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#1
Posted to rec.audio.tubes
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5Y3 Rectifier Question
I'm working on my first project, which is a reverb amp that I'm trying
to turn into a guitar amp. I'm confused about the rectifier circuit. It's a 5Y3 tube. The heater goes to pins 2 & 8. Pin 8 is tapped to a large electrolytic cap. The question is... Is the heater and the cathode the same, or at least next to each other? If so wouldn't the tap to the cap be negative? Shouldn't the cathode be negative? |
#2
Posted to rec.audio.tubes
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5Y3 Rectifier Question
FLY135 wrote:
I'm working on my first project, which is a reverb amp that I'm trying to turn into a guitar amp. I'm confused about the rectifier circuit. It's a 5Y3 tube. The heater goes to pins 2 & 8. Pin 8 is tapped to a large electrolytic cap. The question is... Is the heater and the cathode the same, or at least next to each other? If so wouldn't the tap to the cap be negative? Shouldn't the cathode be negative? The heater is the cathode in the 5y3, and it's bigger brother the 5u4. It's "pulled" positive by the positive going AC swing at the plates/anodes. (rather crude explanation, maybe someone will elaborate) The high voltage winding of the transformer has a center tap that is usually tied to ground. The alternating rectification of the high voltage AC becomes pulses of DC at pins 2 and/or 8, smoothed by the cap, to give you the DC (B+) that makes the magic. Play Safe! Paul |
#3
Posted to rec.audio.tubes
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5Y3 Rectifier Question
"FLY135" wrote in message ups.com... ** Groper alert ! I'm working on my first project, which is a reverb amp that I'm trying to turn into a guitar amp. I'm confused about the rectifier circuit. It's a 5Y3 tube. The heater goes to pins 2 & 8. Pin 8 is tapped to a large electrolytic cap. The question is... Is the heater and the cathode the same, or at least next to each other? ** The same. If so wouldn't the tap to the cap be negative? ** Its all relative. Shouldn't the cathode be negative? ** It is, relative to the plates when they are conducting current - about 50 volts negative. But seeing as the plates are *hundreds of volts positive* relative to ground, the cathode is still very much positive at those times ( at the maxima of each half cycle of the AC voltage). The cap charges up to this positive voltage and does it best to hold onto it. ......... Phil |
#4
Posted to rec.audio.tubes
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5Y3 Rectifier Question
Güs wrote: FLY135 wrote: I'm working on my first project, which is a reverb amp that I'm trying to turn into a guitar amp. I'm confused about the rectifier circuit. It's a 5Y3 tube. The heater goes to pins 2 & 8. Pin 8 is tapped to a large electrolytic cap. The question is... Is the heater and the cathode the same, or at least next to each other? If so wouldn't the tap to the cap be negative? Shouldn't the cathode be negative? The heater is the cathode in the 5y3, and it's bigger brother the 5u4. It's "pulled" positive by the positive going AC swing at the plates/anodes. (rather crude explanation, maybe someone will elaborate) The high voltage winding of the transformer has a center tap that is usually tied to ground. The alternating rectification of the high voltage AC becomes pulses of DC at pins 2 and/or 8, smoothed by the cap, to give you the DC (B+) that makes the magic. Play Safe! Paul This pic on wikipedia made it a lot clearer to me. Doh! http://en.wikipedia.org/wiki/Image:VacRect2E.png |
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