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APR501 and APR502

50w Valve Amplifiers



With circuitry inspired by the classic designs of the 1950's and 1960's and two totally independant pre-amp channels, the APR500 series amps offer the purest classic valve tone.





Features and Options

  • Completely handcrafted and Point to Point handwired.
  • 50 Watts RMS output power at 5% THD (over 90wrms when cranked)
  • Two totally independant pre-amp channels - each with its own input.
  • Channel switching achieved with the use of a simple A/B box.
  • "Link" switch - enables the blending of both channels while using only one input.
  • "Boost" switch on Channel B.
  • "Phase" switch - keeps Channel A in phase with Channel B regardless of Boost position.
  • "Output" switch - Changes output valves from Pentode to Triode operation - effectively a Half Power switch.
  • "Negative Feedback" switch - switches between High and Low negative feedback impedances.
  • Switchable output impedance - 4, 8 and 16 ohms.
  • Powdercoated galvanised steel chassis. Aluminium chassis are optional.



    Channel A -
  • Is inspired by the circuits typical of the Brownface and Blackface American amps of the early 60's. It provides a warm, clear tone - a big round bottom end with sparkling highs and a smooth breakup.


  • 501 Channel B -
  • Boost Off - Is based on the famous Western Electric circuit used by Leo for his '59 Bassman and by Jim for his JTM45. Slight changes have been made to enhance the bottom end response and add to its beautifully full and bright tone.
  • Boost On - Takes gain to Classic Master Volume levels.


  • 502 Channel B -
  • Boost Off - Provides gain of Classic Master Volume levels (basically the same as the 501 with Boost On)
  • Boost On - This switches in another valve stage and takes the gain up one more level - yet still provides wonderful sensitivity to touch, and cleans up beautifully with the guitar's volume control.

  • Options on both the 501 and 502 include an "Output" switch and a "Negative Feedback" switch

    Read a review of the APR501 here at Harmony Central.