Announcement

Collapse
No announcement yet.

Good outputs for a 2K CT OT "15 Watts?"

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Good outputs for a 2K CT OT "15 Watts?"

    Folks,

    I've got a Stancor A-8098 OT "new" in the box that I've been meaning to put into an amp for some time. This beast - rated 20-20kHz - is quite massive for "15 Watts" and, since I'm thinking about a MI/guitar amp, I'm sure that I can get much greater wattage at a more narrow frequency band. Now the thang has 8-16-32 ohm output taps so I could reflect a greater primary Z my mismatching but that would require using 16 ohm speakers.
    Any suggestions for valves that would match the primary Z of 1K per tube? Other than the 50C5, et al, types. I'd like to be able to design around 20 watts or so and see what happen. Oh, and since I've hundreds of tubes in the attic "TV" output types are suitable suggestions.

    Rob

  • #2
    Additional info on this tranny

    FYI - I tracked down specs on this OT to see if I could determine the output tubes that it was originally designed for and they were EL-34s! "Huh?" You state, the impedance's too low! Well the circuit was one referred to at "twin coupled" and, as best I can tell, it was an attempt to emulate the MacIntosh output circuit with the load split between the cathode and the plate. In this case two indentical A-8098s were used - one had a primary winding side in each PP plate and the other in the cathodes - the secondaries were paralleled! Funky stuff! And as these were never designed solely as the plate load for any "common" PP circuit you can understand why I've had trouble matching up an "appropriate" tube. But I think I'll try 6Y6s and see how it turns out. The impedance is a tad low but not out of proportion to the mismatch I've seen in other guitar amp curcuits.

    Rob

    Comment

    Working...
    X