New (to me) amp - Speaker connection question

[txtune]

I'd bust out the meter, measure the VDC against what's on the schematics posted earlier.  start at the cathodes of the PA (.5vdc), bias vdc (-35).  and the 500vdc on the power rail, if their close, do the preamp plate voltage.


if they fall in line;
i'd monitor the PA cathodes, 2 meters, one one each pair and run the amp with music at 50% for maybe 15-30minutes (what I call the smoke test:)
If you have a temp monitor, measure the PT temp at start, then every 5 minutes of play

I will try this out next week, the parts just came in for my other hobby (CNC Plasma table) and I need to get it back together and cutting. 

FWIW - I had the amp on for about 45 mins yesterday, between 50 and 75 percent volume (on a tablet playing pandora radio) and neither the PT or OTs even felt warm to the touch. The rectifier tube was bright compared to any other tube. Maybe that is normal for a rectifier tube to work harder than the rest, but it appeared to be in overdrive.

I am going to do more research before I do anything with it. As I said earlier, the fellow who sold it to me is in the process of downsizing his lifelong collection. I initially purchased two Telefunken tubes from him on eBay, when I went to pick them up he showed me his 'bat cave' of radios, ham equipment, and thousands of tubes. As I was leaving he showed me this amp. I had to help get it out from underneath a shelf and move some other stuff that was in the way and stacked on top of the box it was in. It's heavy, 47lbs to be exact. He said he had planned to sell the OTs but if I wanted it (and would lug it off his property) he would sell it for $280 right then on the spot. I asked if that included the tubes, he winced, then agreed. I would have paid $280 for it without the tubes, but after that I could not pay the man fast enough. The $280 price came up so quickly it led me to believe that is the price he paid for it... and it was probably a project he never got around to working on. I do have a conscious, I asked the fellow several times if he was sure, he said "yes... go figure that thing out."     

[shooter]

I do suspect the rectifier tube is your "weak link", easy enough to use modern diodes down the road.  I suspect you have a keeper "as is".
There are many of us in the wild that would rather loose a couple $$'s "passing on" to the "next gen", than making bank on the market

[txtune]

I do suspect the rectifier tube is your "weak link", easy enough to use modern diodes down the road.  I suspect you have a keeper "as is".
There are many of us in the wild that would rather loose a couple $$'s "passing on" to the "next gen", than making bank on the market

Could a larger, or even multiple, rectifier tube(s) be installed?

Also, what about the power amp is leading everyone to believe it is too small? The physical size of it??

[shooter]

your amp appears to be a 2 in 1, rebuild, so my guess he used one of the 2 PT's, rectifier, got it to work, maybe used it a couple times n shelfed it 


If you go by the original mono, it wants 150mA per mono.  300mA is pretty big for a single tube rectifier.  I didn't look up specs so that's something to verify