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LME49600 simple headamplifier

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#25
PCB is fine

Hi,
I just received this PCB and it is just fine.

I agree..., the TI application engineers did a fine job.

There is no problem with the ground layout ("Fill"). it is less wasteful to fab the board and hence, more environmentally friendly.

The DC Servo is there to counter DC offsets within the circuit and does a great job at it. DC Servo's are not used for "Protection". If one is worried about "DC - Protection" they will need to add a Speaker protection ckt/pcb diy kit.

Thanks for making this fine PCB available.
 
#26
new design pcb amplifier

the new printed circuit for the construction of the headphone amplifier with lme49600 is now available.
the design has been improved, increased power supply with more capacitors, the heat sinks are now on the pcb, the volume control is set up for the installation of a commercial alps potentiometer and finally, input capacitors have been added.
the assembly of the integrated ones is upside down to allow the installation of the heatsinks as in the old pcb.
the wiring diagram is visible in the original TI datasheet.
who is interested in receiving the pcb can contact me also with private messages.
s-l500.jpg

49600_2.png
 
#27
pcb available

scafas said:
the new printed circuit for the construction of the headphone amplifier with lme49600 is now available.
the design has been improved, increased power supply with more capacitors, the heat sinks are now on the pcb, the volume control is set up for the installation of a commercial alps potentiometer and finally, input capacitors have been added.
the assembly of the integrated ones is upside down to allow the installation of the heatsinks as in the old pcb.
the wiring diagram is visible in the original TI datasheet.
who is interested in receiving the pcb can contact me also with private messages.
An externally hosted image should be here but it was not working when we last tested it.

49600_2.png
Click to expand...
pcb are available for 12$ incluse ship .
 
#30
scafas said:
no security , I trust the technology of texas Instrumens 🙂
Click to expand...

I really think the "security" is the DC-servo already implemented: "To allow for a DC-coupled signal path and to ensure minimal output DC voltage regardless of the closed-loop gain, the other half of the U2 is configured as a DC servo. By constantly monitoring U2-A’s output, the servo creates a voltage that compensates for any DC voltage that may be present at the output. A correction voltage is generated and applied to the feedback node at U2-A, pin 2.", unless the input source has a DC-voltage more than the input opamp used in the voltage-amplification-stage, in our case it could be LME49720, so +/-2V more or less from the power rails +/-13V if +/-15V rail is used), based on http://www.ti.com/lit/ds/symlink/lme49720.pdf.

However, a 4.7uF could be easily added between the input source and the amplifier, but there's no need for 2 input dual-opamps anymore and entire PCB might need rework to save some costs. However, AFAIK DC-servo is considered to be an upgrade over the non-polarized caps on the input of an amplifier.

The idea with the output buffer mounted vice-versa is awesome and I was thinking many times why manufacturers are not using this in their products. I really think they think at the base price and not the heat dissipated to the PCB around the buffers.
 
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