• Re: FS-007 - mqracing 18:21:27 10/28/04 (6)
  In Reply to: FS-007 posted by John Q on October 28, 2004 at 09:59:55:

  John had asked:

  ::::Also I lookng for max possible B+ and max primary current ?::::

  for B+ I don't recommend going much higher than 600VDC. The reason is that the insulation materials we use are not *ideally* suited for ultra high voltages (say 1000 plus)...

  If I were building a transformer for 1,000 volts or higher B+ then I would want to use insulations with good corona resistance. But the drawback is that the materials which tend towards having good corona resistance aren't the materials with the best dielectric K or dissapation factors... the insulation packet in your 007 was optimized for low dielectric K and a very good dissapation factor...

  max primary current? It is rated at 60 mils but our ratings are usually conservative... look at for instance our FS-030 and it's current versus inductance meausurements. On the 007 I wouldn't personally go any more than 80 mils... and would try to stick down toward the 60 mil rating... as this conserves the greatest amount of AC magnetic headroom and since it keeps the flux low... the distortion stays low....

  what tube and what operating points were you thinking of?

  
  ::::If possible the gap size ?::::

  this info we do consider proprietary.

  :::I ask about the gap size because maybe I like to open it a little::::

  I wouldn't recommend this. Your unit is wax impregnated and part of what keeps the e's and i's together is the "adhesive" function or benefit of waxing both the coil and the core.

  You could snap it apart... but run the risk of not ever getting it back together as well as we did... and you'd be on your own entirely...

  ::::Only info I found on web say FS-007 is designed to 60mA.::::

  we've sold a bunch in Japan. I can remember years ago asking what folks in Japan was using the 007 for and was told that it was popular with the 71A tube!!!! Which really blew my mind... that's a lot of iron for 800 milliwatts output....

  another app I can think of... would be a low voltage 845 tube.... where you can run right around 60 mils or so....

  but tell us what you had in mind...

  Mike
  
  
  

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  • Re: FS-007 - John Q 00:30:20 10/29/04 (5)
    In Reply to: Re: FS-007 posted by MQracing on October 28, 2004 at 18:21:27:

    Mike.
    Thanks for all info about 007.I not decided which tube I can use.
    The 71A is not a option I needed minimum 8-10 Watts.
    For 845 I have 10K James so here no plan for low voltage.
    Only tube in my stash is 814 wired as triode and push 007 hard
    at 75mA.Based on my test 814 Rp will be around 1600 Ohms in this
    area under 600V on plate.
    I needed test 814 with CCS on cathode with adjustable B+ to found
    amplification factor and few more things.
    Max G2 voltage from datasheet is 400V but here no data for audio.
    Similiar 828 has audio data with G2 max 750V.
    May 814 will handled 600V as triode who know.
    Regards,
    John
    
    

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    • Re: FS-007 - Jeff Lessard 06:34:03 10/29/04 (4)
      In Reply to: Re: FS-007 posted by John Q on October 29, 2004 at 00:30:20:

      Why don't you try a 807 in SE.

      Gordon published a really nice circuit in Sound Practice no.2. If I remember well, the PDF of this amp and the now famous Bugle were available at some time on his web site (or did I imagine it?).

      I've heard Gordon's 807 and liked it a lot. Plus the purple glow of the OD3 it does use is so cool.
      
      

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      • Re: FS-007 - John Q 08:49:41 10/29/04 (0)
        In Reply to: Re: FS-007 posted by Jeff Lessard on October 29, 2004 at 06:34:03:

        Jeff.
        Reason it's simple I have 7 NOS RCA 814 and not even one 807.
        Why not try unknown tube :> )))I have no problem with this.
        John
        
        

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      • The bugle was a 45 design... - Bas Horneman 08:05:44 10/29/04 (2)
        In Reply to: Re: FS-007 posted by Jeff Lessard on October 29, 2004 at 06:34:03:

        but here is a link to the article
        
        To infinity and beyond!!!
        

        • Bugle   (Open in New Window)

        
        

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        • Re: The bugle was a 45 design... - Jeff Lessard 08:14:00 10/29/04 (1)
          In Reply to: The bugle was a 45 design... posted by Bas Horneman on October 29, 2004 at 08:05:44:

          Yes, I was just mentioning the Bugle for the record. But reading my post again, I must confess it does read weird.

          Did you ever saw the PDF of the Sound Practice article on 807 SE amp I am referring too? Or did I just imagine seeing it online?

          
          
          

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          • I can't remember specifically the 807 pdf.. - Bas Horneman 07:03:00 11/01/04 (0)
            In Reply to: Re: The bugle was a 45 design... posted by Jeff Lessard on October 29, 2004 at 08:14:00:

            but Gordon did mention the article in SP a couple of posts below....

            Regards,
            Bas
            To infinity and beyond!!!
            
            

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• here's part of an answer - mqracing 13:47:40 10/28/04 (0)
  In Reply to: FS-007 posted by John Q on October 28, 2004 at 09:59:55:

  for hookup instructions please go to

  http://www.magnequest.com/030.htm

  it is the same as the FS-030 SE trans.

  
  I will try to answer your other Q's perhaps after dinner.

  Mike
  
  

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