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• Re: It's really SE. I guess they tie both cathodes together and bypass everything. nt - Charlie G 12:28:16 05/13/02 (5)
  In Reply to: It's really SE. I guess they tie both cathodes together and bypass everything. nt posted by Kurt Strain on May 12, 2002 at 23:07:17:

  Right. Whoops :)

  I suppose it's possible it could be biased for 90ma/channel (it does take 300B's). But since he was talking about 45's, I just assumed it was for both, since while 45ma is a little crazy, 90ma is... certain death.

  Charlie
  
  

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  • Common tied cathodes have been done before and provide 2X bias current.. - Kurt Strain 13:57:16 05/13/02 (4)
    In Reply to: Re: It's really SE. I guess they tie both cathodes together and bypass everything. nt posted by Charlie G on May 13, 2002 at 12:28:16:

    ...through the cathode resistor, one resistor for both channels. It's cheaper to do it that way and it's okay since a big cathode bypass capacitor keeps both cathodes at AC ground simultaneously, so no significant crosstalk. It's just not very commonly done.

    Kurt
    
    

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    • Re: Common tied cathodes have been done before and provide 2X bias current.. - dave slagle 19:16:58 05/13/02 (2)
      In Reply to: Common tied cathodes have been done before and provide 2X bias current.. posted by Kurt Strain on May 13, 2002 at 13:57:15:

      well you have never seen one of my amps have you???

      i owe 'ol mr. 1626 himself bob danialak for this tip... well worth the clip lead for an experiment.

      btw a pair of series AA nimh cells does wonders to a stereo pair of 6C45's

      dave
      
      

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      • That'll never work! - J Epstein 09:41:23 05/14/02 (0)
        In Reply to: Re: Common tied cathodes have been done before and provide 2X bias current.. posted by dave slagle on May 13, 2002 at 19:16:58:

        What a stupid idea!

        Solder the leads to the battery for best results ;)

        -j
        
        

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      • I'd better be carefull here... - Charlie G 21:56:34 05/13/02 (0)
        In Reply to: Re: Common tied cathodes have been done before and provide 2X bias current.. posted by dave slagle on May 13, 2002 at 19:16:58:

        ... as I'm headed into DIY territory. :)

        Do you mean both tubes sharing a single (well, 2 in series) battery for bias? My other thought was those small(ish) D-cell Lead Acid batteries. 2.15-2.2v, once charged. What op point would that be then? I've heard quite a range, even up to 200v, 45ma.

        I was thinking about some 6C45 spud amps. Most expensive thing in the amp will be the OPT's. Might start off with some 5k PP OPT's (it'll be parafeed) until I can save up for Mikey's 5K nickels.

        Charlie

        
        
        

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    • Re: Common tied cathodes have been done before and provide 2X bias current.. - dave slagle 19:16:17 05/13/02 (0)
      In Reply to: Common tied cathodes have been done before and provide 2X bias current.. posted by Kurt Strain on May 13, 2002 at 13:57:15:

      well you have never seen one of my amps have you???

      i owe 'ol mr. 1626 himself bob danialak for this tip... well worth the clip lead for an experiment.

      btw a pair of AA nimh cells does wonders to a stereo pair of 6C45's

      dave
      
      

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