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EE & PC Board Design Solutions for Hobbyist,Experimenters and Industry


Frequently Asked Questions

What is the HOWLER?

  • The HOWLER is the Lupine Systems Model LS-10B pure-tube integrated stereo amplifier.
  • What is an integrated amplifier?

  • An integrated amplifier is an audio amplifier with built-in pre-amplifiers necessary to boost the audio signals from a turntable cartridge or microphone.
  • Can you hook up any stereo component to the HOWLER?

  • Yes. The LS-10B amplifier can accept up to 5 input sources including one phono source.
  • The HOWLER also accepts inputs from an auxillary mixer board and can output pre-amplified signals to an external auxillary power amplifier. You can also connect two LS-10B amplifiers together to form a quadraphonic system or to drive bi-amp speaker systems.
  • How does the HOWLER switch between signal sources?

  • You can select between the input sources by rotating the SELECT knob on the front panel. The unique design of the HOWLER switches the audio sources using small sealed signal relays located as close to the input jacks as possible. The knob on the front panel switches ON or OFF each of these relays according to the knob setting. Using relays to do the switching keeps signal lines short and improves noise immunity. It also eliminates noise caused by aging or weak rotary front panel switches.
  • What are the front panel controls?

  • The front panel controls are:
    • Power Switch
      Green-Jeweled Power Indicator
      Speaker Select -- selects between headphones and speakers
      Headphone Jack
      Input Selector Switch
      Separate BASS and TREBLE controls for each channel
      BALANCE control
      VOLUME control

    Does the HOWLER work with any stereo speakers?

  • Yes. The HOWLER has a rotary switch on the back panel to select the proper speaker impedance. You can use 4, 8 or 16 ohm speakers or speakers wired in combination to produce any of these impedances.
  • How much power does the HOWLER produce?

  • The HOWLER is rated at 50 watts per channel when used with 8-ohm speaker systems.
  • What style of amplifier is the HOWLER's final stage?

  • The HOWLER uses dual EL-84 (6BQ5) tubes in a push-pull grid-feedback configuration.
  • Is the HOWLER printed-circuit or point-to-point construction?

  • The HOWLER is built using printed-circuits made from computer-grade FR-4 2-ounce copper plated through boards. These are the highest quality printed circuits available.
  • Features

  • 50 watts per channel @ 8-ohms at 1KHz output power
  • Separate BASS and TREBLE controls for each channel
  • Rotary switch selectable speaker impedance
  • Pure-tube amplifier. No solid-state used for any amp component
  • Edcor USA® Professional Output and Power Transformers
  • Computer-Grade 2-ounce Printed Circuit construction
  • Sealed-Signal Relay Audio Switching -- Contacts NEVER corrode!

  • PCB Ordering Information

    The printed circuit for the LS-10B HOWLER is available directly from Lupine Systems.

    For more information, please send an E-mail to WOOFY