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Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum |
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#11 |
diyAudio Member
Join Date: Nov 2008
Location: Brisbane QLD
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Thank you, I can work with that. The B+ from the power tranny I have may be a bit on the high side, I think I can get it down to a reasonable value. Will start construction this week. And no problem trying lower G2 voltages too...
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#12 |
diyAudio Member
Join Date: Jun 2004
Location: near Torino
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Actually I have a question about audio transformer. Digging in a carton box I've found an all black transformer, I believe it was manufactured by Philips between 1959 and 1966. The secondary, depending on straps, is good for 14 or 7 ohm speakers. The code number is PK 51099.
Anybody can tell me about its specifications and if it is worth to use it for a PP amp of EL34 ? |
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#13 | |
diyAudio Member
Join Date: Nov 2008
Location: Brisbane QLD
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Quote:
45, can you answer this question please? When a loadline passes way below the knee of the 0V grid curve, like in the loadline I posted, and the tube grid1 is driven to 0V, what actually happens to the tube or amp in this situation? I know its a bad idea, but I don't understand what happens, does it just square wave the output of the tube? 300b-luc, you can measure the primary impedance of your transformer, this will let you know what tubes it would be suitable for. There are a few threads around that describe how to do this. If you can't find one, let us know. |
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#14 |
diyAudio Member
Join Date: Jun 2004
Location: near Torino
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Ian444, even if I measure the primary impedence, due to my poor instrumentation I cannot get enough information to decide that the transformer is worth to be used for a PP amp. I hoped that someone had the Philips data sheet.
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#15 | |
diyAudio Member
Join Date: Sep 2010
Location: Melbourne
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Quote:
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#16 |
diyAudio Member
Join Date: Nov 2008
Location: Brisbane QLD
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Metalsculptor, thanks very much for the info. I have found very little info on PP loadlines regarding how hard you can go before something blows up, I guess *average* power dissipation is taken for granted by those who know the subject well. Now I understand...
I have begun drilling the top plate, work is in progress... Edit: 300b-luc, put 10 or 20V AC into the primary and measure the V AC at the secondary with no load. From that the primary impedance can be easily calculated. All you need is an AC supply and a multimeter. Last edited by Ian444; 12th October 2010 at 08:52 AM. |
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