This is a design I've had in use for rather a long time. It started life as a design exercise to see if I could do a more space-efficient board for my original AEM6000 based amps, as I wanted something that would fit on a 50mm high heatsink. It's a very, very close friend to my 50W version with a couple of extra output transistors and a bit of a compensation tweak. Along the way it changed a little from Tilbrook's original in topology, and rather a lot in component choice. It has better performance than my original design, both through a better tighter layout and also through the use of faster transistors.
I've built a few of these. Nowhere near as many as the 50W flavour.
Lots of component substitution is reasonable. I like to use MELF resistors, but that's mostly just bloody-mindedness. An exception is the feedback divider. No, it won't work with vertical MOSFETs.
I have checked just now, and every single component is currently (December 2020) available.
The design is free for use for non-commercial purposes.
In the design folder I have placed:
Google Drive link to design files
I've built a few of these. Nowhere near as many as the 50W flavour.
Lots of component substitution is reasonable. I like to use MELF resistors, but that's mostly just bloody-mindedness. An exception is the feedback divider. No, it won't work with vertical MOSFETs.
I have checked just now, and every single component is currently (December 2020) available.
The design is free for use for non-commercial purposes.
In the design folder I have placed:
PDF file of schematic
PDF file of construction notes
Top and bottom layer stuffing diagrams
PDF file of parts list with supplier info
Gerbers and drill file for board manufacture.
PDF file of construction notes
Top and bottom layer stuffing diagrams
PDF file of parts list with supplier info
Gerbers and drill file for board manufacture.
Google Drive link to design files
G'day Suzy
Is there any reason you didn't use the double die mosfets on your smaller boards and bump up the supply rails to suit?
Is there any reason you didn't use the double die mosfets on your smaller boards and bump up the supply rails to suit?
The reason was purely historical. When I built the amp 2SK1058 and 2SJ162 were plentiful, so I designed everything around them. I've only swapped to the Exicon devices because the Renesas ones are no longer available.
The dual die Exicon parts look like a really easy way to extend to 200W though. I note the footprint is ever-so-slightly too big to fit the amp as designed.
Also to drive four pairs of die I'd probably want a follower on the VAS...
The dual die Exicon parts look like a really easy way to extend to 200W though. I note the footprint is ever-so-slightly too big to fit the amp as designed.
Also to drive four pairs of die I'd probably want a follower on the VAS...
There's another reason, as I've just remembered while laying out a 200W version in KiCAD. I wanted to get the amplifier to fit on a 50mm wide heatsink, and I the larger TO-264 part doesn't want to do that.
That makes sense. I've only used the double die TO3s before and didn't realise the flat packs were different sizes. It would be easy to space the boards up a bit to mount the larger flatpacks if there are interference issues.
Oh absolutely.
At normal levels, it sounds like angels farting in the bath. High notes are reminiscent of the pitter-patter of tiny elephant hoofs galloping across the sweeping arctic wilderness. When you really wind the wick up, it sounds like victory.
Honestly, it sounds like the music you put through it, right up until it clips, and then it doesn't.
😀The first line very colorful .
Normaly I like a warm presentation of the sound .
But if there's a the right amount of bass according the rest I can live with any different kind of amp .
At this moment my reference amp is the Maya 200 of Hugh Dean (Aspen Amps)
Normaly I like a warm presentation of the sound .
But if there's a the right amount of bass according the rest I can live with any different kind of amp .
At this moment my reference amp is the Maya 200 of Hugh Dean (Aspen Amps)
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Ahhh, you desire warmth. The most straightforward way to get warmth is to increase the bias. The stock value for R35 and RV2 only allow for ~75mA per FET. If you've got ample heatsink, you can substitute 1K for both R35 and RV2. That should allow you to set the bias current to 1A per output FET.
At this bias, the source resistors will be dissipating 220mW, so they'll be hot, but not ouchies-burnies hot. The MOSFETS will be dissipating something like 56 watts each. This is easily inside the SOA for the lateral MOSFETs, but you'll want a good and proper heatsink for this (and likely a fan), as the whole lot will be running at 220W.
Then you'll be class-A right up to 16 Watts into 8Ω.
While that makes some sense in cold places, we can't do that in Australia, on account of the climate.
At this bias, the source resistors will be dissipating 220mW, so they'll be hot, but not ouchies-burnies hot. The MOSFETS will be dissipating something like 56 watts each. This is easily inside the SOA for the lateral MOSFETs, but you'll want a good and proper heatsink for this (and likely a fan), as the whole lot will be running at 220W.
Then you'll be class-A right up to 16 Watts into 8Ω.
While that makes some sense in cold places, we can't do that in Australia, on account of the climate.
I have this Italian commercial but if I post it I will probably be banned forever.
Do NOT click if you or your household can be offended.
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Du you if there are any suitable devices? I'll those are vertical mosfets, the normal type these days.
I guess Exicon latfets 10N20 and 10P20 should work fine. They are still manufactured.
Are boards for the single output pair 50 W version available?
I'll make them available at AUD$5 each plus actual postage cost. It would make sense to combine orders to one country, if outside Australia, to save on postage costs.
The boards are 2oz copper ENIG finish.
They were ordered last week. I am expecting them soon.