OTL Asylum

Posted by Cbird (A) on September 26, 2006 at 08:29:17

Hi,

I have an old pair of M50's. Managed to smoke up one of the power trannies...subtronic sti-1520 Dv-130. Would like to do Ralph's complete upgrade...with the new trannies, caps etc, but lack the $3100 fee at present(will do it down the line). Broke without music is unacceptable. Does anyone know where I can get another subronic or a couple of the new trannies they're using at atmasphere. I don't know what transformers they're using at present, but I need some Mozart.

thanks,

Cbird

• Re: power trannies for m-50's - tubevibb 08:57:53 09/26/06 (7)
  In Reply to: power trannies for m-50's posted by Cbird on September 26, 2006 at 08:29:17:

  I would upgrade big time, 5kva, each winding 2500,Toroid corp.#749-1202 $80. each,Or diy,surplus parts $40.each all u need is any Isolation transformer.120v in 120v out. After diodes You end up 140v135v. Need more?
  
  

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  • Re: power trannies for m-50's - Cbird 09:37:15 09/26/06 (6)
    In Reply to: Re: power trannies for m-50's posted by tubevibb on September 26, 2006 at 08:57:53:

    That sounds about right. Where can I find Toroid corp. on line? I have a friend who does all my stereo stuff since
    I don't know a soldering iron from a water stick.
    Do I need new diodes as well?
    
    
    

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    • Re: power trannies for m-50's - tubevibb 09:50:49 09/26/06 (5)
      In Reply to: Re: power trannies for m-50's posted by Cbird on September 26, 2006 at 09:37:15:

      No big deal,Digi-key,all u need,even ratshak 400v3a.diodes.
      
      

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      • diodes - Lew 07:08:10 09/27/06 (4)
        In Reply to: Re: power trannies for m-50's posted by tubevibb on September 26, 2006 at 09:50:49:

        Ultra fast recovery diodes (i.e., Hexfreds, Harris, IXYS, etc) sound better than just any old diode and do make an audible difference in sound quality. Schottky diodes also promise to be superior to standard ones, but I have no personal experience. Diodes do make a difference. Cbird, you will want some technical assistance in doing this work; it is not trivial. You need to build a "full-wave bridge" from 4 discrete diodes and know where to tap it to get the positive and negative rails.
        
        

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        • Re: diodes - tubevibb 09:07:47 09/27/06 (3)
          In Reply to: diodes posted by Lew on September 27, 2006 at 07:08:10:

          Just as the isolation transformer,any well work as long as voltage are, transfomer 120p 120s 5kva, diode bridge 200v 35a.Any CIRCLOTRON is better NO CIRCLOTRON. I have used schotty do make diff.Big money. Diodebridge $2.50ea u need 4ea Thank,s
          
          

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          • Re: diodes - Lew 06:56:00 09/28/06 (2)
            In Reply to: Re: diodes posted by tubevibb on September 27, 2006 at 09:07:47:

            In my direct experience the slight extra cost of ultra fast soft recovery diodes (Hexfreds) or Schottky diodes is well worth it. Conventional diodes or silicon bridges sound gray-ish and "washed out" by comparison. Of course, any diode one uses has to meet the electrical requirements of the circuit, as you state above. It's just a no-brainer and very cheap actually compared to the cost of high quality coupling caps and resistors (and transformers, by the way). But if you don't like 'em, you are entitled to your opinion.
            
            

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            • Re: diodes - tubevibb 07:20:16 09/28/06 (1)
              In Reply to: Re: diodes posted by Lew on September 28, 2006 at 06:56:00:

              I did not no u were paying! By the way Ralph is asking $600.For hearter transformer,s for my M-60II.Thank u
              
              

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              • Re: diodes - Lew 16:56:30 09/28/06 (0)
                In Reply to: Re: diodes posted by tubevibb on September 28, 2006 at 07:20:16:

                "I did not no u were paying!" - What the heck does that mean? I may have to go back to ignoring you.
                
                

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• Re: power trannies for m-50's - Legendre 08:44:25 09/26/06 (0)
  In Reply to: power trannies for m-50's posted by Cbird on September 26, 2006 at 08:29:17:

  Hi Cbird,

  I don't recognise the part number - is this the filament / HV transformer, or the B+?

  The Subtronics (just like the Talema and Avel Lindberg) transformers were custom made for Atma-Sphere. I can check if we have any of the old M-50 Subtronics parts laying around, but I don't think the odds are too good.

  If it's the B+ part that is bad, you'd be best off buying a pair of current M-60 transformers, and retrofitting each amp. It's really not all that difficult. If it's the filament / HV part, that can be replaced with seperate 6.3V and HV transformers. You might be able to find an off-the-shelf 6.3 @ 20A part, but you will want to order the HV part from Atma-Sphere.

  Hope that helps, Bill.
  
  

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