Output Transformer Question

Discussion in 'Shock Brother's DIY Amps' started by Rock_Glenn, Mar 6, 2017.

  1. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Can I use the output transformer from a Pro Jr as the OT in a 5W class A single ended amp, if I only use the primary and center tap and tape off the third primary side wire?
     
  2. dan40

    dan40 Tele-Afflicted

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    Ideally an SE ot would be built with an air gap. I have read of people using a PP ot in this configuration but I don't believe that it would sound very good.
     
  3. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Yeah the more I think about this, it's definitely not worth the risk. I can probably get a proper OT for 30 bucks. Than you
     
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  4. Rock_Glenn

    Rock_Glenn TDPRI Member

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    And I actually have another question, this time on the Power Transformer. I plan to use a 600V Bridge rectifier I have laying around. It's a GBPC series. The Power transformer doesn't have center taps on the Secondary High voltage or the filament taps. The PT is clearly designed for a bridge rectifier but do I need to do anything to create artificial center taps on the filaments or the high voltage secondary? Would adding an artificial center tap make the rectifier work improperly? Would not having it there create a safety hazard?

    Feeding one EL84 and one 12AX7 in a single ended amp, what DC voltage should I be targeting on the positive leg of my rectifier?

    I plan on fusing the B+ at 250mA.
     
  5. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Do a normal bridge rectifier install and you'll be fine. You will need an artificial center tap for your 6.3v heaters. The heater center tap will not interfere with the bridge rectifier.
     
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  6. dan40

    dan40 Tele-Afflicted

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    I have a small se amp with one 12ax7 and one el84. B+ is right at 280vdc and the amp sounds great. You have some wiggle room but with an el84 it may be best to keep it under 350vdc.
     
  7. Rock_Glenn

    Rock_Glenn TDPRI Member

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    Thank you very much. I'll proceed accordingly.
     
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