Harry Joyce 50/100 watt
The Harry Joyce 50/100 watt amplifiers are an A-B class amplifier. These are all point to point, hand built by George Scholz right here in the U.S.
It provides 4 inputs:
This amplifier is a master volume design which includes:
Gain controls for Normal or Brilliant inputs, Tone controls for Bass, Treble, Mids and Presence. The pre-amp stage uses 4 ECC83 (12AX7) Pre-amp tubes for inputs, tone, voltage amp, and driver. The output stage (output transformer) is designed for EL34 (6CA7) power tubes.
On the back side, voltage and ohm selector, 2 speaker outputs (in parallel) and an unbalanced slave output (signal is tapped directly off the output transformer). Hum balance, send and return (effect loop), as well as, fuse holders for power, high voltage supply and I.E.C. Power Entry Module.
Upgrades on newer units include:
-Stainless steel chassis (9 lbs)
-Enlarged filtering in power and bias supply
-All ceramic tube sockets
-Improve shielding & layout
-2 watt resistor value
Specs for 50 & 100 Watt amps:
Input resistance-High: 1meg ohm
Input resistance-Low: 136K ohm
Inputs can be linked from channel to channel
Input sensitivity 2.5 M.v.@ 500Hz
Bass + minus -20db
Treble -6 to 30db with presence
50 Watt Amplifier / 100Watt Amplifier
Output Power RMS: 50 Watts / 100Watts
Total Peak Power: 50 watt head 125 Watts, 100 watt head 250Watts
Input Volt Selector: 100V, 115V, 230V , 240V (not connected)
Output Ohm Selector:50 watt 8,16 ohms,100 watt 4,8,16 ohms
Effect Loop: 50/100 -Send through master output, return input 1 meg ohm
Slave Output: 50/100- Level Dependant
Preamp Tube: 50/100- 4x ECC83 (12AX7)
Power Tube: 50 watt- 2x EL34 (6CA7) ,100 watt- 4xEL34 (6CA7)
Rectification: 50 watt- 3x 1N 5408, 100 watt- 5x 1N 5408
Fuse Power: 50 watt -3A @ 250V slow acting , 100 watt – 4A @ 250V slow acting
Fuse High Voltage: 50 watt 500mA slow acting,100 watt 1A slow acting
Cabinet Dimension Approx: 50/100 -11″ H x 22.5 ” W x 10.5″ D
Weight: Approx. 50 watt 48 lbs.- 100 watt 51 lbs.