OK not all SMD but a good proportion is.
The resistors are 2512 so not too bad to handle.
4 small capacitors were a bit fiddly but it worked out ok in the end.
The resistors are 2512 so not too bad to handle.
4 small capacitors were a bit fiddly but it worked out ok in the end.
An externally hosted image should be here but it was not working when we last tested it.
The output mosfets are IRFP240/9240.
The rest of the circuit is based on an old Hitachi lateral mosfet application note.
I added a Vbe multiplier and vertical mosfets to the design.
I added some decoupling to the front end and this cuts out any residual hum from the power supply
I was surprised to find I could solder something so small, my hands are shaky at the best of times.
A decent pair of tweezers helps with grips on them.
Some of the components arent spot on but the pcb works OK.
I made the SMD pads are little larger than the component to make it easier to hand solder.
The rest of the circuit is based on an old Hitachi lateral mosfet application note.
I added a Vbe multiplier and vertical mosfets to the design.
I added some decoupling to the front end and this cuts out any residual hum from the power supply
I was surprised to find I could solder something so small, my hands are shaky at the best of times.
A decent pair of tweezers helps with grips on them.
Some of the components arent spot on but the pcb works OK.
I made the SMD pads are little larger than the component to make it easier to hand solder.
looks good nigel,
i rest my hand against the bench when using the tweezers to place a part, helps with the shaking and alignment. use a 10x jewelers loup for mag/inspection. also 15mil glow core no clean eutectic solder works the best for me.
what are you using for small sig devices, sot-23 pkg I assume. no, it looks like you are using to-92 and thru-hole ecaps in a mixed tech layout.
have you discovered the fairchild fjv992/1845 devices? if you want to go away from to-92
i rest my hand against the bench when using the tweezers to place a part, helps with the shaking and alignment. use a 10x jewelers loup for mag/inspection. also 15mil glow core no clean eutectic solder works the best for me.
what are you using for small sig devices, sot-23 pkg I assume. no, it looks like you are using to-92 and thru-hole ecaps in a mixed tech layout.
have you discovered the fairchild fjv992/1845 devices? if you want to go away from to-92
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i am sure you have lots of those mpsa parts to use, so why not use them if you have them. to-92 do not take up much room.
fjv992/1845 are 120V devices and really low noise too, great for the input stages, even good for a MM phono amp. that is if you ever decide to use more smt instead of to-92.
i am so near sighted I can read the numbers on a 0603 resistor
good luck with your ckt.
fjv992/1845 are 120V devices and really low noise too, great for the input stages, even good for a MM phono amp. that is if you ever decide to use more smt instead of to-92.
i am so near sighted I can read the numbers on a 0603 resistor
good luck with your ckt.
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