Restored World Audio Designs integrated valve amplifier. EL34 output valves 40 watts per channel.
Orignal set of valves and full WAD construction manual.
Description:
EL34 push pull stereo amplifier. Input valves are 6AU6 pentodes running in triode mode. Phase spliiter/driver valves are ECC82's. Output valves are EL34 push pull in pentode mode.
Three line level inputs, one tape input and one tape output with source/tape selector switch. Input impedance 100K ohms.
"Panasonic For Audio" 100K stereo volume control potentiometer.
Swiss Elma line level input selector switch with gold plated contacts.
Input sensitivity for full output: 300mV.
This amplifier came to me in a non-working condition with its original valves, but with a faulty mains transformer and a number of other faults.
Restoration work completed:
Original mains transformer had a short circuited primary winding. Replaced with new custom wound transformer from Toroidy in Poland.
Original three pin XLR speaker sockets replaced with Neutrik 2 pole Speakon sockets.
Added 4mm binding post speaker connectors to rear panel.
Replaced all original paper washer insulated RCA sockets with new gold plated inslulated RCA sockets.
Replaced captive mains input cable with new IEC mains socket.
Added rear panel mounted mains fuse holder.
Added internal PCB mount fuse in B+ AC supply line.
Full re-cap carried out. All new electrolytic capacitors replaced. All new film and foil capacitors fitted with uprated voltage specification.
Replaced under rated anode load resistors to ECC82 driver valves.
Replaced noisy anode load resistors to 6AU6 input valves.
Replaced original rotary input source selector switch with better quality Elma selector switch.
Added in rush protection thermistor to incoming mains supply.
Added capacitor bleeder discharge resistors to B+ power supply for safely reasons.
Added adjustable brightness green LED mains power indicator adjacent to front panel power switch.
Replaced all original single wire signal wiring with screened signal cable.
Price for the amplifier with the original tested and working valves £185.
Price for the amplifer with original working valves plus two brand new Shuguang matched pairs of EL34's £280.
New boxed pair 6AU6 add £15.
Pair used but tested good Mullard ECC82's add £25.
Wam Taxi or collection only from NN13 Northants. Buyer to inspect/audition and collect.
Notes:
The amplifier is working fine and sounds very good indeed, there is some low level residual hum present at the loudspeaker terminals, likely due to the fact there is no smoothing choke in the B+ supply.
The input sensitivity is quite high at 300mV, so it gets quite loud at low level settings on the volume control with a 2V RMS output signal from a CD player or streamer.
The original Svetlana EL34 output valves are working and tested OK on my AVO CT160, but they are obviously used and are no longer a perfectly matched set.
Orignal set of valves and full WAD construction manual.
Description:
EL34 push pull stereo amplifier. Input valves are 6AU6 pentodes running in triode mode. Phase spliiter/driver valves are ECC82's. Output valves are EL34 push pull in pentode mode.
Three line level inputs, one tape input and one tape output with source/tape selector switch. Input impedance 100K ohms.
"Panasonic For Audio" 100K stereo volume control potentiometer.
Swiss Elma line level input selector switch with gold plated contacts.
Input sensitivity for full output: 300mV.
This amplifier came to me in a non-working condition with its original valves, but with a faulty mains transformer and a number of other faults.
Restoration work completed:
Original mains transformer had a short circuited primary winding. Replaced with new custom wound transformer from Toroidy in Poland.
Original three pin XLR speaker sockets replaced with Neutrik 2 pole Speakon sockets.
Added 4mm binding post speaker connectors to rear panel.
Replaced all original paper washer insulated RCA sockets with new gold plated inslulated RCA sockets.
Replaced captive mains input cable with new IEC mains socket.
Added rear panel mounted mains fuse holder.
Added internal PCB mount fuse in B+ AC supply line.
Full re-cap carried out. All new electrolytic capacitors replaced. All new film and foil capacitors fitted with uprated voltage specification.
Replaced under rated anode load resistors to ECC82 driver valves.
Replaced noisy anode load resistors to 6AU6 input valves.
Replaced original rotary input source selector switch with better quality Elma selector switch.
Added in rush protection thermistor to incoming mains supply.
Added capacitor bleeder discharge resistors to B+ power supply for safely reasons.
Added adjustable brightness green LED mains power indicator adjacent to front panel power switch.
Replaced all original single wire signal wiring with screened signal cable.
Price for the amplifier with the original tested and working valves £185.
Price for the amplifer with original working valves plus two brand new Shuguang matched pairs of EL34's £280.
New boxed pair 6AU6 add £15.
Pair used but tested good Mullard ECC82's add £25.
Wam Taxi or collection only from NN13 Northants. Buyer to inspect/audition and collect.
Notes:
The amplifier is working fine and sounds very good indeed, there is some low level residual hum present at the loudspeaker terminals, likely due to the fact there is no smoothing choke in the B+ supply.
The input sensitivity is quite high at 300mV, so it gets quite loud at low level settings on the volume control with a 2V RMS output signal from a CD player or streamer.
The original Svetlana EL34 output valves are working and tested OK on my AVO CT160, but they are obviously used and are no longer a perfectly matched set.
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