Jason's using the Diyaudio 3u 400mm chassis, after 1 hour of running its about 48-50deg doesn't go above it.
Pretty sure he ran the amp from 1khz-25khz no funny nonsense to be seen.
See attached.
Attachments
There is a bit of overshoot on the sq wave tests he did. That may be causing that second harmonic...
I haven’t visited that Facebook diy audio forum before but I’d imagine people here would be more knowledgeable/helpful than other places. Especially if their last name is Pass. You should send him here.
Like this comment ? He pm'd Jason stating Nelson didn't know what he was talking about and that this F5 using the IXYS is a ticking time bomb 😱😱😱
Attachments
I don’t know if it’s a time bomb or not, zen mod knows what he is talking about, but it’s definitely not a first time build or something people here should lego set together. Some caution is warranted. Some of the modifications Nelson made to the f5 turbo in the feedback section might make the amp more stable.
But on the other hand a lot of people here like to try new stuff and listening impressions vs. a stock f5 would be nice.
I see it as more of an “f5 turbo rev2” situation. An f5 for those who want increased bias capability without the need to match output mosfets.
But yeah, “by the book” it has some issues. But how does it sound?
Also, putting that amp in a 3U chassis would not be my first choice.
But on the other hand a lot of people here like to try new stuff and listening impressions vs. a stock f5 would be nice.
I see it as more of an “f5 turbo rev2” situation. An f5 for those who want increased bias capability without the need to match output mosfets.
But yeah, “by the book” it has some issues. But how does it sound?
Also, putting that amp in a 3U chassis would not be my first choice.
A 3u-400 mm chassis is working perfectly according to him, and the heatsinks are staying well with in spec.
Dissipante 3U – diyAudio Store
How does it sound, I will know later next week.
Yes, you can build the amp in a 3U chassis but it’s really only scratching the surface of what that amp is possible of at the bias levels required by the 3U chassis. I would’ve used a 4U or 5U since the ixys pucks allow far more dissipation per device than the Fairchild or IRF fets. Kind of the whole point, in my opinion.
Interesting experiment, but I think I will wait on XA252 and its coming "symmetry" winter version and really get in the area of what these outputs are capable of. That and I have no idea what I'm doing doesn't encourage me to go off the path.
Nothing wrong with trying it out. Have a look at Pico's F6 mod with this sort of outputs.
I've got my F6 boards, jenson tranformers, (to replace the ones I pirated for Iron Pre) to try this. Along with a dozen other 1/2 cooked projects.
Russellc
Nothing wrong with trying it out. Have a look at Pico's F6 mod with this sort of outputs.
I've got my F6 boards, jenson tranformers, (to replace the ones I pirated for Iron Pre) to try this. Along with a dozen other 1/2 cooked projects.
Russellc
If you are concerned about stability into cables then use an RC network to ground at the output.
I have built the 50W-SE-Schade-amp with the IXYS-Mosfets (IXFN140n20P).
It is running at around 3,2 A. Needs a lot of heatsink and sounds great - in my opinion. For sure it is another topology (Mu-follower with Schade -feedback).
I want to build a new amp with the IXYS-Mosfets (complementary outputstage). I have the IXYS-Mosfets and I am collecting parts at the moment.
I was thinking about something like the M2X - with a bit more juice.
But the approach with the F5-topology is also very interesting! Although I would use the driver board of the F5T with cascode and perhaps two pairs of Jfets. And - higher railvoltages than +-25V. Those IXYS-babies will be driven.
And care should be taken for thermal runaway.
Only some thoughts...🙄
Cheers
Dirk 😀
It is running at around 3,2 A. Needs a lot of heatsink and sounds great - in my opinion. For sure it is another topology (Mu-follower with Schade -feedback).
I want to build a new amp with the IXYS-Mosfets (complementary outputstage). I have the IXYS-Mosfets and I am collecting parts at the moment.
I was thinking about something like the M2X - with a bit more juice.
But the approach with the F5-topology is also very interesting! Although I would use the driver board of the F5T with cascode and perhaps two pairs of Jfets. And - higher railvoltages than +-25V. Those IXYS-babies will be driven.
And care should be taken for thermal runaway.
Only some thoughts...🙄
Cheers
Dirk 😀
to ZenMod
Yes1 Why not a Stasis - concept?... 😉
But I made pcbs with a cascoded BA-3 frontend. I will test those first....
But all this is asking for heat
GreetsDirk 😀
Yes1 Why not a Stasis - concept?... 😉
But I made pcbs with a cascoded BA-3 frontend. I will test those first....
But all this is asking for heat
GreetsDirk 😀
Yes1 Why not a Stasis - concept?... 😉
But I made pcbs with a cascoded BA-3 frontend. I will test those first....
But all this is asking for heat
GreetsDirk 😀
But heat is good 🙂 You have pcb's ? I collect pcb's for projects More details yes ?
to jamesvhf #35
Hello jamesvhf,
I let produce my pcbs for the cascoded BA-3 frontend.
One board for one channel. I was inspired by generg in the F4 beast builders thread.
Possibility for TO-92 and SMD -JFets
Cascode BJTs have EBC pinout (TO-126)
Output-Mosfets - GSD pinout. (TO-126)
But these boards are in the testing status... And I have very limited time at the moment... 🙄
Greets
Dirk
Hello jamesvhf,
I let produce my pcbs for the cascoded BA-3 frontend.
One board for one channel. I was inspired by generg in the F4 beast builders thread.
Possibility for TO-92 and SMD -JFets
Cascode BJTs have EBC pinout (TO-126)
Output-Mosfets - GSD pinout. (TO-126)
But these boards are in the testing status... And I have very limited time at the moment... 🙄
Greets
Dirk
Attachments
Cascode BJTs have BEC - pinout. Don't ask me why I have chosen BEC instead
of EBC?
I used Toshiba TTA/TTC004 for the cascode for testing with twisted legs.
Cheers
Dirk
of EBC?
I used Toshiba TTA/TTC004 for the cascode for testing with twisted legs.
Cheers
Dirk
Building an amplifier with -inter-stage- transformers in it takes me right back to my Heathkit AA-22 that I built when I was 15 years old. I guess next, we will be building amplifiers with germanium output devicess again. 
I did build a DAC that has no active analog output stage, and instead uses a pair of Jensen line transformers that are fed directly from the output of the DAC chip. It does sound pretty fantastic.
I did build a DAC that has no active analog output stage, and instead uses a pair of Jensen line transformers that are fed directly from the output of the DAC chip. It does sound pretty fantastic.
