got mine too and my worst fear is a reality - the board is about 2mm too long on either end to fit into my M2X 
If someone didn't get in on the GB and is looking for a set , pm me.
they are quite versatile from a design perspective, that I am sure i I will find a use for them if no one needs them.
..dB
If someone didn't get in on the GB and is looking for a set , pm me.
they are quite versatile from a design perspective, that I am sure i I will find a use for them if no one needs them.
..dB
not your fault at all and no blame intended - I knew it would be a snug fit and opted to risk it. I guesstimated that it might just squeak in based on the measurments and my sloppy cardboard cut out.
many options.
..dB
dB,
Be careful
. From what I see, the MOSFET output transistors, have long leads going to the main board, and that *may* lead to instability. Mounting the whole board and MOSFETs directly to the heatsink is a better option but I figure your heatsinks are just too short and this looks like a retro fit given how compact the case is. Good luck,
Anand.
oooh, very nicely done. Now that would fit
I would be up to building this when / if it becomes available.
dB,
Be careful
Good luck,
Anand.
Thx for the concern Anand. Longer leads than I would normally want but no longer than the mosfet legs themselves. The amp is surprisingly stable and has been running well for a little while now. I did have trouble with the thermal barrier before I switched to ceramic. But that was a different saga.
..dB
That’s fantastically quick work, JP! With some tweaks, we could probably bring this back to an “opamp” format - that is, all gain and compensation input coupling provided by user off-board. But it’s amazing that you got it to fit on two stacked wood pile boards. That’s not too big at all.
Please tell us what POPI stands for?
Please tell us what POPI stands for?
If you use the stuffing guide (pdf attachment) in post 1, it makes installing the parts correctly, much easier. Mine worked the first time with no issues. Here is re-post in PNG format for easier viewing/printing. Note the orientation of the leads on the vertically mounted resistors.
Attachments
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I wonder if anyone has started building their Melbourne yet? It is a pretty simple project actually - just very tight layout, but that was necessitated by need to make it compatible with available board real estate on M2X main amp board.
A thought just occurred to me, one could use the Melbourne as a front end (input + VAS + driver stages) for *any* power amp output stage up to 50w. Just design the 4+1 bolt attachment points (extra bolt for GND) into your own PCB and concentrate on the output stage (whether it be push pull, quasi symmetric, SE Class A, etc.).
An interesting way to test the sound quality of different output topologies is to make several amps (all same rail voltage and same power) that all use same Melb front end.
A thought just occurred to me, one could use the Melbourne as a front end (input + VAS + driver stages) for *any* power amp output stage up to 50w. Just design the 4+1 bolt attachment points (extra bolt for GND) into your own PCB and concentrate on the output stage (whether it be push pull, quasi symmetric, SE Class A, etc.).
An interesting way to test the sound quality of different output topologies is to make several amps (all same rail voltage and same power) that all use same Melb front end.
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I'm still building my M2x platform. I plan to start with the Ishikawa input stage and listen to that for a while to get a sense of how the M2 sounds in its basic form. I'm currently using a couple of ACAs in altered forms, so it will be interesting to experience a larger Papa amplifier.
The Melbourne's ability to add a tweakable amount of gain will come in handy. I plan to use this to get a little more signal boost from my Audible Illusions tube preamp. I'm thinking an extra 6 dB will be about right in addition to the 14 dB from the Edcor transformer. I plan to configure my second set of Melbourne daughtercards for the full 29 to 30 dB of gain in a Yara preamp that is capable of driving my F4 to full output.
The Melbourne's ability to add a tweakable amount of gain will come in handy. I plan to use this to get a little more signal boost from my Audible Illusions tube preamp. I'm thinking an extra 6 dB will be about right in addition to the 14 dB from the Edcor transformer. I plan to configure my second set of Melbourne daughtercards for the full 29 to 30 dB of gain in a Yara preamp that is capable of driving my F4 to full output.
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