that works.
The alternative is to fix your outcome at the start, choosing a schematic that is tried and tested, then order the bits you need. To do justice to your tubes you are going to have to throw some money at OPTs anyway, why spoil the boat for a ha'pe'th of tar? Ordering what is used in the schematic saves the pain of learning the modelling software.
Hi Hector,
That's why I chose the Mullard 5-20.
The EL34 are quite similar to the GU-50 and have found quite a few people who made the same circuit with the same tubes.
I don't mind getting decent OPT and want to do it right.
Funny thing is I was starting to understand the schematics and the CT feedback and Bias etc.
Then a few questions came up and I feel I am back at square 1 and understand nothing at all.
That's why I chose the Mullard 5-20.
The EL34 are quite similar to the GU-50 and have found quite a few people who made the same circuit with the same tubes.
I don't mind getting decent OPT and want to do it right.
Funny thing is I was starting to understand the schematics and the CT feedback and Bias etc.
Then a few questions came up and I feel I am back at square 1 and understand nothing at all.
I would have at least slapped a rectifier, caps and a couple dummy loads on it while I was waiting for the damn windows to update. Probably would have had your answer in 20 minutes. Then you’d have PSUD ready for the next time. If you find a bunch of 4.7k -ish 22 watt resistors surplus for cheap, buy them. 20 or 30 of them and you can make just about any dummy load you need.
I once waited ALL night for Windows to update just so I could file a tax return. That’s what happens when you don’t use that particular computer every day.
VERY true - you might be surprised to find out how many “designers” of the most complex technology can’t function at all without their simulators - even for the most simple tasks like putting together a 20 watt audio amp on a perf board or a simple switching circuit they need to test one of their prototypes in the lab (because they don’t have the instrument driver they need for that yet, and the BU needs the answer TODAY). Catches up with you eventually, though - eventually you get “sent to Siberia” - to a cold dark corner of the organization doing the jobs nobody wants.
My second biggest beef with simulators is that they can lie. If your model is incomplete, the answer will be a lie. Fortunately, power transformers are relatively easy to model, but you need to know some basic electronics to do it.
If wanted to calculate the exact peak diode current in a cap input filter I would resort to a simulator. A few hand calculations will get you in the ballpark to get the right size diode, and that usually what matters. But solving simultaneous integro-differential equations by hand tests my patience a bit too much.