Aetherkruiser AK1501 2nd Version

Condition and performance:

	Cabinet	60%
	Reception AM	70%
	Sound Quality AM	70%
	Sound Quality P.U.	70%

Features:

	P.U. Entrance:	Yes
	Tape Recorder Entrance:	No
	Extra Loudspeaker Output:	Yes, 7 Ohms
	Loudness:	Yes, only on bass
	Treble Control:	Yes
	Bass Control:	No
	Tone Register Switches:	No
	AM Bandwidth Switch or Control:	No
	Tuning Indicator:	No
	Build-in Antenna:	No
	Build in Ferrite or Window Antenna:	No

Technical Specifications (Partially measured):

	Tubes:	ECH42, EF41, EBC41, EL41, AZ41.
	Wave Bands:	LW, MW, SW from 16 - 50 meters
	Intermediate Frequency (IF):	452 kHz
	Loudspeaker:	Single cone, 18 cm in diameter, 7 Ohms
	Resonance Frequency Fs:	?
	Frequency Range Power Amplifier:	?
	RMS Output Power at 7 Ohms:	3 Watts
	Cabinet:	Wood, light brown lacquered, dark brown on top and bottom side.
	Dimensions:	43 x 27.5 x 22.5 cm (knobs excluded).
	Mains Power Voltages:	110, 125, 150, 200, 220, 250 Volts~
	Mains Power Consumption	45 Watts

Description:

Repairs:

• All paper/tar capacitors are replaced because of leakage, increased value and probable explosion danger.
• Electrolytic capacitor C41 of 100 µF 12.5 Volt is replaced by 100 µF 100 Volt.
  Reason: Power amplifier oscillated at very low frequencies (motor-boating).
• Coupling capacitor C34 of 10 nF is replaced by 10 nF 630 Volt.
  Reason: Optimal safety for the EL41 and a better low frequency response.
• Capacitor C35 of 5000 pF on the output transformer is replaced by 4700 pF 1000 Volt and is now connected over the primary winding of the output transformer.
  Reason: Connecting C35 over the primary winding of the output transformer prevents damage of the output transformer in case C35 becomes defective.
• G1 voltage of EBC41 becomes positive and the anode voltage of the EBC41 is too low.
  Reason: EBC41 has an internal shortcut and is replaced.
• Grid capacitor C28 to the EBC41 of 2500 pF is replaced by 22 nF 630 Volt.
  Reason: Less hum and a better low frequency response.
• Loudness network R10 of 15K and C26 of 20 nF are replaced by 27K and 10 nF.
  Reason: Better loudness control and a more full sound.
• R4 and C46 are completely removed.
  Reason: The type of sound was too sharp.
• Grounding tag of the volume potentiometer is connected at the negative feedback tap of the output transformer.
  Reason: Proper amplification gain and a wider frequency response.
• R22 of 2x 47K parallel is replaced by 2x 47K 3 Watts.
  Reason: These resistors are increased in value due to aging and the high voltage across these resistors. Now the reception and sensitivity is better.
• R28 of 2K7 is replaced by 2K7 2 Watts.
  Reason: EF41 is defective and made a short cut.
• EF41 is replaced.
  Reason: Shortcut in the EF41.
• Reception of the lower frequencies on the LW, MW and SW bands is losing.
  Reason: Bad earth sliding contacts of the variable capacitor. This is cleaned and works now perfectly.
• IF and HF circuits are re-aligned with an Philips GM2882 oscillator.
  Reason: Less sensitivity and too much AM audio bandwidth.
• When using an active AM loop antenna, the sound of local broadcast is distorted.
  To do: Find out the reason. Probably it is the delayed AGC (Automatic Gain Control) circuit, which has usually more negative voltage.
• High voltage supply is only 200 Volts and must be 280 Volt.
  Reason: AZ41 is worn out and need to be renewed.
  
  

Performance: