F2J clone Build thread

Official Court Jester
Joined 2003
Paid Member
as Indra sez, that I sez ..... :rofl:

use any you can have

differences are smaller between 065/100/125 in amps having some feedback (J2, Aleph Jango) than in this one, but considering everything , I'm not finding possible differences big enough to care about ..... nor I'm expecting to be able to hear them
 
I am keeping the F2 as an idea on the side as something very different to build.
However the amp is a champion of inefficiency dissipating about 75W, right? for only 2 good Watts (at 5W the distortion is already huge by conventional standards; even if it was pleasing in character).

What kind of speakers are you guys using for this amp? I would be interested to see some examples if you do not mind posting. Are you all into Lowthers and alike like Papa uses with this amp?
 
Official Court Jester
Joined 2003
Paid Member
any sensitive and efficient, with benign impedance

Lowther certainly isn't my cup of tea, even if I'm primarily FR guy

even Pa found just one model being good enough for him ( PM6 Silver)

put your brain in Off state , build an amp, search for speaker which would sing with it

you don't need brain going FR + Flea Watt route - all you need is luck

written in another way - I'm so damn old that I earned my luck with pure mileage

:rofl:
 
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Joined 2008
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So far I went with mostly used 8” fullrange options I could afford in front horns that I allowed to play down to about 150Hz with my F2J. Below that I used a SLOB and subwoofer.

I’ve tried Fostex 206e, Tang Band W8-1808 and Lowther DX3.

To my ears the Fostex had the most “umph” as far as impact..it was the one that could play Rock most satisfactorily.

The Tang Band was the most laid back and least efficient...yet easy to listen to.

The Lowther is an interesting puzzle. It actually spent more time in the horns than the other options even with the dreaded “shout” everyone complains about.

I have a few theories why.

Perhaps firstly, I have one of Papa’s B5 active crossovers. That being the case, even though I am a complete simpleton regarding filters, I was able to play with the shelving filters and find a setting I could enjoy.

Another reason I suspect I could live with the rising response of the Lowther is because I am 54 and have had my doctor note that I have scarring on at least one of my ear drums from childhood ear infections.

I suspect the response helps me to hear high frequency detail better to an extent... although I am still sensitive to certain high frequencies and even find them irritating.

I listen to a lot of small Jazz ensemble live recordings chamber music and the like.

I am currently working on a new multi horn system that will use a more efficient CD driver in as broad a range as possible.

I’ve come to realize that more than rising response being disaggreable that the beaming from these fullrange drivers in the horns was more bothersome to me.

I hope to come up with a solution that will give me better dispersion so that the stereo image doesn’t have my head in a vise.

All these “tuning” issues aside, the F2J has always had enough juice for me to enjoy enthusiastic listening levels.
 
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Joined 2018
Paid Member
I have these left over from a prior project. Message me if interested.
 

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I have the Antek AS-4220 20V transform and want to know if I use it in the F2J is there going to be an issue. I don't see any issue with any of the components handling the extra voltage, but what about setting bias, is setting it the same? Or should I be concerned of any potential issues?
 
Approaching the finish line on my build. Just need to wire it up, test it, and adjust the bias. I need to learn how to scope to set the bias, so for now I will try it with the settings that kinku posted at the beginning of the thread. This will be my first SE NP amp. Looking forward to hearing it.