JPB-10.5

JPB-10.5 (Cunning Runt)
(Photo shows prototype)

Description:

  • 10W,
  • All tube push-pull circuit
  • 2X6BM8EH  Pentode-Triode Tubes + 1 NOS made-in-Holland Amperex ECC88/6DJ8 dual triode 'Totem Pole' preamp. (6DJ8s are in current production).
  • Bootstrapped cathodyne phase inverter for exceptional drive tone.
  • Internal 6" speaker, jack for 16-ohm external load.
  • One volume control -- that's it! No extra stuff to suck tone.
  • Twice the power of a Tweed Champ in smaller package.
  • Circuit breaker -- no searching for fuses.
  • This hand-wired amp is an original design -- nothing else quite like it out there.

This was the first amp that I built which implemented the Cascodyne Architecture

The current-production 6BM8 tubes from Electro Harmonix each contain a power pentode (essentially an EL82), and a triode with similar characteristics to a 5751  This permits construction of an entire amp with a single tube, or, as in this case, a higher-power push-pull power section, including phase inverter, with just one pair. The cascode 'totem-pole' configuration of the first preamp stage deliver much of the tonal complexity and touch sensitivity of a small-signal pentode without the attendant tendency toward microphonics (a concern in so small an enclosure).

Output transformer is a high-quality USA-made units from Edcor, while the Antek torroidal power transformer was selected for compact size and low noise. Speaker is a 15W, paper-coned 6" unit selected specifically for this application.

Despite the small enclosed cabinet, no issues with heat (after several 60-minute sessions the guard is just warm to the touch.)

The enclosure for this prototype is from a solid-state practice amp I had on hand. Production versions will use a high-quality solid pine cabinet of similar size.

Details:


Videos:



PRICE: $699.00

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