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#1
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zino13
Greetings to you All
Just joined the board I'm doing a rebuild/ mod on a magnavox cosole pull. It has the....... 2- 6EU7 input/phase inverter tubes, 4- 6V6GT output tubes 1 6CA4 rectifier tube. I'd like to beef up the power transformer how large can I go? and Where could I purchase? |
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#2
Posted to rec.audio.tubes
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zino13
"zino13" wrote in message ... Greetings to you All Just joined the board I'm doing a rebuild/ mod on a magnavox cosole pull. It has the....... 2- 6EU7 input/phase inverter tubes, 4- 6V6GT output tubes 1 6CA4 rectifier tube. I'd like to beef up the power transformer how large can I go? and Where could I purchase? Would you mind explaining why you want to beef up the power xfr so we can better advise you? west -- zino13 |
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#3
Posted to rec.audio.tubes
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zino13
On Nov 29, 7:46 am, zino13 wrote:
Greetings to you All Just joined the board I'm doing a rebuild/ mod on a magnavox cosole pull. It has the....... 2- 6EU7 input/phase inverter tubes, 4- 6V6GT output tubes 1 6CA4 rectifier tube. I'd like to beef up the power transformer how large can I go? and Where could I purchase? Zino: If all you are doing is a very modest modifications there may be no need to "beef up" the power transformer unless you perceive it to be seriously overheating as-found. Even there, do not write off the existing unit until you have at least changed the filter-caps, replaced any paper caps and otherwise cleaned up the unit on your first pass (in other words, rebuild it "to spec. first). You might find out that with good filters the current draw is significantly reduced. One other (small) expedient would be to install a solid-state rectifier ILO the 6CA4. That is a full-wave rectifier, so you will have to be careful about voltages and how you set up a SS rectifier (no real trick, just some care) but you would save 1A of current. So, it gets down to your "mods". If you are adding tubes or installing heavier output tubes (each 6V6 is 0.45A), then you would calculate based on your final tube count and intended uses, required B+ voltage and so forth. It seems like from what you have written that the transformer has one filament winding and one HV winding, and perhaps that the HV tap is center-tapped. No schematic, pure speculation - wild guess on my part. If so, then you could go to the Hammond site and pick from what is available there based on what you have (filament tap(s)) and HV AC secondary). You could even pick a transformer with a separate rectifier filament winding - if that fits your intent. How big "can" you go? No limit outside your pocketbook. How big "should" you go? Possibly not at all depending on your ultimate intentions. But you are right to ask, Magnavox did not exactly over-design their power transformers. Even though they were a bit more conservative than Zenith. Faint praise, that, however. Just for your information: 6EU6 = 0.3A filament current x 4 = 1.20A 6V6 = 0.45A filament current x 2 = 0.90A 6CA4 = 1A filament current x 1 = 1.00A ________ 3.10A total filament current (calculated) 370DAX 370DAZ 378CX Are Hammond part-numbers that fit the calculation superficially and without additional information. Look here for much more and better info: http://www.hammondmfg.com/300series.htm And, of course, Hammond is not the only fish in the sea, but are amongst the lowest cost-for-reliability. Peter Wieck Wyncote, PA |
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#4
Posted to rec.audio.tubes
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zino13
On Nov 29, 3:42 pm, Peter Wieck wrote:
On Nov 29, 7:46 am, zino13 wrote: Greetings to you All Just joined the board I'm doing a rebuild/ mod on a magnavox cosole pull. It has the....... 2- 6EU7 input/phase inverter tubes, 4- 6V6GT output tubes 1 6CA4 rectifier tube. I'd like to beef up the power transformer how large can I go? and Where could I purchase? Zino: If all you are doing is a very modest modifications there may be no need to "beef up" the power transformer unless you perceive it to be seriously overheating as-found. Even there, do not write off the existing unit until you have at least changed the filter-caps, replaced any paper caps and otherwise cleaned up the unit on your first pass (in other words, rebuild it "to spec. first). You might find out that with good filters the current draw is significantly reduced. One other (small) expedient would be to install a solid-state rectifier ILO the 6CA4. That is a full-wave rectifier, so you will have to be careful about voltages and how you set up a SS rectifier (no real trick, just some care) but you would save 1A of current. So, it gets down to your "mods". If you are adding tubes or installing heavier output tubes (each 6V6 is 0.45A), then you would calculate based on your final tube count and intended uses, required B+ voltage and so forth. It seems like from what you have written that the transformer has one filament winding and one HV winding, and perhaps that the HV tap is center-tapped. No schematic, pure speculation - wild guess on my part. If so, then you could go to the Hammond site and pick from what is available there based on what you have (filament tap(s)) and HV AC secondary). You could even pick a transformer with a separate rectifier filament winding - if that fits your intent. How big "can" you go? No limit outside your pocketbook. How big "should" you go? Possibly not at all depending on your ultimate intentions. But you are right to ask, Magnavox did not exactly over-design their power transformers. Even though they were a bit more conservative than Zenith. Faint praise, that, however. Just for your information: 6EU6 = 0.3A filament current x 4 = 1.20A 6V6 = 0.45A filament current x 2 = 0.90A 6CA4 = 1A filament current x 1 = 1.00A ________ 3.10A total filament current (calculated) 370DAX 370DAZ 378CX Are Hammond part-numbers that fit the calculation superficially and without additional information. Look here for much more and better info: http://www.hammondmfg.com/300series.htm And, of course, Hammond is not the only fish in the sea, but are amongst the lowest cost-for-reliability. Peter Wieck Wyncote, PA WHOOOPSSSSS!!! 4 x 6V6 @ 0.45A = 1.8A 2 x 6EU6 @ 0.30A = 0.60A 1 x 6CA4 @ 1.0A = 1.0A Total is 3.40A Doesn't change the suggested part numbers, however based on superficial results. Peter Wieck Wyncote, PA |
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#5
Posted to rec.audio.tubes
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zino13
"Peter Wieck" wrote in message ... On Nov 29, 3:42 pm, Peter Wieck wrote: On Nov 29, 7:46 am, zino13 wrote: Greetings to you All Just joined the board I'm doing a rebuild/ mod on a magnavox cosole pull. It has the....... 2- 6EU7 input/phase inverter tubes, 4- 6V6GT output tubes 1 6CA4 rectifier tube. I'd like to beef up the power transformer how large can I go? and Where could I purchase? Zino: If all you are doing is a very modest modifications there may be no need to "beef up" the power transformer unless you perceive it to be seriously overheating as-found. Even there, do not write off the existing unit until you have at least changed the filter-caps, replaced any paper caps and otherwise cleaned up the unit on your first pass (in other words, rebuild it "to spec. first). You might find out that with good filters the current draw is significantly reduced. One other (small) expedient would be to install a solid-state rectifier ILO the 6CA4. That is a full-wave rectifier, so you will have to be careful about voltages and how you set up a SS rectifier (no real trick, just some care) but you would save 1A of current. So, it gets down to your "mods". If you are adding tubes or installing heavier output tubes (each 6V6 is 0.45A), then you would calculate based on your final tube count and intended uses, required B+ voltage and so forth. It seems like from what you have written that the transformer has one filament winding and one HV winding, and perhaps that the HV tap is center-tapped. No schematic, pure speculation - wild guess on my part. If so, then you could go to the Hammond site and pick from what is available there based on what you have (filament tap(s)) and HV AC secondary). You could even pick a transformer with a separate rectifier filament winding - if that fits your intent. How big "can" you go? No limit outside your pocketbook. How big "should" you go? Possibly not at all depending on your ultimate intentions. But you are right to ask, Magnavox did not exactly over-design their power transformers. Even though they were a bit more conservative than Zenith. Faint praise, that, however. Just for your information: 6EU6 = 0.3A filament current x 4 = 1.20A 6V6 = 0.45A filament current x 2 = 0.90A 6CA4 = 1A filament current x 1 = 1.00A ________ 3.10A total filament current (calculated) 370DAX 370DAZ 378CX Are Hammond part-numbers that fit the calculation superficially and without additional information. Look here for much more and better info: http://www.hammondmfg.com/300series.htm And, of course, Hammond is not the only fish in the sea, but are amongst the lowest cost-for-reliability. Peter Wieck Wyncote, PA WHOOOPSSSSS!!! 4 x 6V6 @ 0.45A = 1.8A 2 x 6EU6 @ 0.30A = 0.60A 1 x 6CA4 @ 1.0A = 1.0A Total is 3.40A Doesn't change the suggested part numbers, however based on superficial results. Peter Wieck Wyncote, PA Relax big boy. If someone asked you for the time do you give them a discourse on how a watch is made? No wonder why Mrs.Wieck sold the encyclopedias. west |
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#6
Posted to rec.audio.tubes
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zino13
On Nov 29, 9:38 pm, "West" wrote:
"Peter Wieck" wrote in message ... On Nov 29, 3:42 pm, Peter Wieck wrote: On Nov 29, 7:46 am, zino13 wrote: Greetings to you All Just joined the board I'm doing a rebuild/ mod on a magnavox cosole pull. It has the....... 2- 6EU7 input/phase inverter tubes, 4- 6V6GT output tubes 1 6CA4 rectifier tube. I'd like to beef up the power transformer how large can I go? and Where could I purchase? Zino: If all you are doing is a very modest modifications there may be no need to "beef up" the power transformer unless you perceive it to be seriously overheating as-found. Even there, do not write off the existing unit until you have at least changed the filter-caps, replaced any paper caps and otherwise cleaned up the unit on your first pass (in other words, rebuild it "to spec. first). You might find out that with good filters the current draw is significantly reduced. One other (small) expedient would be to install a solid-state rectifier ILO the 6CA4. That is a full-wave rectifier, so you will have to be careful about voltages and how you set up a SS rectifier (no real trick, just some care) but you would save 1A of current. So, it gets down to your "mods". If you are adding tubes or installing heavier output tubes (each 6V6 is 0.45A), then you would calculate based on your final tube count and intended uses, required B+ voltage and so forth. It seems like from what you have written that the transformer has one filament winding and one HV winding, and perhaps that the HV tap is center-tapped. No schematic, pure speculation - wild guess on my part. If so, then you could go to the Hammond site and pick from what is available there based on what you have (filament tap(s)) and HV AC secondary). You could even pick a transformer with a separate rectifier filament winding - if that fits your intent. How big "can" you go? No limit outside your pocketbook. How big "should" you go? Possibly not at all depending on your ultimate intentions. But you are right to ask, Magnavox did not exactly over-design their power transformers. Even though they were a bit more conservative than Zenith. Faint praise, that, however. Just for your information: 6EU6 = 0.3A filament current x 4 = 1.20A 6V6 = 0.45A filament current x 2 = 0.90A 6CA4 = 1A filament current x 1 = 1.00A ________ 3.10A total filament current (calculated) 370DAX 370DAZ 378CX Are Hammond part-numbers that fit the calculation superficially and without additional information. Look here for much more and better info: http://www.hammondmfg.com/300series.htm And, of course, Hammond is not the only fish in the sea, but are amongst the lowest cost-for-reliability. Peter Wieck Wyncote, PA WHOOOPSSSSS!!! 4 x 6V6 @ 0.45A = 1.8A 2 x 6EU6 @ 0.30A = 0.60A 1 x 6CA4 @ 1.0A = 1.0A Total is 3.40A Doesn't change the suggested part numbers, however based on superficial results. Peter Wieck Wyncote, PA Relax big boy. If someone asked you for the time do you give them a discourse on how a watch is made? Westiepoo, westiepoo, westiepoo, Your pillock habits are wretchedly hard to break, aren't they? When someone suggests that they might clean an old watch, and perhaps add a stronger mainspring it is not quite like asking for the time. It is "I found this old watch of unknown antecedents and unknown functionality that I want to make run. Furthermore, I might want it to run longer or more accurately. Would a larger mainspring help? You are singularly stupid today, at least as reflected by your posts. Peter Wieck Wyncote, PA |
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