Nope.About the same as the official one....,I only changed the input.. I wanted something quick. I will order my own design boards that I have shown in a previous post with SMD parts at the input section.
If you added a low pass filter at the amplifier input and that solved your problem, it points to an issue with your source feeding your amplifier.
As for your frequency sweep, perhaps your maximum input frequency was below the frequency causing the issue?
As for your frequency sweep, perhaps your maximum input frequency was below the frequency causing the issue?
Μaybe....Ben.
Maybe the high idss 8.92 ma cause the overshooting in this version F5 amp ....A change Jfet Gr about 3-6ma It would show something different We'll see. Any other member who has built this amplifier would be interested in showing measurements with an oscilloscope.....
But now the square sign is much better than the original one.
Maybe the high idss 8.92 ma cause the overshooting in this version F5 amp ....A change Jfet Gr about 3-6ma It would show something different We'll see. Any other member who has built this amplifier would be interested in showing measurements with an oscilloscope.....
But now the square sign is much better than the original one.
How hard ( difficult, possible ) would it be to power an F5m with some kind of ready made Meanwell?
I just got the full kit, but I still need to buy the chassis and transformer ( and other ancillary non electronic parts ). If I could drive it off a Meanwell brick to start with I could make the F5m into a smaller chassis and sort of break up the process.
It's been eons since I built a full sized amp, so Divide And Conquer would help a lot...
Seems to me like the power supply is the most likely spot where I will smoke things.
I just got the full kit, but I still need to buy the chassis and transformer ( and other ancillary non electronic parts ). If I could drive it off a Meanwell brick to start with I could make the F5m into a smaller chassis and sort of break up the process.
It's been eons since I built a full sized amp, so Divide And Conquer would help a lot...
Seems to me like the power supply is the most likely spot where I will smoke things.
I've been wondering for a long time, has anyone tested their amplifier with a square wave signal generator and an oscilloscope? Has anyone? Not that it's necessary.....just out of curiosity....
I can't imagine that everyone is just take it, stick it and leave it.
I can't imagine that everyone is just take it, stick it and leave it.
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Most certainly Mr. Pass has done that.
We all more or less trust what he says he saw, or found, or tested.
Not sure what your point is re. square wave tests with a CRO.
I cannot believe your build will differ much from anyone else's when using the stock PCBs and parts.
So that leads me to the next point:
If you want to discuss your build, with your own PCBs, maybe, just maybe, open a new thread.
As the name at the top says: this one is for the F5m kit, as supplied by the store.
We all more or less trust what he says he saw, or found, or tested.
Not sure what your point is re. square wave tests with a CRO.
I cannot believe your build will differ much from anyone else's when using the stock PCBs and parts.
So that leads me to the next point:
If you want to discuss your build, with your own PCBs, maybe, just maybe, open a new thread.
As the name at the top says: this one is for the F5m kit, as supplied by the store.
Thank you very much for the response again... But all of this is known that you are quoting.. I am not ignoring you but I was hoping that you would show some tests.. Thank you very much..
Is this what you are talking about:
This is from the article. The original F5 had such a high bandwidth (in part due to it's much higher feedback) that it was more prone to oscillations. The F5m has a much lower feedback which is my preference for both sound and better oscillation control.
Pass really knocked it out of the park with the F5m. I am curious as to what the next two F5 varients will bring.
This is from the article. The original F5 had such a high bandwidth (in part due to it's much higher feedback) that it was more prone to oscillations. The F5m has a much lower feedback which is my preference for both sound and better oscillation control.
Pass really knocked it out of the park with the F5m. I am curious as to what the next two F5 varients will bring.
I think Nikos is asking someone to run a square wave on a home built F5m, capture it and post here. If I had an F5m, I'd offer. Been looking for a reason to learn more about testing amps.
If an F5m is built from the store kit why would you expect its square wave to differ from what was published in the article?
why not test just to test? Learn how in the process? Verify that you built it to spec?
Why all this hesitancy to practice some actual science and engineering instead of solder-by-numbers?
Why all this hesitancy to practice some actual science and engineering instead of solder-by-numbers?
@6sX7: your point is well taken for any person that wants to verify their own build and learn a new skill in the process. Perhaps you could point him to a primer on how to do a basic square wave oscilloscope test with square wave generator, with key things to know and potential “gotchas” that can refer results meaningless or actually destroy equipment. I would do it myself, but I do not own oscilloscope and never learned how to do that test.
@Nikos - If I get a moment, I will see if I can capture it for you. I am listening to an F5M now, but it is biased only at 1A3 b/c it is in a 2U chassis. It will need to be a photo. My old oscilloscope still uses a floppy drive. So, I don't capture images with it. 
Hopefully today, but it may be later in the week.
Hopefully today, but it may be later in the week.
Hi Nikos & all,
please have a look at the square wave response of my F5m.
-3 dB points are at 380 kHz as upper limit, and well below 2 Hz on the lower side (didn't test with less than 2 Hz, and at that frequency, RMS was still 1.72V compared to 2.0V at 1 kHz).
Some caveats:
1 kHz square wave:
and 10 kHz square wave:
Best regards,
Claas
please have a look at the square wave response of my F5m.
-3 dB points are at 380 kHz as upper limit, and well below 2 Hz on the lower side (didn't test with less than 2 Hz, and at that frequency, RMS was still 1.72V compared to 2.0V at 1 kHz).
Some caveats:
- please ignore the ripple on the square wave. I built my F5m with an SMPS, and this was still before I installed the PO89ZB filters. See posts #2649 and #2651.
- I have built my F5m with Toshiba 2SJ201 / 2SK1530, so the square wave response might look a bit different from a standard build. (for one, bandwidth is higher than in Nelson Pass' build, as per the article).
1 kHz square wave:
and 10 kHz square wave:
Best regards,
Claas
I have the 2SJ201 / 2SK1530 mosfets in my F5mX at the moment. I never thought to try them in the F5m. Did you try lowering the source resistance?