Oops, I'm sorry I posted in the wrong thread. The boards I have had made are the 50W single output pair version.
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Yes, I have built many, many hundreds of boards of this type of construction (MELF SMD), mainly for RF purposes for work, but for home also.
I have a recipe for soldering that’s something from my work. I use a a lot of RMA paste flux while working (Flux Gel RMA 10cc Syringe with Plunger - Okay Technologies), and while I’m working I use a cotton bud soaked in isopropyl alcohol to mop the flux up after I’ve soldered components.
When the board is completed, I dip it in very hot water (80 degrees or so), with about 10% concentration safewash detergent (Electrolube Safewash Super 5L from Electrolube). At work we used to use straight safewash in an ultrasonic cleaner, but the stuff is expensive and a 10% or even 5% concentration works just fine.
I leave it to soak for a few minutes, then scrub it with a pcb cleaning brush. The safewash makes any flux you’ve missed turn white, so it’s easy to see if it needs any more work.
Finally I rinse in deionised water, then dry with a hair dryer.
Exicon make them, and they’re distributed by profusion in England (Lateral MOSFETs (Buy Online) | Profusion). I find they’re very much equivalents of the old Hitachi parts.
I just did too ! Only issue is, getting the outputs. I secured 2 full sets to build 2 amplifier modules.
can the output driver 2sa1381 and 2sc3503 be used to drive 2 pairs of double die output power mosfet?
Thanks
Thanks
I haven’t tried it in practice, but in simulation it’s doable, but not ideal. The compensation tweaks necessary to make it work with the added gate capacitance do nothing for slew rate, and at the 200W point you’re really wanting to improve slew rate, not degrade it.
You can get the slew rate back by adding followers to the VAS, but I’m bored of brute force and am more keen on finding interesting ways to make 200W and more, that don’t just involve heating up the house. See my class H version as an example of what’s blowing my hair back. No need for dual die FETs there - just increase efficiency and it all works. I think!
TBH the sweet spot is 100-200. Even at that, it's alot. Nothing wrong with a little bit of head room though.
Suzy, I wish I have RF experience like yours. Packaging and power rating of some Lateral RF Power Mosfet like the RD100HHF1 and MRF151 are pretty rugged and are currently being sold at relatively low price. I'd like to use them but have no idea at all on how to handle them properly to prevent oscillation.
Biggest problem with RF parts is lack of complements. RD16HHF1 for example would make a lovely headphone amplifier, but there’s no P-channel equivalent, at least that I know of.
Hi Suzy,
You can always use the circlotron topology for the output stage in case you are stuck with only N channel parts. I did it with tubes and it works perfectly.
The Power supply is not that much more complex since you already need a differential +/- supply with a center tap for your complementary N/P builds.
Best regards,
Silviu
You can always use the circlotron topology for the output stage in case you are stuck with only N channel parts. I did it with tubes and it works perfectly.
The Power supply is not that much more complex since you already need a differential +/- supply with a center tap for your complementary N/P builds.
Best regards,
Silviu
Hi Meanman1964,
4 pcb available from Germany (black pcb, whiite silk, HASL, 1,6mm 35µ)
contactme if interested
schillg11
I just came upon this PCB design and I had to order up some boards to build and try......I really want to finally hear angels farting, tiny elephant hoofs galloping, and yes, the sound of victory (although I hope it doesn't smell like napalm in the morning..🙄.
TY Suzyj!
Pete
