The Fisher

---------------- On 7/5/2003 6:08:35 PM DeanG wrote: Is the following statement true? "The electrical source has two terminals, designated positive (+) and negative (-). As long as there is an unbroken connection from source to load and back again as shown here, electrons will be pushed from the negative terminal of the source, through the load, and then back to the positive terminal of the source. I decided to pretend I don't know anything, and started from the beginning -- I then discovered I don't know anything. BTW -- does it matter which way plastic caps are pointed? ---------------- Hi Dean, What is described above is the operating theory for direct current (DC). All semiconductors and tubes operate on this theory. Current flow is from negative to positive, or from the MOST negative to the less negative. In semiconductors, there are these things called "holes". Holes are not protons, neutrons, or electrons, they are merely described as having a depletion of electrons. In a transistor, a negative depletion region occurs at the PN junction. Electron flow is towards the holes. Capacitors for DC use are usually electrolytic, or non-polarized electrolytic. Tantalum are also polarized. The capacitors you describe are coupling capacitors, having an outer foil. These are not polarized, and are usually used to block DC, while letting only AC pass. The outer foil doesn't indicate a polarized capacitor, but the outer foil should be connected to 0V potential if used in an RF application. For audio use, you can connect them in the circuit any way you want. Bill wjkubacki@aol.com

---------------- On 7/5/2003 11:02:49 AM garymd wrote: Believe it or not, Pioneer and Kenwwod made excellent SS receivers in the 70s. I still own a Kenwood KR-9600. Pioneer SX-1200 series is great too. I don't think you can go wrong with the Marantz either. Just be careful it's in good condition. Sometime parts aren't available anymore. ---------------- Don't you just love those Pioneer SX series receivers? I especially like the cool "black out" display, very retro! These Pioneer receivers were a masterpiece, and they could really crank out the power! I also like some of the Sansui receivers, such as the 9090DB. It is built like a tank, has great sound, and more than enough power to drive just about any speaker. They don't make em' like this anymore. Bill wjkubacki@aol.com

Craig, The 7199 isnt a better audio tube than a 6U8, 6AN8, 6BL8, or any other dual section tubes. The only extra feature of a 7199 is its spiral, hum canceling filament. But in reality, the hum canceling has little to no effect on actually reducing induced hum picked up by the filament. If you look at the operating characteristics of the 7199 and 6U8, youll see that theyre identical. The majority of Scott amplifiers utilizing a split-load phase inverter design used the 6U8 tube, but this was before the 7199 came out. Later on after Scott introduced the 299C, the 7199 tube was released by RCA, and claimed to be superior to any other dual element tube. RCA stated in their tube manual that the 7199 was designed strictly for AF (audio frequency) applications. However, the tube really wasnt that much better. Many 7199s had high failure rates, and were more expensive. Scott used the 7199 for a short time in the 299C and 222C, and then switched back to the 6U8 tube. During this short period, no circuit changes were needed to accommodate the 7199. There are more brands of the 6U8 tube available than the 7199. The 7199 was marketed by RCA, Sylvania, and Westinghouse. The 6U8 was made by dozens of manufacturers, some better than others. You have a greater variety to choose from if using 6U8 tubes. The circuit modification is simple, and only requires that a few pins be switched around. No sound improvement or difference will be experienced. The whole idea of the mod is to save money. The 6U8 and 7199 typically last around 2-3 years, depending on how many hours the amplifier was used. Ive searched around the internet and the cheapest price I found on the 7199 (all makes) was $25. Then I searched for the 6U8, and found them as low as $0.99. I used to get 6U8s at Radio Shack for $0.99, but they quit selling tubes last summer. Bottom line: There is no great difference between a 6U8 or 7199. Both are good tubes when performing up to spec. At $25 a pop, the 7199 really isnt a good investment when you could use an identical tube for much cheaper. Bill wjkubacki@aol.com

Craig, The 7199 isnt a better audio tube than a 6U8, 6AN8, 6BL8, or any other dual section tubes. The only extra feature of a 7199 is its spiral, hum canceling filament. But in reality, the hum canceling has little to no effect on actually reducing induced hum picked up by the filament. If you look at the operating characteristics of the 7199 and 6U8, youll see that theyre identical. The majority of Scott amplifiers utilizing a split-load phase inverter design used the 6U8 tube, but this was before the 7199 came out. Later on after Scott introduced the 299C, the 7199 tube was released by RCA, and claimed to be superior to any other dual element tube. RCA stated in their tube manual that the 7199 was designed strictly for AF (audio frequency) applications. However, the tube really wasnt that much better. Many 7199s had high failure rates, and were more expensive. Scott used the 7199 for a short time in the 299C and 222C, and then switched back to the 6U8 tube. During this short period, no circuit changes were needed to accommodate the 7199. There are more brands of the 6U8 tube available than the 7199. The 7199 was marketed by RCA, Sylvania, and Westinghouse. The 6U8 was made by dozens of manufacturers, some better than others. You have a greater variety to choose from if using 6U8 tubes. The circuit modification is simple, and only requires that a few pins be switched around. No sound improvement or difference will be experienced. The whole idea of the mod is to save money. The 6U8 and 7199 typically last around 2-3 years, depending on how many hours the amplifier was used. Ive searched around the internet and the cheapest price I found on the 7199 (all makes) was $25. Then I searched for the 6U8, and found them as low as $0.99. I used to get 6U8s at Radio Shack for $0.99, but they quit selling tubes last summer. Bottom line: There is no great difference between a 6U8 or 7199. Both are good tubes when performing up to spec. At $25 a pop, the 7199 really isnt a good investment when you could use an identical tube for much cheaper. Bill wjkubacki@aol.com