Hey guys.
New to the forum, well not quite new just used it as a source of information in the past. Im very keen on a F7 build. Do we have any ETA when the official schematic will be released?
Seen plenty clones being spoken about on this thread just would love to see the official version vs the clones.
So many clever guys on this forum. Keep up the great work all
New to the forum, well not quite new just used it as a source of information in the past. Im very keen on a F7 build. Do we have any ETA when the official schematic will be released?
Seen plenty clones being spoken about on this thread just would love to see the official version vs the clones.
So many clever guys on this forum. Keep up the great work all
Welcome to the forum. There’s never any official word until it’s official. 😂 Nelson’s project list for our consumption is enormous and I think is working on many things at the moment.
It gets here when it gets here is the appropriate motto.
It gets here when it gets here is the appropriate motto.
Thanks for the update. Guess I'll be building an F5 until the F7 is officially available. I have a set of the matched jfets might as well use them.
trying to build my own F7 clone maybe i miss something but i don't understand that at the jfet input there are one series 39K resistor and one 39K to ground so it should be a 78K input impesance and not a 10K ?
You need to put it on a simulator and understand how PFB works. Where did you get the 39k values from?
any book having operational amplifier as subject will give you an answer
think inverted, think virtual GND
well, if you want to understand, it's possible only with your head
if looking at principal scheme of inverting OP, you have 2 resistors in NFB loop - one folding back from output to negative input, second one in series - in between source and negative input
as that, negative input can be declared as virtual GND for NFB loop, so source is having one resistor between its output and (virtual) GND, so value of said resistor can be declared as Rin of entire stage
little more complicated when having all that gismo at output (establishing current positive feedback) but roughly it's still as that
if looking at principal scheme of inverting OP, you have 2 resistors in NFB loop - one folding back from output to negative input, second one in series - in between source and negative input
as that, negative input can be declared as virtual GND for NFB loop, so source is having one resistor between its output and (virtual) GND, so value of said resistor can be declared as Rin of entire stage
little more complicated when having all that gismo at output (establishing current positive feedback) but roughly it's still as that
Hi together,
Does anybody tried the F7 based pcb from aliexpress with the Exicon transistors?
Alex
Does anybody tried the F7 based pcb from aliexpress with the Exicon transistors?
Alex
I started on an F7 clone a two years ago and got halfway there, then Covid and other stuff happened that summer.
Anyway, it works, it sounds nice and all but I didn't get positive feedback working properly. If anyone inside EU (postage..) want to continue this project, give me a ping.
Boards from mareli include an unused PS board. Mosfets are Exicon Ecw20p👎20.
Anyway, it works, it sounds nice and all but I didn't get positive feedback working properly. If anyone inside EU (postage..) want to continue this project, give me a ping.
Boards from mareli include an unused PS board. Mosfets are Exicon Ecw20p👎20.
Maybe there are approximately 10K resistors across the inputs right at the connectors themselves. We don't know as there is no official schematic and by the looks of the actual boards posted by some magazines it doesn't look like any 10K resistors on the boards themselves. I have a sim and with just the 39K resistors the input impedance is 100K (Vin/Iin).
Found my problem, bad connection in my wiring to the cct board. I am using M/F crimp on spade connectors. All good now.
Hi!
I think I want to build a small class A amplifier and want to get opinions on what to choose, I am contemplating the X.25 and the Babelfish J2.
Does anyone know how they compare to F7?. At the moment, X.25 is the most tempting, but I would like to be convinced otherwise...
Thank you!
🙂 morten
I think I want to build a small class A amplifier and want to get opinions on what to choose, I am contemplating the X.25 and the Babelfish J2.
Does anyone know how they compare to F7?. At the moment, X.25 is the most tempting, but I would like to be convinced otherwise...
Thank you!
🙂 morten
Well... since no official F7 schematics or kit exists for the F7, the only ones able to properly answer are the owners of a genuine F7.
I have an ACA, ACA mini and an F6 amplifier. As of now, only the ACA mini is in use in my study. For a new project a Aleph Jzm would be high on my list.
First and foremost; a small project like the ACA mini will get way more in return for the investment in time and money than a more complex build. And also that you can listen to music from an ACA mini while building something bigger and way more expensive.
I have an ACA, ACA mini and an F6 amplifier. As of now, only the ACA mini is in use in my study. For a new project a Aleph Jzm would be high on my list.
First and foremost; a small project like the ACA mini will get way more in return for the investment in time and money than a more complex build. And also that you can listen to music from an ACA mini while building something bigger and way more expensive.
The problem is adjust it, it has both, positive and negative feedback and needs a spectrum analizer.
The original transistors
The original transistors
only confirmation is missing, from Highest Source ........ and I doubt you'll get that
I have two similar upcoming releases for this year, one of which which is an F5 with laterals
and the other which is the Twilight Zone edition....
and the other which is the Twilight Zone edition....