F4 power amplifier

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#163
:clown:
I am cheating too😀 I stripped out my Aleph 5 and popped in the F4🙂 Have a look. In case some of you with keen eyes are wondering; no the faceplate is not yet mounted😉

Steen😎
 

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#166
~oo~


Papa,

I was having coffee break, once again looking at F4 schematic.
Ahh . . . almost dropped the coffee mug.
My body started sweating cold drops . . .
I was really scared by your mysterious smile hidden behind the
voltage swing at the input.

How many more do you have scary things ^^?


:darkside:
 
#167
My body started sweating cold drops . . .
Click to expand...
You can start sweating the hot ones😉 I have been listening to the F4 all afternoon and man, does it sound great. I am stunned and (nearly) speechless🙂 Its a most jawdropping experience, listening to the F4. I have no idea how Mr. Pass does it, but this amp has just turned my world, upside down! I am not kidding😎
Here you go:Speakers are ProAc Response 2.5 clones, rating in at 86-87 dB sensitivity, so pretty much on the borderline!! First I tried it with the X-BosoZ but it was way too whimpy. Sounding great, it couldnt get any reasonable soundlevel from the F4. I blame it on using the X-Bos singleended out! Installing the Threshold NS10, made things a lot better. The NS10 can drive the F4 to nearly max output. The NS10 is pretty brutal, as you might know. Still, it cant drive the ProAc's to full output, using the F4. At full throttle, the sound is still very pleasant!!
Here is an account on the sound: The bottomend is very firm and very deep, pretty much the best I've heard. Voices are present and precise like never before and the topend is really stretched out and detailed. I think the F4 put on, at least 2 octaves in the topend, being very detailed and pleasant to listen to, at that.
The soundstage is huge, tremendously wide and deep. All instruments and voices are clearly cut out, in the overall "picture"!
The "sweet spot" seems to have widened too, with the F4. One doesnt have to be bang on the spot, as much as we are used to.
I am sure everyone listening to my system right now, would agree! I will absolutely build these as monoblocks and drive them balanced. The great thing is that I can use the PSU and chassis's from my A-X's🙂 I am sure the F4 will benefit even more from a huge PSU made up by big Rifa's and Magura's inductors😉 This was just a fast build to see if the "rumours" were true🙂 Thanks a lot Mr Pass for this magnificent amplifier! Thanks to cviller for a genious board layout!

Steen (very impressed, indeed)😎
 

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#168
Steen

Great to hear that your F4 sounds so magnificent, you steer my desire.

What rail voltage are you using?

I know that these are apple and pears regarding a comparison with your AX but would be interesting to hear your comments soundwise.
 
#169
Great you finally carried the it the 10 meters into your living room! 😉

I'm happy to hear you like the sound so much - great info on the preamp! I guess my preamp only drives it to 25% or so, but I'll agree with you that it sounds very nice indeed! 😀

Are you running it with 250mV across resistors? Mine had very noticeable distortion at 80mV, but 300mV is too much for the box I have mounted it in right now.
 
#170
Hi Tony🙂 I am using 2, 300VA trafos with 2x18V secondaries.
The rails run at about 22V DC, but I didnt take an excact reading.
Its all about apples and pears, allright, but I have no doubt, the F4 is the best sounding amp, that I have ever made/heard! My A-X's are about to be under heavy modification😀 The A-X's might be almost as good in the bottom, but the middle and topend register is much better with the F4! When I first sat down and listened, carefully, I first thought: whats that trembling noise?? I then realised it was the drummers slight touches on the brass's!!
Thats how amazing the F4 is! Drop all your other projects, and go straight to the F4! Beleive me, you wont regret it😉

Steen😎
 
#171
Are you running it with 250mV across resistors?
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Yep I am🙂 I am getting tired of this hobby!! Right now I feel like throwing out all my other amps:devilr: That NP guy is a bit viscious, aint he?😀 Commin' up with one amp after the other, all sounding incrisingly better, is not being fair!! So for now, NP needs to come up with the preamp that he promised me, long ago😀 (Joking only ofcourse(almost😀 )) I am all set for building a preamp that can drive the F4 to its full potential. In the meantime, I will make 2, F4 monoblocks:smash:

Steen😎
 
#172
Hi Steen

Thank you for the overwhelming review. Are you really going re-cycle the A-X's so soon after you finished them? You're beginning to scare me. You're also starting to make me think thoughts I don't like to think. I like my AX100's my man!

Cheers,
Graeme
 
#173
Thank you for the overwhelming review.
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You are welcome, Graeme🙂 I am just as overwhelmed, as my review points out. I like my A-X 100's a lot too, but listening to something better I have to respond🙂 Dont be scared, just make a basic F4 and listen to it🙂 Its very easy with cvillers board layout🙂 You will in the end agree with me 😉 This is the third or fourth amp (at least) that just worked right away for me😀 😀 But thats another story.

Steen😎

BTW, I will try and hook the F4 up with the Abby clones, later! Might give a better account of the X-Bos?
 
#174
steenoe said:
You are welcome, Graeme🙂 I am just as overwhelmed, as my review points out. I like my A-X 100's a lot too, but listening to something better I have to respond🙂 Dont be scared, just make a basic F4 and listen to it🙂 Its very easy with cvillers board layout🙂 You will in the end agree with me 😉 This is the third or fourth amp (at least) that just worked right away for me😀 😀 But thats another story.

Steen😎
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steen,my man.......I'm glad for ya 😉

but....do not underestimate other amps you already make ;

F4 is (seems....sounds 😉 ) best amp for your speakers .


with other spks or with different approach to listening ,mebbe F1 will blow everything you have ......

hehe
mebbe even I will make 16E F4 one day........
 
#175
That's real cool Steen. Now you got me goin'! I was going to use a 'one off' trafo but the thought of potential mono blocs changes that

🙂

Yep, NP sure has a way of making us run in circles. Did you see his comment in the Aleph-x thread:bawling:
 
#177
How crushing steenoe! :smash: I have the makings for Babblefish and now... F4 🙄 Do the those ProAc clones of yours have a similar top end to ProAc 1sc's (Ie..in the same ballpark as my biamped Ls35a's) ( I think my NS10 + 12db from active XO can swing it).

-Mal
 
#178
Hey Steen,

This a bit:xeye: off topic but... Regarding your ProAc clones. Do you really like them? I've heard the real thing under limited conditions and I thought they sounded just fine. BUT can your clones fill a room with sound?... Can they crank up good and stay sounding good?? Bass? Where did you get your info? What is the meaning of life?

I'm looking for a worthy speaker project.

Feel free to shoot me an email if you don't want to litter this 🙄 unlittered🙄 thread.
 
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