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01-29-2019, 05:32 PM
Hi TiCatFan
I suppose we assume that you checked the voltages first without tubes and going through the PLSS ? Then tried tubes still through the limiter? Note that even with modest limiting from a pair of 150W lamps in parallel, all the voltages will be lower than stock. If you bypass the lamps the voltages will rise up a bit.
Simply changing the filter caps will not cause a reduction in voltage unless there is a bad connection, but then you would expect to see a drastic reduction and have quite a bit of hum.
The OT has no effect on screen voltage unless it is wired ultralinear. In that case, Vs is only a few volts lower than Va if at all and could actually be slightly higher depending on the DC resistance of the sections of the OT primary.
The solder connections in the amp are pretty large which gives them good longevity, but even so, after enough time they will become fragile and go cold. If you are careful, you can redo all the connections and eliminate that mode of nuisance or failure. To redo a connection, add fresh solder and use a Soldapult or similar to remove the solder with live heat. Then add fresh solder. Go to the next connection. Each connection should not take very long to do. Of course, you won't be able to remove all the solder from an eyelet or from around wire or component ends bent around the tube socket solder lugs - don't take the connections apart! - just remove the bulk solder and add fresh.
Also, when you go to sites like Mouser and Digikey, they have quite good search engines. For a given component type, there will be many parameters listed and as you refine the search by using the "Apply Filters, each updated search will show more and/or different parameters. I try to keep each segment of a search limited to two or three parameters - sometimes just a single parameter - especially if I will be searching for similar parts but say different values. This keeps the one search open to looking for the different values just by going back one step. In any case, the dimensions of the caps are often right there in the master search. Dimensions are often the make or break point for finding a replacement part or something to fit into a new build.
I suppose we assume that you checked the voltages first without tubes and going through the PLSS ? Then tried tubes still through the limiter? Note that even with modest limiting from a pair of 150W lamps in parallel, all the voltages will be lower than stock. If you bypass the lamps the voltages will rise up a bit.
Simply changing the filter caps will not cause a reduction in voltage unless there is a bad connection, but then you would expect to see a drastic reduction and have quite a bit of hum.
The OT has no effect on screen voltage unless it is wired ultralinear. In that case, Vs is only a few volts lower than Va if at all and could actually be slightly higher depending on the DC resistance of the sections of the OT primary.
The solder connections in the amp are pretty large which gives them good longevity, but even so, after enough time they will become fragile and go cold. If you are careful, you can redo all the connections and eliminate that mode of nuisance or failure. To redo a connection, add fresh solder and use a Soldapult or similar to remove the solder with live heat. Then add fresh solder. Go to the next connection. Each connection should not take very long to do. Of course, you won't be able to remove all the solder from an eyelet or from around wire or component ends bent around the tube socket solder lugs - don't take the connections apart! - just remove the bulk solder and add fresh.
Also, when you go to sites like Mouser and Digikey, they have quite good search engines. For a given component type, there will be many parameters listed and as you refine the search by using the "Apply Filters, each updated search will show more and/or different parameters. I try to keep each segment of a search limited to two or three parameters - sometimes just a single parameter - especially if I will be searching for similar parts but say different values. This keeps the one search open to looking for the different values just by going back one step. In any case, the dimensions of the caps are often right there in the master search. Dimensions are often the make or break point for finding a replacement part or something to fit into a new build.
