Sorry for the confusion. I meant 18V (or 15V) secondaries (not 18VA). The trafo would be either 300VA or 400VA.thanh1973 said:
Me again 😀
In the F5 manual for unregulated supply, Mr.Pass recommends 15000uF/25v x 4 plus some resistors in series per rail.. Thats ok.
But I have some (actually 20pcs) 1,500uF/35v Panasonic FM caps in my drawer.. And I'd like to use them for this project. In their datasheet, Panasonic guys say; they have 3750mA (for 100Khz) and ~2750mA (for 50Hz) ripple capacity.. So if I connect them in parallel as 5 per rail (per amplifier) that makes ~13-14A ripple capacity per rail. If you consider I will use that amp with 2x20v transformer per amplifier and will use 8 ohm speakers, do you think these caps will enough to have a really quiet amplifier?
In the F5 manual for unregulated supply, Mr.Pass recommends 15000uF/25v x 4 plus some resistors in series per rail.. Thats ok.
But I have some (actually 20pcs) 1,500uF/35v Panasonic FM caps in my drawer.. And I'd like to use them for this project. In their datasheet, Panasonic guys say; they have 3750mA (for 100Khz) and ~2750mA (for 50Hz) ripple capacity.. So if I connect them in parallel as 5 per rail (per amplifier) that makes ~13-14A ripple capacity per rail. If you consider I will use that amp with 2x20v transformer per amplifier and will use 8 ohm speakers, do you think these caps will enough to have a really quiet amplifier?
Dxvideo said:
If you parallel capacitors, you can add the capacitance. So papa uses 2x30000uF per stereo amp. If you are planning making monoblocks with 2x7500uF (2x5x1.5mF) in each you'll not have enough capacitance for a class a amp. Even if you just planning on making one stereo amp you'll be using 2x15mF - half the amount of capacitance papa uses, which I think is bad idea.
Short answer: no
So you don't consider the total ripple capacity!
Anyway,
In fact I am agree with you that we must respect the designers concept.. However as I can see, Mr.Pass (or Papa 🙂 ) uses the same power supply design for the F4 also.. It's a stronger amplifier and naturally it needs more current.. So the F5 must need less "unrippled" power for especially 8R s..
What do you think?
Anyway,
In fact I am agree with you that we must respect the designers concept.. However as I can see, Mr.Pass (or Papa 🙂 ) uses the same power supply design for the F4 also.. It's a stronger amplifier and naturally it needs more current.. So the F5 must need less "unrippled" power for especially 8R s..
What do you think?
Dxvideo said:
I don't think ripple current capacity is all that important, because you need to have low voltage ripple and to get that you need larger caps than the current capabilities indicate.
The F4 has more fets, but with less bias current for each device - the total is about the same.
Hi,
paralleled smoothing capacitors are great for achieving high ripple capacity, when it's needed.
The first stage of a CRC or CLC PSU needs lots of ripple capacity.
A ClassA amplifier draws lots of current continuously and this requires good ripple capacity. But, that is only part of the requirement.
The high current draw ensures that ripple in the PSU output is much higher than when a ClassAB amplifier is idling @ Iq=50mA.
You need capacitance to keep the ripple down to acceptable levels.
The F5 requires good ripple capacity to prevent the smoothing caps overheating and excellent capacity to keep ripple down to an acceptable level.
Design for both, not one exclusively over the other.
paralleled smoothing capacitors are great for achieving high ripple capacity, when it's needed.
The first stage of a CRC or CLC PSU needs lots of ripple capacity.
A ClassA amplifier draws lots of current continuously and this requires good ripple capacity. But, that is only part of the requirement.
The high current draw ensures that ripple in the PSU output is much higher than when a ClassAB amplifier is idling @ Iq=50mA.
You need capacitance to keep the ripple down to acceptable levels.
The F5 requires good ripple capacity to prevent the smoothing caps overheating and excellent capacity to keep ripple down to an acceptable level.
Design for both, not one exclusively over the other.
So you say, to make a smooth bank with paralelled Low ESR 1500u caps works under this condition?
yes, but how many do you need to get up to the capacity recommended by the designer?Dxvideo said:
If my arithmetic is any good you will needs 80 off 1500uF to create a +-30mF/channel PSU.
Your 20 off gets to only one quarter of the 30mF.
Ten per rail per amplifier.. Makes totally 40. But I have half!
That means I need 20 more is it?
I think this way is cheaper, because they will cost €1.6 each to me. Then total cost will be €64.
That means I need 20 more is it?
I think this way is cheaper, because they will cost €1.6 each to me. Then total cost will be €64.
Fore a small AB amp I could do what you suggest, using small caps
Fore classA I would use nothing but big caps, they are tougher
As Andrew explains, too small caps can get pretty hot, if overloaded, and wont last long
Fore classA I would use nothing but big caps, they are tougher
As Andrew explains, too small caps can get pretty hot, if overloaded, and wont last long
I don't agree.tinitus said:
small caps usually have small ripple capacity.
paralleling small caps to equal the capacity of one large cap usually results in more ripple capacity. It thus reduces the risk of overheating and thus increases the life of the capacitors, provided the caps have cool air circulating around them.
sure
But the question is what is small and what is big
And how many are many
In my book, 22.000uf just starts to get big
And anything below 10.000uf is small
10.000uf I consider neither small nor big
🙂
But the question is what is small and what is big
And how many are many
In my book, 22.000uf just starts to get big
And anything below 10.000uf is small
10.000uf I consider neither small nor big
🙂
Hi,
small and large don't affect the conclusion you drew.
Many parallel capacitors have a higher ripple capacity than a single capacitor of the same capacity and similar quality. It matters not whether we are looking at pF or nF or uF or mF.
You said
small and large don't affect the conclusion you drew.
Many parallel capacitors have a higher ripple capacity than a single capacitor of the same capacity and similar quality. It matters not whether we are looking at pF or nF or uF or mF.
You said
I did not say that.
AndrewT said:
Maybe my english isnt that good 🙄
But thats what it meant to me
I may simplify a bit too much
Sorry if I dont understand what you say
Or "quoted" you poorly
btw, do you know "FTcap"
Just saw them on BMM site
Up to 220.000uf in 40V
🙂
For each channel i use four 12000uf audio grade Elna (made in Thaïland) which do the job very well. I must say that bias is set at 1 amp.
Hi Ozgur,
To choose the right filter capacitance, we should know what is our DC load current and what should be our target ripple voltage. We are however lucky because Papa has done all these for us in his F5 design.
If you want to apply the same bias current of total 2.6A for both channels, try to keep the CRC filter values of the same as the original. It doesn't matter capacitances are pralleled or not as long as the total capacitance is the same. Meanwhile, if you want to reduce the bias current or increase it, you could change CRC values linearly according to the change-rate of the bias.
🙂
To choose the right filter capacitance, we should know what is our DC load current and what should be our target ripple voltage. We are however lucky because Papa has done all these for us in his F5 design.
If you want to apply the same bias current of total 2.6A for both channels, try to keep the CRC filter values of the same as the original. It doesn't matter capacitances are pralleled or not as long as the total capacitance is the same. Meanwhile, if you want to reduce the bias current or increase it, you could change CRC values linearly according to the change-rate of the bias.
🙂