Thank you for the kind words everyone! 
Looking forward to hearing how the 3U/300 build goes Ripson. My old F2 build was built with salvaged heatsinks that are probably similar to 3U/300 size and that one gets quite hot but not so hot I can't keep my hand on it so I think you will be fine. Do your boards fit in a 300mm case?
I realized my pictures are missing the happy blue glow. Channel PCB leds are left long for now because I can't decide if I want leds on the front panel or not yet
Looking forward to hearing how the 3U/300 build goes Ripson. My old F2 build was built with salvaged heatsinks that are probably similar to 3U/300 size and that one gets quite hot but not so hot I can't keep my hand on it so I think you will be fine. Do your boards fit in a 300mm case?
I realized my pictures are missing the happy blue glow. Channel PCB leds are left long for now because I can't decide if I want leds on the front panel or not yet
There. Even better now.
yup
added Papa's Secret Ingredient
though, rumor sez that his latest amps are double better, needing help of just one Blue LED
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Much has changed in the last 13 years but the long wait has definitely been worth it. Even though there was much experimentation in devices (which is still going on) an F2J with Semisouth is a definite must-build for me so I hope you can enjoy the visual as I enjoy the audio
It's built in a store 3U/400mm case and easily controls temperatures. It's stable below 48C and absolutely no noise/hum/hiss and drives my Frugalhorns (mk1) beautifully.
Fantastic!
Superb layout
Beautiful! Can I ask, how are supplying the primaries to your transformer? I see something coming out of the middle PSU board- what exactly is that? and is that shielding of some kind?
I'm still trying to get a low volume hum out of my AJ.
I'm still trying to get a low volume hum out of my AJ.
Much has changed in the last 13 years but the long wait has definitely been worth it. Even though there was much experimentation in devices (which is still going on) an F2J with Semisouth is a definite must-build for me so I hope you can enjoy the visual as I enjoy the audio
It's built in a store 3U/400mm case and easily controls temperatures. It's stable below 48C and absolutely no noise/hum/hiss and drives my Frugalhorns (mk1) beautifully.
Thank you Papa!
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F2 that I built in 2008
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AC goes through the middle of the PSU board. The thing sticking up in the middle of the PSU board is a thermostat that will cut the AC supply if it gets too hot inside the amp. I am using 70C thermostat but you can find them in other values.
Blocked
The F2 uses just a single rail (+24V) so very different from Aleph J (+/- 24V). There is a thread with lots of activity recently on dealing with hum in Aleph J by separating the input ground from the power and speaker ground using 10R resistor.
Blocked
The F2 uses just a single rail (+24V) so very different from Aleph J (+/- 24V). There is a thread with lots of activity recently on dealing with hum in Aleph J by separating the input ground from the power and speaker ground using 10R resistor.
Thanks Twitchie
I need to be careful with ZM, last time I was banned by him for disliking audio transformers
This F2J was created exactly as per Papa's recipe, plus the mains filter in the mains socket. I had to modify the values of three resistors per channel as JFET has lower VGS(ON) than IRFP240 MOSFET.
The upcoming projects are going to be inspired by Papa's works, but slightly modified to makes things a bit different, so I am not obligated to put FW logo
F2 sounds great, with Karlsonators (dual 3FE25) the bass is slightly compressed, but F2J is intended also for upcoming FR speakers projects The High frequencies are extremely well defined.
I need to be careful with ZM, last time I was banned by him for disliking audio transformers
This F2J was created exactly as per Papa's recipe, plus the mains filter in the mains socket. I had to modify the values of three resistors per channel as JFET has lower VGS(ON) than IRFP240 MOSFET.
The upcoming projects are going to be inspired by Papa's works, but slightly modified to makes things a bit different, so I am not obligated to put FW logo
F2 sounds great, with Karlsonators (dual 3FE25) the bass is slightly compressed, but F2J is intended also for upcoming FR speakers projects
The High frequencies are extremely well defined.
I don't have much to contribute these days, but still read the threads.. And I want to post something..
I don't think I've posted a pic of my old f2j. (started as regular f2, and got upgraded). Built it around 08.
I built the case from a bunch of random heatsinks and aluminum bar. It has an analog color changing light inside which very very slowly and truly randomly cycles colors that you can just see through the frosted front. (You can't really see the colors changing if you look at it, but if you walk away and come back 10 min later, you'd notice it's changing)
It doesn't ever get hot.. Maybe a slight increase over ambient temps.
It's a great amp.. Part of a bi-amped speaker system now.
I don't think I've posted a pic of my old f2j. (started as regular f2, and got upgraded). Built it around 08.
I built the case from a bunch of random heatsinks and aluminum bar. It has an analog color changing light inside which very very slowly and truly randomly cycles colors that you can just see through the frosted front. (You can't really see the colors changing if you look at it, but if you walk away and come back 10 min later, you'd notice it's changing)
It doesn't ever get hot.. Maybe a slight increase over ambient temps.
It's a great amp.. Part of a bi-amped speaker system now.
Attachments
I didn't post a pic of the inside for a good reason, hah..
But since you've all been kind enough to reply, I'll show you the mess.
This is from my early early days of electronics.. And you will see I was going down the capacitor rabbit hole at the time.. Knowing what I do now, I'm pretty sure a single high quality electrolytic would be better than the mess I've got.. But eh.. It is what it is.. (I forget what they are, but all the smaller electro's I strung together were highly regarded audio grade capacitors at the time)
My later work is definitely neater..
Otherwise, it's a good design.. Lots of airflow and big heat sinks.
The light I mentioned just sits in the middle on top of the big row of caps, and subtly illuminates the front and back panels.
But since you've all been kind enough to reply, I'll show you the mess.
This is from my early early days of electronics.. And you will see I was going down the capacitor rabbit hole at the time.. Knowing what I do now, I'm pretty sure a single high quality electrolytic would be better than the mess I've got.. But eh.. It is what it is.. (I forget what they are, but all the smaller electro's I strung together were highly regarded audio grade capacitors at the time)
My later work is definitely neater..
Otherwise, it's a good design.. Lots of airflow and big heat sinks.
The light I mentioned just sits in the middle on top of the big row of caps, and subtly illuminates the front and back panels.
