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RE: Transistors?

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1973shovel

In Reply to: RE: Transistors? posted by petercapo on June 28, 2020 at 03:46:23

I should have added that I was speculating about the CCS vs non-CCS versions of the same circuit. My version has no sand (other than the bias diodes) and my impression has always been that it lacks a certain musicality.

It's always good to read your posts!

Follow Ups:

Reimagined Dynacos - petercapo 06:44:09 06/30/20 (7)
Very interesting. Wonder if it has anything to do with the long tail pair topology. In 2018, Stereophile magazine reviewed a Cary amplifier where the reviewer said he prefers its cathodyne phase inverter topology to other designs - I find his description interesting to read and reminiscent of what I hear from my Dynacos. As we know, the original Dynaco used the cathodyne phase inverter.
Always good to read your posts, as well!
- Stereophile review of Cary Audio SLI-100 (Open in New Window)
Edits: 06/30/20 06/30/20 06/30/20 06/30/20
- That's a good question - 1973shovel 13:34:43 07/02/20 (6)
  I don't know enough about circuits to determine why one sounds more musical than the next.
  
  Next fall/winter my plan is to try and tweak the three tube 12AU7 input circuit a bit by trying different coupling caps and adjusting feedback. If that doesn't make it to my liking, my plan is to take the board out and try a new input stage.
  
  I've been thinking I'll try the 6GH8A circuit, which I already have a board for, except that I'll try the 7643 tubes in place of the 6GH8A. I write to someone who modified his Sherwood S5000 to take 6GH8As in place of the original 7199s. He said he much prefers the 7643 tubes over the 6GH8A, so that gives me some hope that it'll improve my ST-70.
  - RE: That's a good question - petercapo 14:17:35 07/02/20 (5)
    It's good to have options. Please let us know how you do!
    - I will post my results - 1973shovel 06:57:00 07/03/20 (4)
      But it's not going to be anytime soon. I have a few other projects ahead of the ST-70, most notably, a ST-35 clone on a ST-70 sized chassis.
      
      I'm going to build it using a 12AX7 and a 12AU7, instead of the single envelope 7247/12DW7. The new production 7247 doesn't sound nearly as good as old stock, according to my source. And NOS are scarce and expensive, so it doesn't make sense to build a new amp around it.
      
      And until winter, when motorcycle season slows down, all the Hi-Fi projects are on hold.
      
      Happy Independence Day!
      - Looks Great! (nt) - petercapo 13:18:23 07/03/20 (3)
        
        In Reply to: RE: I will post my results posted by 1973shovel on July 03, 2020 at 06:57:00
        
        nt
        
        I hope mine turns out as well - 1973shovel 17:32:13 07/04/20 (2)
        
        In Reply to: RE: Looks Great! (nt) posted by petercapo on July 03, 2020 at 13:18:23
        
        I should have added that I lifted the picture, just to show the general set-up I'll be using. Mine won't have the wood sides, although I suppose I could add them if I got ambitious.
        
        One thing I know won't look as good as that picture is my power transformer, which is from an SCA-35. Every original one I've ever seen, including the two I own, look like they were plucked from the depths of the La Brea tar pits.
        
        Jed Clampett's property? - petercapo 18:32:52 07/04/20 (1)
        
        In Reply to: RE: I hope mine turns out as well posted by 1973shovel on July 04, 2020 at 17:32:13
        
        Isn't that the spot on the ground where Uncle Jed was shootin' for some food, and up through the ground come a bubbling crude?
        
        Uncle Jed's Black Gold is the only oil I will use in my capacitors - 1973shovel 07:36:10 07/06/20 (0)
        
        In Reply to: RE: Jed Clampett's property? posted by petercapo on July 04, 2020 at 18:32:52
        
        But the transformer tar comes straight from La Brea. Apparently David Hafler felt it was the best sounding tar, after extensive testing.

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