OS is practically the same, regarding dynamic capabilities
which one you're going to use ..... if you take care of rails and appropriate resistors for biasing stage, they are the same/applicable for all rails values
in short - with same rails, they're having same Cojones
which one you're going to use ..... if you take care of rails and appropriate resistors for biasing stage, they are the same/applicable for all rails values
in short - with same rails, they're having same Cojones
take one normal ( as made by FW) stereo F4
feed it with 2 channel SE - you have two channels of 25W@8R each, 50W@4R each
feed it with balanced signal, you have balanced monoblock of 100W@8R and 200W@4R .......... more or less, I don't care
- if you care ( too much) - buy better speakers; you'll need much less power
- no need and no place to involve term "parallel" if speaking of simple bridge
-that (above) and everything else is really clearly drawn in F4 article/manual
feed it with 2 channel SE - you have two channels of 25W@8R each, 50W@4R each
feed it with balanced signal, you have balanced monoblock of 100W@8R and 200W@4R .......... more or less, I don't care
- if you care ( too much) - buy better speakers; you'll need much less power
- no need and no place to involve term "parallel" if speaking of simple bridge
-that (above) and everything else is really clearly drawn in F4 article/manual
OK, awesome, thanks. I guess the word "parallel' is misleading and incorrect, it is indeed bridged. And yes, the manual/article describes that, but for a second I had a doubt.
I purchased some used Audio Notes that I'm using with a single F4 driven by a tube preamp ( 20V max, single ended ).
The sound is really, REALLY good... but now I would like to hear what the F4s can do with my Magnepans. So, I'm on a path to go with a BA3B and dual F4s.
I'm currently driving the Maggies with A2s.
The F4 amp does sound.... hmm.. it has NO sound really. It is really good.
I purchased some used Audio Notes that I'm using with a single F4 driven by a tube preamp ( 20V max, single ended ).
The sound is really, REALLY good... but now I would like to hear what the F4s can do with my Magnepans. So, I'm on a path to go with a BA3B and dual F4s.
I'm currently driving the Maggies with A2s.
The F4 amp does sound.... hmm.. it has NO sound really. It is really good.
as you can see - I forgot (any) smiley above 
now - regarding the speakers :
- normally that I feel strongly that everyone is entitled to have own ........... everything , including even own choice of speakers
so, I'm perfectly aware that there are people either stuck with, or simply really preferring speakers heavy to drive/move/even tickle to think that they are really speakers and not just piece of dead rock placed in room
- PL is perfect firm to feel for that kind of people, to produce and then sell mighty amps to them; I'm happy if Pa is rich and happy, so Greedy Boyz are happy getting new small amp every 2 weeks or so
-I really understand people liking dead speakers; that's their right; human, constitutional, masculine etc.
-but I'm really not in obligation to feel 1% of sympathy for people liking dead speakers
-my best friend Vladimir - AR2 - he adores Apogee speakers ....... and that's source of neverending joy for me, just to tease him and remind how his speakers are starting something to sing only when his X600 monoblocks are near clipping level
ok, now seriously - as long you're happy, nothing else is important
if you're not completely happy, cry here ( as we all were/are/will) and somebody will help
edit: which Maggies exactly you have?
now - regarding the speakers :
- normally that I feel strongly that everyone is entitled to have own ........... everything , including even own choice of speakers
so, I'm perfectly aware that there are people either stuck with, or simply really preferring speakers heavy to drive/move/even tickle to think that they are really speakers and not just piece of dead rock placed in room
- PL is perfect firm to feel for that kind of people, to produce and then sell mighty amps to them; I'm happy if Pa is rich and happy, so Greedy Boyz are happy getting new small amp every 2 weeks or so
-I really understand people liking dead speakers; that's their right; human, constitutional, masculine etc.
-but I'm really not in obligation to feel 1% of sympathy for people liking dead speakers
-my best friend Vladimir - AR2 - he adores Apogee speakers ....... and that's source of neverending joy for me, just to tease him and remind how his speakers are starting something to sing only when his X600 monoblocks are near clipping level
ok, now seriously - as long you're happy, nothing else is important
if you're not completely happy, cry here ( as we all were/are/will) and somebody will help
edit: which Maggies exactly you have?
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Sometimes, you see, the First Watt is not enough.... 
Sometimes, you see, the First Hundred Watts are important.
The presentation is different.
The Apogees, well, those are cruel loads with a very low impedance... the Maggies are simple current hogs with mostly a benign resistive load.
My direct radiator speakers (90db/w, 6 ohms) with the F4 offer a middle of the hall sound with a realistic stage depth and wide orchestra.. heck the sound comes for the outside! All with just 35 watts. The Maggies (83db/w, 4 ohms) with the A2s, OTOH, offer a front of the hall sound with a very deep stage all around you.
I did try the F4 with direct radiators (85 db/w, 6ohm) and they didn't really come to live with large scale works at all... I'd say they were sort of "dead" for that. I mean, even the Grateful Dead were... dead....
Que vive la difference! On to the bridged F4 quest. I hope the damping factor doesn't get hosed....
Yes, it is interesting that some speakers just don't dance at all, they are wallflowers at the dance hall... I bought some small Elacs for my wife so I could reclaim my AE1s from her office system. From a first listen, the first note, they sounded "dead". I mean, they sound OK, but, but.. it's like a speaker that takes a 24/96 source file and makes it sound like MP3 128KB CBR. Not even an XS300 could raise that from the grave. So, she keeps the AE1s.
Note, it's early in the day, i'm supposed to be working, not posting, so I haven't had a nightcap 🍸yet. I promised I would not post after my nightcap.
Sometimes, you see, the First Hundred Watts are important.
The presentation is different.
The Apogees, well, those are cruel loads with a very low impedance... the Maggies are simple current hogs with mostly a benign resistive load.
My direct radiator speakers (90db/w, 6 ohms) with the F4 offer a middle of the hall sound with a realistic stage depth and wide orchestra.. heck the sound comes for the outside! All with just 35 watts. The Maggies (83db/w, 4 ohms) with the A2s, OTOH, offer a front of the hall sound with a very deep stage all around you.
I did try the F4 with direct radiators (85 db/w, 6ohm) and they didn't really come to live with large scale works at all... I'd say they were sort of "dead" for that. I mean, even the Grateful Dead were... dead....
Que vive la difference! On to the bridged F4 quest. I hope the damping factor doesn't get hosed....
Yes, it is interesting that some speakers just don't dance at all, they are wallflowers at the dance hall... I bought some small Elacs for my wife so I could reclaim my AE1s from her office system. From a first listen, the first note, they sounded "dead". I mean, they sound OK, but, but.. it's like a speaker that takes a 24/96 source file and makes it sound like MP3 128KB CBR. Not even an XS300 could raise that from the grave. So, she keeps the AE1s.
Note, it's early in the day, i'm supposed to be working, not posting, so I haven't had a nightcap 🍸yet. I promised I would not post after my nightcap.
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To anwer your question:
I got the 1.7 out in the open. Larger Maggies won't fit in the living room, unless I get rid of the couch. I already got rid of the coffee table.
I got a pair of older 12s in a box. Can't bring myself to sell them.
I was gonna build a LEDE set up, but I needed like 600 watts in the DE to match the 25 watts in the LE.
So, instead, I might build a quad system someday.
Remember SQ, QS, CD-4? I got all of that in the closet.
I got the 1.7 out in the open. Larger Maggies won't fit in the living room, unless I get rid of the couch. I already got rid of the coffee table.
I got a pair of older 12s in a box. Can't bring myself to sell them.
I was gonna build a LEDE set up, but I needed like 600 watts in the DE to match the 25 watts in the LE.
So, instead, I might build a quad system someday.
Remember SQ, QS, CD-4? I got all of that in the closet.
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@tonyEE
then building pair of regular stereo F4 is cheapest and far from worst scenario
then just drive them balanced with any Bal FE of choice (BA3Bal also being cheapest and far from worst), you can certainly expect all vividness you can get from your Maggies
105db and still under 200W........ heck, that's the same as almost 5W through Klipsch Horns, and that's loud!
or just go wild - take BA3 OS, double them ( same as with F4) so that you have in each phase more mosfet pairs and also higher rails, set Iq according to case you chose, drive it balanced with BA3Bal FE with rails according to OS rails
300W... 400W...... say when !
you have A2 as basic reference about power - do you need same or you need more
choose case of adequate size, choose what/which OS you sympatize ....... say power ....... and we'll crunch some numbers
then building pair of regular stereo F4 is cheapest and far from worst scenario
then just drive them balanced with any Bal FE of choice (BA3Bal also being cheapest and far from worst), you can certainly expect all vividness you can get from your Maggies
105db and still under 200W........ heck, that's the same as almost 5W through Klipsch Horns, and that's loud!
or just go wild - take BA3 OS, double them ( same as with F4) so that you have in each phase more mosfet pairs and also higher rails, set Iq according to case you chose, drive it balanced with BA3Bal FE with rails according to OS rails
300W... 400W...... say when !
you have A2 as basic reference about power - do you need same or you need more
choose case of adequate size, choose what/which OS you sympatize ....... say power ....... and we'll crunch some numbers
A2 power is perfect for Maggies. 200 wpc. No need for more power. So I want the same power from F4s.
AN speakers, 6 ohms. Factory claims it can handle 150 wpc... so at 90 db/w that's 112 db? That's way too loud enough. I respect my ears nowadays.
I think I'll stick with the normal BA3B preamp. I just need 15V per side, actually, I'd like 20V for side so we have operating headroom. I don't want to operate the preamp at full gain, I would like a bit of reserve. just the way my CJ PV9 tube preamp is running now. ( 20V peak single ended ).
Give me a few months... hopefully before summer I'll be cranking.
Thanks.
AN speakers, 6 ohms. Factory claims it can handle 150 wpc... so at 90 db/w that's 112 db? That's way too loud enough. I respect my ears nowadays.
I think I'll stick with the normal BA3B preamp. I just need 15V per side, actually, I'd like 20V for side so we have operating headroom. I don't want to operate the preamp at full gain, I would like a bit of reserve. just the way my CJ PV9 tube preamp is running now. ( 20V peak single ended ).
Give me a few months... hopefully before summer I'll be cranking.
Thanks.
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Soldering up new boards. Had the thought that I have matched MOSFETs but not matched source and gate resistors which would cause slightly different operating points across the triplets. How close should I match the source and gate resistors for MOSFET triplets? Bought 1% parts for both but wondering if doing some tighter matching might be worth it.
Was recommended this set: https://www.etsy.com/listing/958609584/first-watt-f4-ba2-ba3-mosfet-kit?click_key=eb7f0caccbe331b90a0d8d26a121bf5860f34b0a:958609584&click_sum=40162d72&ref=shop_home_active_5&sts=1
Vgs matching was done at 170mA. Still much to learn. I'm guessing that is where curve traces come in handy.
Vgs matching was done at 170mA. Still much to learn. I'm guessing that is where curve traces come in handy.
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