I was just writing on an Italian forum about my under construction dual mono FW F4 to couple my AR SP9 to drive the vintage JBL L220 and a member whose knowledge seems quite justified stated:
"Per quando riguarda il first watt difficilmente farà suonare le 220....se non sbaglio è addirittura a mosfet....
Per suonare le 220 occorrono finali a bjt ad alta corrente.
Io me le sono godute anni con il ksa 100, prima del ksa100 ci avrò provato 20 finali."
Which more or less goes like "with regards to the FW it will hardly drive the 220... if I am not wrong it even is a misfit amp...
To drive the 220 it takes high current bjt amps
I did enjoy them years ago with a ksa100 and before that I probably tested like 20 power amps"
I have no clue about bjt, fet etc but the common idea seems being if wattage is not a three digits number they won't even consider it an amp to drive the big white JBL woofers...
Any direct experience with an F4 driving such speakers (they are rated 90db/W/m)?
it really depends, and we are trying to be better than trusting in everything written on internet
my friend is driving his JBL 4343B with SissySIT, which is 18W/8R/ch and certainly less current capable of F4
and I certainly trust in his judgment, him breathing everything Big JBL, for last 3 decades
my friend is driving his JBL 4343B with SissySIT, which is 18W/8R/ch and certainly less current capable of F4
and I certainly trust in his judgment, him breathing everything Big JBL, for last 3 decades
I think most of the judgment (...) we read online is biased, to be honest when I switched from the little solid state Adcom to the chinese KT88 I loved the improved and different (...) sound and the L220 never felt like struggling, I trust the F4 delivering as I read from each and every source, now I strongly doubt the above comment is from somebody who ever tested one...
Ah, you won't be that very well then welcome on Italian forums, let's don't share this, ok? ;-)
Grazie for your feedback
are we talking about "spaces between instrument" or maybe "The XX bends over backwards to deliver an exuberant and enjoyable performance, and it was its unmatched enthusiasm and concrete drive that we took to instantly"
I do admit I prefer my F4's paired to my full range crossover less speaker than my complex 3 way speakers...matter of flesh.
This Papa (et. al?) article is enlighting on this subject:
https://www.passlabs.com/technical_article/loudspeakers-lament/
That said, I think trying different circuits on different speakers is a good idea. Within reason of course. One might find a surprising match. And apparently there are several examples of seemingly poor matches turning out pretty darn good.
I used my ACP+ to fuel 92db Alpairs for 3 months, and it worked pretty good.
Puts 1kW amps in perspective.
Of course, when trying to find out which amp to build for certain speakers, auditioning the unbuilt circuit is out of the question. And so one choose to play it safe.
Wish we all had an amplifier and speaker ballpark to play with. I heard there is one in Serbia somewhere
Regards,
Andy
https://www.passlabs.com/technical_article/loudspeakers-lament/
That said, I think trying different circuits on different speakers is a good idea. Within reason of course. One might find a surprising match. And apparently there are several examples of seemingly poor matches turning out pretty darn good.
I used my ACP+ to fuel 92db Alpairs for 3 months, and it worked pretty good.
Puts 1kW amps in perspective.
Of course, when trying to find out which amp to build for certain speakers, auditioning the unbuilt circuit is out of the question. And so one choose to play it safe.
Wish we all had an amplifier and speaker ballpark to play with. I heard there is one in Serbia somewhere
Regards,
Andy
Would love to get some guidance from collective wisdom of the group.
Has anyone tried lateral mosfets for F4 build; something like ECW20N20 and ECW20P20?
If not much current needed, one can just go with a single pair of them (instead of 3 pairs of IRFP240/9240 in the normal build) and maybe take out the degeneration resistors to have a super simple amplifier for nearfield listening/efficient speakers etc.
Or maybe I am saying something completely stupid
Has anyone tried lateral mosfets for F4 build; something like ECW20N20 and ECW20P20?
If not much current needed, one can just go with a single pair of them (instead of 3 pairs of IRFP240/9240 in the normal build) and maybe take out the degeneration resistors to have a super simple amplifier for nearfield listening/efficient speakers etc.
Or maybe I am saying something completely stupid