AMP HEAD II Build Thread
Posted: Tue Jul 11, 2017 8:01 pm
AMP HEAD II
AMP HEAD II kit is a small but extremely powerful stereo headphone amp kit with balanced inputs, buss connector, volume control and has dual stereo input mixing for mixing inputs together or directly plug in our Talkback Comp and can take large dual 24mm and 16mm with pull switch volume pots. Pull switch can be set to mute, dim or mono function.
Mono and mute options can be added with one center off toggle switch and no other parts wired across the 4 outside pot terminals.
Several AMP Head II's can be power and audio connected with one 10 wire IDC ribbon cable.
Can sum several balanced inputs into AMP HEAD II with STATTEN and or DSUB4 kit.
Can handle full overload into short circuit permanently.
Can drive 8 to 600ohm headphones easily.
Frequency response 0, -1dB = 5Hz to 200kHz (or 5Hz to 50kHz if 220pF caps added under PCB across R7 and R8)
THD = 0.006% until onset of clipping.
Idle current = 50mA per AMP HEAD II kit.
Max current = 90mA per AMP HEAD II kit.
Can be powered by symmetrical +/-12v to +/-24v power rails.
Can also be powered by single 12v to 48v power rail between +V & -V as long as 2 zeners rated at half the voltage used are fitted to the PCB.
(for example 2 x 24v zeners fitted to make +/-24v from one of our 48v SMPS supplies. Any DC connector must be isolated type.)
+/-6v to +/-18v for NE5532AP and most dual type opamps. (Will work with lots of dual opamp type BUT they must be able to drive a 600ohm load.)
+/-12v to +/-24v can be used with OPA2604AP.
Note1: Current Ver1 PCB mono jumpers for pull pot doesn't work. All other functions work fine.
AMP HEAD II PCB. Size 3.35" (85mm) x 1.4" (35.55mm)
]
Fit all parts to pcb except zeners if not needed.
The 2 x *10R are 10R if powering with 36vdc and have 18v zeners fitted to the PCB. Or if using any +/-12v to +/-18v with no 18v zeners fitted.
Use step by step build map at this link http://jlmaudio.com/builds/maps/ampheadIImap.html
AMP HEAD II Parts list
1 x AMP HEAD II PCB
1 x Cliff S4 6.3mm Socket
1 x Cliff S4 6.3mm Chrome nut
1 x Cliff S4 6.3mm plastic dress trim
2 x Cliff S4 6.3mm Fibre washer
2 x DIP16 machined pin socket
1 x 20pin IDC header
1 x 3 pin socket & pre wired 3 pin plug
1 x 3 way terminal block
2 x 2 way terminal block
2 x 100uF 25v electro cap
4 x 10uF 25v Bi Polar electro cap
2 x 100nF mono cap
2 x 470R 5pin SIL Buss resistor packs
2 x 10R carbon 1/4 watt resistor
2 x 1k Metal film 1/4 watt resistor
20 x 10k Metal film 1/4 watt resistor
Options
4 x NE5532AP or None
1 x Dual 24mm 10k log pot or 16mm 10k log pot with switch or None
2 x 1watt zener diodes which are only needed in special setups and not included in the kit.
Extra 100nF decoupling caps can be mounted in the ZD+ & ZD- positions if zeners are not used.
If fitting zeners the 2 x 10R RF+ and RF-may need to change value depending on zener diode voltage and +/-V.
AMP HEAD II kit is a small but extremely powerful stereo headphone amp kit with balanced inputs, buss connector, volume control and has dual stereo input mixing for mixing inputs together or directly plug in our Talkback Comp and can take large dual 24mm and 16mm with pull switch volume pots. Pull switch can be set to mute, dim or mono function.
Mono and mute options can be added with one center off toggle switch and no other parts wired across the 4 outside pot terminals.
Several AMP Head II's can be power and audio connected with one 10 wire IDC ribbon cable.
Can sum several balanced inputs into AMP HEAD II with STATTEN and or DSUB4 kit.
Can handle full overload into short circuit permanently.
Can drive 8 to 600ohm headphones easily.
Frequency response 0, -1dB = 5Hz to 200kHz (or 5Hz to 50kHz if 220pF caps added under PCB across R7 and R8)
THD = 0.006% until onset of clipping.
Idle current = 50mA per AMP HEAD II kit.
Max current = 90mA per AMP HEAD II kit.
Can be powered by symmetrical +/-12v to +/-24v power rails.
Can also be powered by single 12v to 48v power rail between +V & -V as long as 2 zeners rated at half the voltage used are fitted to the PCB.
(for example 2 x 24v zeners fitted to make +/-24v from one of our 48v SMPS supplies. Any DC connector must be isolated type.)
+/-6v to +/-18v for NE5532AP and most dual type opamps. (Will work with lots of dual opamp type BUT they must be able to drive a 600ohm load.)
+/-12v to +/-24v can be used with OPA2604AP.
Note1: Current Ver1 PCB mono jumpers for pull pot doesn't work. All other functions work fine.
AMP HEAD II PCB. Size 3.35" (85mm) x 1.4" (35.55mm)
]
Fit all parts to pcb except zeners if not needed.
The 2 x *10R are 10R if powering with 36vdc and have 18v zeners fitted to the PCB. Or if using any +/-12v to +/-18v with no 18v zeners fitted.
Use step by step build map at this link http://jlmaudio.com/builds/maps/ampheadIImap.html
AMP HEAD II Parts list
1 x AMP HEAD II PCB
1 x Cliff S4 6.3mm Socket
1 x Cliff S4 6.3mm Chrome nut
1 x Cliff S4 6.3mm plastic dress trim
2 x Cliff S4 6.3mm Fibre washer
2 x DIP16 machined pin socket
1 x 20pin IDC header
1 x 3 pin socket & pre wired 3 pin plug
1 x 3 way terminal block
2 x 2 way terminal block
2 x 100uF 25v electro cap
4 x 10uF 25v Bi Polar electro cap
2 x 100nF mono cap
2 x 470R 5pin SIL Buss resistor packs
2 x 10R carbon 1/4 watt resistor
2 x 1k Metal film 1/4 watt resistor
20 x 10k Metal film 1/4 watt resistor
Options
4 x NE5532AP or None
1 x Dual 24mm 10k log pot or 16mm 10k log pot with switch or None
2 x 1watt zener diodes which are only needed in special setups and not included in the kit.
Extra 100nF decoupling caps can be mounted in the ZD+ & ZD- positions if zeners are not used.
If fitting zeners the 2 x 10R RF+ and RF-may need to change value depending on zener diode voltage and +/-V.