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I saw the review about the vintage ampeg but I just wanted to be certain..this tube is rated 19W but my amp is only 15W. Would the 19 want to pull too hard on the system or is 4W not gonna make a difference. I know some systems can't handle that much difference but those we low voltage, sensitive electronics
Asked by ergonomical69 on March 3rd, 2018.
The output power rating of a given amp hinges largely on the amp's power supply voltage. Designers are careful to choose voltages for the output circuit that won't push the tubes past their (max) power ratings. The 7591 is nominally listed at a max sustained capacity of 19WRMS, and your amp limits the output supply (plate) voltage so that the tube can safely operate below that maximum, at just 15 watts. In brief, your tube lasts a lot longer, and run a little cooler. And don't worry, this in no way reduces an amp's ability to sing its little heart out. As a general rule, this
practice has been an industry-wide standard for a long time, for almost every popular amp, including those used by celebrated players.
The datasheet on your website for the JJ 7591S has a couple of errors. It identifies Pin 5 as Grid 1. Pin 5 should be Cathode and Grid 3. Also, it identifies Pin 8 as "K" for cathode. Pin 8 should be Grid 2. The internal wiring on the specsheet is drawn correctly but the identification labels are wrong.
Asked by Anonymous on June 26th, 2019.
The JJ Specification drawing is wrong but the tube is made correctly and functions properly. I have compared the Westinghouse and Sylvania spec sheets for the 7591 tubes and they agree. Pinnouts as follows: 1 -no pin on tube, 2=Heater, 3=Plate, 4=Grid 2, 5=Cathode & Grid 3, 6=Grid 1, 7=Heater, 8= another Grid 2.