Babowana said:
However, there is an operational shift of sorts as your load draws more than twice the idle current 😱
The design has about 1.5A Iq. That means the system will maintain Class A operation up to 3A of peak load current. That "might" happen with a 6.5-7 ohm load just before clipping. This is a function of the input and rail voltage. Using a 4 ohm load however, the 3A point would be reached well before the max output voltage. Bout 12Vp output(24Vp-p). That might be 18Wrms or so I think. This has all been under Class A operation. If you drive the input harder, with the 4 ohm load, say up to the output voltage clipping point or so, you have run the amp into Class AB. That is, beyond 12Vpeak, on a 4 ohm load, the amp can still deliver current to the load, but, only the top, or bottom half of the output stage is conducting during that respective "1/2" cycle above the 12V point. I beleive you can drive 5A to the load with a 4 ohm load from N.P.s specs. This calculates to about 50WRMS. Just like N.P. says. But only the first 18W were class A operation...
Something to consider possibly
Oh thanks flg for explanation 🙂
Is there someone for curiousity that have tried to drive a minimonitor like LS35/A with the F4? My speaker are only 83dB but I do not need extreme high levels, and I listen at only 2meters in my 5x4 m room 😀
Cheers,
Paolo
Is there someone for curiousity that have tried to drive a minimonitor like LS35/A with the F4? My speaker are only 83dB but I do not need extreme high levels, and I listen at only 2meters in my 5x4 m room 😀
Cheers,
Paolo
flg said:
Assuming the bias of 1.5A, I have thought that the upper part (group of IRFP240) does class A swing of max. 3A at the first approximation (ideally). Meanwhile, the lower group of IRFP9240 also does the same amount of swing. But, they are having opposite polarities. Therefore, the amp could see the max peak class A swing of 3-(-3) = "6", i.e. 6A peak-to-peak ideally. But, at the third approximation or at the acceptable distortion level, 5A peak-to-peak. . . Maybe. . .
Forgive me if I'm wrong. These days I can't concentrate. I have had a kind of feeling of sea-sick/vomiting already more than three days after my 4th anti-cancer chemi treatment. . .whew. . .whek. . .
Cheers,
🙂
You're right, but peak-to-peak doesn't have a lot of practical value.
Sorry to hear about the chemo.
🙁
OT POST
Sorry to hear as well.
Babowana - If you can get Zofran or generic (very expensive) for this, it is worth it.
Babowana said:
Sorry to hear as well.
Babowana - If you can get Zofran or generic (very expensive) for this, it is worth it.
Thanks, Papa, for the confirmation.
Thanks, meThomas, for the info. I wrote down the names.
At present I'm following Dr's prescriptions, and mine is shrinking smaller and smaller. So, I will wait and see. . .
Oh. . . let's go back to the F4.
These days, I'm really enjoing blues/jazz music from F4 with time. Nice!
Cheers,
🙂
Thanks, meThomas, for the info. I wrote down the names.
At present I'm following Dr's prescriptions, and mine is shrinking smaller and smaller. So, I will wait and see. . .
Oh. . . let's go back to the F4.
These days, I'm really enjoing blues/jazz music from F4 with time. Nice!
Cheers,
🙂
Babowana,
Having lost both parents and several other family members to cancer, I take the subject rather seriously. Do me a favor...
WIN!
Grey
Having lost both parents and several other family members to cancer, I take the subject rather seriously. Do me a favor...
WIN!
Grey
Papa and dear friends,
Thanks for your warm encouragement and praying. I will WIN.
Now. . . let's focus on the F4.
Cheers,
Thanks for your warm encouragement and praying. I will WIN.
Now. . . let's focus on the F4.
Cheers,
For Babo!
Get it yet now because of that let me be OT again.
Already at least, that I do not talk about the amplifier.
I may be praying for somebody yet now, already if there is somebody, who hears the man's prayer.
A lot depend on your faith however. You have to believe in the fact that you heal in him.
Possibly this to say neither would have been needed.
And think about them being who are left without you here possibly in the worst situation.
I know this very well unfortunately.
Sounding with a Hungarian poet's words:
"I do not have a father, neither my mother, neither my god, neither my homeland."
And I do not have son already now, more than since two years. Only my outrageous big pain.
But it at least continuously.
So that gather yourself up, and heal!
Otherwise we look at the good side of the thing:
You look in that manner on this picture, than a Buddhist monk went bald in a honour.
Forgive this morbid humour for me.
But the music, the good friends and the humour keep the man alive.
Forgive it, that now as I read through this whole one, as if would be about me mostly.
But you have to know about the fact that I read your writings with pleasure always.
And I hope that this will be in this manner yet for a long time very much!
Get it yet now because of that let me be OT again.
Already at least, that I do not talk about the amplifier.
I may be praying for somebody yet now, already if there is somebody, who hears the man's prayer.
A lot depend on your faith however. You have to believe in the fact that you heal in him.
Possibly this to say neither would have been needed.
And think about them being who are left without you here possibly in the worst situation.
I know this very well unfortunately.
Sounding with a Hungarian poet's words:
"I do not have a father, neither my mother, neither my god, neither my homeland."
And I do not have son already now, more than since two years. Only my outrageous big pain.
But it at least continuously.
So that gather yourself up, and heal!
Otherwise we look at the good side of the thing:
You look in that manner on this picture, than a Buddhist monk went bald in a honour.
Forgive this morbid humour for me.
But the music, the good friends and the humour keep the man alive.
Forgive it, that now as I read through this whole one, as if would be about me mostly.
But you have to know about the fact that I read your writings with pleasure always.
And I hope that this will be in this manner yet for a long time very much!
Another F4 is born 🙂 I know, it's not pretty. Sounds a lot better then it look though.
http://s527.photobucket.com/albums/cc353/habsrock93/F4/
http://s527.photobucket.com/albums/cc353/habsrock93/F4/
Very nice. I would probably nail those bridges to the chassis so they
get some heat sinking...
😎
get some heat sinking...
😎
habsrock93 said:
Congratulations!
Is that an Antek 400va transformer? I tried to buy another couple dual 18v 300va Plitrons and the new sales manager said they only accept a minimum purchase of $250 now 😡
Tom
Yes it is the Antec 400va. Seems to work just fine. Even when I set the bias to max ( 330mV ) by accident the voltages didn't sag very much at all. Heatsinks got pretty hot though 🙂
As it stands right now I can only get the bias up to 110mV before the heatsinks start cooking. I decided to "save money" and purchased the cheap heatsinks, but ended up spending even more on the 240v ac fans and thermal switches that are en route right now (won't be doing that again 🙂 )