Hey guys, I picked up a faulty A100 recently, a couple issues which should be fixed soon
Unfortunately as a couple resistors and zeners got incredibly hot, not only has this visually burned the board but also the solder pads have either snapped off or are peeling, I wouldn't be happy with the amp even if it were working knowing that I've had to bridge legs to nearby pads or had to solder directly to a trace after scratching off the insulation
So, as any sane and rational human being would do, I'm replicating the board 1:1 in PCB software and I am having a new board printed, minimum order is 5 boards so I'll be stuck with 4 spares
Just wanted to show you what I had done so far, I'm keeping it to the original but I am moving some components over a little bit to make the layout more symmetrical and visually pleasing, I'm also straightening up the trace tracks as I do prefer the look of right angle traces
I'm hoping to get this done within a week, so far I have physically measured the board and all the holes so that I have a solid base to work on and I've laid out the preamp
If anyone has any recommendations for mods and upgrades that are within my technical knowledge then please let me know!
I'm sure there's been advancements in audio components over the years which come with a different footprint/leg spacings, so if there are any go to upgrades of components then please let me know as I can incorporate the footprint of the components directly into the amplifier for native support
I'll have the boards printed in matte black to give it that premium look 😉
Unfortunately as a couple resistors and zeners got incredibly hot, not only has this visually burned the board but also the solder pads have either snapped off or are peeling, I wouldn't be happy with the amp even if it were working knowing that I've had to bridge legs to nearby pads or had to solder directly to a trace after scratching off the insulation
So, as any sane and rational human being would do, I'm replicating the board 1:1 in PCB software and I am having a new board printed, minimum order is 5 boards so I'll be stuck with 4 spares
Just wanted to show you what I had done so far, I'm keeping it to the original but I am moving some components over a little bit to make the layout more symmetrical and visually pleasing, I'm also straightening up the trace tracks as I do prefer the look of right angle traces
I'm hoping to get this done within a week, so far I have physically measured the board and all the holes so that I have a solid base to work on and I've laid out the preamp
If anyone has any recommendations for mods and upgrades that are within my technical knowledge then please let me know!
I'm sure there's been advancements in audio components over the years which come with a different footprint/leg spacings, so if there are any go to upgrades of components then please let me know as I can incorporate the footprint of the components directly into the amplifier for native support
I'll have the boards printed in matte black to give it that premium look 😉
The 24v that you see on my A100 and on my PCB sketch is apparently an error by MF, they are not 24v they are 38v
They will be changed when I have the board printed, but for now it's just for continuity with the design process
They will be changed when I have the board printed, but for now it's just for continuity with the design process
Strongly suggest that you purchase all the board mounted components first and have them in house
before going further. Then check and measure the components to be sure that they will fit, including
the leads fitting into the holes. Only then order the boards.
before going further. Then check and measure the components to be sure that they will fit, including
the leads fitting into the holes. Only then order the boards.
I've got the components right in front of me on the board, I just measure and make PCB footprints for the PCB software
The DIP slot was luckily already available to download and the leg spacings measure the same as mine
The only critical things to get right are the spacings for the caps, DIP slots and capacitors, all the resistors and zeners can have spacings any size as they are flexible to leg hole width, although they have been measured and the stock board the resistor leg spacings are 12mm
The DIP slot was luckily already available to download and the leg spacings measure the same as mine
The only critical things to get right are the spacings for the caps, DIP slots and capacitors, all the resistors and zeners can have spacings any size as they are flexible to leg hole width, although they have been measured and the stock board the resistor leg spacings are 12mm
Although the leg spacings for the phono inputs and the tape monitor and cartridge select switch will have to be perfect, both in terms of board placement and leg spacings
What are people's opinions on ditching the stock phono jacks and having panel mounted jacks?
You'd have to manually wire them up but at least you could pick and choose your phono jacks, get some higher quality ones ect
You'd have to manually wire them up but at least you could pick and choose your phono jacks, get some higher quality ones ect
If using the old components on the new board, they may be damaged while removing them,
or they could already be defective. If buying all new components for the new board, some
exact replacements may not be available any longer.
Progress so far, board and holes are measured up and replicated
Phono input sockets are there, the same goes with the top right switch and input selector
There might be already made footprints for these components but I'd still have to measure and compare them to mine to double check, so I might as well make mine from scratch
I've measured each component and solder pad a million times to make sure it's correct, but seeing as these require being pretty exact as they go through holes in the case, I've made the pads bigger than normal, the hole and solder pad are twice standard size, this allows any minute measurement issues and allow for wiggle room just in case they are ever ever so slightly out, better safe than sorry!
The preamp is essentially done, need to finish some other sections of the circuit before I can trace up the last connections from it
Phono input sockets are there, the same goes with the top right switch and input selector
There might be already made footprints for these components but I'd still have to measure and compare them to mine to double check, so I might as well make mine from scratch
I've measured each component and solder pad a million times to make sure it's correct, but seeing as these require being pretty exact as they go through holes in the case, I've made the pads bigger than normal, the hole and solder pad are twice standard size, this allows any minute measurement issues and allow for wiggle room just in case they are ever ever so slightly out, better safe than sorry!
The preamp is essentially done, need to finish some other sections of the circuit before I can trace up the last connections from it
Re: the RCA sockets, #6. As a general rule, the shorter the leads connecting the signal sockets to the PCB, the better. I'm apprehensive when I see chassis mounted sockets because that's how I went about building before I learned that you could achieve better performance by using shortest possible connections that had a particular PCB grounding and shielding layout, giving optimal isolation and avoiding chassis mounting, even though that's more robust. Chassis mounted sockets are also quite a problem if you need to remove the PCB for any reason.
Perhaps the critical part that you need to be aware of, is how best to lay out the separate grounding circuits for signal in and out. This may be suggested by the existing PCB's tracks but there are large numbers of clear pics on the net that show the methods used in many qualities of amplifiers. Pick a respected brand/model or two and study.
Otherwise, you're probably aware of the different metal finishes on sockets and banks of sockets, such as nickel plated, tinned, and gold flashed, all of which have their weaknesses but reasonable quality sockets may at least have thicker plating which withstands cleaning and routine use, which can't be a bad thing.
Perhaps the critical part that you need to be aware of, is how best to lay out the separate grounding circuits for signal in and out. This may be suggested by the existing PCB's tracks but there are large numbers of clear pics on the net that show the methods used in many qualities of amplifiers. Pick a respected brand/model or two and study.
Otherwise, you're probably aware of the different metal finishes on sockets and banks of sockets, such as nickel plated, tinned, and gold flashed, all of which have their weaknesses but reasonable quality sockets may at least have thicker plating which withstands cleaning and routine use, which can't be a bad thing.
Ian that's a good point about it being a hassle to remove the PCB if there's case mounted jacks that are wired to the board
What I've done is I've measured the pins and board placement a thousand times to make sure it's correct, I've also made the solder pads and holes bigger to allow for wiggle room, I'm 99% certain I've got it perfect but the slightly oversized holes let me be 95% certain haha
What I've done is I've measured the pins and board placement a thousand times to make sure it's correct, I've also made the solder pads and holes bigger to allow for wiggle room, I'm 99% certain I've got it perfect but the slightly oversized holes let me be 95% certain haha
I've been getting sloppy with my time spent on the PCB, either haven't felt like it or I've had stuff come up
I'd say I am at the 90% mark, I'm just sorting out the power rails, connecting the circuits together and then I'll go in for a final triple check
I'd say I am at the 90% mark, I'm just sorting out the power rails, connecting the circuits together and then I'll go in for a final triple check
Progress update, been slacking off
Components are all laid and so are the traces, now I've just got to go back in and double check everything and make sure everything is connected and connected correctly
Components are all laid and so are the traces, now I've just got to go back in and double check everything and make sure everything is connected and connected correctly
I'm sure it is, but I have been moving components around a tiny bit to make them more symmetrical, I'm also redoing some traces to neaten them up
It's a 1:1 as far as function, but there's creative freedom in terms of placing a bank of resistors parallel instead of scattered everywhere like the stock board
It's a 1:1 as far as function, but there's creative freedom in terms of placing a bank of resistors parallel instead of scattered everywhere like the stock board
