His power transformer is already damaged from him using a 1k load resistor and drawing over 400mA when the max. rating is 200mA.
When a power transformer is smoking, the insulation on the secondary windings is certainly compromised.
Thanks for your helpful critiques. I learned breadboarding/building circuits in a weird way. I can read schematics and place components as they appear on schematics or designs but I fall short when it comes to EMI, pcb design, and component placement which I know I need to work on. I am also doing the best with what I have. I’ll get a dim bulb tester and variac as you say would help with my testing. I plan on doing these amps as not only a hobby but something I plan on making business from.
Wait, so you’re having trouble wiring up diodes for the power supply, and you want to build a push pull parallel tube amplifier of your own design, as a first project?
Please don’t take this the wrong way, but you need to slow down, back up, and start with something simpler…. if not, this could end in disaster.
I’m not trying to rain on your parade, but this is not a simple task. It’s also got deadly voltages and chances of success without the proper tools and testing equipment are next to zero…..
I recommend Morgan Jones, volume 4, give it a read, it’s worth its weight in gold😎
Please don’t take this the wrong way, but you need to slow down, back up, and start with something simpler…. if not, this could end in disaster.
I’m not trying to rain on your parade, but this is not a simple task. It’s also got deadly voltages and chances of success without the proper tools and testing equipment are next to zero…..
I recommend Morgan Jones, volume 4, give it a read, it’s worth its weight in gold😎
I know this isn’t a simple task but I know basic electricity. I also know the working on push pull amps on the transistor level.. which means they should work similar at the tube level. Trust me, I know these are dangerous voltages lol. I have been working on this project for over 1 year now, have been tapped by the HT a few times, but I haven’t died yet, now I know a little better about electrical safety while working with tubes. Please know I am not doing this out of random. This is the ultimate test of my knowledge and I know it is difficult. I have done my loadline calculations, filters, power supply tap calculations.. it is just a lot and I am trying my best to make a good product.
The bleeders were there bro, always have been. Just haven’t had the right values. Sometimes I tend to get lost in the theory when building and looking for “correct” things.
This transformer model (and do not use this specific transformer in a finished amp!) is really adequate to power only a single channel at your proposed 150mA. Most of that power will be consumed by the EL34 output stage. You are asking for trouble if you expect an EL34 to dissipate much more than 20W on a continuous basis so this is about 100mA for a single pair at a supply voltage of 400V.
My rule of thumb for power transformer life is the maximum DC load current should be <70% of the transformer AC rating. Many will recommend 50%. I built tube power amps commercially in the distant past and replaced power transformers that shorted due to overloading. (I did not follow the above rule initially.) Generally the HV secondary developed a winding to winding short, but I also saw a couple with shorted primary winding.
My rule of thumb for power transformer life is the maximum DC load current should be <70% of the transformer AC rating. Many will recommend 50%. I built tube power amps commercially in the distant past and replaced power transformers that shorted due to overloading. (I did not follow the above rule initially.) Generally the HV secondary developed a winding to winding short, but I also saw a couple with shorted primary winding.
They are not interchangeable, so you need both, but especially the fused Variac.
The bulb tester is just a bulb, socket, and a power cord cut in half, mounted on a board, or in a box.