Need Some Guidance For Testing Process On Vacuum Tube Amp

[Planobilly]

Hi Jim,

I am sure I will need to study this whole transformer issue in much more detail. I am also sure I will have some questions for you.

In general, I am trying to get a handle on some basic concepts and reduce things to the most basic factors. That was the reason I ask the question about what causes things to over heat. i.e the current question. I am well aware that electronic circuits can get pretty complex in their inter relationships but there is not an unlimited amount of cause and effect relationships. Also when something is not working there are faults that are much more likely than others to be the cause. I am trying to come to a method of step by step troubleshooting combined with a good "guess" style of troubleshooting.

I assume everyone at times thinks "this is the answer" without any apparent way of knowing why they think that. I don't know how that works and I guess it is not really important how it works. It just does, and when it does it is a super fast way to get to the solution. Because just guessing does not work very often, a method that always works need to be devised.

Your advice and direction put me on the path of a much better understanding of of this amp. It took me many hours ( perhaps 30 hours) to get to the final solution. It was time well spent.

Yesterday I started on the second one I own which had several issues and was displaying the same sort of symptoms. The troubleshooting time to resolution went from 30 hours to 30 minutes!
I have one more that I will work on this afternoon. It will be instructive to see if this reduced troubleshooting time line continues!

In any event, thank you ever so much for the kind help and putting up with my questions.

All the best,

Billy

 

[jim hardy]

Your advice and direction put me on the path of a much better understanding of of this amp. It took me many hours ( perhaps 30 hours) to get to the final solution. It was time well spent.

time well spent indeed.
"Junk" has enriched my life too.
When i was 13 i bought, for $6 from a Miami junk shop, and carried home on my bicycle handlebars a bushel of outboard motor parts.
With advice from a kindly couple who ran a boat shop i was able to assemble a Johnson QD11 ten hp outboard. Wow, did i learn a lot !
Used that motor all through my teen years.

If your other amps have blown output transformers too,
i would add that 'snubber' resistor across secondary. Fifty or a hundred ohms won't waste enough power to notice. Ear being logarithmic, 2X the power is barely noticeable..

Also feel your transformers. Same plate current that heats the tubes heats the transformer, so your early on attention to the output tubes is prudent.

Salvador has started a thread on vacuum tube amp, maybe you can help him along..
https://www.physicsforums.com/threads/vacuum-tube-x-ray-question.859427/

 

[Planobilly]

Thanks Jim...be glad to take a look at Salvador's post.

I had to finish a small machining job for a friend this morning. Built a transport part for a CD juke box from Europe which we could not buy. Crazy I know...lol

Like my grand father use to tell me..."with 300 dollars worth of tools you can build a 3 dollar ironing board' !...lol

I hear my wife calling me for lunch...I have learned the correct to all her questions. "Yes dear"

BIlly

 

[jim hardy]

I get a lot of mileage from
"That's a big ten-Yes,dear !"