sluckey wrote: ↑Tue Oct 08, 2019 5:41 pm
Guys, read this statement, especially the part I underlined, bolded, and italicized...
Oddvar R wrote: ↑Tue Oct 08, 2019 8:34 am
...you sen two leads from the transformer into to rows of diodes ending in a single point, without any other connection, will there be a DC reading of some significance...
The answer to that is there can be no dc reading until the center tap is connected. His center tap is just floating in air.
No doubt he has other problems.
My friend Sluckey, you have helped me a lot in the past years. I won't dwell on the fact that you in effect are calling me a liar. I wouldn't know why. I am just a hobbyist, who likes building tube amplifiers that I never would have had the money to buy. "No doubt he has other problems", you are definitely right, basically I understand more of amps now, then when I started building them some 15 working tube amps ago, but still I have a lot of dark spots all over. That's why a ask questions, often stupid ones, especially to knowledgeable persons like yourself. But without questions, no amps, and thanks to forums like this it is made possible, by patient, helpful people. So I hope that I can get help also in the future in the same spirit, from persons like you, and other people here that have been very kind to amateurs like me, who happens to have amps as a hobby.
But to the case you mention above, my CT's are floating at the moment, due to the fact they can't be connected anywhere without the Bulb limiter really lighting up, whatever I do. That's why I wonder what I had to connect to get a read of DC from the conversion from Ac to DC across the diodes, with unneeded distraction.
sluckey wrote: ↑Tue Oct 08, 2019 5:41 pm
Guys, read this statement, especially the part I underlined, bolded, and italicized...
Oddvar R wrote: ↑Tue Oct 08, 2019 8:34 am
...you sen two leads from the transformer into to rows of diodes ending in a single point, without any other connection, will there be a DC reading of some significance...
The answer to that is there can be no dc reading until the center tap is connected. His center tap is just floating in air.
No doubt he has other problems.
My friend Sluckey, you have helped me a lot in the past years. I won't dwell on the fact that you in effect are calling me a liar. I wouldn't know why. I am just a hobbyist, who likes building tube amplifiers that I never would have had the money to buy. "No doubt he has other problems", you are definitely right, basically I understand more of amps now, then when I started building them some 15 working tube amps ago, but still I have a lot of dark spots all over. That's why a ask questions, often stupid ones, especially to knowledgeable persons like yourself. But without questions, no amps, and thanks to forums like this it is made possible, by patient, helpful people. So I hope that I can get help also in the future in the same spirit, from persons like you, and other people here that have been very kind to amateurs like me, who happens to have amps as a hobby.
But to the case you mention above, my CT's are floating at the moment, due to the fact they can't be connected anywhere without the Bulb limiter really lighting up, whatever I do. That's why I wonder what I had to connect to get a read of DC from the conversion from Ac to DC across the diodes, with unneeded distraction.
Maybe it's a communication barrier, but you've had 3 different people tell you that grounding the center tap is mandatory, yet you seem to be unclear if you're doing it or not. There's been previous such issues as well, I think sluckey is just expressing his frustration that he's not getting easily understandable or consistent results from you, thus why he's repeating himself. (but I'm just guessing, I'm not sluckey) it can be very frustrating for anyone to give an answer that isn't heeded.
If you ground the center tap and the bulb lights brightly, shut off the amp, get your multimeter in continuity mode and check all points of the power rail for continuity to ground. You should NOT have any continuity to ground except at the point where the red wires come in(they do have ground reference due to the center tap, but once you pass the diodes they will not allow backwards current to ground).
Then once you confirm there are 0 referece to ground on the power rail, things should be fine for power up.
I've had one time where I accidentally caught an under board jumper in a standoff that was carrying B+ and I shorted it to ground. That's the kind of thing to look for.
Oddvar R wrote: ↑Tue Oct 08, 2019 6:26 pm
I won't dwell on the fact that you in effect are calling me a liar. I wouldn't know why.
I don't mince words. If I wanted to call you a liar, I would have. I said, "I don't trust much of what Oddvar says." That means the info you provide is often not reliable enough for anyone to diagnose your issue. You seldom give enough info, or the info you give is just impossible. I've been around you more than long enough to realize you love to build amps and have built more than I ever will. But you still don't know what you're doing and you don't seem to learn anything from one build to another. It's like you do a total brain dump when you finish one project. Then you have the same or similar problems on your next project. How can a simple power switch be so confusing to anyone with your experience?
But, I don't seem to be helping. It's just too frustrating to try to help you, so I will just shut up and silently follow with amusement.
By the way, if you get the short worked out, the 372JX transformer is awesome for a Trainwreck. I have a 272JX in on of mine and it has plenty of gas. I’m about to build a Marshally thing with one of those transformers.
